Adding upstream version 115.7.0esr.upstream/115.7.0esr upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 19:33:14 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-07 19:33:14 +0000
commit: 36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree: 105e8c98ddea1c1e4784a60a5a6410fa416be2de /js/xpconnect/tests
parent: Initial commit. (diff)
download: firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
476 files changed, 21832 insertions, 0 deletions
diff --git a/js/xpconnect/tests/browser/browser.ini b/js/xpconnect/tests/browser/browser.ini
new file mode 100644
index 0000000000..86c28d0ad8
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser.ini
@@ -0,0 +1,17 @@
+[DEFAULT]
+support-files =
+  browser_consoleStack.html
+  browser_deadObjectOnUnload.html
+  browser_realm_key_object_prototype_top.html
+  browser_realm_key_object_prototype_frame.html
+  browser_realm_key_promise_top.html
+  browser_realm_key_promise_frame.html
+  browser_promise_userInteractionHandling.html
+[browser_dead_object.js]
+[browser_exception_leak.js]
+[browser_freeze_builtins.js]
+[browser_parent_process_hang_telemetry.js]
+[browser_realm_key_and_document_domain.js]
+[browser_promise_userInteractionHandling.js]
+[browser_import_mapped_jsm.js]
+[browser_weak_xpcwjs.js]
diff --git a/js/xpconnect/tests/browser/browser_consoleStack.html b/js/xpconnect/tests/browser/browser_consoleStack.html
new file mode 100644
index 0000000000..37bfdb32f6
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_consoleStack.html
@@ -0,0 +1,21 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+Test page for https://bugzilla.mozilla.org/show_bug.cgi?id=1471989
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test page for Bug 1471989</title>
+</head>
+<body onUnload="onUnload();">
+<p><span id="samplepage">sample page</span></p>
+<script type="application/javascript">
+  // Get something sent to ConsoleStorageAPI that has a stack.
+  console.trace("whatever");
+
+  function onUnload() {
+    console.log('in unload');
+  }
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/browser/browser_deadObjectOnUnload.html b/js/xpconnect/tests/browser/browser_deadObjectOnUnload.html
new file mode 100644
index 0000000000..ceb40b20b6
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_deadObjectOnUnload.html
@@ -0,0 +1,18 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+Test page for https://bugzilla.mozilla.org/show_bug.cgi?id=1242643
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test page for Bug 1242643</title>
+</head>
+<body onUnload="onUnload();">
+<p><span id="samplepage">sample page</span></p>
+<script type="application/javascript">
+  function onUnload() {
+    console.log('in unload');
+  }
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/browser/browser_dead_object.js b/js/xpconnect/tests/browser/browser_dead_object.js
new file mode 100644
index 0000000000..b8b2dd0688
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_dead_object.js
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+// For bug 773980, test that Components.utils.isDeadWrapper works as expected.
+
+add_task(async function test() {
+  const url =
+    "http://mochi.test:8888/browser/js/xpconnect/tests/browser/browser_deadObjectOnUnload.html";
+  let newTab = await BrowserTestUtils.openNewForegroundTab(gBrowser, url);
+  let browser = gBrowser.selectedBrowser;
+  let innerWindowId = browser.innerWindowID;
+  let contentDocDead = await ContentTask.spawn(
+    browser,
+    { innerWindowId },
+    async function (args) {
+      let doc = content.document;
+      let { TestUtils } = ChromeUtils.importESModule(
+        "resource://testing-common/TestUtils.sys.mjs"
+      );
+      let promise = TestUtils.topicObserved(
+        "inner-window-nuked",
+        (subject, data) => {
+          let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
+          return id == args.innerWindowId;
+        }
+      );
+      content.location = "http://mochi.test:8888/";
+      await promise;
+      return Cu.isDeadWrapper(doc);
+    }
+  );
+  is(contentDocDead, true, "wrapper is dead");
+  BrowserTestUtils.removeTab(newTab);
+});
diff --git a/js/xpconnect/tests/browser/browser_exception_leak.js b/js/xpconnect/tests/browser/browser_exception_leak.js
new file mode 100644
index 0000000000..be860355bc
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_exception_leak.js
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+// For bug 1471989, test that an exception saved by chrome code can't leak the page.
+
+add_task(async function test() {
+  const url =
+    "http://mochi.test:8888/browser/js/xpconnect/tests/browser/browser_consoleStack.html";
+  let newTab = await BrowserTestUtils.openNewForegroundTab(gBrowser, url);
+  let browser = gBrowser.selectedBrowser;
+  let innerWindowId = browser.innerWindowID;
+
+  let stackTraceEmpty = await ContentTask.spawn(
+    browser,
+    { innerWindowId },
+    async function (args) {
+      let { TestUtils } = ChromeUtils.importESModule(
+        "resource://testing-common/TestUtils.sys.mjs"
+      );
+      let { Assert } = ChromeUtils.importESModule(
+        "resource://testing-common/Assert.sys.mjs"
+      );
+
+      const ConsoleAPIStorage = Cc[
+        "@mozilla.org/consoleAPI-storage;1"
+      ].getService(Ci.nsIConsoleAPIStorage);
+      let consoleEvents = ConsoleAPIStorage.getEvents(args.innerWindowId);
+      Assert.equal(
+        consoleEvents.length,
+        1,
+        "Should only be one console event for the window"
+      );
+
+      // Intentionally hold a reference to the console event.
+      let leakedConsoleEvent = consoleEvents[0];
+
+      // XXX I think this is intentionally leaking |doc|.
+      // eslint-disable-next-line no-unused-vars
+      let doc = content.document;
+
+      let promise = TestUtils.topicObserved(
+        "inner-window-nuked",
+        (subject, data) => {
+          let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
+          return id == args.innerWindowId;
+        }
+      );
+      content.location = "http://mochi.test:8888/";
+      await promise;
+
+      // This string should be empty. For that to happen, two things
+      // need to be true:
+      //
+      // a) ConsoleCallData::mStack is not null. This means that the
+      // stack trace was not reified before the page was nuked. If it
+      // was, then the correct |filename| value would be stored on the
+      // object. (This is not a problem, except that it stops us from
+      // testing the next condition.)
+      //
+      // b) ConsoleData::mStack.mStack is null. This means that the
+      // JSStackFrame is keeping alive the JS object in the page after
+      // the page was nuked, which leaks the page.
+      return leakedConsoleEvent.stacktrace[0].filename;
+    }
+  );
+
+  is(
+    stackTraceEmpty,
+    "",
+    "JSStackFrame shouldn't leak mStack after window nuking"
+  );
+
+  BrowserTestUtils.removeTab(newTab);
+});
diff --git a/js/xpconnect/tests/browser/browser_freeze_builtins.js b/js/xpconnect/tests/browser/browser_freeze_builtins.js
new file mode 100644
index 0000000000..905224094e
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_freeze_builtins.js
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+function checkCtor(global, name, description) {
+  ok(Object.isFrozen(global[name]), `${description} ${name} is frozen`);
+  ok(
+    Object.isSealed(global[name].prototype),
+    `${description} ${name}.prototype is sealed`
+  );
+
+  let descr = Object.getOwnPropertyDescriptor(global, name);
+  ok(!descr.configurable, `${description} ${name} should be non-configurable`);
+  ok(!descr.writable, `${description} ${name} should not be writable`);
+}
+
+function checkGlobal(global, description) {
+  checkCtor(global, "Object", description);
+  checkCtor(global, "Array", description);
+  checkCtor(global, "Function", description);
+}
+
+add_task(async function () {
+  let systemGlobal = Cu.getGlobalForObject(Services);
+  checkGlobal(systemGlobal, "system global");
+});
diff --git a/js/xpconnect/tests/browser/browser_import_mapped_jsm.js b/js/xpconnect/tests/browser/browser_import_mapped_jsm.js
new file mode 100644
index 0000000000..385f4e33c0
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_import_mapped_jsm.js
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// Verify Cu.import and ChromeUtils.import works for JSM URL even after
+// ESM-ification, and any not-in-tree consumer doesn't break.
+//
+// This test modules that's commonly used by not-in-tree consumers, such as
+// privilege extensions and AutoConfigs.
+
+const JSMs = [
+  "resource:///modules/AboutNewTab.jsm",
+  "resource:///modules/CustomizableUI.jsm",
+  "resource:///modules/UITour.jsm",
+  "resource:///modules/distribution.js",
+  "resource://gre/modules/AddonManager.jsm",
+  "resource://gre/modules/AppConstants.jsm",
+  "resource://gre/modules/AsyncShutdown.jsm",
+  "resource://gre/modules/Console.jsm",
+  "resource://gre/modules/FileUtils.jsm",
+  "resource://gre/modules/LightweightThemeManager.jsm",
+  "resource://gre/modules/NetUtil.jsm",
+  "resource://gre/modules/PlacesUtils.jsm",
+  "resource://gre/modules/PluralForm.jsm",
+  "resource://gre/modules/PrivateBrowsingUtils.jsm",
+  "resource://gre/modules/Timer.jsm",
+  "resource://gre/modules/XPCOMUtils.jsm",
+  "resource://gre/modules/addons/XPIDatabase.jsm",
+  "resource://gre/modules/addons/XPIProvider.jsm",
+  "resource://gre/modules/addons/XPIInstall.jsm",
+  "resource:///modules/BrowserWindowTracker.jsm",
+];
+
+if (AppConstants.platform === "win") {
+  JSMs.push("resource:///modules/WindowsJumpLists.jsm");
+}
+
+add_task(async function test_chrome_utils_import() {
+  for (const file of JSMs) {
+    try {
+      ChromeUtils.import(file);
+      ok(true, `Imported ${file}`);
+    } catch (e) {
+      ok(false, `Failed to import ${file}`);
+    }
+  }
+});
+
+add_task(async function test_cu_import() {
+  for (const file of JSMs) {
+    try {
+      // eslint-disable-next-line mozilla/use-chromeutils-import
+      Cu.import(file, {});
+      ok(true, `Imported ${file}`);
+    } catch (e) {
+      ok(false, `Failed to import ${file}`);
+    }
+  }
+});
diff --git a/js/xpconnect/tests/browser/browser_parent_process_hang_telemetry.js b/js/xpconnect/tests/browser/browser_parent_process_hang_telemetry.js
new file mode 100644
index 0000000000..f9b325c216
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_parent_process_hang_telemetry.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Check that we record hangs in the parent process in telemetry events.
+ * This test would be an xpcshell test except xpcshell does not think
+ * it is running e10s (see bug 1568333).
+ */
+add_task(async function test_browser_hang() {
+  // Trip some testing code to ensure we can test this. Sadly, this is a magic
+  // number corresponding to code in XPCJSContext.cpp
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.max_chrome_script_run_time", 2]],
+  });
+  await SpecialPowers.promiseTimeout(0);
+
+  // Hang for 1.2 seconds.
+  let now = Date.now();
+  let i = 0;
+  info("Start loop");
+  while (Date.now() - now < 2500) {
+    // The system clock can go backwards. Don't time out the test:
+    if (Date.now() - now < 0) {
+      info("Yikes, the system clock changed while running this test.");
+      now = Date.now();
+    }
+    i++;
+  }
+  let duration = (Date.now() - now) / 1000;
+  info("Looped " + i + " iterations.");
+
+  let events;
+  await TestUtils.waitForCondition(() => {
+    events = Services.telemetry.snapshotEvents(
+      Ci.nsITelemetry.DATASET_ALL_CHANNELS,
+      false
+    );
+    return events.parent?.some(e => e[1] == "slow_script_warning");
+  }, "Should find an event after doing this.").catch(e => ok(false, e));
+  events = events.parent || [];
+  let event = events.find(e => e[1] == "slow_script_warning");
+  ok(event, "Should have registered an event.");
+  if (event) {
+    is(event[3], "browser", "Should register as browser hang.");
+    let args = event[5];
+    is(args.uri_type, "browser", "Should register browser uri type.");
+    Assert.greater(
+      duration + 1,
+      parseFloat(args.hang_duration),
+      "hang duration should not exaggerate."
+    );
+    Assert.less(
+      duration - 1,
+      parseFloat(args.hang_duration),
+      "hang duration should not undersell."
+    );
+  }
+});
diff --git a/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.html b/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.html
new file mode 100644
index 0000000000..72f8ef3ee1
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test UserInteractionHandling propagation</title>
+</head>
+<body>
+<button id="button">Meow</button>
+</body>
+</html>
diff --git a/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.js b/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.js
new file mode 100644
index 0000000000..612471be53
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.js
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+add_task(async function test_explicit_object_prototype() {
+  const url =
+    "http://mochi.test:8888/browser/js/xpconnect/tests/browser/browser_promise_userInteractionHandling.html";
+  await BrowserTestUtils.withNewTab(url, async browser => {
+    await SpecialPowers.spawn(browser, [], async () => {
+      const DOMWindowUtils = EventUtils._getDOMWindowUtils(content.window);
+      is(
+        DOMWindowUtils.isHandlingUserInput,
+        false,
+        "not yet handling user input"
+      );
+      const button = content.document.getElementById("button");
+
+      let resolve;
+      const p = new Promise(r => {
+        resolve = r;
+      });
+
+      button.addEventListener("click", () => {
+        is(DOMWindowUtils.isHandlingUserInput, true, "handling user input");
+        content.document.hasStorageAccess().then(() => {
+          is(
+            DOMWindowUtils.isHandlingUserInput,
+            true,
+            "still handling user input"
+          );
+          Promise.resolve().then(() => {
+            is(
+              DOMWindowUtils.isHandlingUserInput,
+              false,
+              "no more handling user input"
+            );
+            resolve();
+          });
+        });
+      });
+
+      EventUtils.synthesizeMouseAtCenter(button, {}, content.window);
+
+      await p;
+    });
+  });
+});
diff --git a/js/xpconnect/tests/browser/browser_realm_key_and_document_domain.js b/js/xpconnect/tests/browser/browser_realm_key_and_document_domain.js
new file mode 100644
index 0000000000..2f6910cd5d
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_realm_key_and_document_domain.js
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+async function test_document(url) {
+  await BrowserTestUtils.withNewTab(url, async function (browser) {
+    let result = await ContentTask.spawn(browser, {}, async function () {
+      let result = content.document.getElementById("result");
+      return result.innerText;
+    });
+    is(result, "OK", "test succeeds");
+  });
+}
+
+add_task(async function test_explicit_object_prototype() {
+  await test_document(
+    "http://mochi.test:8888/browser/js/xpconnect/tests/browser/browser_realm_key_object_prototype_top.html"
+  );
+});
+
+add_task(async function test_implicit_object_prototype() {
+  await test_document(
+    "http://mochi.test:8888/browser/js/xpconnect/tests/browser/browser_realm_key_promise_top.html"
+  );
+});
diff --git a/js/xpconnect/tests/browser/browser_realm_key_object_prototype_frame.html b/js/xpconnect/tests/browser/browser_realm_key_object_prototype_frame.html
new file mode 100644
index 0000000000..5f3c0b5c2c
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_realm_key_object_prototype_frame.html
@@ -0,0 +1,11 @@
+<script type="text/javascript">
+// Access to the top-level window property before getting access.
+// This will create an entry in cross-origin realm map.
+try {
+  window.top.Object;
+} catch (e) {}
+
+document.domain = "mochi.test";
+
+window.top.check();
+</script>
diff --git a/js/xpconnect/tests/browser/browser_realm_key_object_prototype_top.html b/js/xpconnect/tests/browser/browser_realm_key_object_prototype_top.html
new file mode 100644
index 0000000000..fdd342ff59
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_realm_key_object_prototype_top.html
@@ -0,0 +1,12 @@
+<script type="text/javascript">
+document.domain = "mochi.test";
+function check() {
+  // Ensure frame's Object.prototype is accessible.
+  if (document.getElementById("frame").contentWindow.Object.prototype.toString.call({}) == "[object Object]") {
+    document.getElementById("result").textContent = "OK";
+  }
+}
+</script>
+<iframe id="frame" src="http://test2.mochi.test:8888/browser/js/xpconnect/tests/browser/browser_realm_key_object_prototype_frame.html">
+</iframe>
+<span id="result"></span>
diff --git a/js/xpconnect/tests/browser/browser_realm_key_promise_frame.html b/js/xpconnect/tests/browser/browser_realm_key_promise_frame.html
new file mode 100644
index 0000000000..dfb08085cf
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_realm_key_promise_frame.html
@@ -0,0 +1,17 @@
+<script type="text/javascript">
+// Access to the top-level window property before getting access.
+// This will create an entry in cross-origin realm map.
+try {
+  window.top.P;
+} catch (e) {}
+
+document.domain = "mochi.test";
+
+// Ensure that frame's Object.prototype is accessible from top-level frame
+// when getting incumbent global object inside Promise handling.
+window.top.P.then(v => {
+  if (v == 10) {
+    window.top.document.getElementById("result").textContent = "OK";
+  }
+});
+</script>
diff --git a/js/xpconnect/tests/browser/browser_realm_key_promise_top.html b/js/xpconnect/tests/browser/browser_realm_key_promise_top.html
new file mode 100644
index 0000000000..fe31fb6182
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_realm_key_promise_top.html
@@ -0,0 +1,7 @@
+<script type="text/javascript">
+document.domain = "mochi.test";
+window.P = new Promise(r => r(10));
+</script>
+<iframe src="http://test2.mochi.test:8888/browser/js/xpconnect/tests/browser/browser_realm_key_promise_frame.html">
+</iframe>
+<span id="result"></span>
diff --git a/js/xpconnect/tests/browser/browser_weak_xpcwjs.js b/js/xpconnect/tests/browser/browser_weak_xpcwjs.js
new file mode 100644
index 0000000000..b8c8c2f85d
--- /dev/null
+++ b/js/xpconnect/tests/browser/browser_weak_xpcwjs.js
@@ -0,0 +1,238 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Some basic tests of the lifetime of an XPCWJS with a weak reference.
+
+// Create a weak reference, with a single-element weak map.
+let make_weak_ref = function (obj) {
+  let m = new WeakMap();
+  m.set(obj, {});
+  return m;
+};
+
+// Check to see if a weak reference is dead.
+let weak_ref_dead = function (r) {
+  return !SpecialPowers.nondeterministicGetWeakMapKeys(r).length;
+};
+
+add_task(async function gc_wwjs() {
+  // This subtest checks that a WJS with only a weak reference to it gets
+  // cleaned up, if its JS object is garbage, after just a GC.
+  // For the browser, this probably isn't important, but tests seem to rely
+  // on it.
+  const TEST_PREF = "wjs.pref1";
+  let wjs_weak_ref = null;
+  let observed_count = 0;
+
+  {
+    Services.prefs.clearUserPref(TEST_PREF);
+
+    // Create the observer object.
+    let observer1 = {
+      QueryInterface: ChromeUtils.generateQI(["nsISupportsWeakReference"]),
+      observe() {
+        observed_count += 1;
+        info(TEST_PREF + " pref observer.");
+      },
+    };
+
+    // Register the weak observer.
+    Services.prefs.addObserver(TEST_PREF, observer1, true);
+
+    // Invoke the observer to make sure it is doing something.
+    info("Flipping the pref " + TEST_PREF);
+    Services.prefs.setBoolPref(TEST_PREF, true);
+    is(observed_count, 1, "Ran observer1 once after first flip.");
+
+    wjs_weak_ref = make_weak_ref(observer1);
+
+    // Exit the scope, making observer1 garbage.
+  }
+
+  // Run the GC.
+  info("Running the GC.");
+  SpecialPowers.forceGC();
+
+  // Flip the pref again to make sure that the observer doesn't run.
+  info("Flipping the pref " + TEST_PREF);
+  Services.prefs.setBoolPref(TEST_PREF, false);
+
+  is(observed_count, 1, "After GC, don't run the observer.");
+  ok(weak_ref_dead(wjs_weak_ref), "WJS with weak ref should be freed.");
+
+  Services.prefs.clearUserPref(TEST_PREF);
+});
+
+add_task(async function alive_wwjs() {
+  // This subtest checks that a WJS with only a weak reference should not get
+  // cleaned up if the underlying JS object is held alive (here, via the
+  // variable |observer2|).
+  const TEST_PREF = "wjs.pref2";
+  let observed_count = 0;
+
+  Services.prefs.clearUserPref(TEST_PREF);
+  let observer2 = {
+    QueryInterface: ChromeUtils.generateQI(["nsISupportsWeakReference"]),
+    observe() {
+      observed_count += 1;
+      info(TEST_PREF + " pref observer");
+    },
+  };
+  Services.prefs.addObserver(TEST_PREF, observer2, true);
+
+  Services.prefs.setBoolPref(TEST_PREF, true);
+  is(observed_count, 1, "Run observer2 once after first flip.");
+
+  await new Promise(resolve =>
+    SpecialPowers.exactGC(() => {
+      SpecialPowers.forceCC();
+      SpecialPowers.forceGC();
+      SpecialPowers.forceCC();
+
+      Services.prefs.setBoolPref(TEST_PREF, false);
+
+      is(observed_count, 2, "Run observer2 again after second flip.");
+
+      Services.prefs.removeObserver(TEST_PREF, observer2);
+      Services.prefs.clearUserPref(TEST_PREF);
+
+      resolve();
+    })
+  );
+});
+
+add_task(async function cc_wwjs() {
+  // This subtest checks that a WJS with only a weak reference to it, where the
+  // underlying JS object is part of a garbage cycle, gets cleaned up after a
+  // cycle collection. It also checks that things held alive by the JS object
+  // don't end up in an unlinked state, although that's mostly for fun, because
+  // it is redundant with checking that the JS object gets cleaned up.
+  const TEST_PREF = "wjs.pref3";
+  let wjs_weak_ref = null;
+  let observed_count = 0;
+  let canary_count;
+
+  {
+    Services.prefs.clearUserPref(TEST_PREF);
+
+    // Set up a canary object that lets us detect unlinking.
+    // (When an nsArrayCC is unlinked, all of the elements are removed.)
+    // This is needed to distinguish the case where the observer was unlinked
+    // without removing the weak reference from the case where we did not
+    // collect the observer at all.
+    let canary = Cc["@mozilla.org/array;1"].createInstance(Ci.nsIMutableArray);
+    let someString = Cc["@mozilla.org/supports-string;1"].createInstance(
+      Ci.nsISupportsString
+    );
+    someString.data = "canary";
+    canary.appendElement(someString);
+    canary.appendElement(someString);
+    is(canary.Count(), 2, "The canary array should have two elements");
+
+    // Create the observer object.
+    let observer3 = {
+      QueryInterface: ChromeUtils.generateQI(["nsISupportsWeakReference"]),
+      canary,
+      cycle: new DOMMatrix(),
+      observe() {
+        observed_count += 1;
+        canary_count = this.canary.Count();
+        info(TEST_PREF + " pref observer. Canary count: " + canary_count);
+      },
+    };
+
+    // Set up a cycle between C++ and JS that requires the CC to collect.
+    // |cycle| is a random WebIDL object that we can set an expando on to
+    // create a nice clean cycle that doesn't involve any weird XPConnect stuff.
+    observer3.cycle.backEdge = observer3;
+
+    // Register the weak observer.
+    Services.prefs.addObserver(TEST_PREF, observer3, true);
+
+    // Invoke the observer to make sure it is doing something.
+    info("Flipping the pref " + TEST_PREF);
+    canary_count = -1;
+    Services.prefs.setBoolPref(TEST_PREF, true);
+    is(
+      canary_count,
+      2,
+      "Observer ran with expected value while observer3 is alive."
+    );
+    is(observed_count, 1, "Ran observer3 once after first flip.");
+
+    wjs_weak_ref = make_weak_ref(observer3);
+
+    // Exit the scope, making observer3 and canary garbage.
+  }
+
+  // Run the GC. This is necessary to mark observer3 gray so the CC
+  // might consider it to be garbage. This won't free it because it is held
+  // alive from C++ (namely the DOMMatrix via its expando).
+  info("Running the GC.");
+  SpecialPowers.forceGC();
+
+  // Note: Don't flip the pref here. Doing so will run the observer, which will
+  // cause it to get marked black again, preventing it from being freed.
+  // For the same reason, don't call weak_ref_dead(wjs_weak_ref) here.
+
+  // Run the CC. This should detect that the cycle between observer3 and the
+  // DOMMatrix is garbage, unlinking the DOMMatrix and the canary. Also, the
+  // weak reference for the WJS for observer3 should get cleared because the
+  // underlying JS object has been identifed as garbage. You can add logging to
+  // nsArrayCC's unlink method to see the canary getting unlinked.
+  info("Running the CC.");
+  SpecialPowers.forceCC();
+
+  // Flip the pref again to make sure that the observer doesn't run.
+  info("Flipping the pref " + TEST_PREF);
+  canary_count = -1;
+  Services.prefs.setBoolPref(TEST_PREF, false);
+
+  isnot(
+    canary_count,
+    0,
+    "After CC, don't run the observer with an unlinked canary."
+  );
+  isnot(
+    canary_count,
+    2,
+    "After CC, don't run the observer after it is garbage."
+  );
+  is(canary_count, -1, "After CC, don't run the observer.");
+  is(observed_count, 1, "After CC, don't run the observer.");
+
+  ok(
+    !weak_ref_dead(wjs_weak_ref),
+    "WJS with weak ref shouldn't be freed by the CC."
+  );
+
+  // Now that the CC has identified observer3 as garbage, running the GC again
+  // should free it.
+  info("Running the GC again.");
+  SpecialPowers.forceGC();
+
+  ok(weak_ref_dead(wjs_weak_ref), "WJS with weak ref should be freed.");
+
+  info("Flipping the pref " + TEST_PREF);
+  canary_count = -1;
+  Services.prefs.setBoolPref(TEST_PREF, true);
+
+  // Note: the original implementation of weak references for WJS fails most of
+  // the prior canary_count tests, but passes these.
+  isnot(
+    canary_count,
+    0,
+    "After GC, don't run the observer with an unlinked canary."
+  );
+  isnot(
+    canary_count,
+    2,
+    "After GC, don't run the observer after it is garbage."
+  );
+  is(canary_count, -1, "After GC, don't run the observer.");
+  is(observed_count, 1, "After GC, don't run the observer.");
+
+  Services.prefs.clearUserPref(TEST_PREF);
+});
diff --git a/js/xpconnect/tests/browser/moz.build b/js/xpconnect/tests/browser/moz.build
new file mode 100644
index 0000000000..67b1ac4bbb
--- /dev/null
+++ b/js/xpconnect/tests/browser/moz.build
@@ -0,0 +1,7 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+BROWSER_CHROME_MANIFESTS += ["browser.ini"]
diff --git a/js/xpconnect/tests/chrome/bug503926.xhtml b/js/xpconnect/tests/chrome/bug503926.xhtml
new file mode 100644
index 0000000000..d62a6b575f
--- /dev/null
+++ b/js/xpconnect/tests/chrome/bug503926.xhtml
@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=503926
+-->
+<window title="Mozilla Bug 503926"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=503926"
+     target="_blank">Mozilla Bug 503926</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+      var gWindowUtils = window.windowUtils;
+      var passed = false;
+      // eslint-disable-next-line mozilla/use-chromeutils-generateqi
+      var obj = { QueryInterface() { passed = true; } }
+      gWindowUtils.xpconnectArgument(obj);
+      var isDialog = location.hash != '#iframe';
+      var outer = Cu.waiveXrays(isDialog ? window.arguments[0] : parent);
+      outer.ok(passed, "chrome/chrome test passed: " + (isDialog ? "dialog" : "iframe"));
+      if (isDialog)
+        close();
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/chrome.ini b/js/xpconnect/tests/chrome/chrome.ini
new file mode 100644
index 0000000000..0057d6e193
--- /dev/null
+++ b/js/xpconnect/tests/chrome/chrome.ini
@@ -0,0 +1,128 @@
+[DEFAULT]
+skip-if = os == 'android'
+support-files =
+  bug503926.xhtml
+  file_bug484459.html
+  file_bug618176.xhtml
+  file_bug996069.html
+  file_bug1281071.html
+  file_discardSystemSource.html
+  file_empty.html
+  file_evalInSandbox.html
+  file_expandosharing.jsm
+  outoflinexulscript.js
+  subscript.js
+  utf8_subscript.js
+  worker_discardSystemSource.js
+  !/js/xpconnect/tests/mochitest/bug500931_helper.html
+  !/js/xpconnect/tests/mochitest/bug571849_helper.html
+  !/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html
+  !/js/xpconnect/tests/mochitest/file_bug706301.html
+  !/js/xpconnect/tests/mochitest/file_bug738244.html
+  !/js/xpconnect/tests/mochitest/file_bug760131.html
+  !/js/xpconnect/tests/mochitest/file_bug795275.html
+  !/js/xpconnect/tests/mochitest/file_bug799348.html
+  !/js/xpconnect/tests/mochitest/file_bug860494.html
+  !/js/xpconnect/tests/mochitest/file_documentdomain.html
+  !/js/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
+  !/js/xpconnect/tests/mochitest/file_empty.html
+  !/js/xpconnect/tests/mochitest/file_exnstack.html
+  !/js/xpconnect/tests/mochitest/file_expandosharing.html
+  !/js/xpconnect/tests/mochitest/file_nodelists.html
+  !/js/xpconnect/tests/mochitest/file_evalInSandbox.html
+  !/js/xpconnect/tests/mochitest/file_xrayic.html
+prefs =
+  javascript.options.large_arraybuffers=true
+  javascript.options.experimental.enable_new_set_methods=false
+
+[test_APIExposer.xhtml]
+[test_bug361111.xhtml]
+[test_bug448587.xhtml]
+[test_bug484459.xhtml]
+skip-if = os == 'win' || os == 'mac' || (os == 'linux' && !debug) # bug 1131110, 1255284
+[test_bug500931.xhtml]
+[test_bug503926.xhtml]
+[test_bug533596.xhtml]
+[test_bug571849.xhtml]
+[test_bug610390.xhtml]
+[test_bug614757.xhtml]
+[test_bug616992.xhtml]
+[test_bug618176.xhtml]
+[test_bug654370.xhtml]
+[test_bug658560.xhtml]
+[test_bug658909.xhtml]
+[test_bug664689.xhtml]
+[test_bug679861.xhtml]
+[test_bug706301.xhtml]
+[test_bug726949.xhtml]
+[test_bug732665.xhtml]
+[test_bug738244.xhtml]
+[test_bug743843.xhtml]
+[test_bug760076.xhtml]
+[test_bug760131.html]
+[test_bug763343.xhtml]
+[test_bug771429.xhtml]
+[test_bug773962.xhtml]
+[test_bug792280.xhtml]
+[test_bug793433.xhtml]
+[test_bug795275.xhtml]
+[test_bug799348.xhtml]
+[test_bug801241.xhtml]
+[test_bug812415.xhtml]
+[test_bug853283.xhtml]
+[test_bug853571.xhtml]
+[test_bug858101.xhtml]
+[test_bug860494.xhtml]
+[test_bug865948.xhtml]
+[test_bug866823.xhtml]
+[test_bug895340.xhtml]
+[test_bug932906.xhtml]
+allow_xul_xbl = true
+[test_bug996069.xhtml]
+[test_bug1041626.xhtml]
+[test_bug1042436.xhtml]
+[test_bug1065185.html]
+[test_bug1074863.html]
+[test_bug1092477.xhtml]
+[test_bug1124898.html]
+[test_bug1126911.html]
+[test_bug1281071.xhtml]
+[test_bug1390159.xhtml]
+[test_bug1430164.html]
+[test_bug1516237.html]
+[test_chrometoSource.xhtml]
+[test_cloneInto.xhtml]
+[test_cows.xhtml]
+[test_private_field_cows.xhtml]
+[test_discardSystemSource.xhtml]
+[test_documentdomain.xhtml]
+[test_doublewrappedcompartments.xhtml]
+[test_evalInSandbox.xhtml]
+[test_evalInWindow.xhtml]
+[test_exnstack.xhtml]
+[test_expandosharing.xhtml]
+[test_exposeInDerived.xhtml]
+[test_inlineScripts.html]
+[test_localstorage_with_nsEp.xhtml]
+[test_matches.xhtml]
+[test_nodelists.xhtml]
+[test_nsScriptErrorWithStack.html]
+[test_onGarbageCollection.html]
+[test_precisegc.xhtml]
+[test_sandboxImport.xhtml]
+[test_secureContexts.html]
+[test_scriptSettings.xhtml]
+[test_scripterror.html]
+[test_sharedChromeCompartment.html]
+[test_weakmap_keys_preserved.xhtml]
+[test_weakmap_keys_preserved2.xhtml]
+[test_weakref.xhtml]
+[test_windowProxyDeadWrapper.html]
+[test_wrappers.xhtml]
+[test_xrayic.xhtml]
+[test_xrayLargeTypedArray.html]
+skip-if = bits == 32 # Large ArrayBuffers not supported on 32-bit.
+[test_xrayToJS.xhtml]
+[test_bug1530146.html]
+support-files = file_bug1530146.html file_bug1530146_inner.html
+[test_envChain_event_handler.html]
diff --git a/js/xpconnect/tests/chrome/file_bug1281071.html b/js/xpconnect/tests/chrome/file_bug1281071.html
new file mode 100644
index 0000000000..2398ce4a57
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug1281071.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<script>
+  function tryLocationGet() {
+    var desc = Object.getOwnPropertyDescriptor(window, "location");
+    try {
+      desc.get.call(parent);
+      return "get succeeded";
+    } catch (e) {
+      return e.message;
+    }
+  }
+</script>
+  
diff --git a/js/xpconnect/tests/chrome/file_bug1530146.html b/js/xpconnect/tests/chrome/file_bug1530146.html
new file mode 100644
index 0000000000..5414ea407d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug1530146.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<script>
+  // eslint-disable-next-line no-self-assign
+  document.domain = document.domain;
+</script>
+<iframe></iframe>
diff --git a/js/xpconnect/tests/chrome/file_bug1530146_inner.html b/js/xpconnect/tests/chrome/file_bug1530146_inner.html
new file mode 100644
index 0000000000..db642cf81d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug1530146_inner.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<script>
+  var obj = { a: "hello" }
+</script>
diff --git a/js/xpconnect/tests/chrome/file_bug484459.html b/js/xpconnect/tests/chrome/file_bug484459.html
new file mode 100644
index 0000000000..27be5463a2
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug484459.html
@@ -0,0 +1,10 @@
+<html>
+<head>
+  <title>helper for bug 484459</title>
+</head>
+<body>
+  <script type="application/javascript">
+    var x=3;
+  </script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/file_bug618176.xhtml b/js/xpconnect/tests/chrome/file_bug618176.xhtml
new file mode 100644
index 0000000000..3aea153159
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug618176.xhtml
@@ -0,0 +1,48 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=618176
+-->
+<window title="Mozilla Bug 618176"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  onload="start()">
+  <label value="Mozilla Bug 618176"/>
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    /* global messageManager */
+    const TEST_PAGE = Services.io.newURI(
+      "data:text/html,<script>var a=[1,2,3];</script>Hi"
+    );
+
+    const FRAME_SCRIPT = 
+"data:,addEventListener('pageshow', function() { sendAsyncMessage('test', content.wrappedJSObject.a) }, false);";
+   // s/content.wrappedJSObject.a/[ 1, 2, 3]/ and the test passes
+
+    function recvTest(m) {
+      var a = m.json;
+      window.arguments[0].is(a.length, 3, "array was serialized and deserialized");
+
+      messageManager.removeMessageListener("test", recvTest);
+      finish();
+    }
+
+    function start() {
+      messageManager.addMessageListener("test", recvTest);
+      messageManager.loadFrameScript(FRAME_SCRIPT, true);
+      let triggeringPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
+      setTimeout(function () {
+        document.getElementById("browser").loadURI(TEST_PAGE, {triggeringPrincipal});
+      }, 0);
+    }
+
+    function finish() {
+      window.arguments[0].setTimeout(function() { this.done(); }, 0);
+      window.close();
+    }
+
+  ]]></script>
+
+  <browser id="browser" type="content" style="width: 200px; height: 200px;"/>
+</window>
diff --git a/js/xpconnect/tests/chrome/file_bug996069.html b/js/xpconnect/tests/chrome/file_bug996069.html
new file mode 100644
index 0000000000..e4bed07806
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_bug996069.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<head></head>
+<body>
+  <script>
+    if (window.opener && window.opener.finishTest) {
+      window.opener.finishTest();
+    }
+  </script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/file_discardSystemSource.html b/js/xpconnect/tests/chrome/file_discardSystemSource.html
new file mode 100644
index 0000000000..5dc9e9e7ba
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_discardSystemSource.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script>
+  function canary() {
+    // eslint-disable-next-line no-unused-vars
+    var someBitOfSource = 42;
+  }
+  function inner() {
+    throw new Error("some error");
+  }
+  function throwSomething() {
+    inner();
+  }
+</script>
+</head>
+<body onload="someBitOfSource = 42">
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/file_empty.html b/js/xpconnect/tests/chrome/file_empty.html
new file mode 100644
index 0000000000..b3bfe19c0b
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_empty.html
@@ -0,0 +1,2 @@
+<!DOCTYPE html>
+<html><head><title>test page</title></head><body>there is nothing to see</body></html>
diff --git a/js/xpconnect/tests/chrome/file_evalInSandbox.html b/js/xpconnect/tests/chrome/file_evalInSandbox.html
new file mode 100644
index 0000000000..fb58f2bb41
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_evalInSandbox.html
@@ -0,0 +1 @@
+<html><body><script>document.foo = 'bar';</script></body></html>
diff --git a/js/xpconnect/tests/chrome/file_expandosharing.jsm b/js/xpconnect/tests/chrome/file_expandosharing.jsm
new file mode 100644
index 0000000000..f680ae20a9
--- /dev/null
+++ b/js/xpconnect/tests/chrome/file_expandosharing.jsm
@@ -0,0 +1,12 @@
+var EXPORTED_SYMBOLS = ["checkFromJSM"];
+
+function checkFromJSM(target, is_op) {
+  is_op(target.numProp, 42, "Number expando works");
+  is_op(target.strProp, "foo", "String expando works");
+  // If is_op is todo_is, target.objProp will be undefined.
+  try {
+    is_op(target.objProp.bar, "baz", "Object expando works");
+  } catch (e) {
+    is_op(0, 1, "No object expando");
+  }
+}
diff --git a/js/xpconnect/tests/chrome/moz.build b/js/xpconnect/tests/chrome/moz.build
new file mode 100644
index 0000000000..d371d3051f
--- /dev/null
+++ b/js/xpconnect/tests/chrome/moz.build
@@ -0,0 +1,12 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+MOCHITEST_CHROME_MANIFESTS += ["chrome.ini"]
+
+TEST_HARNESS_FILES.testing.mochitest.tests.js.xpconnect.tests.chrome += [
+    "file_discardSystemSource.html",
+    "worker_discardSystemSource.js",
+]
diff --git a/js/xpconnect/tests/chrome/outoflinexulscript.js b/js/xpconnect/tests/chrome/outoflinexulscript.js
new file mode 100644
index 0000000000..14b99048e9
--- /dev/null
+++ b/js/xpconnect/tests/chrome/outoflinexulscript.js
@@ -0,0 +1,5 @@
+// Some unicode characters that must be decoded:
+// ………………………………………………………………………………………………………………………………
+function outoflinefunction() {
+  return 42;
+}
diff --git a/js/xpconnect/tests/chrome/subscript.js b/js/xpconnect/tests/chrome/subscript.js
new file mode 100644
index 0000000000..c2708f6e9b
--- /dev/null
+++ b/js/xpconnect/tests/chrome/subscript.js
@@ -0,0 +1,4 @@
+/* global base */
+var ns = {};
+Services.scriptloader.loadSubScript(base + "file_expandosharing.jsm", ns);
+var checkFromJSM = ns.checkFromJSM;
diff --git a/js/xpconnect/tests/chrome/test_APIExposer.xhtml b/js/xpconnect/tests/chrome/test_APIExposer.xhtml
new file mode 100644
index 0000000000..b327abe44d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_APIExposer.xhtml
@@ -0,0 +1,48 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=634156
+-->
+<window title="Testing API exposing capabilities"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=634156"
+     target="_blank">Mozilla Bug 634156</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      var sandbox = new Cu.Sandbox("about:blank");
+      sandbox.ok = ok;
+      sandbox.is = is;
+      Cu.evalInSandbox("Object.defineProperty(Object.prototype, 'getProp', { get: function() { throw 'FAIL: called getter' }, set: function() { throw 'FAIL: called setter'; } })", sandbox);
+
+      var obj = Cu.createObjectIn(sandbox);
+      is(obj, Cu.waiveXrays(obj), "createObjectIn waives");
+      is(Object.getPrototypeOf(obj), Cu.waiveXrays(Cu.evalInSandbox("Object.prototype", sandbox)),
+         "Object is a sandbox object");
+
+      function genPropDesc(value) {
+          return { enumerable: true, configurable: true, writable: true,
+                   value };
+      }
+      const props = {
+          'getProp': genPropDesc(function() { ok(true, "called prop that shadowed a getter"); }),
+          'argument': genPropDesc(function(arg) { is(arg, 42, "can pass arguments through"); }),
+          'returnval': genPropDesc(function() { return 42; })
+      };
+      Object.defineProperties(obj, props);
+      Cu.makeObjectPropsNormal(obj);
+
+      sandbox.api = obj;
+      Cu.evalInSandbox("ok(Object.getPrototypeOf(api) === Object.prototype, 'we have the object we expected'); \
+      api.getProp(); api.argument(42); is(api.returnval(), 42, 'return value was correct');\
+      ok(typeof api.getProp === 'function', 'functions are functions');\
+      ok(Object.getPrototypeOf(api.getProp) === Function.prototype, 'functions come from our scope');", sandbox);
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1041626.xhtml b/js/xpconnect/tests/chrome/test_bug1041626.xhtml
new file mode 100644
index 0000000000..61d7630838
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1041626.xhtml
@@ -0,0 +1,60 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1041626
+-->
+<window title="Mozilla Bug 1041626"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1041626"
+     target="_blank">Mozilla Bug 1041626</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 1041626 **/
+  SimpleTest.waitForExplicitFinish();
+  function go() {
+
+    //
+    // Location
+    //
+
+    ok(Cu.isXrayWrapper(window[0].location), "Location is Xrayed");
+    let xrayOwnProperties = Object.getOwnPropertyNames(window[0].location);
+
+    let realOwnProperties = Object.getOwnPropertyNames(window[0].wrappedJSObject.location);
+    ok(realOwnProperties.length > 2);
+
+    is(xrayOwnProperties.sort().toSource(), realOwnProperties.sort().toSource(),
+       "Xray enumerates location properties properly");
+
+    //
+    // Document
+    //
+
+    ok(Cu.isXrayWrapper(window[0].document), "Document is Xrayed");
+    xrayOwnProperties = Object.getOwnPropertyNames(window[0].document);
+
+    realOwnProperties = Object.getOwnPropertyNames(window[0].wrappedJSObject.document);
+    ok(!!realOwnProperties.length);
+
+    is(xrayOwnProperties.sort().toSource(), realOwnProperties.sort().toSource(),
+       "Xray enumerates document properties properly");
+
+
+
+    SimpleTest.finish();
+  }
+
+
+
+  ]]>
+  </script>
+  <iframe onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1042436.xhtml b/js/xpconnect/tests/chrome/test_bug1042436.xhtml
new file mode 100644
index 0000000000..4c86839fd9
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1042436.xhtml
@@ -0,0 +1,54 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1042436
+-->
+<window title="Mozilla Bug 1042436"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1042436"
+     target="_blank">Mozilla Bug 1042436</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 1042436 **/
+  SimpleTest.waitForExplicitFinish();
+
+  var contentSb = Cu.Sandbox("https://www.example.com");
+  var nonXrayableObj = contentSb.eval("new Map()[Symbol.iterator]()");
+  nonXrayableObj.wrappedJSObject.someExpandoProperty = 42;
+  nonXrayableObj.wrappedJSObject.someOtherExpandoProperty = 52;
+
+
+  SimpleTest.expectConsoleMessages(function() {
+      // Create sandboxes in fresh compartments, because the warning state is
+      // stored per compartment.
+      var chromeSb1 = Cu.Sandbox(this, {freshCompartment: true});
+      chromeSb1.nonXrayableObj = nonXrayableObj;
+      Cu.evalInSandbox(`
+        nonXrayableObj.someExpandoProperty;
+        nonXrayableObj.someOtherExpandoProperty;
+      `, chromeSb1);
+
+      var chromeSb2 = Cu.Sandbox(this, {freshCompartment: true});
+      var contentObjWithGetter = contentSb.eval('({ get getterProp() {return 42;}, valueProp: 42 })');
+      is(contentObjWithGetter.wrappedJSObject.getterProp, 42, "Getter prop set up correctly");
+      is(contentObjWithGetter.getterProp, undefined, "Xrays work right");
+      is(contentObjWithGetter.valueProp, 42, "Getter prop set up correctly");
+      chromeSb2.contentObjWithGetter = contentObjWithGetter;
+      Cu.evalInSandbox('contentObjWithGetter.getterProp; contentObjWithGetter.valueProp; contentObjWithGetter.getterProp;',
+                       chromeSb2, "1.7", "https://phony.example.com/file.js", 99);
+  },
+  [{ errorMessage: /property "someExpandoProperty" \(reason: object is not safely Xrayable/, sourceName: /test_bug1042436/, isWarning: true },
+   { errorMessage: /property "getterProp" \(reason: property has accessor/, sourceName: /phony/, lineNumber: 99, isWarning: true } ],
+  SimpleTest.finish.bind(SimpleTest));
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1065185.html b/js/xpconnect/tests/chrome/test_bug1065185.html
new file mode 100644
index 0000000000..bc5b6027f2
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1065185.html
@@ -0,0 +1,64 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1065185
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1065185</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 1065185 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function doMonitor(rgxps) {
+    var messages = rgxps.map((x) => ({ errorMessage: x, isWarning: true }));
+    info("Expecting console messages: " + messages.toSource());
+    SimpleTest.monitorConsole(() => SimpleTest.executeSoon(() => window[0].location.reload()), messages, /* forbidUnexpected = */ true);
+  }
+  function endMonitor() {
+    SimpleTest.executeSoon(SimpleTest.endMonitorConsole.bind(SimpleTest));
+  }
+
+  var gLoadCount = 0;
+  function loaded() {
+    switch(gLoadCount++) {
+      case 0:
+        doMonitor([/access to property "a"/i]);
+        window[0].wrappedJSObject.probe = { a: 2 };
+        is(window[0].eval('probe.a'), undefined, "Accessed exposed prop");
+        endMonitor();
+        break;
+      case 1:
+        doMonitor([/access to property "a"/i]);
+        window[0].wrappedJSObject.probe = { a: 2 };
+        is(window[0].eval('probe.a'), undefined, "Non-exposed prop undefined");
+        is(window[0].eval('probe.a'), undefined, "Non-exposed prop undefined again");
+        endMonitor();
+        break;
+      case 2:
+        SimpleTest.finish();
+        break;
+      default:
+        ok(false, "Unexpected load");
+        SimpleTest.finish();
+        break;
+    }
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1065185">Mozilla Bug 1065185</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+<iframe onload="loaded();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1074863.html b/js/xpconnect/tests/chrome/test_bug1074863.html
new file mode 100644
index 0000000000..2fbe69a547
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1074863.html
@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1074863
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1074863</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 1074863 **/
+  var sb = new Cu.Sandbox("https://www.example.com");
+  sb.namedCtor = Image;
+  ok(true, "Didn't assert");
+
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1074863">Mozilla Bug 1074863</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1092477.xhtml b/js/xpconnect/tests/chrome/test_bug1092477.xhtml
new file mode 100644
index 0000000000..d79cd6604d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1092477.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1092477
+-->
+<window title="Mozilla Bug 1092477"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1092477"
+     target="_blank">Mozilla Bug 1092477</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+var exn;
+var url = "resource://non-existent/script.js";
+try {
+    Services.scriptloader.loadSubScript(url);
+    ok(false, "This line should never be reached!");
+}
+catch (e) {
+    exn = String(e);
+}
+var msg = "loadSubScript should throw an exception for trying to load a non-existent script"
+is(exn, "Error opening input stream (invalid filename?): " + url, msg);
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1124898.html b/js/xpconnect/tests/chrome/test_bug1124898.html
new file mode 100644
index 0000000000..0b6c2b7451
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1124898.html
@@ -0,0 +1,52 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1124898
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1124898</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 1124898 **/
+  SimpleTest.waitForExplicitFinish();
+  (async () => {
+    await SpecialPowers.pushPrefEnv({"set": [["security.allow_eval_with_system_principal", true]]});
+
+    SimpleTest.expectAssertions(0, 1); // Dumb unrelated widget assertion - see bug 1126023.
+
+    var w = window.browsingContext.topChromeWindow.open("about:blank", "w", "chrome");
+    is(w.eval('typeof getAttention'), 'function', 'getAttention exists on regular chrome window');
+    is(w.eval('typeof messageManager'), 'object', 'messageManager exists on regular chrome window');
+    var contentURL = "https://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html";
+    w.location = contentURL;
+    tryWindow();
+
+    function tryWindow() {
+      if (w.document.title != 'empty test page') {
+        info("Document not loaded yet - retrying");
+        SimpleTest.executeSoon(tryWindow);
+        return;
+      }
+      is(w.eval('typeof getAttention'), 'undefined', 'getAttention doesnt exist on content-in-chrome window');
+      is(w.eval('typeof messageManager'), 'undefined', 'messageManager doesnt exist on content-in-chrome window');
+      w.close();
+      SimpleTest.finish();
+    }
+  })();
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1124898">Mozilla Bug 1124898</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1126911.html b/js/xpconnect/tests/chrome/test_bug1126911.html
new file mode 100644
index 0000000000..bbb2a00f54
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1126911.html
@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1126911
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1126911</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 1126911 **/
+  var sb = new Cu.Sandbox(null);
+  sb.win = window;
+  sb.loc = location;
+  function checkThrows(expr) {
+    try {
+      Cu.evalInSandbox(expr, sb);
+      ok(false, "Should have thrown: " + expr);
+    } catch (e) {
+      ok(/denied|insecure/.test(e), "should get security exception: " + e);
+    }
+  }
+  checkThrows('win.top');
+  checkThrows('loc.replace');
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1126911">Mozilla Bug 1126911</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1281071.xhtml b/js/xpconnect/tests/chrome/test_bug1281071.xhtml
new file mode 100644
index 0000000000..e1ab036d55
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1281071.xhtml
@@ -0,0 +1,32 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1281071
+-->
+<window title="Mozilla Bug 1281071"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    SimpleTest.waitForExplicitFinish();
+    function go() {
+      var w = $('ifr').contentWindow.wrappedJSObject;
+      is(w.tryLocationGet(), "Permission to call 'get location' denied.",
+         "Trying to get our location object should throw");
+      SimpleTest.finish();
+    }
+  ]]></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <iframe type="content"
+            src="http://mochi.test:8888/chrome/js/xpconnect/tests/chrome/file_bug1281071.html"
+            onload="go()"
+            id="ifr">
+    </iframe>
+  </body>
+
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1390159.xhtml b/js/xpconnect/tests/chrome/test_bug1390159.xhtml
new file mode 100644
index 0000000000..7d5b917a27
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1390159.xhtml
@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1390159
+-->
+<window title="Mozilla Bug 1390159"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    function test() {
+      var xulRuntime = Services.appinfo;
+
+      // Make sure it has an inSafeMode property. This is just an arbitrary
+      // readonly property.
+      var oldValue = xulRuntime.inSafeMode;
+      is(typeof oldValue, "boolean", "Expected an inSafeMode property");
+
+      // Changing a readonly property doesn't throw, but shouldn't change
+      // the value.
+      xulRuntime.inSafeMode = !oldValue;
+      is(xulRuntime.inSafeMode, oldValue, "Should not have modified prop");
+
+      // Adding a new property should throw.
+      let ex = null;
+      try {
+        xulRuntime.foobar = 1;
+      } catch (e) {
+        ex = e;
+      }
+      is(ex.toString().includes("Cannot modify"), true, "Expected an error");
+      is(xulRuntime.foobar, undefined, "Property not defined");
+    }
+    test();
+  ]]></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug1430164.html b/js/xpconnect/tests/chrome/test_bug1430164.html
new file mode 100644
index 0000000000..609e662ad5
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1430164.html
@@ -0,0 +1,31 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1430164
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1430164</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+  /** Test for Bug 1430164 **/
+      var s = new Cu.Sandbox(window, { sandboxPrototype: window } );
+      var t;
+      var desc;
+      try {
+          t = Cu.evalInSandbox('Node === Node', s);
+          ok(t, "Object identity should be sane");
+
+          t = Cu.evalInSandbox('Node === this.Node', s);
+          ok(t, "Node should match this.Node in toplevel");
+
+          t = Cu.evalInSandbox('Node === window.Node', s);
+          ok(t, "Node should match window.Node");
+      } catch (e) {
+          ok(false, "Should not get an exception: " + e);
+      }
+  </script>
+</head>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1516237.html b/js/xpconnect/tests/chrome/test_bug1516237.html
new file mode 100644
index 0000000000..e7b92461bf
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1516237.html
@@ -0,0 +1,50 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1516237
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1516237</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+/** Test for Bug 1516237 **/
+ChromeUtils.import("resource://testing-common/TestUtils.jsm");
+
+function go() {
+    SimpleTest.waitForExplicitFinish();
+
+    var frame = $('subframe');
+    frame.onload = null;
+
+    // Get a CCW wrapping an Xray waiver wrapping a WindowProxy.
+    var w = frame.contentWindow;
+    var ccwToWaiver = w.wrappedJSObject;
+    ccwToWaiver.testProp = 1;
+    is(ccwToWaiver.testProp, 1, "Can set properties on content window");
+
+    // Load a chrome page in the content frame. This might create a realm in
+    // the current chrome compartment - in that case we nuke the CCW to the
+    // waiver.
+    frame.onload = function() {
+        is(Cu.getClassName(w.Math, /* unwrap = */ false), "Math",
+           "Window must be in same system compartment");
+        ok(Cu.isDeadWrapper(ccwToWaiver),
+           "Nuked CCW to same-compartment window");
+        SimpleTest.finish();
+    };
+    frame.src = "file_empty.html";
+}
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1516237">Mozilla Bug 1516237</a>
+
+<iframe id="subframe" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" onload="go()"></iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug1530146.html b/js/xpconnect/tests/chrome/test_bug1530146.html
new file mode 100644
index 0000000000..59be912027
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug1530146.html
@@ -0,0 +1,58 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1530146
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1530146</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 1530146 **/
+  SimpleTest.waitForExplicitFinish();
+
+  addLoadEvent(setupTest);
+
+  var sb;
+
+  function setupTest() {
+    // Create a sandbox with an expanded principal for our iframe.
+    sb = new Cu.Sandbox([frames[0].document.nodePrincipal],
+                        {sandboxPrototype: frames[0]});
+    // Grab a waiver for the subframe in the sandbox to make sure the waiver
+    // stays alive.  It would be nice if we could just use waiveXray in the
+    // sandbox: https://bugzilla.mozilla.org/show_bug.cgi?id=1531614
+    Cu.evalInSandbox('this.waiver = document.querySelector("iframe").contentWindow.wrappedJSObject',
+                     sb);
+    var ifr = frames[0].document.querySelector("iframe");
+    ifr.onload = doTest;
+    ifr.src = "file_bug1530146_inner.html";
+  }
+
+function doTest() {
+    // Create a new sandbox for the iframe's subframe
+    var sb2 = new Cu.Sandbox([frames[0][0].document.nodePrincipal],
+                             {sandboxPrototype: frames[0][0]});
+    // Reget the waiver; this is where things can go awry.
+    Cu.evalInSandbox('this.waiver = window.wrappedJSObject', sb2);
+    is(Cu.evalInSandbox("this.waiver.obj.a", sb2), "hello",
+       "Should get the right value and not crash");
+    is(Cu.evalInSandbox("(new this.waiver.Image()).localName", sb2), "img",
+       "Should create an image and not crash");
+    SimpleTest.finish();
+  }
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1530146">Mozilla Bug 1530146</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+<iframe src="http://mochi.test:8888/chrome/js/xpconnect/tests/chrome/file_bug1530146.html"></iframe>
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug361111.xhtml b/js/xpconnect/tests/chrome/test_bug361111.xhtml
new file mode 100644
index 0000000000..4f1f89cf86
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug361111.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=361111
+-->
+<window title="Mozilla Bug 361111"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=361111"
+     target="_blank">Mozilla Bug 361111</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+    /** Test for Bug 361111 **/
+    window.onerror = null;
+    SimpleTest.waitForExplicitFinish();
+    document.documentElement.setAttribute("onclick", "%");
+    is(1, 1, "Good, setting a bogus onclick did not throw.");
+
+    // Bonus test - make sure that flushPrefEnv is appropriately
+    // called at the end of the test. It would be nice if there were
+    // somewhere in the harness that this could live, but there isn't.
+    SpecialPowers.pushPrefEnv({set: [['testing.some_arbitrary_pref', true]]},
+                              function() { SimpleTest.finish(); });
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug448587.xhtml b/js/xpconnect/tests/chrome/test_bug448587.xhtml
new file mode 100644
index 0000000000..cedab9ebbd
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug448587.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=448587.xul
+-->
+<window title="Mozilla Bug 503926"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=448587"
+     target="_blank">Mozilla Bug 448587</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  // Bonus test - collaborate with test_bug361111.xhtml to make sure that
+  // flushPrefEnv is appropriately called.
+  ok(!SpecialPowers.Services.prefs.prefHasUserValue('testing.some_arbitrary_pref'),
+     "Pref shouldn't carry over from previous test!");
+
+
+  /** Test for Bug 448587 **/
+  var sandbox = new Cu.Sandbox("about:blank");
+  var fwrapper = Cu.evalInSandbox("function f() {} f", sandbox);
+  is(Cu.unwaiveXrays(Cu.waiveXrays(fwrapper).prototype), Cu.evalInSandbox("f.prototype", sandbox),
+     ".prototype visible through .wrappedJSObject");
+  is(fwrapper.prototype, undefined, ".prototype invisible through Xrays");
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug484459.xhtml b/js/xpconnect/tests/chrome/test_bug484459.xhtml
new file mode 100644
index 0000000000..59f2f4ea60
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug484459.xhtml
@@ -0,0 +1,37 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=484459
+-->
+<window title="Mozilla Bug 484459"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <iframe type="content"
+      src="./file_bug484459.html"
+      onload="go()"
+      id="ifr">
+    </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    SimpleTest.waitForExplicitFinish();
+    var url = "chrome://mochitests/content/chrome/js/xpconnect/tests/chrome/test_bug484459.xhtml";
+    function go() {
+      var w = $('ifr').contentWindow.wrappedJSObject;
+      var sandbox = new Cu.Sandbox(w);
+      sandbox.__proto__ = w;
+      is(location.href, url, "location.href is set properly");
+      ok(w.location.href.endsWith("file_bug484459.html"),
+         "contents of w.location are correct");
+      is(Cu.evalInSandbox("x * 4", sandbox), 12,
+         "Unexpected return from the sandbox");
+      SimpleTest.finish();
+    }
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug500931.xhtml b/js/xpconnect/tests/chrome/test_bug500931.xhtml
new file mode 100644
index 0000000000..68effb7342
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug500931.xhtml
@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500931
+-->
+<window title="Mozilla Bug 500931"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=500931"
+     target="_blank">Mozilla Bug 500931</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 500931 **/
+
+  function go() {
+    var ifr = document.getElementById("ifr");
+    var doc = ifr.contentDocument;
+    ok(Cu.isXrayWrapper(doc), "doc is an XrayWrapper");
+    var weak = Cu.getWeakReference(doc);
+    ok(Cu.isXrayWrapper(weak.get()), "weak reference returns a wrapper");
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content"
+          src="http://example.org/tests/js/xpconnect/tests/mochitest/bug500931_helper.html"
+          onload="go()"
+          id="ifr">
+  </iframe>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug503926.xhtml b/js/xpconnect/tests/chrome/test_bug503926.xhtml
new file mode 100644
index 0000000000..cfe6315fd8
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug503926.xhtml
@@ -0,0 +1,58 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=503926
+-->
+<window title="Mozilla Bug 503926"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=503926"
+     target="_blank">Mozilla Bug 503926</a>
+
+  <iframe id="ifr" type="content" onload="loaded()" src="bug503926.xhtml#iframe"/>
+  <iframe id="ifrContent" type="content" onload="loaded()" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"/>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  SimpleTest.expectAssertions(0, 1);
+
+  var gLoadCount = 0;
+  function loaded() {
+    if (++gLoadCount == 2)
+      go();
+  }
+
+  /** Test for Bug 503926 **/
+  function go() {
+    var gWindowUtils = window.windowUtils;
+
+    // Try with a chrome object.
+    var passed = false;
+    // eslint-disable-next-line mozilla/use-chromeutils-generateqi
+    var obj = { QueryInterface() { passed = true; } };
+    gWindowUtils.xpconnectArgument(obj);
+    ok(passed, "trusted QIs should be called");
+
+    // Try with a content object.
+    var contentWin = $('ifrContent').contentWindow.wrappedJSObject;
+    contentWin.passed = false;
+    var contentObj = contentWin.eval('({ QueryInterface: function() { passed = true; } })');
+    gWindowUtils.xpconnectArgument(contentObj);
+    ok(!contentWin.passed, "untrusted QI should not be called");
+
+    // Try with a dialog.
+    window.browsingContext.topChromeWindow.openDialog("bug503926.xhtml", "chromeDialog", "modal", window);
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug533596.xhtml b/js/xpconnect/tests/chrome/test_bug533596.xhtml
new file mode 100644
index 0000000000..3c3e610e81
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug533596.xhtml
@@ -0,0 +1,58 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=533596"
+     target="_blank">Mozilla Bug 533596</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  // XPCNativeWrapper is not defined globally in ESLint as it may be going away.
+  // See bug 1481337.
+  /* global XPCNativeWrapper */
+
+  /** Test for Bug 533596 **/
+
+  function go() {
+    try { XPCNativeWrapper.unwrap(); } catch (e) {}
+    try { XPCNativeWrapper.unwrap(0); } catch (e) {}
+    try { XPCNativeWrapper.unwrap(null); } catch (e) {}
+
+    var o = {};
+    is(o, XPCNativeWrapper.unwrap(o), "unwrap on a random object returns it");
+
+    var win = $('ifr').contentWindow;
+    var utils = window.windowUtils;
+    is(utils.getClassName(win), "Proxy", "win is a Proxy");
+    ok("x" in XPCNativeWrapper.unwrap(win), "actually unwrapped");
+    is(utils.getClassName(XPCNativeWrapper.unwrap(win)), "Proxy",
+       "unwrap on an Proxy returns the same object");
+    is(utils.getClassName(XPCNativeWrapper.unwrap(new XPCNativeWrapper(win))), "Proxy",
+       "unwrap on an explicit NW works too");
+
+    ok(utils.getClassName(window) !== "XPCNativeWrapper", "window is not a native wrapper");
+    ok(utils.getClassName(XPCNativeWrapper.unwrap(new XPCNativeWrapper(window))) !== "XPCSafeJSObjectWrapper",
+       "unwrapping a chrome object returns the object itself");
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content"
+          src="http://example.org/tests/js/xpconnect/tests/mochitest/bug500931_helper.html"
+          onload="go()"
+          id="ifr">
+  </iframe>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug571849.xhtml b/js/xpconnect/tests/chrome/test_bug571849.xhtml
new file mode 100644
index 0000000000..3e4f6d6cc1
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug571849.xhtml
@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500931
+-->
+<window title="Mozilla Bug 500931"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=500931"
+     target="_blank">Mozilla Bug 500931</a>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 500931 **/
+
+  function go() {
+    var ifr = document.getElementById('ifr');
+    var docnodes = ifr.contentDocument.body.childNodes;
+    var index, value;
+    for (let i of Object.entries(docnodes)) {
+      index = i[0];
+      value = i[1];
+    }
+    is(index, "0", "enumerated the 0th element");
+    ok(Text.isInstance(value), "the 0th element was a text node");
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content"
+          src="http://example.org/tests/js/xpconnect/tests/mochitest/bug571849_helper.html"
+          onload="go()"
+          id="ifr">
+  </iframe>
+  </body>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug610390.xhtml b/js/xpconnect/tests/chrome/test_bug610390.xhtml
new file mode 100644
index 0000000000..e4d8a48477
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug610390.xhtml
@@ -0,0 +1,32 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=610390
+-->
+<window title="Mozilla Bug 610390"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <iframe type="content"
+      xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+      src="data:text/html,&lt;script&gt;var x=3&lt;/script&gt;"
+      onload="go()"
+      id="ifr">
+    </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    SimpleTest.waitForExplicitFinish();
+
+    function go() {
+      var w = $('ifr').contentWindow;
+      is(w.wrappedJSObject, w.wrappedJSObject, "wrappedJSObject identity not maintained");
+      SimpleTest.finish();
+    }
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug614757.xhtml b/js/xpconnect/tests/chrome/test_bug614757.xhtml
new file mode 100644
index 0000000000..34058e38a3
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug614757.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=614757
+-->
+<window title="Mozilla Bug 601803"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=614757"
+     target="_blank">Mozilla Bug 614757</a>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 614757 **/
+
+  function go() {
+    is($('ifr').contentDocument.wrappedJSObject.getElementsByTagName('body')[0].toString().indexOf('Xray'),
+       -1, "Properly deep wrap");
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content" src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_evalInSandbox.html" onload="go()" id="ifr" />
+  </body>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug616992.xhtml b/js/xpconnect/tests/chrome/test_bug616992.xhtml
new file mode 100644
index 0000000000..52a97cee3d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug616992.xhtml
@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=616992
+-->
+<window title="Mozilla Bug 601803"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=616992"
+     target="_blank">Mozilla Bug 616992</a>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 616992 **/
+
+  var sandbox = new Cu.Sandbox(window);
+  sandbox.w = window;
+  var actual = Cu.evalInSandbox("Object.keys(w.NodeFilter)", sandbox).sort().toString();
+  var expected = Object.keys(NodeFilter).sort().toString();
+  is(actual, expected, "interface constants are visible inside sandboxes");
+
+  ]]></script>
+  </body>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug618176.xhtml b/js/xpconnect/tests/chrome/test_bug618176.xhtml
new file mode 100644
index 0000000000..63e93c9b56
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug618176.xhtml
@@ -0,0 +1,30 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=618176
+-->
+<window title="Mozilla Bug 618176"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=618176"
+     target="_blank">Mozilla Bug 618176</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+  SimpleTest.waitForExplicitFinish();
+
+  function done() {
+    SimpleTest.finish();
+  }
+
+  addLoadEvent(function() {
+    window.openDialog("file_bug618176.xhtml", "", "chrome,noopener", window);
+  });
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug654370.xhtml b/js/xpconnect/tests/chrome/test_bug654370.xhtml
new file mode 100644
index 0000000000..e1afc32e38
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug654370.xhtml
@@ -0,0 +1,27 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=654370
+-->
+<window title="Mozilla Bug 654370"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=654370"
+     target="_blank">Mozilla Bug 654370</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+var sandbox = new Cu.Sandbox(window);
+var script = "(function (obj, type) { return obj instanceof type; })";
+var instanceOf = Cu.evalInSandbox(script, sandbox, "1.8", "Test", 1);
+ok(!instanceOf({}, Window), "instanceOf from the sandbox gets the right result");
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug658560.xhtml b/js/xpconnect/tests/chrome/test_bug658560.xhtml
new file mode 100644
index 0000000000..78b623a828
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug658560.xhtml
@@ -0,0 +1,38 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=658560
+-->
+<window title="Mozilla Bug 658560"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=658560"
+     target="_blank">Mozilla Bug 658560</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+      SimpleTest.waitForExplicitFinish();
+      function go() {
+        var win = $('ifr').contentWindow.wrappedJSObject;
+        let o = { prop: true };
+        win.foo = o;
+
+        is(win.foo, o, "should have === identity through a CrossOriginWrapper");
+        SimpleTest.finish();
+      }
+
+  ]]></script>
+
+  <iframe
+      src="http://example.org/tests/js/xpconnect/tests/mochitest/file_bug658560.html"
+          id="ifr"
+          type="content"
+          onload="go()" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug658909.xhtml b/js/xpconnect/tests/chrome/test_bug658909.xhtml
new file mode 100644
index 0000000000..360b8045e2
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug658909.xhtml
@@ -0,0 +1,92 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=658909
+-->
+<window title="Mozilla Bug 658909"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=658909"
+     target="_blank">Mozilla Bug 658909</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for call/apply-ing Xray methods.**/
+  SimpleTest.waitForExplicitFinish();
+
+  let gLoadCount = 0;
+  function frameLoaded() {
+    if (++gLoadCount == frames.length)
+      go();
+  }
+
+  function msg(a, b, testName) {
+    return "(" + a.name + ", " + b.name + "): " + testName;
+  }
+
+  var testFunctions = {
+    testDocumentElement(a, b, name) {
+      var getter = Object.prototype.__lookupGetter__.call(a.document, 'documentElement');
+      is(getter.call(b.document), b.document.documentElement, msg(a, b, name));
+    },
+
+    testInvalidCall(a, b, name) {
+      var getter = Object.prototype.__lookupGetter__.call(a.document, 'documentElement');
+      var threw = false;
+      try { getter.call(b.document.body); } catch (e) { threw = true; };
+      ok(threw, msg(a, b, name));
+    },
+
+    testStatus(a, b, name) {
+      var setter = Object.prototype.__lookupSetter__.call(a, 'status');
+      is(b.status, "", "Empty status");
+      setter.call(b, "foopy");
+      is(b.status, "foopy", msg(a, b, name));
+      b.status = "";
+    },
+
+    testCreateElement(a, b, name) {
+      is(a.document.createElement.call(b.document, 'div').ownerDocument, b.document, msg(a, b, name));
+    },
+
+    testWindowName(a, b, name) {
+      var getter = Object.prototype.__lookupGetter__.call(a, 'name');
+      is(getter.call(b), b.name, msg(a, b, name));
+    },
+
+    testCanvas(a, b, name) {
+      var canvasA = a.document.createElement('canvas');
+      var canvasB = b.document.createElement('canvas');
+      var contextA = canvasA.getContext('2d');
+      var contextB = canvasB.getContext('2d');
+      var getter = Object.prototype.__lookupGetter__.call(contextA, 'canvas');
+      is(getter.call(contextB), canvasB, msg(a, b, name));
+    }
+  };
+
+  function go() {
+    for (let i = 0; i < frames.length; ++i)
+        frames[i].name = 'frame' + i;
+    for (let i = 0; i < frames.length; ++i) {
+      for (let j = 0; j < frames.length; ++j) {
+        for (let k in testFunctions)
+          testFunctions[k](frames[i], frames[j], k);
+      }
+    }
+
+    SimpleTest.finish();
+  }
+
+
+  ]]>
+  </script>
+  <iframe id="frame1" onload="frameLoaded();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+  <iframe id="frame2" onload="frameLoaded();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+  <iframe id="frame3" onload="frameLoaded();" type="content" src="http://example.com/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug664689.xhtml b/js/xpconnect/tests/chrome/test_bug664689.xhtml
new file mode 100644
index 0000000000..45a39b1be9
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug664689.xhtml
@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=658560
+-->
+<window title="Mozilla Bug 658560"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=658560"
+     target="_blank">Mozilla Bug 658560</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+      var sandbox = new Cu.Sandbox("about:blank");
+      var contentObj = Cu.evalInSandbox("({ get foo() { return 42 } })", sandbox);
+      var propdesc = Object.getOwnPropertyDescriptor(Cu.waiveXrays(contentObj), "foo");
+      is(typeof propdesc, "object", "got a property descriptor back");
+      ok("get" in propdesc, "getter exists");
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug679861.xhtml b/js/xpconnect/tests/chrome/test_bug679861.xhtml
new file mode 100644
index 0000000000..302b66c966
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug679861.xhtml
@@ -0,0 +1,38 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500931
+-->
+<window title="Mozilla Bug 601803"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=601803"
+     target="_blank">Mozilla Bug 601803</a>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 601803 **/
+
+  function go() {
+    var doc = document.getElementById('ifr').contentDocument;
+    var list = doc.getElementsByTagName("body");
+    var zeroAsString = "0";
+    is(typeof list[zeroAsString], "object",
+       "can lookup nodelist items by string");
+    is(typeof list[0], "object",
+       "can lookup nodelist items by integer after the lookup by string");
+    SimpleTest.finish();
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content" src="about:blank" onload="go()" id="ifr" />
+  </body>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug706301.xhtml b/js/xpconnect/tests/chrome/test_bug706301.xhtml
new file mode 100644
index 0000000000..867f9222d2
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug706301.xhtml
@@ -0,0 +1,52 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=706301
+-->
+<window title="Mozilla Bug 706301"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=706301"
+     target="_blank">Mozilla Bug 706301</a>
+  <iframe id="ifr" src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_bug706301.html" onload="doTest();" />
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 706301 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  function getLengthInChrome(nodelist) {
+
+    // Make sure the object is Xray wrapped.
+    is(nodelist, Cu.unwaiveXrays(nodelist),
+       "object passed from content to chrome should be Xray-wrapped.");
+
+    // Perform the operation.
+    Object.getOwnPropertyDescriptor(nodelist, 'length');
+    return !nodelist.length;
+  }
+
+  function finishTestInChrome() {
+    SimpleTest.finish();
+  }
+
+  function doTest() {
+
+    // Set up the callbacks for content.
+    $('ifr').contentWindow.wrappedJSObject.getLengthInChrome = getLengthInChrome;
+    $('ifr').contentWindow.wrappedJSObject.finishTestInChrome = finishTestInChrome;
+    $('ifr').contentWindow.wrappedJSObject.ok = ok;
+
+    // Kick off the test.
+    $('ifr').contentWindow.postMessage({}, '*');
+  }
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug720619.xhtml b/js/xpconnect/tests/chrome/test_bug720619.xhtml
new file mode 100644
index 0000000000..335218886b
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug720619.xhtml
@@ -0,0 +1,46 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=720619
+-->
+<window title="Mozilla Bug 720619"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=720619"
+     target="_blank">Mozilla Bug 720619</a>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+  /** Test for Bug 720619 **/
+  var obj = {
+    valueOf () {
+      return 42;
+    },
+    toString () {
+      return 'str';
+    }
+  };
+
+  var content = new Cu.Sandbox("about:blank");
+  content.obj = obj;
+
+  ok(Cu.evalInSandbox("obj + ''", content) == "[object Object]");
+  ok(Cu.evalInSandbox("'' + obj", content) == "[object Object]");
+  ok(isNaN(Cu.evalInSandbox("obj - 0", content)));
+  ok(Cu.evalInSandbox("String(obj)", content) == "[object Object]");
+
+  var chrome = new Cu.Sandbox(window);
+  chrome.obj = obj;
+
+  ok(Cu.evalInSandbox("obj + ''", chrome) == "42");
+  ok(Cu.evalInSandbox("'' + obj", chrome) == "42");
+  ok(Cu.evalInSandbox("obj - 0", chrome) == 42);
+  ok(Cu.evalInSandbox("String(obj)", chrome) == "str");
+  ]]></script>
+  </body>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug726949.xhtml b/js/xpconnect/tests/chrome/test_bug726949.xhtml
new file mode 100644
index 0000000000..b02b200893
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug726949.xhtml
@@ -0,0 +1,41 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=726949
+-->
+<window title="Mozilla Bug 726949"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        style="display: block;">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=726949"
+     target="_blank">Mozilla Bug 726949</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 726949 **/
+      var s = new Cu.Sandbox(window, { sandboxPrototype: window } );
+      var t;
+      var desc;
+      try {
+          t = Cu.evalInSandbox('top', s);
+          is(t, window.top, "Should have gotten the right thing back");
+          desc = Cu.evalInSandbox('Object.getOwnPropertyDescriptor(Object.getPrototypeOf(this), "Cu")', s);
+          isnot(desc, undefined,
+                "Should have an own 'Cu' property");
+          is(desc.value, Cu, "Should have the right value");
+          var loc = Cu.evalInSandbox('location', s);
+          is(loc.href, location.href, "Should have the right location");
+          var display = Cu.evalInSandbox('getComputedStyle(document.documentElement, "").display', s);
+          is(display, "block", "Should be able to call getComputedStyle");
+      } catch (e) {
+          ok(false, "Should not get an exception: " + e);
+      }
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug732665.xhtml b/js/xpconnect/tests/chrome/test_bug732665.xhtml
new file mode 100644
index 0000000000..0ffba66ebc
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug732665.xhtml
@@ -0,0 +1,92 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=732665
+-->
+<window title="Mozilla Bug 732665"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=732665"
+     target="_blank">Mozilla Bug 732665</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({"set": [["security.allow_eval_with_system_principal",
+                                            true]]});
+  //
+  // Important! If this test starts failing after a tricky platform-y change,
+  // the stack quota numbers in XPCJSContext probably need twiddling. We want
+  // to maintain the invariants in this test (at least to some approximation)
+  // for security reasons.
+  //
+
+  // Executes f() d steps from the probed native stack limit, and returns
+  // the number of steps to the recursion limit from the caller.
+  function nearNativeStackLimit(d, f) {
+    f = f || function() {};
+    let failed = null;
+    function inner() {
+      try {
+        // eslint-disable-next-line no-eval
+        var stepsFromLimit = eval("inner()"); // Use eval to force a number of native stackframes to be created.
+        if (stepsFromLimit == d) {
+          try {
+            f();
+          } catch(e) {
+            // If we didn't have enough stack space to call the (possibly
+            // trivial) test function above, we obviously can't expect to call
+            // into the test harness assertion code successfully.
+            failed = e;
+          }
+        }
+        return stepsFromLimit + 1;
+      } catch(e) {
+      // It would be nice to check here that the exception is actually an
+      // over-recursion here. But doing so would require toString()ing the
+      // exception, which we may not have the stack space to do.
+        return 0;
+      }
+    }
+    let result = inner();
+    ok(!failed, `nearNativeStackLimit callback threw: ${failed}`);
+    return result;
+  }
+
+  var contentSb = new Cu.Sandbox("https://www.example.com");
+  var chromeSb = new Cu.Sandbox(window);
+  chromeSb.ok = contentSb.ok = ok;
+  Cu.evalInSandbox(nearNativeStackLimit.toSource(), chromeSb);
+  Cu.evalInSandbox(nearNativeStackLimit.toSource(), contentSb);
+  var chromeLimit = Cu.evalInSandbox("nearNativeStackLimit(0);", chromeSb);
+  var contentLimit = Cu.evalInSandbox("nearNativeStackLimit(0)", contentSb);
+  ok(chromeLimit >= contentLimit + 10,
+     "Chrome should be able to have at least 10 heavy frames more stack than content: " + chromeLimit + ", " + contentLimit);
+
+  // Exhaust the stack space in content, and then make sure we can still get 10
+  // heavy frames in chrome.
+  //
+  // Note that sometimes, if we pass |0| to nearNativeStackLimit, we can end up
+  // so close to the border in content that we can't even get ourselves together
+  // enough to make the cross-compartment call. So rather than exhausting the
+  // stack entirely and then checking for 10 chrome frames, we leave ourselves
+  // one frame's worth, and check for 11.
+  //
+  // If this assertion fails, the current work-around so far is to measure
+  // again the worst frame size, by using the JS Shell to run
+  // test_bug732665_meta.js . This script will output numbers to update
+  // XPCJSContext.cpp comment, as well as the kTrustedScriptBuffer constant.
+  contentSb.nnslChrome = chromeSb.nearNativeStackLimit;
+  var nestedLimit = Cu.evalInSandbox("nearNativeStackLimit(1, function() { nestedLimit = nnslChrome(0);}); nestedLimit;", contentSb);
+  ok(nestedLimit >= 11, "Chrome should be invokable from content script with an exhausted stack: " + nestedLimit);
+});
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug732665_meta.js b/js/xpconnect/tests/chrome/test_bug732665_meta.js
new file mode 100644
index 0000000000..92bf9066b3
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug732665_meta.js
@@ -0,0 +1,34 @@
+/* globals stackPointerInfo */
+
+var stackBottom = stackPointerInfo();
+var stackTop = stackBottom;
+
+function nearNativeStackLimit() {
+  function inner() {
+    try {
+      stackTop = stackPointerInfo();
+      // eslint-disable-next-line no-eval
+      var stepsFromLimit = eval("inner()"); // Use eval to force a number of native stackframes to be created.
+      return stepsFromLimit + 1;
+    } catch (e) {
+      // It would be nice to check here that the exception is actually an
+      // over-recursion here. But doing so would require toString()ing the
+      // exception, which we may not have the stack space to do.
+      return 1;
+    }
+  }
+  return inner();
+}
+
+var nbFrames = nearNativeStackLimit();
+var frameSize = stackBottom - stackTop;
+print(
+  "Max stack size:",
+  frameSize,
+  "bytes",
+  "\nMaximum number of frames:",
+  nbFrames,
+  "\nAverage frame size:",
+  Math.ceil(frameSize / nbFrames),
+  "bytes"
+);
diff --git a/js/xpconnect/tests/chrome/test_bug738244.xhtml b/js/xpconnect/tests/chrome/test_bug738244.xhtml
new file mode 100644
index 0000000000..96d0d880e6
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug738244.xhtml
@@ -0,0 +1,58 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  <iframe src="http://example.org/tests/js/xpconnect/tests/mochitest/file_bug738244.html"
+          onload="xrayTest(this)">
+  </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+      SimpleTest.waitForExplicitFinish();
+
+      function xrayTest(ifr) {
+        var win = ifr.contentWindow;
+        var doc = ifr.contentDocument;
+
+        doc.getElementById = 42;
+        is(doc.getElementById, 42,
+           "Native property cannot be shadowed on the xray");
+
+        is(doc.form1.name, "form1",
+           "Form elements cannot be found by name on the document through xray");
+
+        is(doc.form1.input1.name, "input1",
+           "Input element cannot be found by name on a form element through xray");
+
+        is(typeof doc.form1.appendChild, "function",
+           "Input element shadows native property with its name through xray");
+
+        is(win.frame1, undefined,
+           "IFrames should not be found by name on the window through xray");
+
+        is(win[0].name, "frame1",
+           "IFrames should be found by index on the window through xray");
+
+        win["1000"] = "foopy";
+        ok(!("1000" in win), "Shouldn't be able to add indexed expandos to xray");
+        
+        win["1000a"] = "foopy";
+        ok("1000a" in win, "Should be able to add named expandos to xray");
+
+        SimpleTest.finish();
+      }
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug743843.xhtml b/js/xpconnect/tests/chrome/test_bug743843.xhtml
new file mode 100644
index 0000000000..a80134ff9e
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug743843.xhtml
@@ -0,0 +1,39 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=743843
+-->
+<window title="Mozilla Bug 743843"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=743843"
+     target="_blank">Mozilla Bug 743843</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Components.Exception options objects. **/
+
+  // Note: We pass |window| as the 'data' field here because Components.Exception
+  // doesn't handle JS Objects here all that nicely. See bug 743121.
+
+  // Test the old interface.
+  var e1 = Components.Exception('foo', Cr.NS_BINDING_ABORTED, null, window);
+  is(e1.result, Cr.NS_BINDING_ABORTED, "Result should get set properly");
+  is(e1.data, window, "User data should get set properly");
+
+  // Test the options object.
+  var e2 = Components.Exception('foo', { result: Cr.NS_BINDING_ABORTED,
+                                         data: window,
+                                         foobar: 2 });
+  is(e2.result, Cr.NS_BINDING_ABORTED, "Result should get set properly");
+  is(e2.data.window, window, "User data should get set properly");
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug760076.xhtml b/js/xpconnect/tests/chrome/test_bug760076.xhtml
new file mode 100644
index 0000000000..9d56455024
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug760076.xhtml
@@ -0,0 +1,49 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=760076
+-->
+<window title="Mozilla Bug 760076"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=760076"
+     target="_blank">Mozilla Bug 760076</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for constructing COW-ed functions in content. **/
+
+  // This gets decompiled and run in the sandbox.
+  function sandboxCode() {
+    /* globals chromeFunction */
+    try {
+      is(chromeFunction(), 42, "Should call successfully");
+    } catch(e) { ok(false, "Shouldn't throw when calling"); }
+
+    try {
+      ok(typeof (new chromeFunction()) !== 'undefined',
+         "Should construct successfully");
+    } catch(e) { ok(false, "Shouldn't throw when constructing"); }
+  }
+
+  // Set up the sandbox.
+  var sb = new Cu.Sandbox("https://www.example.com");
+
+  // Import the functions it needs.
+  sb.ok = ok;
+  sb.is = is;
+  sb.chromeFunction = function() { ok(true, "Called chrome function"); return 42; }
+  Cu.evalInSandbox(sandboxCode.toSource(), sb);
+
+  // Do the test.
+  Cu.evalInSandbox("sandboxCode();", sb);
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug760131.html b/js/xpconnect/tests/chrome/test_bug760131.html
new file mode 100644
index 0000000000..eca4467c8d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug760131.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=760131
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 760131</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=760131">Mozilla Bug 760131</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  <iframe id="frame"></iframe>
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 760131 **/
+
+var frame = document.getElementById("frame");
+function runTest()
+{
+  var win = frame.contentWindow;
+  win.wrappedJSObject.ok = ok;
+  var doc = win.document;
+  var empty = doc.createTouchList();
+  var event = doc.createEvent("touchevent");
+  event.initTouchEvent("touchstart", true, true, win, 0, false, false, false, false, empty, empty, empty);
+  doc.getElementById("target").dispatchEvent(event);
+
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForExplicitFinish();
+SpecialPowers.pushPrefEnv(
+  {"set": [["dom.w3c_touch_events.legacy_apis.enabled", true]]},
+  function() {
+    frame.onload = runTest;
+    frame.src = "http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_bug760131.html";
+  }
+);
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_bug763343.xhtml b/js/xpconnect/tests/chrome/test_bug763343.xhtml
new file mode 100644
index 0000000000..db3acd37c0
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug763343.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=763343
+-->
+<window title="Mozilla Bug 763343"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=763343"
+     target="_blank">Mozilla Bug 763343</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for Cross-compartment nsIClassInfo singleton wrapping. **/
+  // We need an object here that has singleton classinfo.  For now, the console
+  // service works.
+  var singleton = Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIClassInfo);
+  ok(singleton.flags & Ci.nsIClassInfo.SINGLETON_CLASSINFO,
+     "Should have singleton classinfo");
+  var sb = new Cu.Sandbox(window);
+
+  // Don't crash.
+  sb.singleton = singleton;
+  ok(true, "didn't crash");
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug771429.xhtml b/js/xpconnect/tests/chrome/test_bug771429.xhtml
new file mode 100644
index 0000000000..c5846dd6ac
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug771429.xhtml
@@ -0,0 +1,66 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=771429
+-->
+<window title="Mozilla Bug 771429"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=771429"
+     target="_blank">Mozilla Bug 771429</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+      /** Test for Bug 771429 **/
+      function f() {}
+      function g() { return this; }
+      function h() { "use strict"; return this; }
+      function ctor() { this.x = 1; }
+      f.x = 2;
+      f.g = g;
+      function test(freshCompartment) {
+        var s = new Cu.Sandbox(window, {
+          sandboxPrototype: window,
+          freshCompartment,
+        });
+        try {
+          is(Cu.evalInSandbox('g()', s), window,
+             "Should get window as this object of non-strict global function");
+          is(Cu.evalInSandbox('h()', s), undefined,
+             "Should get undefined as this object of strict global function");
+          is(Cu.evalInSandbox('f.x', s), 2,
+             "Should have gotten the right thing back");
+          if (freshCompartment) {
+            is(Cu.evalInSandbox('f.g()', s), f,
+               "Should have the right function object");
+          } else {
+            // In the same-compartment case we don't go through a compartment
+            // boundary so when we call f.g() we don't unwrap the "callable
+            // proxy" around f and the test above fails. We accept this slight
+            // difference in behavior and assert a weaker invariant.
+            is(Cu.evalInSandbox('f.g()', s).toString(), f.toString(),
+               "Should have the right function object");
+          }
+          is(Cu.evalInSandbox('var x = { z: 7 }; g.call(x).z', s), 7,
+             "Should not rebind calls that are already bound");
+          // And test what happens when we use the normal Function.prototype.call
+          // on g instead of whatever our proxies happen to return.
+          is(Cu.evalInSandbox('var x = { z: 7 }; Function.prototype.call.call(g, x).z', s), 7,
+             "Should not rebind calls that are already bound");
+          is(Cu.evalInSandbox('new ctor();', s).x, 1,
+             "Should get a properly constructed object out of the sandbox");
+        } catch (e) {
+          ok(false, "Should not get an exception: " + e);
+        }
+      }
+      test(false);
+      test(true);
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug773962.xhtml b/js/xpconnect/tests/chrome/test_bug773962.xhtml
new file mode 100644
index 0000000000..2bdb43f6fc
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug773962.xhtml
@@ -0,0 +1,88 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=773962
+-->
+<window title="Mozilla Bug 773962"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=773962"
+     target="_blank">Mozilla Bug 773962</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for remapping Xray waivers during brain transplant. **/
+  SimpleTest.waitForExplicitFinish();
+
+  var gFramesLoaded = 0;
+  function frameLoaded() {
+    ++gFramesLoaded;
+    if (gFramesLoaded == 2)
+      startTest();
+    if (gFramesLoaded == 3)
+      finishTest();
+  }
+
+  var win1;
+  var win2;
+  var node1;
+  var loc1;
+  var win1Waiver;
+  var node1Waiver;
+  var loc1Waiver;
+
+  function startTest() {
+    // grab the windows and the node.
+    win1 = document.getElementById('frame1').contentWindow;
+    win2 = document.getElementById('frame2').contentWindow;
+    node1 = win1.document.getElementById('text');
+    loc1 = win1.location;
+
+    // Grab some Xray waivers.
+    win1Waiver = win1.wrappedJSObject;
+    node1Waiver = node1.wrappedJSObject;
+    loc1Waiver = win1Waiver.location;
+
+    // Adopt node1 into win2. This causes node1 to be transplanted.
+    win2.document.adoptNode(node1);
+
+    // Navigate win1. This causes win1 to be transplanted.
+    win1.location = "https://test2.example.org/tests/js/xpconnect/tests/mochitest/file_empty.html";
+
+    // The above happens async. Our onload handler will call finishTest() when we're ready.
+  }
+
+  function finishTest() {
+    // Now, recompute some wrappers.
+    Cu.recomputeWrappers();
+
+    // First, pat ourselves on the back for not asserting/crashing. That's most of
+    // what we're really testing here.
+    ok(true, "Didn't crash!");
+
+    // Now, make sure everything is set up how we expect.
+    ok(Cu.isDeadWrapper(win1Waiver), "window waiver should go away after navigation");
+    ok(node1Waiver === node1.wrappedJSObject, "waivers still work");
+    ok(Cu.unwaiveXrays(node1Waiver) === node1, "waivers still work");
+
+    // The semantics of location are tricky, because win1 now has a new location object.
+    // In fact, loc1 should be a dead object proxy. Let's make sure we get this right.
+    ok(loc1 !== win1.location, "navigation means different window.location");
+    ok(loc1Waiver !== win1.location.wrappedJSObject, "navigation means different window.location");
+
+    // Whew.
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="frame1" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+  <iframe id="frame2" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug792280.xhtml b/js/xpconnect/tests/chrome/test_bug792280.xhtml
new file mode 100644
index 0000000000..1e1a197e57
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug792280.xhtml
@@ -0,0 +1,43 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=792280
+-->
+<window title="Mozilla Bug 792280"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=792280"
+     target="_blank">Mozilla Bug 792280</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 792280 **/
+  function checkSb(sb, expect) {
+    var target = new Cu.Sandbox("https://www.example.com");
+    Cu.evalInSandbox('function fun() { return arguments.callee.caller; };', target);
+    sb.fun = target.fun;
+    let allowed = false;
+    try {
+      allowed = Cu.evalInSandbox('function doTest() { return fun() == doTest; }; doTest()', sb);
+      isnot(expect, "throw", "Should have thrown");
+    } catch (e) {
+      is(expect, "throw", "Should expect exception");
+      ok(/denied|insecure/.test(e), "Should be a security exception: " + e);
+    }
+    is(allowed, expect == "allow", "should censor appropriately");
+  }
+
+  // Note that COWs are callable, but XOWs are not.
+  checkSb(new Cu.Sandbox("https://www.example.com"), "allow");
+  checkSb(new Cu.Sandbox("https://www.example.org"), "throw");
+  checkSb(new Cu.Sandbox(window), "censor");
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug793433.xhtml b/js/xpconnect/tests/chrome/test_bug793433.xhtml
new file mode 100644
index 0000000000..eed7166efc
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug793433.xhtml
@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=793433
+-->
+<window title="Mozilla Bug 793433"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=793433"
+     target="_blank">Mozilla Bug 793433</a>
+  <p id="display"></p>
+  <div id="content" style="display: none"/>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+function shouldThrow(fun, args, msg) {
+  try {
+    fun.apply(this, args);
+    ok(false, msg);
+  } catch (e) {
+    ok(true, msg+" -- "+e);
+  }
+}
+
+function do_registerTopLevelWindow(win) {
+  Services.appShell.registerTopLevelWindow(win);
+}
+
+shouldThrow(
+  do_registerTopLevelWindow, [null],
+  "registering null as a top-level window should throw");
+
+shouldThrow(
+  do_registerTopLevelWindow, [{}],
+  "registering a void object as a top-level window should throw");
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug795275.xhtml b/js/xpconnect/tests/chrome/test_bug795275.xhtml
new file mode 100644
index 0000000000..a151a1a2b7
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug795275.xhtml
@@ -0,0 +1,80 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=795275
+-->
+<window title="Mozilla Bug 795275"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=795275"
+     target="_blank">Mozilla Bug 795275</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Warning in content scopes about Components. **/
+
+  SimpleTest.waitForExplicitFinish();
+  SimpleTest.executeSoon(function() {
+    SpecialPowers.pushPrefEnv({set: [["dom.use_components_shim", true]]},
+                              startLoad)
+  });
+  function startLoad() {
+    for (var i = 1; i <= document.getElementsByTagName('iframe').length; ++i) {
+      var frame = document.getElementById('frame' + i);
+      frame.contentWindow.location = 'http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_bug795275.html';
+      frame.onload = frameLoaded;
+    }
+  }
+
+  // Set up our console listener.
+  var gWarnings = 0;
+  function onWarning(consoleMessage) {
+    if (/soon be removed/.test(consoleMessage.message))
+      gWarnings++;
+  }
+  var gListener = {
+    observe: onWarning,
+    QueryInterface: ChromeUtils.generateQI(["nsIConsoleListener"])
+  };
+  Services.console.registerListener(gListener);
+
+  // Wait for all four child frame to load.
+  var gLoadCount = 0;
+  function frameLoaded() {
+    if (++gLoadCount == document.getElementsByTagName('iframe').length)
+      go();
+  }
+
+  function getWin(id) { return document.getElementById(id).contentWindow.wrappedJSObject; }
+  function go() {
+    getWin('frame1').touchComponents();
+    getWin('frame2').touchInterfaces();
+    getWin('frame4').touchComponents();
+    getWin('frame4').touchInterfaces();
+
+    // Warnings are dispatched async, so stick ourselves at the end of the event
+    // queue.
+    setTimeout(done, 0);
+  }
+
+  function done() {
+    Services.console.unregisterListener(gListener);
+    is(gWarnings, 3, "Got the right number of warnings");
+    SimpleTest.finish();
+  }
+
+  ]]>
+
+  </script>
+  <iframe id="frame1"/>
+  <iframe id="frame2"/>
+  <iframe id="frame3"/>
+  <iframe id="frame4"/>
+
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug799348.xhtml b/js/xpconnect/tests/chrome/test_bug799348.xhtml
new file mode 100644
index 0000000000..91de48164f
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug799348.xhtml
@@ -0,0 +1,47 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=799348
+-->
+<window title="Mozilla Bug 799348"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=799348"
+     target="_blank">Mozilla Bug 799348</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 799348 **/
+  SimpleTest.waitForExplicitFinish();
+  var gCalledOnload = false;
+  var myObserver = {
+    QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+    observe(win, topic, data) {
+      if (topic == "domwindowopened") {
+        ok(!gCalledOnload, "domwindowopened notification fired before onload");
+        win.addEventListener("load", function(evt) {
+          gCalledOnload = true;
+          win.close();
+        });
+      } else if (topic == "domwindowclosed") {
+        ok(gCalledOnload, "should have called onload");
+        Services.ww.unregisterNotification(myObserver);
+        SimpleTest.finish();
+      } else {
+        ok(false, "unknown topic");
+      }
+    }
+  };
+  Services.ww.registerNotification(myObserver);
+
+
+  ]]>
+  </script>
+  <iframe id="frame" type="content" src="http://test1.example.org/tests/js/xpconnect/tests/mochitest/file_bug799348.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug801241.xhtml b/js/xpconnect/tests/chrome/test_bug801241.xhtml
new file mode 100644
index 0000000000..5c83429afa
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug801241.xhtml
@@ -0,0 +1,48 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=801241
+-->
+<window title="Mozilla Bug 801241"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=801241"
+     target="_blank">Mozilla Bug 801241</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 801241 **/
+  SimpleTest.waitForExplicitFinish();
+
+  /* globals win */
+
+  // This is decompiled and run inside the sandbox;
+  function sbCode() {
+    try {
+      // eslint-disable-next-line no-self-assign
+      win.location = win.location;
+      ok(true, "Didn't throw setting from location");
+    } catch (e) {
+      ok(false, "Threw setting location from sandbox");
+    }
+  }
+
+  function go() {
+    document.getElementById('ifr').onload = null;
+    var sb = new Cu.Sandbox(this);
+    sb.win = document.getElementById('ifr').contentWindow;
+    sb.ok = ok;
+    Cu.evalInSandbox('(' + sbCode.toSource() + ')()', sb);
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug812415.xhtml b/js/xpconnect/tests/chrome/test_bug812415.xhtml
new file mode 100644
index 0000000000..71dc23768e
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug812415.xhtml
@@ -0,0 +1,90 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=812415
+-->
+<window title="Mozilla Bug 812415"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=812415"
+     target="_blank">Mozilla Bug 812415</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 812415 and Bug 823348 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  function testWaiving(iwin, sb) {
+    sb.win = iwin;
+    is(Cu.evalInSandbox('win', sb), iwin, "Basic identity works");
+    is(Cu.evalInSandbox('win.wrappedJSObject.expando', sb), 42, "Waivers work via .wrappedJSObject");
+    is(Cu.evalInSandbox('XPCNativeWrapper.unwrap(win).expando', sb), 42, "Waivers work via XPCNativeWrapper.unwrap");
+    is(Cu.evalInSandbox('win.wrappedJSObject.document.defaultView.expando', sb), 42, "Waivers are deep");
+  }
+
+  function checkThrows(expression, sb, msg) {
+    var result = Cu.evalInSandbox('(function() { try { ' + expression + '; return "allowed"; } catch (e) { return e.toString(); }})();', sb);
+    ok(!!/denied/.exec(result), msg);
+  }
+
+  function testAsymmetric(regular, expanded) {
+
+    // Set up objects.
+    expanded.regFun = Cu.evalInSandbox('function reg() { return 42; }; reg', regular);
+    expanded.regObj = Cu.evalInSandbox('new Object({foo: 2})', regular);
+    regular.expFun = Cu.evalInSandbox('function exp() { return 41; }; exp', expanded);
+    regular.expObj = Cu.evalInSandbox('new Object({bar: 3})', expanded);
+
+    // Check objects.
+    is(Cu.evalInSandbox('regObj.foo', expanded), 2, "Expanded can see regular object prop");
+    checkThrows('expObj.bar', regular, "Regular shouldn't read properties");
+    Cu.evalInSandbox('regObj.foo = 20', expanded);
+    is(expanded.regObj.foo, 20, "Expanded can set properties");
+    checkThrows('expFun.bar = 0', regular, "Regular shouldn't write properties");
+
+    // Check functions.
+    is(Cu.evalInSandbox('regFun()', expanded), 42, "Expanded can call regular function");
+    checkThrows('expFun()', regular, "Regular cannot call expanded function");
+    is(Cu.evalInSandbox('regFun.name', expanded), 'reg', "Expanded can see regular function's name");
+    checkThrows('expFun.name', regular, "Regular can't see expanded function's name");
+    Cu.evalInSandbox('regFun.expando = 30', expanded);
+    is(Cu.evalInSandbox('regFun.expando', expanded), 30, "Expanded can set expandos");
+    checkThrows('expFun.expando = 29', regular, "Regular can't set expandos");
+
+    // Check __proto__ stuff.
+    is(Cu.evalInSandbox('regFun.__proto__', expanded), regular.Function.prototype, "expanded can get __proto__");
+    checkThrows('expFun.__proto__', regular, "regular can't use __proto__");
+    checkThrows('expFun.__proto__ = {}', regular, "regular can't mutate __proto__");
+  }
+
+  function go() {
+    var iwin = document.getElementById('ifr').contentWindow;
+    iwin.wrappedJSObject.expando = 42;
+
+    // Make our sandboxes. We pass wantXrays=false for the nsEP to ensure that
+    // the Xrays we get are the result of being an nsEP, not from the wantXrays
+    // flag.
+    var regular = new Cu.Sandbox(iwin);
+    var expanded = new Cu.Sandbox([iwin], {wantXrays: false});
+
+    // Because of the crazy secret life of wantXrays, passing wantXrays=false
+    // has the side effect of waiving Xrays on the returned sandbox. Undo that.
+    expanded = Cu.unwaiveXrays(expanded);
+
+    testWaiving(iwin, regular);
+    testWaiving(iwin, expanded);
+    testAsymmetric(regular, expanded);
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug853283.xhtml b/js/xpconnect/tests/chrome/test_bug853283.xhtml
new file mode 100644
index 0000000000..6cdd5027b8
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug853283.xhtml
@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=853283
+-->
+<window title="Mozilla Bug 853283"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=853283"
+     target="_blank">Mozilla Bug 853283</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test nsNavigatorSH::Resolve in conjunction with Xrays.**/
+  SimpleTest.waitForExplicitFinish();
+
+  function go() {
+    // This chrome document already has Xrays to the content scope, but we use a
+    // a sandbox anyway to make sure that the global in play here isn't an
+    // nsIDOMWindow. Otherwise, the resolve hook might just end up squeaking by
+    // with the chrome window.
+    var iwin = $('ifr').contentWindow;
+    var sb = new Cu.Sandbox(window);
+    sb.iwin = iwin;
+    sb.ok = ok;
+    Cu.evalInSandbox('try {iwin.navigator.mozContacts; ok(true, "Didnt throw"); } catch (e) { ok(false, "Threw: " + e);}', sb);
+    SimpleTest.finish();
+  }
+
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug853571.xhtml b/js/xpconnect/tests/chrome/test_bug853571.xhtml
new file mode 100644
index 0000000000..2f16915666
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug853571.xhtml
@@ -0,0 +1,62 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=853571
+-->
+<window title="Mozilla Bug 853571"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=853571"
+     target="_blank">Mozilla Bug 853571</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 853571 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function* mainTest() {
+    var iwin = $('ifr').contentWindow;
+
+    // Test with a simple sandbox with no prototype.
+    checkSource(iwin, new Cu.Sandbox(iwin), null, "should get null source with no sandboxPrototype");
+    yield;
+
+    // Test with a sandboxPrototype.
+    checkSource(iwin, new Cu.Sandbox(iwin, { sandboxPrototype: iwin }), iwin, "should be able to impersonate the prototype");
+    yield;
+
+    SimpleTest.finish();
+    yield; // Prevent StopIteration from being thrown.
+  }
+
+  var gen;
+  function runTest() {
+    gen = mainTest();
+    gen.next();
+  }
+
+  function checkSource(target, sb, expectedSource, message) {
+    target.addEventListener("message", function listener(event) {
+      is(event.source, expectedSource, message);
+      let {done} = gen.next();
+      if (done) {
+        // We're done.
+      }
+    },
+    { once: true});
+
+    sb.target = target;
+    Cu.evalInSandbox("target.postMessage('foo', '*');", sb);
+  }
+
+
+  ]]>
+  </script>
+  <iframe id="ifr" type="content" onload="runTest()" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug858101.xhtml b/js/xpconnect/tests/chrome/test_bug858101.xhtml
new file mode 100644
index 0000000000..5ff9f28dc7
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug858101.xhtml
@@ -0,0 +1,55 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=858101
+-->
+<window title="Mozilla Bug 858101"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=858101"
+     target="_blank">Mozilla Bug 858101</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for [[DefaultValue]] on XrayWrappers. **/
+  SimpleTest.waitForExplicitFinish();
+
+  function muckWithToString() {
+    function tricky() { return "hah"; };
+
+    window.toString = document.toString = document.body.toString = tricky;
+    window.valueOf = document.valueOf = document.body.valueOf = tricky;
+
+    Window.prototype.toString = Window.prototype.valueOf = tricky;
+    Document.prototype.toString = Document.prototype.valueOf = tricky;
+    HTMLBodyElement.toString = HTMLBodyElement.valueOf = tricky;
+  }
+
+  function go() {
+    var iwin = $('ifr').contentWindow;
+    iwin.wrappedJSObject.eval('(' + muckWithToString.toSource() + ')()');
+
+    // Check behavior with vanilla CCWs.
+    ok(!!/hah/.exec(iwin.wrappedJSObject + ""), "Waivers should get content-defined window stringification");
+    ok(!!/hah/.exec(iwin.document.wrappedJSObject + ""), "Waivers should get content-defined document stringification");
+    ok(!!/hah/.exec(iwin.document.body.wrappedJSObject + ""), "Waivers should get content-defined body stringification");
+
+    // Check Xray behavior.
+    ok(!/hah/.exec(iwin + ""), "Xrays should not get content-defined window stringification");
+    ok(!/hah/.exec(iwin.document + ""), "Xrays should not get content-defined document stringification");
+    ok(!/hah/.exec(iwin.document.body + ""), "Xrays should not get content-defined body stringification");
+
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug860494.xhtml b/js/xpconnect/tests/chrome/test_bug860494.xhtml
new file mode 100644
index 0000000000..26bd1e13bd
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug860494.xhtml
@@ -0,0 +1,57 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=860494
+-->
+<window title="Mozilla Bug 860494"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=860494"
+     target="_blank">Mozilla Bug 860494</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 860494 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  function go() {
+    var iwin = $('ifr').contentWindow;
+    // NB: mochitest-chrome actually runs the test as a content docshell.
+    is(iwin.top, window.top, "iframe names shouldn't shadow |top| via Xray");
+    is(iwin.parent, window, "iframe names shouldn't shadow |parent| via Xray");
+    ok(!!/http/.exec(iwin.location), "iframe names shouldn't shadow |location| via Xray");
+    is(iwin.length, 7, "iframe names shouldn't shadow |length| via Xray");
+    is(iwin.window, iwin, "iframe names shouldn't shadow |window| via Xray");
+    is(iwin.navigator, Cu.unwaiveXrays(iwin.wrappedJSObject.navigator),
+       "iframe names shouldn't shadow |navigator| via Xray");
+    ok(iwin.alert instanceof Function,
+       "iframe names shouldn't shadow |alert| via Xray");
+
+    // Now test XOWs.
+    var sb = new Cu.Sandbox("https://www.example.com");
+    sb.win = iwin;
+    sb.topWin = top;
+    sb.parentWin = window;
+    sb.is = is;
+    sb.ok = ok;
+    Cu.evalInSandbox('ok(win.top === topWin, "iframe names shouldnt shadow |top| via cross-origin Xray");', sb);
+    Cu.evalInSandbox('ok(win.parent === parentWin, "iframe names shouldnt shadow |parent| via cross-origin Xray");', sb);
+    Cu.evalInSandbox('is(win.length, 7, "iframe names shouldnt shadow |length| via cross-origin Xray");', sb);
+    Cu.evalInSandbox('ok(win.window === win, "iframe names shouldnt shadow |window| via cross-origin Xray");', sb);
+    Cu.evalInSandbox('ok(win.navigator === win[5], "iframe names that correspond to non-cross-origin-visible properties should expose the subframe: navigator");', sb);
+    Cu.evalInSandbox('ok(win.alert === win[6], "iframe names that correspond to non-cross-origin-visible properties should expose the subframe: alert");', sb);
+
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" type="content" onload="go();" src="https://example.org/tests/js/xpconnect/tests/mochitest/file_bug860494.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug865948.xhtml b/js/xpconnect/tests/chrome/test_bug865948.xhtml
new file mode 100644
index 0000000000..85fb86874d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug865948.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=865948
+-->
+<window title="Mozilla Bug 865948"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=865948"
+     target="_blank">Mozilla Bug 865948</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for Bug 865948 **/
+  SimpleTest.waitForExplicitFinish();
+  function go() {
+    $('ifr').onload = null;
+    var sb = Cu.Sandbox(["https://example.com", "https://example.org"]);
+    sb.iwin = $('ifr').contentWindow;
+    sb.ok = ok;
+    Cu.evalInSandbox('try { iwin.location = "about:mozilla"; ok(false, "didnt throw"); } catch (e) { ok(!!/denied/.exec(e), "threw: " + e); }', sb);
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+<iframe id="ifr" type="content" onload="go();" src="https://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug866823.xhtml b/js/xpconnect/tests/chrome/test_bug866823.xhtml
new file mode 100644
index 0000000000..39a24fc14e
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug866823.xhtml
@@ -0,0 +1,49 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=866823
+-->
+<window title="Mozilla Bug 866823"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=866823"
+     target="_blank">Mozilla Bug 866823</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 866823 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function go() {
+    var iwin = $('ifr').contentWindow;
+
+    // Make sure that Xray waivers can't be transitively extended onto objects
+    // for whom the extender may not waive.
+    var sb = new Cu.Sandbox(iwin, { wantXrays: true });
+    sb.iwin = iwin;
+    ok(Cu.evalInSandbox('iwin.wrappedJSObject.top == iwin.top', sb), "Waiver does not propagate");
+    Cu.evalInSandbox('iwin.wrappedJSObject.waiver = iwin.wrappedJSObject', sb);
+    ok(iwin.wrappedJSObject.eval('waiver == window'), "Waivers disappear same-compartment");
+
+    // Make sure that standard prototypes don't get COWs.
+    sb.objProto = Object.prototype;
+    try {
+      sb.eval('objProto.toString;', sb);
+      ok(false, "Should have thrown");
+    } catch (e) {
+      ok(/denied|insecure/, "No silent failure when accessing properties on forbidden prototype");
+    }
+
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug895340.xhtml b/js/xpconnect/tests/chrome/test_bug895340.xhtml
new file mode 100644
index 0000000000..ded70e6dd4
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug895340.xhtml
@@ -0,0 +1,50 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=895340
+-->
+<window title="Mozilla Bug 895340"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=895340 "
+     target="_blank">Mozilla Bug 895340 </a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  SimpleTest.waitForExplicitFinish();
+  SimpleTest.expectUncaughtException();
+
+  var finished = false;
+
+  let listener = {
+    QueryInterface: ChromeUtils.generateQI(["nsIConsoleListener"])
+  };
+
+  listener.observe = function(aMessage) {
+    if (aMessage.message.includes("Will you report me?") && !finished) {
+      finished = true;
+      ok(true, "exception reported");
+      Services.console.unregisterListener(listener);
+      SimpleTest.finish();
+    }
+  };
+
+  Services.console.registerListener(listener);
+
+  /* Throw an exception and verify that it gets reported. */
+  let foo_obs = function() {
+    throw new Error("Will you report me?");
+  };
+
+  Services.obs.addObserver(foo_obs, "foo");
+  Services.obs.notifyObservers(null, "foo", "foo");
+  Services.obs.removeObserver(foo_obs, "foo");
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug932906.xhtml b/js/xpconnect/tests/chrome/test_bug932906.xhtml
new file mode 100644
index 0000000000..f7e839d980
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug932906.xhtml
@@ -0,0 +1,69 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=932906
+-->
+<window title="Mozilla Bug 932906"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=932906"
+     target="_blank">Mozilla Bug 932906</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 932906 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function passToContent(shouldThrow) {
+    try {
+      $('ifr').contentWindow.obs = Services.obs;
+      ok(!shouldThrow, "Didn't throw when passing non-DOM XPCWN to content");
+    } catch (e) {
+      ok(shouldThrow, "Threw when passing non-DOM XPCWN to content");
+      ok(/denied/.test(e), "Threw correct exception: " + e);
+    }
+  }
+
+  var gLoadCount = 0;
+  function loaded() {
+    ++gLoadCount;
+    if (gLoadCount == 1)
+      part1();
+    else if (gLoadCount == 2)
+      part2();
+    else
+      ok(false, "Didn't expect three loads");
+  }
+
+  function part1() {
+
+    // Make sure that the pref is what we expect for mochitests.
+    is(Services.prefs.getBoolPref('dom.use_xbl_scopes_for_remote_xul'), true,
+       "Test harness set up like we expect");
+
+
+    // First, test that we can't normally pass non-DOM XPCWNs to content.
+    passToContent(/* shouldThrow = */ true);
+
+    // Now, make sure we _can_ for the remote xul case. We use SpecialPowers
+    // for the pref munging because it cleans up after us.
+    SpecialPowers.pushPrefEnv({set: [['dom.use_xbl_scopes_for_remote_xul', false]]}, function() {
+      $('ifr').contentWindow.location.reload();
+    });
+  }
+
+  function part2() {
+      passToContent(/* shouldThrow = */ false);
+      SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="loaded();" type="content" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_bug996069.xhtml b/js/xpconnect/tests/chrome/test_bug996069.xhtml
new file mode 100644
index 0000000000..5693fd3447
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_bug996069.xhtml
@@ -0,0 +1,52 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=996069
+-->
+<window title="Mozilla Bug 996069"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=996069"
+     target="_blank">Mozilla Bug 996069</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 996069 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function loaded() {
+    var ifr = document.getElementById("ifr").contentWindow;
+    var sb = new Cu.Sandbox([ifr],
+                            { sandboxPrototype: ifr });
+
+    ifr.wrappedJSObject.finishTest = function() {
+      // If we got here we did not hit the NS_ReleaseAssert...
+      ok(true, "ExpandedPrincipal should not be inherited by content windows");
+
+      // But let's be sure that the new window does not have nsEP
+      newWin.wrappedJSObject.obj = Cu.evalInSandbox("var obj = { foo: 'bar' }; obj", sb);
+      try {
+        newWin.eval("obj.foo");
+        ok(false, "newWin should not have access to object from a scope with ExpandedPrincipal");
+      } catch (e) {
+        ok(/Permission denied/.exec(e.message), "newWin should not have access to object from a scope with ExpandedPrincipal");
+      }
+      newWin.close();
+      SimpleTest.finish();
+    };
+
+    var newWin = Cu.evalInSandbox(
+      "window.open('https://example.org/chrome/js/xpconnect/tests/chrome/file_bug996069.html');",
+      sb);
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="loaded();" type="content" src="https://example.org/chrome/js/xpconnect/tests/chrome/file_bug996069.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_chrometoSource.xhtml b/js/xpconnect/tests/chrome/test_chrometoSource.xhtml
new file mode 100644
index 0000000000..b9920603a0
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_chrometoSource.xhtml
@@ -0,0 +1,68 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Mozilla Bug 761723"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=761723" target="_blank">Mozilla Bug 761723</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript" src="outoflinexulscript.js"></script>
+  <script type="application/javascript"><![CDATA[
+const {NetUtil} = ChromeUtils.import("resource://gre/modules/NetUtil.jsm");
+let base = /.*\//.exec(window.location.href)[0];
+const {checkFromJSM} = ChromeUtils.import(base + "file_expandosharing.jsm");
+
+function inlinefunction() {
+         return 42;
+}
+
+var src;
+src = inlinefunction.toSource();
+isnot(src.indexOf("return 42"), -1, "inline XUL script should have source");
+is(src.charAt(src.length - 1), "}", "inline XUL source should end with '}'");
+src = outoflinefunction.toSource();
+isnot(src.indexOf("return 42"), -1, "out of line XUL script should have source")
+is(src.charAt(src.length - 1), "}", "out of line XUL source should end with '}'");
+src = checkFromJSM.toSource();
+isnot(src.indexOf("catch"), -1, "JSM should have source");
+var ns = {};
+Services.scriptloader.loadSubScript(base + "file_expandosharing.jsm", ns);
+src = ns.checkFromJSM.toSource();
+isnot(src.indexOf("catch"), -1, "subscript should have source");
+
+var reg = Cc["@mozilla.org/chrome/chrome-registry;1"].getService(Ci.nsIChromeRegistry);
+var resolvedBase = reg.convertChromeURL(NetUtil.newURI(base)).spec;
+
+ns = {
+  base,
+};
+Services.scriptloader.loadSubScript(resolvedBase + "subscript.js", ns);
+src = ns.checkFromJSM.toSource();
+isnot(src.indexOf("catch"), -1, "subscript of a subscript should have source");
+
+ns = {};
+Services.scriptloader.loadSubScript(resolvedBase + "utf8_subscript.js", ns);
+src = ns.f.toSource();
+isnot(src.indexOf("return 42;"), -1, "encoded subscript should have correct source");
+
+ns = {};
+Services.scriptloader.loadSubScriptWithOptions(resolvedBase + "utf8_subscript.js",
+                                               {target: ns, ignoreCache: true});
+src = ns.f.toSource();
+isnot(src.indexOf("return 42;"), -1, "encoded subscript should have correct source");
+
+ns = {};
+let b = new Blob([
+  "var Exported = 17;"
+]);
+var blobUrl = URL.createObjectURL(b);
+Services.scriptloader.loadSubScript(blobUrl, ns);
+is(ns.Exported, 17, "subscript from a blob URL should work");
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_cloneInto.xhtml b/js/xpconnect/tests/chrome/test_cloneInto.xhtml
new file mode 100644
index 0000000000..aa874bda96
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_cloneInto.xhtml
@@ -0,0 +1,194 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<window title="Mozilla Bug 503926"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=964293"
+     target="_blank">Cu.cloneInto()</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  const TypedArrayThings = [
+    'Int8Array',
+    'Uint8Array',
+    'Uint8ClampedArray',
+    'Int16Array',
+    'Uint16Array',
+    'Int32Array',
+    'Uint32Array',
+    'Float32Array',
+    'Float64Array',
+  ];
+
+  function checkThrows(f, msg, rgxp) {
+    try {
+      f();
+      ok(false, "Should have thrown: " + msg);
+    } catch (e) {
+      ok(true, "Threw correctly - " + msg + " - " + e);
+      if (rgxp)
+        ok(rgxp.test(e), "Should throw correct exception: " + e);
+    }
+  }
+
+  function getType(a) {
+    if (a === null || a === undefined)
+      return 'null';
+
+    if (Array.isArray(a))
+      return 'array';
+
+    if (File.isInstance(a))
+      return 'file';
+
+    if (Blob.isInstance(a))
+      return 'blob';
+
+    if (TypedArrayThings.includes(a.constructor.name))
+      return a.constructor.name;
+
+    if (typeof a == 'object')
+      return 'object';
+
+    if (typeof a == 'function')
+      return 'function';
+
+    return 'primitive';
+  }
+
+  function compare(a, b) {
+    is (getType(a), getType(b), 'Type matches');
+
+    var type = getType(a);
+    if (type == 'array') {
+      is (a.length, b.length, 'Array.length matches');
+      for (var i = 0; i < a.length; ++i) {
+        compare(a[i], b[i]);
+      }
+
+      return;
+    }
+
+    if (type == 'file' || type == 'blob') {
+      ok ( a === b, 'They should match');
+      return;
+    }
+
+    if (type == 'object') {
+      ok ( a !== b, 'They should not match');
+
+      var aProps = [];
+      for (let p in a) aProps.push(p);
+
+      var bProps = [];
+      for (let p in b) bProps.push(p);
+
+      is (aProps.length, bProps.length, 'Props match');
+      is (aProps.sort().toString(), bProps.sort().toString(), 'Props names match');
+
+      for (let p in a) {
+        compare(a[p], b[p]);
+      }
+
+      return;
+    }
+
+    if (type == 'function') {
+      ok ( a !== b, 'They should not match');
+      return;
+    }
+
+    if (type != 'null') {
+      is (a, b, 'Same value');
+    }
+  }
+
+  var sandboxOptions = {
+    wantXrays: true,
+    wantExportHelpers: true,
+  };
+  var sandbox = new Cu.Sandbox(window, sandboxOptions);
+  // The second sandbox is for testing the exportHelper version of the cloneInto
+  var sandbox2 = new Cu.Sandbox("https://example.com", sandboxOptions);
+  sandbox.sandbox2 = sandbox2;
+  sandbox2.sandbox = sandbox;
+
+  function cloneAndTest(test) {
+    var output = sandbox.test = Cu.cloneInto(test, sandbox);
+    compare(test, output);
+
+    output = Cu.evalInSandbox('cloneInto(test, sandbox2)', sandbox);
+    compare(test, output);
+  }
+
+  function cloneAndTestWithFunctions(test) {
+    var output = sandbox.test = Cu.cloneInto(test, sandbox, { cloneFunctions: true });
+    compare(test, output);
+
+    output = Cu.evalInSandbox('cloneInto(test, sandbox2, { cloneFunctions: true })', sandbox);
+    // Note - We need to waive here, because functions are filtered out by object Xrays.
+    compare(test, Cu.waiveXrays(output));
+  }
+
+  var tests = [
+    1,
+    null,
+    true,
+    'hello world',
+    [1, 2, 3],
+    { a: 1, b: 2 },
+    new Date(),
+    { a: 1, b: {}, c: [1, 2, 3, {} ], e: 'hello world' },
+  ];
+
+  for (var i = 0; i < tests.length; ++i) {
+    cloneAndTest(tests[i]);
+  }
+
+  checkThrows(function() { Cu.cloneInto({ a() {} }, sandbox); },
+              'Function should not be cloned by default');
+
+  checkThrows(function() { Cu.cloneInto({ a: document }, sandbox); },
+              'Reflectors should not be wrapped by default');
+
+  var withReflectors = Cu.cloneInto({ doc: document, win: window }, sandbox,
+                                    { wrapReflectors: true });
+  is(Cu.unwaiveXrays(Cu.waiveXrays(withReflectors).doc), document, "Document passes");
+  is(Cu.unwaiveXrays(Cu.waiveXrays(withReflectors).win), window, "Window passes");
+
+
+  checkThrows(function() { Cu.evalInSandbox('cloneInto({}, sandbox)', sandbox2); },
+              'CloneInto should only work on less privileged target scopes.',
+              /denied|insecure/);
+
+  var cloneTarget = new Cu.Sandbox("https://example.com");
+  var sameOriginSB = new Cu.Sandbox("https://example.com", { wantGlobalProperties: ['XMLHttpRequest'] });
+  var crossOriginSB = new Cu.Sandbox("https://example.net", { wantGlobalProperties: ['XMLHttpRequest'] });
+  sandbox2.cloneTarget = cloneTarget;
+  sandbox2.soXHR = Cu.evalInSandbox('new XMLHttpRequest()', sameOriginSB);
+  sandbox2.xoXHR = Cu.evalInSandbox('new XMLHttpRequest()', crossOriginSB);
+  sandbox2.chromeDoc = document;
+  Cu.evalInSandbox('function tryToClone(x) { return cloneInto({val: x}, cloneTarget, { wrapReflectors: true }).val; }', sandbox2);
+  is(Cu.evalInSandbox('tryToClone(soXHR)', sandbox2), sandbox2.soXHR, 'Same-origin wrapReflectors works');
+  checkThrows(function() { Cu.evalInSandbox('tryToClone(chromeDoc)', sandbox2); },
+              'wrapReflectors may not wrap cross-origin reflectors', /unsupported value type/);
+
+
+  var test = { a() { return 42; } };
+  cloneAndTestWithFunctions(test);
+
+  // Check that inputs are properly passed through cloned functions:
+  test = { a(obj) { return obj; } };
+  var clonedTest = Cu.cloneInto(test, sandbox, {cloneFunctions: true});
+  var testInput = {};
+  is(clonedTest.a(testInput), testInput, "Objects should be identical");
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_cows.xhtml b/js/xpconnect/tests/chrome/test_cows.xhtml
new file mode 100644
index 0000000000..69d7d3e9e6
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_cows.xhtml
@@ -0,0 +1,207 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500931
+-->
+<window title="Mozilla Bug 522764"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=522764 "
+     target="_blank">Mozilla Bug 522764 </a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+add_task(async () => {
+var sandbox = new Cu.Sandbox("about:blank");
+
+await SpecialPowers.pushPrefEnv({"set": [["security.allow_eval_with_system_principal",
+                                          true]]});
+
+/* eslint-disable no-eval */
+
+function getCOW(x) {
+  if (typeof x != 'object' && typeof x != 'function')
+    return x;
+  x = Cu.waiveXrays(x);
+  var rval = {};
+  if (typeof x == "function")
+    rval = eval(`(${x.toString()})`);
+  for (var i in x) {
+    if (x.__lookupGetter__(i))
+      rval.__defineGetter__(i, eval(`(${x.__lookupGetter__(i).toString()})`))
+    else
+      rval[i] = getCOW(x[i]);
+  }
+  return rval;
+}
+
+// Give the sandbox a way to create ChromeObjectWrapped objects.
+sandbox.getCOW = getCOW;
+
+// Define test API functions in the sandbox.
+const TEST_API = ['is', 'isnot', 'ok', 'todo_is', 'todo_isnot', 'todo'];
+TEST_API.forEach(function(name) { sandbox[name] = window[name]; });
+
+sandbox.chromeGet = function (obj, prop) { return obj[prop]; };
+
+function COWTests() {
+    function getNames(cow) {
+        let names = [];
+        for (let name in cow) {
+            names.push(name);
+        }
+        return names;
+    }
+
+    // This function is actually stringified and run inside a
+    // sandbox with content privileges.
+
+    // TODO: This could use some refactoring; creating helper
+    // functions like assertIsWritable(myObj, 'someproperty') might
+    // be useful.
+
+    function isPropHidden(obj, propName, desc) {
+      try {
+          is(obj[propName], undefined,
+             "getting " + propName + " on " + desc + " should return undefined");
+          ok(!(propName in obj),
+             propName + " on " + desc + " should act as if it doesn't exist");
+          ok(!Object.hasOwnProperty.call(obj, propName),
+             propName + " on " + desc + " should act as if it doesn't exist");
+      } catch (e) {
+          ok(false, "getting " + propName + " on " + desc + " threw " + e);
+      }
+    }
+
+    const PROPS_TO_TEST = ['foo', 'bar', 'prototype'];
+
+    var empty = {};
+    var nonempty = {foo: 42, bar: 33};
+    is(getCOW(empty).foo, undefined,
+       "shouldn't throw when accessing exposed properties that don't exist");
+
+    PROPS_TO_TEST.forEach(function(name) {
+        isPropHidden(getCOW(nonempty), name, "object without exposedProps");
+    });
+
+    // Test function objects.
+    var func = function(x) { return 42; };
+    func.foo = "foo property";
+    var funcCOW = getCOW(func);
+    try {
+      funcCOW.foo;
+      ok(false, 'Functions are no longer COWable');
+    } catch (e) {
+      ok(/denied|insecure/.test(e), 'Functions are no longer COWable');
+    }
+    is(funcCOW(), 42, "Chrome functions should be callable");
+
+    // Test writable property
+    var writable = getCOW({});
+    try {
+        ok(!("foo" in writable),
+           "non-existing write-only property shouldn't exist");
+        writable.foo = 5;
+        ok(false, "writing to a write-only exposed prop should throw");
+    } catch (e) {
+        ok(/Permission denied/.test(e),
+           "writing to a write-only exposed prop should throw the right error");
+    }
+    is(writable.foo, undefined,
+       "reading from a write-only exposed prop should return undefined");
+    try {
+        delete writable.foo;
+        ok(false, "deleting a write-only exposed prop should throw");
+    } catch (e) {
+        ok(true, "deleting a write-only exposed prop should throw " + e);
+    }
+
+    // Test readable property
+    var readable = { foo: 5,
+                     bar: 6 };
+    try {
+        isPropHidden(getCOW(readable), "foo", undefined,
+                     "reading from a readable exposed prop shouldn't work");
+    } catch (e) {
+        ok(false, "reading from a readable exposed prop shouldn't throw " + e);
+    }
+    try {
+        getCOW(readable).foo = 1;
+        ok(false, "writing to a read-only exposed prop should fail");
+    } catch (e) {
+        ok(/Permission denied/.test(e),
+           "writing to a read-only exposed prop should fail");
+    }
+    try {
+        delete getCOW(readable).foo;
+        ok(false, "deleting a read-only exposed prop shouldn't work");
+    } catch (e) {
+        ok(/Permission denied/.test(e),
+           "deleting a read-only exposed prop should throw error");
+    }
+
+    try {
+        var props = getNames(getCOW(readable));
+        is(props.length, 0, "COW w/ one exposed prop should not enumerate");
+    } catch (e) {
+        ok(false, "COW w/ a readable prop should not raise exc " +
+                  "on enumeration: " + e);
+    }
+
+    // Test read/write property
+    var readwrite = getCOW({});
+    try {
+        ok(!("foo" in readwrite),
+           "non-existing readwrite property shouldn't exist");
+        readwrite.foo = 5;
+        ok(false, "writing to a readwrite exposed prop should throw");
+    } catch (e) {
+        ok(/Permission denied/.test(e),
+           "writing to a readwrite exposed prop should throw the right error");
+    }
+    try {
+        delete readwrite.foo;
+        ok(false, "deleting a readwrite prop should throw");
+    } catch (e) {
+        ok(/Permission denied/.test(e),
+           "deleting a readwrite exposed prop should throw the right error");
+    }
+
+    // Readables and functions
+    try {
+        var COWFunc = getCOW((function() { return 5; }));
+        is(COWFunc(), 5, "COWed functions should be callable");
+    } catch (e) {
+        todo(false, "COWed functions should not raise " + e);
+    }
+}
+
+// Stringify the COW test suite and directly evaluate it in the sandbox.
+Cu.evalInSandbox('(' + COWTests.toString() + ')()', sandbox);
+
+// Test that COWed objects passing from content to chrome get unwrapped.
+function returnCOW() {
+    return getCOW({bar: 6});
+}
+
+var unwrapped = Cu.evalInSandbox(
+    '(' + returnCOW.toString() + ')()',
+    sandbox
+);
+
+try {
+    is(unwrapped.bar, 6,
+       "COWs should be unwrapped when entering chrome space");
+} catch (e) {
+    todo(false, "COWs should be unwrapped when entering chrome space, " +
+                "not raise " + e);
+}
+});
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_discardSystemSource.xhtml b/js/xpconnect/tests/chrome/test_discardSystemSource.xhtml
new file mode 100644
index 0000000000..86a353e580
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_discardSystemSource.xhtml
@@ -0,0 +1,81 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=990353
+-->
+<window title="Mozilla Bug 990353"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=990353"
+     target="_blank">Mozilla Bug 990353</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 990353 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function canary() {
+    // eslint-disable-next-line no-unused-vars
+    var someBitOfSource = 42;
+  }
+
+  var gLoadCount = 0;
+  function frameLoaded() {
+    switch (++gLoadCount) {
+      case 1:
+        ok(/native code/.test(window[0].canary.toString()), "System function should be sourceless: " + window[0].canary.toString());
+        ok(/native code/.test(window[0].onload.toString()), "System event handler should be sourceless: " + window[0].onload.toString());
+        var sb = new Cu.Sandbox("https://www.example.com", { discardSource: true });
+        Cu.evalInSandbox('function canary() { var someBitOfSource = 42; }', sb);
+        ok(/native code/.test(sb.canary.toString()), "Function from sandbox with explicit discarding should be sourceless");
+        try {
+          window[0].throwSomething();
+          ok(false, "should have thrown");
+        } catch (e) {
+          ok(/some error/.test(e), "Threw exception as expected: " + e);
+          ok(/throwSomething/.test(e.stack), "Exception stack trace works: " + e.stack);
+        }
+        window[0].location = "https://example.org/tests/js/xpconnect/tests/chrome/file_discardSystemSource.html";
+        break;
+      case 2:
+        ok(/someBitOfSource/.test(Cu.waiveXrays(window[0]).canary.toString()), "Content function should have source");
+        ok(/someBitOfSource/.test(Cu.waiveXrays(window[0]).onload.toString()), "Content event handler should have source");
+        testWorker();
+        break;
+    }
+  }
+
+  function testWorker() {
+    var worker = new window[0].wrappedJSObject.Worker('worker_discardSystemSource.js');
+    worker.onmessage = function(evt) {
+      ok(/someBitOfSource/.test(evt.data), "Non-chrome worker should have source: " + evt.data);
+      var chromeWorker = new Worker('worker_discardSystemSource.js');
+      chromeWorker.onmessage = function(evt) {
+        ok(/native code/.test(evt.data), "Chrome worker should not have source: " + evt.data);
+        SimpleTest.finish();
+      }
+    }
+  }
+
+  function go() {
+    // We should have our own source, because the pref wasn't enabled when we
+    // were loaded.
+    ok(/someBitOfSource/.test(canary.toString()), "Should have own source");
+
+    window[0].frameElement.onload = frameLoaded;
+    window[0].location = "file_discardSystemSource.html";
+  }
+  addLoadEvent(function() {
+    SpecialPowers.pushPrefEnv({set: [['javascript.options.discardSystemSource', true]]}, go);
+  });
+
+  ]]>
+  </script>
+  <iframe></iframe>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_documentdomain.xhtml b/js/xpconnect/tests/chrome/test_documentdomain.xhtml
new file mode 100644
index 0000000000..8cffdc8e46
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_documentdomain.xhtml
@@ -0,0 +1,100 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=601277
+-->
+<window title="Mozilla Bug 601277"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=601277"
+     target="_blank">Mozilla Bug 601277</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Tests for document.domain. **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  // Wait for the frames to load.
+  var gFramesLoaded = 0;
+  function frameLoaded() {
+    gFramesLoaded++;
+    if (gFramesLoaded == document.getElementsByTagName('iframe').length)
+      startTest();
+  }
+
+  function startTest() {
+
+    // Grab all the content windows and waive Xray. Xray waivers only apply to
+    // chrome, so we can pass these references directly to content.
+    var win1A = document.getElementById('test1A').contentWindow.wrappedJSObject;
+    var win1B = document.getElementById('test1B').contentWindow.wrappedJSObject;
+    var win2 = document.getElementById('test2').contentWindow.wrappedJSObject;
+    var winBase = document.getElementById('base').contentWindow.wrappedJSObject;
+
+    // Check the basics.
+    ok(win1A.tryToAccess(win1B),
+       "Same-origin windows should grant access");
+    ok(!win1A.tryToAccess(win2),
+       "Cross-origin windows should not grant access");
+    ok(!win1A.tryToAccess(winBase),
+       "Subdomain windows should not receive access");
+
+    // Store references now, while test1A and test1B are same-origin.
+    win1A.storeReference(win1B);
+    win1B.storeReference(win1A);
+    ok(win1A.tryToAccessStored(), "Stored references work when same-origin");
+    win1A.evalFromB = Cu.unwaiveXrays(win1B.eval); // Crashtest for bug 1040181.
+    win1B.functionFromA = Cu.unwaiveXrays(win1A.Function); // Crashtest for bug 1040181.
+    ok(!win1A.invokingFunctionThrowsSecurityException('evalFromB'), "Should allow before document.domain");
+    ok(!win1B.invokingFunctionThrowsSecurityException('functionFromA'), "Should allow before document.domain");
+
+    // Set document.domain on test1A. This should grant no access, since nobody
+    // else set it.
+    win1A.setDomain('example.org');
+    ok(!win1A.tryToAccess(winBase), "base must collaborate too");
+    ok(!winBase.tryToAccess(win1A), "base must collaborate too");
+    ok(!win1A.tryToAccess(win1B), "No longer same-origin");
+    ok(win1A.tryToAccessStored(), "We don't revoke access except through Window and Location");
+    ok(!win1B.tryToAccess(win1A), "No longer same-origin");
+    ok(win1B.tryToAccessStored(), "We don't revoke access except through Window and Location");
+    ok(!win1A.invokingFunctionThrowsSecurityException('evalFromB'), "We don't revoke access except through Window and Location");
+    ok(!win1B.invokingFunctionThrowsSecurityException('functionFromA'), "We don't revoke access except through Window and Location");
+
+    // Set document.domain on test1B. Now we're cooking with gas.
+    win1B.setDomain('example.org');
+    ok(!win1B.tryToAccess(winBase), "base must collaborate too");
+    ok(!winBase.tryToAccess(win1B), "base must collaborate too");
+    ok(win1A.tryToAccess(win1B), "same-origin");
+    ok(win1A.tryToAccessStored(), "same-origin");
+    ok(win1B.tryToAccess(win1A), "same-origin");
+    ok(win1B.tryToAccessStored(), "same-origin");
+
+    // Explicitly collaborate with base.
+    winBase.setDomain('example.org');
+    ok(winBase.tryToAccess(win1A), "base collaborates");
+    ok(win1A.tryToAccess(winBase), "base collaborates");
+
+    // All done.
+    SimpleTest.finish();
+  }
+
+
+  ]]>
+  </script>
+
+  <iframe id="test1A" onload="frameLoaded();" type="content"
+          src="http://test1.example.org/tests/js/xpconnect/tests/mochitest/file_documentdomain.html" />
+  <iframe id="test1B" onload="frameLoaded();" type="content"
+          src="http://test1.example.org/tests/js/xpconnect/tests/mochitest/file_documentdomain.html" />
+  <iframe id="test2" onload="frameLoaded();" type="content"
+          src="http://test2.example.org/tests/js/xpconnect/tests/mochitest/file_documentdomain.html" />
+  <iframe id="base" onload="frameLoaded();" type="content"
+          src="http://example.org/tests/js/xpconnect/tests/mochitest/file_documentdomain.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_doublewrappedcompartments.xhtml b/js/xpconnect/tests/chrome/test_doublewrappedcompartments.xhtml
new file mode 100644
index 0000000000..dd8ddd1bef
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_doublewrappedcompartments.xhtml
@@ -0,0 +1,41 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  <iframe type="content"
+          src="http://example.org/tests/js/xpconnect/tests/mochitest/file_doublewrappedcompartments.html"
+          onload="go()"
+          id="ifr">
+  </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      const utils = SpecialPowers.DOMWindowUtils;
+
+      function go() {
+        var wrappedWin = $('ifr').contentWindow;
+        is(typeof wrappedWin.expando, 'undefined', "Shouldn't be able to see the expando");
+
+        var unwrapped = wrappedWin.wrappedJSObject;
+
+        var expando = unwrapped.expando;
+        isnot(expando, 'undefined', 'properly wrapped');
+        is(typeof expando.querySelector, 'function', 'double wrapped');
+
+        SimpleTest.finish();
+      }
+
+      SimpleTest.waitForExplicitFinish();
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_envChain_event_handler.html b/js/xpconnect/tests/chrome/test_envChain_event_handler.html
new file mode 100644
index 0000000000..f492e11512
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_envChain_event_handler.html
@@ -0,0 +1,137 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1782450
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1782450</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+
+// Verify the environment chain for DOM event handlers described in
+// js/src/vm/EnvironmentObject.h.
+
+let count = 0;
+function check(envs, hasEval) {
+  is(envs.length, hasEval ? 8 : 6);
+
+  let i = 0, env;
+
+  if (hasEval) {
+    env = envs[i]; i++;
+    is(env.type, "BlockLexicalEnvironmentObject");
+    is(env.qualified, false);
+    is(env.unqualified, false);
+    is(env.lexical, true, "lexical must live in the function lexical env");
+    is(env.prop, false);
+    is(env.form_prop, false);
+    is(env.document_prop, false);
+    is(env.button_prop, false);
+
+    env = envs[i]; i++;
+    is(env.type, "CallObject");
+    is(env.qualified, true, "qualified var live in the function call object");
+    is(env.unqualified, false);
+    is(env.lexical, false);
+    is(env.prop, false);
+    is(env.form_prop, false);
+    is(env.document_prop, false);
+    is(env.button_prop, false);
+  } else {
+    // qualified var and lexical live in function's frame.
+  }
+
+  env = envs[i]; i++;
+  is(env.type, "NonSyntacticLexicalEnvironmentObject");
+  is(env.qualified, false);
+  is(env.unqualified, false);
+  is(env.lexical, false);
+  is(env.prop, false);
+  is(env.form_prop, false);
+  is(env.document_prop, false);
+  is(env.button_prop, false);
+
+  env = envs[i]; i++;
+  is(env.type, "WithEnvironmentObject");
+  is(env.qualified, false);
+  is(env.unqualified, false);
+  is(env.lexical, false);
+  is(env.prop, true, "this property must live in the with env for button");
+  is(env.form_prop, false);
+  is(env.document_prop, false);
+  is(env.button_prop, true, "button property must live in the with env for button");
+
+  env = envs[i]; i++;
+  is(env.type, "WithEnvironmentObject");
+  is(env.qualified, false);
+  is(env.unqualified, false);
+  is(env.lexical, false);
+  is(env.prop, false);
+  is(env.form_prop, true, "form property must live in the with env for form");
+  is(env.document_prop, false);
+  is(env.button_prop, false);
+
+  env = envs[i]; i++;
+  is(env.type, "WithEnvironmentObject");
+  is(env.qualified, false);
+  is(env.unqualified, false);
+  is(env.lexical, false);
+  is(env.prop, false);
+  is(env.form_prop, false);
+  is(env.document_prop, true, "document property must live in the with env for document");
+  is(env.button_prop, false);
+
+  env = envs[i]; i++;
+  is(env.type, "GlobalLexicalEnvironmentObject");
+  is(env.qualified, false);
+  is(env.unqualified, false);
+  is(env.lexical, false);
+  is(env.prop, false);
+  is(env.form_prop, false);
+  is(env.document_prop, false);
+  is(env.button_prop, false);
+
+  env = envs[i]; i++;
+  is(env.type, "*global*");
+  is(env.qualified, false);
+  is(env.unqualified, true, "unqualified name must live in the global");
+  is(env.lexical, false);
+  is(env.prop, false);
+  is(env.form_prop, false);
+  is(env.document_prop, false);
+  is(env.button_prop, false);
+
+  count++;
+  if (count == 2) {
+    SimpleTest.finish();
+  }
+}
+  </script>
+</head>
+<body>
+<form id="form">
+<button id="button_optimized" onclick="event.preventDefault(); var qualified = 10; unqualified = 20; let lexical = 30; this.prop = 40; const funcs = Cu.getJSTestingFunctions(); const envs = []; let env = funcs.getInnerMostEnvironmentObject(); while (env) { envs.push({ type: funcs.getEnvironmentObjectType(env) || '*global*', qualified: !!Object.getOwnPropertyDescriptor(env, 'qualified'), unqualified: !!Object.getOwnPropertyDescriptor(env, 'unqualified'), lexical: !!Object.getOwnPropertyDescriptor(env, 'lexical'), prop: !!Object.getOwnPropertyDescriptor(env, 'prop'), document_prop: !!Object.getOwnPropertyDescriptor(env, 'document_prop'), form_prop: !!Object.getOwnPropertyDescriptor(env, 'form_prop'), button_prop: !!Object.getOwnPropertyDescriptor(env, 'button_prop'), }); env = funcs.getEnclosingEnvironmentObject(env); } check(envs, false); return false;">Click Me!</button>
+<!-- Put direct eval to de-optimize function scope -->
+<button id="button_unoptimized" onclick="event.preventDefault(); eval(''); var qualified = 10; unqualified = 20; let lexical = 30; this.prop = 40; const funcs = Cu.getJSTestingFunctions(); const envs = []; let env = funcs.getInnerMostEnvironmentObject(); while (env) { envs.push({ type: funcs.getEnvironmentObjectType(env) || '*global*', qualified: !!Object.getOwnPropertyDescriptor(env, 'qualified'), unqualified: !!Object.getOwnPropertyDescriptor(env, 'unqualified'), lexical: !!Object.getOwnPropertyDescriptor(env, 'lexical'), prop: !!Object.getOwnPropertyDescriptor(env, 'prop'), document_prop: !!Object.getOwnPropertyDescriptor(env, 'document_prop'), form_prop: !!Object.getOwnPropertyDescriptor(env, 'form_prop'), button_prop: !!Object.getOwnPropertyDescriptor(env, 'button_prop'), }); env = funcs.getEnclosingEnvironmentObject(env); } check(envs, true);">Click Me!</button>
+</form>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1782450">Mozilla Bug 1782450</a>
+<script type="application/javascript">
+"use strict";
+document.document_prop = 50;
+const form = document.getElementById("form");
+form.form_prop = 50;
+const button_unoptimized = document.getElementById("button_unoptimized");
+button_unoptimized.button_prop = 60;
+button_unoptimized.click();
+const button_optimized = document.getElementById("button_optimized");
+button_optimized.button_prop = 60;
+button_optimized.click();
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_evalInSandbox.xhtml b/js/xpconnect/tests/chrome/test_evalInSandbox.xhtml
new file mode 100644
index 0000000000..ac65151101
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_evalInSandbox.xhtml
@@ -0,0 +1,205 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  <iframe src="http://example.org/tests/js/xpconnect/tests/mochitest/file_evalInSandbox.html"
+          onload="checkCrossOrigin(this)">
+  </iframe>
+  <iframe src="chrome://mochitests/content/chrome/js/xpconnect/tests/chrome/file_evalInSandbox.html"
+          onload="checkSameOrigin(this)">
+  </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      const utils = window.windowUtils;
+
+      function checkCrossOriginSandbox(sandbox)
+      {
+          is(utils.getClassName(sandbox),
+             "Proxy",
+             "sandbox was wrapped correctly");
+
+          is(utils.getClassName(Cu.evalInSandbox("this.document", sandbox)),
+             "Proxy",
+             "return value was rewrapped correctly");
+      }
+
+      function checkCrossOriginXrayedSandbox(sandbox)
+      {
+        ok(Cu.evalInSandbox("!('windowfoo' in window);", sandbox),
+           "the window itself Xray is an XrayWrapper");
+        ok(Cu.evalInSandbox("('wrappedJSObject' in this.document);", sandbox),
+           "wrappers inside eIS are Xrays");
+        ok(Cu.evalInSandbox("!('foo' in this.document);", sandbox),
+           "must not see expandos");
+        ok('wrappedJSObject' in Cu.evalInSandbox("this.document", sandbox),
+           "wrappers returned from the sandbox are Xrays");
+        ok(!("foo" in Cu.evalInSandbox("this.document", sandbox)),
+           "must not see expandos in wrappers returned from the sandbox");
+
+        ok('wrappedJSObject' in sandbox.document,
+           "values obtained from the sandbox are Xrays");
+        ok(!("foo" in sandbox.document),
+           "must not see expandos in wrappers obtained from the sandbox");
+
+      }
+
+      function checkCrossOrigin(ifr) {
+        var win = ifr.contentWindow;
+        var sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win, wantXrays: true } );
+
+        checkCrossOriginSandbox(sandbox);
+        checkCrossOriginXrayedSandbox(sandbox);
+
+        sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win } );
+
+        checkCrossOriginSandbox(sandbox);
+        checkCrossOriginXrayedSandbox(sandbox);
+
+        sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win, wantXrays: false } );
+
+        checkCrossOriginSandbox(sandbox);
+
+        ok(Cu.evalInSandbox("('foo' in this.document);", sandbox),
+           "can see expandos");
+        ok(!("foo" in Cu.evalInSandbox("this.document", sandbox)),
+           "must not see expandos in wrappers returned from the sandbox");
+        ok(("foo" in Cu.waiveXrays(Cu.evalInSandbox("this.document", sandbox))),
+           "must see expandos in waived wrappers returned from the sandbox");
+
+        ok(!("foo" in sandbox.document),
+           "must not see expandos in wrappers obtained from the sandbox");
+        ok("foo" in Cu.waiveXrays(sandbox.document),
+           "must see expandos in wrappers obtained from the sandbox");
+
+        testDone();
+      }
+
+      function checkSameOrigin(ifr) {
+        var win = ifr.contentWindow;
+        var sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win, wantXrays: true } );
+
+        ok(Cu.evalInSandbox("('foo' in this.document);", sandbox),
+           "must see expandos for a chrome sandbox");
+
+        sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win } );
+
+        ok(Cu.evalInSandbox("('foo' in this.document);", sandbox),
+           "must see expandos for a chrome sandbox");
+
+        sandbox =
+          new Cu.Sandbox(win, { sandboxPrototype: win, wantXrays: false } );
+
+        ok(Cu.evalInSandbox("('foo' in this.document);", sandbox),
+           "can see expandos for a chrome sandbox");
+
+        testDone();
+      }
+
+      var testsRun = 0;
+      function testDone() {
+        if (++testsRun == 2)
+          SimpleTest.finish();
+      }
+
+      SimpleTest.waitForExplicitFinish();
+
+      try {
+        var sandbox1 = new Cu.Sandbox(this, { sandboxPrototype: undefined } );
+        ok(false, "undefined is not a valid prototype");
+      }
+      catch (e) {
+        ok(true, "undefined is not a valid prototype");
+      }
+
+      try {
+        var sandbox2 = new Cu.Sandbox(this, { wantXrays: undefined } );
+        ok(false, "undefined is not a valid value for wantXrays");
+      }
+      catch (e) {
+        ok(true, "undefined is not a valid value for wantXrays");
+      }
+
+      // Crash test for bug 601829.
+      try {
+        Cu.evalInSandbox('', null);
+      } catch (e) {
+        ok(true, "didn't crash on a null sandbox object");
+      }
+
+      try {
+        var sandbox3 = new Cu.Sandbox(this, { sameZoneAs: this } );
+        ok(true, "sameZoneAs works");
+      }
+      catch (e) {
+        ok(false, "sameZoneAs works");
+      }
+
+      // The 'let' keyword only appears with JS 1.7 and above. We use this fact
+      // to make sure that sandboxes get explict JS versions and don't inherit
+      // them from the most recent scripted frame.
+      function checkExplicitVersions() {
+        // eslint-disable-next-line no-undef
+        var sb = new Cu.Sandbox(sop);
+        Cu.evalInSandbox('let someVariable = 42', sb, '1.7');
+        ok(true, "Didn't throw with let");
+        try {
+          Cu.evalInSandbox('let someVariable = 42', sb);
+          ok(false, "Should have thrown with let");
+        } catch (e) {
+          ok(true, "Threw with let: " + e);
+        }
+        try {
+          Cu.evalInSandbox('let someVariable = 42', sb, '1.5');
+          ok(false, "Should have thrown with let");
+        } catch (e) {
+          ok(true, "Threw with let: " + e);
+        }
+      }
+      var outerSB = new Cu.Sandbox(this);
+      Cu.evalInSandbox(checkExplicitVersions.toSource(), outerSB, '1.7');
+      outerSB.ok = ok;
+      outerSB.sop = this;
+      Cu.evalInSandbox('checkExplicitVersions();', outerSB);
+
+      const {addDebuggerToGlobal} = ChromeUtils.importESModule("resource://gre/modules/jsdebugger.sys.mjs");
+      addDebuggerToGlobal(globalThis);
+
+      try {
+        let dbg = new Debugger();
+        let sandbox = new Cu.Sandbox(this, {
+          invisibleToDebugger: false,
+          freshCompartment: true,
+        });
+        dbg.addDebuggee(sandbox);
+        ok(true, "debugger added visible value");
+      } catch(e) {
+        ok(false, "debugger could not add visible value");
+      }
+
+      try {
+        let dbg = new Debugger();
+        let sandbox = new Cu.Sandbox(this, { invisibleToDebugger: true });
+        dbg.addDebuggee(sandbox);
+        ok(false, "debugger added invisible value");
+      } catch(e) {
+        ok(true, "debugger did not add invisible value");
+      }
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_evalInWindow.xhtml b/js/xpconnect/tests/chrome/test_evalInWindow.xhtml
new file mode 100644
index 0000000000..00299266f2
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_evalInWindow.xhtml
@@ -0,0 +1,71 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=877673
+-->
+<window title="Mozilla Bug 877673"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      SimpleTest.waitForExplicitFinish();
+      var sb = new Cu.Sandbox("https://example.org", {wantExportHelpers: true});
+      sb.ok = ok;
+
+      function executeIn(frame, script, exceptionCb) {
+        sb.frame = frame;
+        sb.exceptionCb = exceptionCb;
+        if (exceptionCb) {
+          return Cu.evalInSandbox("try {frame.eval('" + script + "'); ok(false, 'Exception should have been thrown.')} catch(e) {exceptionCb(e)}", sb);
+        }
+
+        return Cu.evalInSandbox("frame.eval('" + script + "')", sb);
+      }
+
+      function testSameOrigin(frame) {
+        frame.contentWindow.document.wrappedJSObject.str = "foobar";
+        is(executeIn(frame.contentWindow, "document.str"), "foobar",
+           "Same origin string property access.");
+
+        executeIn(frame.contentWindow, 'document.obj = {prop: "foobar"}');
+        is((executeIn(frame.contentWindow, "document.obj")).prop, "foobar",
+           "Same origin object property access (cloning).");
+        isnot(executeIn(frame.contentWindow, "document.obj"), frame.contentWindow.document.wrappedJSObject.obj,
+              "Ensure cloning for js objects.");
+        is(executeIn(frame.contentWindow, "document"), frame.contentWindow.document,
+           "Xrayables should just pass without cloning.");
+        is( executeIn(frame.contentWindow, "({a:{doc: document}})").a.doc, frame.contentWindow.document,
+           "Deep cloning works.");
+
+        executeIn(frame.contentWindow, "throw 42", function(e){is(e, 42,
+                                                                  "Exception was thrown from script.")});
+
+        testDone();
+      }
+
+      function testCrossOrigin(frame) {
+        executeIn(frame.contentWindow, "var a = 42;", function(e){ok(e.toString().indexOf("Permission denied") > -1,
+                                                                     "Executing script in a window from cross origin should throw.");});
+        testDone();
+      }
+
+      var testsRun = 0;
+      function testDone() {
+        if (++testsRun == 2)
+          SimpleTest.finish();
+      }
+  ]]></script>
+  <iframe src="https://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"
+          onload="testSameOrigin(this)">
+  </iframe>
+  <iframe src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_empty.html"
+          onload="testCrossOrigin(this)">
+  </iframe>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_exnstack.xhtml b/js/xpconnect/tests/chrome/test_exnstack.xhtml
new file mode 100644
index 0000000000..48bcac5243
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_exnstack.xhtml
@@ -0,0 +1,68 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=735544
+-->
+<window title="Mozilla Bug 735544"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=735544"
+     target="_blank">Mozilla Bug 735544</a>
+ <iframe id='ifr0' onload="frameDone(0);" src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_exnstack.html" />
+ <iframe id='ifr1' onload="frameDone(1);" src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_exnstack.html" />
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 735544 - Allow exception stacks to cross compartment boundaries **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  var gFramesDone = [false, false];
+  function frameDone(idx) {
+    gFramesDone[idx] = true;
+    if (gFramesDone[0] && gFramesDone[1])
+      startTest();
+  }
+
+  function throwAsChrome() {
+
+    // Grab the iframe content windows.
+    var cwin0 = document.getElementById('ifr0').contentWindow;
+    var cwin1 = document.getElementById('ifr1').contentWindow;
+
+    // Have cwin0 call a function on cwin1 that throws.
+    cwin0.wrappedJSObject.doThrow(cwin1);
+  }
+
+  function startTest() {
+
+    try {
+      throwAsChrome();
+      ok(false, "should throw");
+    } catch (e) {
+
+      let stackFrames = e.stack.split("\n");
+
+      ok(/throwAsInner/.exec(stackFrames[0]),
+         "The bottom frame should be thrown by the inner");
+
+      ok(/throwAsOuter/.exec(stackFrames[2]),
+         "The 3rd-from-bottom frame should be thrown by the other");
+
+      ok(!/throwAsChrome/.exec(e.stack),
+         "The entire stack should not cross into chrome.");
+    }
+
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+
+</window>
diff --git a/js/xpconnect/tests/chrome/test_expandosharing.xhtml b/js/xpconnect/tests/chrome/test_expandosharing.xhtml
new file mode 100644
index 0000000000..1dc95239f4
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_expandosharing.xhtml
@@ -0,0 +1,147 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=758415
+-->
+<window title="Mozilla Bug 758415"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=758415"
+     target="_blank">Mozilla Bug 758415</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for Cross-Origin Xray Expando Sharing. **/
+  SimpleTest.waitForExplicitFinish();
+
+  // Import our test JSM. We first strip the filename off
+  // the chrome url, then append the jsm filename.
+  var base = /.*\//.exec(window.location.href)[0];
+  const {checkFromJSM} = ChromeUtils.import(base + "file_expandosharing.jsm");
+
+  // Wait for all child frames to load.
+  var gLoadCount = 0;
+  function frameLoaded() {
+    if (++gLoadCount == window.frames.length)
+      go();
+  }
+
+  function go() {
+
+    // Empower the content windows with some functions.
+    var wins = document.getElementsByTagName('iframe');
+    for (var i = 0; i < wins.length; ++i) {
+      var win = wins[i].contentWindow.wrappedJSObject;
+      win.ok = ok;
+      win.is = is;
+    }
+
+    // Grab references to the content windows. We abbreviate the origins as follows:
+    // A: test1.example.org
+    // B: test2.example.org
+    // C: sub1.test1.example.org
+    window.gWinA1 = document.getElementById('frameA1').contentWindow;
+    window.gWinA2 = document.getElementById('frameA2').contentWindow;
+    window.gWinA3 = document.getElementById('frameA3').contentWindow;
+    window.gWinB = document.getElementById('frameB').contentWindow;
+    window.gWinC = document.getElementById('frameC').contentWindow;
+
+    /* globals gWinA1, gWinA2, gWinA3, gWinB, gWinC */
+
+    // Test expando sharing with a JSM for different types of Xrays.
+    testJSM(Cu.unwaiveXrays(gWinC.wrappedJSObject.targetWN));
+    testJSM(Cu.unwaiveXrays(gWinC.wrappedJSObject.targetDOM));
+    testJSM(Cu.unwaiveXrays(gWinC.wrappedJSObject.targetJS));
+
+    // Make sure sandboxes never share expandos with anyone else.
+    testSandbox(Cu.unwaiveXrays(gWinB.wrappedJSObject.targetWN));
+    testSandbox(Cu.unwaiveXrays(gWinB.wrappedJSObject.targetDOM));
+    testSandbox(Cu.unwaiveXrays(gWinB.wrappedJSObject.targetJS));
+
+    // Test Content Xrays.
+    testContentXrays();
+
+    SimpleTest.finish();
+  }
+
+  // Make sure that expandos are shared between us and a JSM.
+  function testJSM(target) {
+    target.numProp = 42;
+    target.strProp = "foo";
+    target.objProp = { bar: "baz" };
+    checkFromJSM(target, is);
+  }
+
+  function testSandbox(target) {
+
+    // This gets both run in this scope and the sandbox scope.
+    var name = "harness";
+    function placeExpando() {
+      target.prop = name;
+    }
+
+    // Set up the sandboxes. Use an expanded principal to get xrays with
+    // exclusive expandos.
+    let sb1 = Cu.Sandbox(["https://test1.example.org", "https://test2.example.org"]);
+    let sb2 = Cu.Sandbox(["https://test1.example.org", "https://test2.example.org"]);
+    sb1.target = target;
+    sb2.target = target;
+    sb1.name = "sandbox1";
+    sb2.name = "sandbox2";
+    placeExpando();
+    Cu.evalInSandbox(placeExpando.toSource() + "placeExpando();", sb1);
+    Cu.evalInSandbox(placeExpando.toSource() + "placeExpando();", sb2);
+
+    // Make sure everyone sees a different value.
+    is(target.prop, "harness", "Harness sees its own value");
+    is(Cu.evalInSandbox("target.prop", sb1), "sandbox1", "Sandbox 1 sees its own value");
+    is(Cu.evalInSandbox("target.prop", sb2), "sandbox2", "Sandbox 2 sees its own value");
+  }
+
+  // Make sure that the origin tagging machinery works correctly and that we don't
+  // mix up chrome and content expandos.
+  function testContentXrays() {
+
+    // Give A1 and A3 xrays to (same-origin) A2.
+    Cu.setWantXrays(gWinA1);
+    Cu.setWantXrays(gWinA3);
+
+    gWinA1.wrappedJSObject.placeExpando('A1_expando', 11, gWinA2.document);
+    gWinA3.wrappedJSObject.placeExpando('A3_expando', 33, gWinA2.document);
+    gWinA2.document.Chrome_expando = 33;
+
+    is(gWinA2.document.Chrome_expando, 33, "Read chrome expando properly");
+    is(typeof gWinA2.document.A1_expando, 'undefined', "Chrome doesn't see content expandos");
+    is(typeof gWinA2.document.A3_expando, 'undefined', "Chrome doesn't see content expandos");
+    gWinA1.wrappedJSObject.checkExpando('A1_expando', 11, gWinA2.document, "Content sees proper expandos");
+    gWinA3.wrappedJSObject.checkExpando('A1_expando', 11, gWinA2.document, "Content sees proper expandos");
+    gWinA1.wrappedJSObject.checkExpando('A3_expando', 33, gWinA2.document, "Content sees proper expandos");
+    gWinA3.wrappedJSObject.checkExpando('A3_expando', 33, gWinA2.document, "Content sees proper expandos");
+    gWinA1.wrappedJSObject.checkExpando('Chrome_expando', null, gWinA2.document, "Content doesn't see chrome expandos");
+    gWinA3.wrappedJSObject.checkExpando('Chrome_expando', null, gWinA2.document, "Content doesn't see chrome expandos");
+
+    // We very explicitly do not support expando sharing via document.domain.
+    // A comment in the implementation explains why.
+    gWinA1.document.domain = 'test1.example.org';
+    gWinA2.document.domain = 'test1.example.org';
+    gWinA3.document.domain = 'test1.example.org';
+    gWinC.document.domain = 'test1.example.org';
+    gWinC.wrappedJSObject.checkExpando('A1_expando', null, gWinA2.document, "document.domain should have no effect here");
+    gWinC.wrappedJSObject.checkExpando('A3_expando', null, gWinA2.document, "document.domain should have no effect here");
+  }
+
+  ]]>
+  </script>
+  <iframe id="frameA1" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_expandosharing.html" />
+  <iframe id="frameA2" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_expandosharing.html" />
+  <iframe id="frameA3" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_expandosharing.html" />
+  <iframe id="frameB" onload="frameLoaded();" type="content" src="https://test2.example.org/tests/js/xpconnect/tests/mochitest/file_expandosharing.html" />
+  <iframe id="frameC" onload="frameLoaded();" type="content" src="https://sub1.test1.example.org/tests/js/xpconnect/tests/mochitest/file_expandosharing.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_exposeInDerived.xhtml b/js/xpconnect/tests/chrome/test_exposeInDerived.xhtml
new file mode 100644
index 0000000000..ee6ad2d229
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_exposeInDerived.xhtml
@@ -0,0 +1,45 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=804630
+-->
+<window title="Mozilla Bug 804630"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=804630"
+     target="_blank">Mozilla Bug 804630</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test to make sure that COWed objects can't expose properties from their prototypes. **/
+  // Set up the sandbox.
+  var sb = new Cu.Sandbox("https://www.example.com");
+  sb.ok = ok;
+  sb.is = is;
+
+  // Make a chrome object that tries to expose objects off its prototype.
+  sb.proto = { read: 42, readWrite: 32 };
+  sb.obj = {};
+  sb.obj.__proto__ = sb.proto;
+
+  // Make sure we can't access any of the properties on the prototype directly.
+  Cu.evalInSandbox('is(proto.read, undefined, "proto.read inaccessible");', sb);
+  Cu.evalInSandbox('var wrote = false; ' +
+                   'try { proto.readWrite = 12; wrote = true; } catch(e) {} ' +
+                   ' ok(!wrote, "Should not write proto property");', sb);
+
+  // Make sure we can't access the exposed properties via the derived object.
+  Cu.evalInSandbox('is(obj.read, undefined, "obj.read inaccessible");', sb);
+  Cu.evalInSandbox('is(obj.readWrite, undefined, "obj.readWrite is not readable");', sb);
+  Cu.evalInSandbox('try { obj.readWrite = 8; ok(false, "obj.readWrite is not writable"); } catch (e) {};',
+                   sb);
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_inlineScripts.html b/js/xpconnect/tests/chrome/test_inlineScripts.html
new file mode 100644
index 0000000000..cb5f5ed530
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_inlineScripts.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+  <meta charset=utf-8>
+  <title>Tests for nsIScriptError</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <div id="log"></div>
+
+  <!-- Verify that column is correct, even for inline scripts with HTML on the same line -->
+  <span>some html</span> <script>var inlineScriptStack = new Error().stack;</script>
+  <script>
+    function waitForError (expectedMessage){
+      return new Promise(resolve => {
+        const listener = {
+          QueryInterface: ChromeUtils.generateQI(["nsIConsoleListener"])
+        };
+
+        listener.observe = function(message) {
+          if (message.message.includes(expectedMessage)) {
+            message.QueryInterface(Ci.nsIScriptError);
+            resolve(message);
+            Services.console.unregisterListener(listener);
+          }
+        };
+
+        Services.console.registerListener(listener);
+      });
+    }
+
+    var onInlineScriptError = waitForError("doThrow");
+    var onModuleError = waitForError("doThrowInModule");
+    SimpleTest.expectUncaughtException();
+  </script>
+  <span>some more html</span><script>doThrow() // eslint-disable-line no-undef</script>
+  <script>var b;</script><hr><script type="module">SimpleTest.expectUncaughtException();doThrowInModule() // eslint-disable-line no-undef</script>
+  <script>
+    add_task(async () => {
+        info("Check line and column information in Error#stack");
+        const { groups } = inlineScriptStack.match(/(?<line>\d+):(?<column>\d+)/);
+        is(groups.line, "9", "line of Error#stack in inline script is correct");
+        is(groups.column, "58", "column of Error#stack in inline script is correct");
+
+        info("Check line and column information Error message in inline script");
+        const errorMessage = await onInlineScriptError;
+        is(errorMessage.lineNumber, 33, "The exception line is correct");
+        is(errorMessage.columnNumber, 38, "The exception column is correct");
+
+        info("Check line and column information Error message in inline module");
+        const errorMessageInModule = await onModuleError;
+        is(errorMessageInModule.lineNumber, 34, "The module exception line is correct");
+        is(errorMessageInModule.columnNumber, 89, "The module exception column is correct");
+    });
+  </script>
+</html>
+\ No newline at end of file
diff --git a/js/xpconnect/tests/chrome/test_localstorage_with_nsEp.xhtml b/js/xpconnect/tests/chrome/test_localstorage_with_nsEp.xhtml
new file mode 100644
index 0000000000..dbc0ea6a61
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_localstorage_with_nsEp.xhtml
@@ -0,0 +1,37 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=980023 
+-->
+<window title="Mozilla Bug 980023 "
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=980023"
+     target="_blank">Mozilla Bug 980023 </a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for localstorage access with expanded principal. **/
+  SimpleTest.waitForExplicitFinish();
+
+  function go() {
+    var iwin = document.getElementById('ifr').contentWindow;
+    var sb = new Cu.Sandbox([iwin], {sandboxPrototype: iwin});
+    Cu.evalInSandbox("window.localStorage.test_localstorage_with_nsEp = 3",sb);
+    is(Cu.evalInSandbox("window.localStorage.test_localstorage_with_nsEp",sb), "3");
+    is(iwin.localStorage.test_localstorage_with_nsEp, "3");
+    iwin.localStorage.removeItem("test_localstorage_with_nsEp");
+    SimpleTest.finish();
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_matches.xhtml b/js/xpconnect/tests/chrome/test_matches.xhtml
new file mode 100644
index 0000000000..96472bc8ac
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_matches.xhtml
@@ -0,0 +1,49 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  <iframe src="http://example.org/tests/js/xpconnect/tests/mochitest/file_matches.html"
+          onload="runTest(this)">
+  </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      SimpleTest.waitForExplicitFinish();
+      function runTest(ifr)
+      {
+        var doc = ifr.contentDocument;
+        var docElem = doc.documentElement;
+        
+        var res = doc.createElement('div').matches('div');
+        is(res, true, "matches call through xray, regular case");
+        
+        res = docElem.matches.call(
+          doc.createElement('div'), 'div');
+        is(res, true, "matches call through xray, with .call");
+                        
+        var sb = new Cu.Sandbox(ifr.contentWindow);
+        sb.doc = doc;
+        var str = "doc.documentElement.matches.call(doc.createElement( 'div' ),'div')";
+        res = Cu.evalInSandbox(str, sb);
+        is(res, true, "matches call through xray (same origin), with .call");
+        
+        docElem.matches = function(){return false};
+        res = docElem.matches.call(doc.createElement( 'div' ),'div');
+        is(res, false, "shadowing matches with an expando on the xray wrapper");
+        
+        SimpleTest.finish();
+      }
+
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_nodelists.xhtml b/js/xpconnect/tests/chrome/test_nodelists.xhtml
new file mode 100644
index 0000000000..d3d4dfc34e
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_nodelists.xhtml
@@ -0,0 +1,49 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Test nodelists from chrome"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      SimpleTest.waitForExplicitFinish();
+
+      function go() {
+        var win = $('ifr').contentWindow;
+        var list = win.document.getElementsByTagName('p');
+        is(list.length, 3, "can get the length");
+        ok(HTMLParagraphElement.isInstance(list[0]), "can get list[0]");
+        is(list[0], list.item(0), "list.item works");
+        is(list.item, list.item, "don't recreate functions for each get");
+
+        var list2 = list[2];
+        ok(HTMLParagraphElement.isInstance(list[2]), "list[2] exists");
+        ok("2" in list, "in operator works");
+
+        is(win.document.body.removeChild(win.document.body.lastChild), list2, "remove last paragraph element");
+        ok(!("2" in list), "in operator doesn't see phantom element");
+        is(list[2], undefined, "no node there!");
+
+        var optionList = win.document.createElement("select").options;
+        var option = win.document.createElement("option");
+        optionList[0] = option;
+        is(optionList.item(0), option, "Creators work");
+
+        option = win.document.createElement("option");
+        optionList[0] = option;
+        is(optionList.item(0), option, "Setters work");
+
+        SimpleTest.finish();
+      }
+  ]]></script>
+
+  <iframe id="ifr"
+          src="http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_nodelists.html"
+          onload="go()" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_nsScriptErrorWithStack.html b/js/xpconnect/tests/chrome/test_nsScriptErrorWithStack.html
new file mode 100644
index 0000000000..99a4727756
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_nsScriptErrorWithStack.html
@@ -0,0 +1,59 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Test for 814497</title>
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<div id="log"></div>
+<script>
+  var c = Cc;
+
+  SimpleTest.waitForExplicitFinish();
+  SimpleTest.expectUncaughtException();
+
+  // /!\ Line number is important in this test,
+  //     we are asserting the following functions line #
+  function failingStack() {
+    nestedFunction();
+  }
+  function nestedFunction() {
+    // eslint-disable-next-line no-undef
+    doesntExistsAndThrow();
+  }
+
+  var TestObserver = {
+    QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+
+    observe: function test_observe(aSubject)
+    {
+      if (!(aSubject instanceof Ci.nsIScriptError)) {
+        return;
+      }
+      dump("stack: "+aSubject.stack+"\n");
+
+      // Main assertions
+      var s = aSubject.stack;
+      ok(!!s, "has first frame");
+      ok(s.source.includes("test_nsScriptErrorWithStack.html"), "source is correct");
+      is(s.line, 19, "line is correct");
+      is(s.column, 5, "column is correct");
+      is(s.functionDisplayName, "nestedFunction");
+      s = s.parent;
+      ok(!!s, "has second frame");
+      ok(s.source.includes("test_nsScriptErrorWithStack.html"), "source is correct");
+      is(s.line, 15, "line is correct");
+      is(s.column, 5, "column is correct");
+      is(s.functionDisplayName, "failingStack");
+      // We shouldn't have any more frame as we used setTimeout
+      ok(!s.parent, "has no more frames");
+
+      // Cleanup
+      Services.console.unregisterListener(TestObserver);
+      SimpleTest.finish();
+    }
+  };
+
+  Services.console.registerListener(TestObserver);
+
+  // use setTimeout in order to prevent throwing from test frame
+  // and so have a clean stack frame with just our method calls
+  setTimeout(failingStack, 0);
+</script>
diff --git a/js/xpconnect/tests/chrome/test_onGarbageCollection.html b/js/xpconnect/tests/chrome/test_onGarbageCollection.html
new file mode 100644
index 0000000000..ce056ed354
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_onGarbageCollection.html
@@ -0,0 +1,48 @@
+<!doctype html>
+<html>
+  <head>
+    <title>Bug 1150253 - Sanity test for the SpiderMonkey Debugger API's onGarbageCollection hook</title>
+    <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js">
+    </script>
+  </head>
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1150253"
+       target="_blank">Mozilla Bug 1150253</a>
+
+    <script type="application/javascript">
+    SimpleTest.waitForExplicitFinish();
+
+    const { gc } = Cu.getJSTestingFunctions();
+
+    // Instantiate `Debugger` in a sandbox as Debugger requires to be created
+    // in a compartment different than the debuggee.
+    let sandbox = Cu.Sandbox(
+      Components.Constructor("@mozilla.org/systemprincipal;1", "nsIPrincipal")(),
+      {
+        freshCompartment: true,
+        wantGlobalProperties: ["ChromeUtils"],
+      }
+    );
+    Cu.evalInSandbox(`
+const { addDebuggerToGlobal } = ChromeUtils.importESModule(
+  'resource://gre/modules/jsdebugger.sys.mjs'
+);
+addDebuggerToGlobal(globalThis);
+`, sandbox
+    );
+
+    const dbg = new sandbox.Debugger(this);
+
+    dbg.memory.onGarbageCollection = function (data) {
+      // Don't keep calling this hook after we finish.
+      dbg.memory.onGarbageCollection = undefined;
+      dbg.removeAllDebuggees();
+
+      ok(data, "The onGarbageCollection hook was fired.");
+      SimpleTest.finish();
+    };
+
+    gc();
+    </script>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_precisegc.xhtml b/js/xpconnect/tests/chrome/test_precisegc.xhtml
new file mode 100644
index 0000000000..56f047843e
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_precisegc.xhtml
@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 661927"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+      Cu.schedulePreciseGC(
+        function() {
+          ok(true, "callback executed");
+          SimpleTest.finish();
+        });
+      SimpleTest.waitForExplicitFinish();
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_private_field_cows.xhtml b/js/xpconnect/tests/chrome/test_private_field_cows.xhtml
new file mode 100644
index 0000000000..24fe9d5e0a
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_private_field_cows.xhtml
@@ -0,0 +1,131 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+
+<window title="Mozilla Bug ????" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+    <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+    <!-- test results are displayed in the html:body -->
+
+    <body xmlns="http://www.w3.org/1999/xhtml">
+        <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=>?????" target="_blank">Mozilla Bug ???? </a>
+    </body>
+
+    <!-- test code goes here -->
+    <script type="application/javascript"><![CDATA[
+            /* eslint-disable no-eval */
+
+            add_task(async () => {
+                var sandbox = new Cu.Sandbox("about:blank");
+
+                await SpecialPowers.pushPrefEnv({
+                    "set": [["security.allow_eval_with_system_principal",
+                        true]]
+                });
+
+                function getCOW(x) {
+                    if (typeof x != 'object' && typeof x != 'function')
+                        return x;
+                    x = Cu.waiveXrays(x);
+                    var rval = {};
+                    if (typeof x == "function")
+                        rval = eval(`(${x.toString()})`);
+                    for (var i in x) {
+                        if (x.__lookupGetter__(i))
+                            rval.__defineGetter__(i, eval(`(${x.__lookupGetter__(i).toString()})`))
+                        else
+                            rval[i] = getCOW(x[i]);
+                    }
+                    return rval;
+                }
+
+                // Give the sandbox a way to create ChromeObjectWrapped objects.
+                sandbox.getCOW = getCOW;
+
+                // Define test API functions in the sandbox.
+                const TEST_API = ['is', 'ok', 'info'];
+                TEST_API.forEach(function (name) { sandbox[name] = window[name]; });
+
+
+                function COWTests() {
+
+                    var empty = {};
+                    var cow = getCOW(empty);
+
+                    // Because private fields may not be enabled, we construct A via the below eval of an IFFE,
+                    // and return early if it syntax errors.
+                    var A;
+                    try {
+                        A = eval(`(function(){
+                                    class Base {
+                                        constructor(o) {
+                                            return o;
+                                        }
+                                    };
+
+                                    class A extends Base {
+                                        #x = 12;
+                                        static gx(o) {
+                                            return o.#x;
+                                        }
+
+                                        static sx(o, v) {
+                                            o.#x = v;
+                                        }
+                                    };
+                                    return A;
+                                })();`);
+                    } catch (e) {
+                        is(e instanceof SyntaxError, true, "Syntax error: Private fields not enabled");
+                        is(/private fields are not currently supported/.test(e.message), true, "correct message");
+                        return;
+                    }
+
+                    new A(empty);
+                    is(A.gx(empty), 12, "Correct value read");
+                    A.sx(empty, 'wrapped');
+
+                    function assertThrewInstance(f, error) {
+                        var threw = true;
+                        try {
+                            f();
+                            threw = false;
+                        } catch (e) {
+                            is(e instanceof error, true, "Correct Error");
+                        }
+                        is(threw, true, "Threw!");
+                    }
+
+                    // Note: These throw warnings:
+                    //
+                    //   WARNING: Silently denied access to property ##x: Access to privileged JS object not permitted (@chrome://mochitests/content/chrome/js/xpconnect/tests/chrome/test_private_field_cows.xhtml:108:27): file /js/xpconnect/wrappers/XrayWrapper.cpp, line 226
+                    //
+                    // It's not clear to me if we ougth to wire this up to -not-? I suspect this is a result of invoking
+                    // the has
+                    assertThrewInstance(() => A.gx(cow), TypeError);
+                    assertThrewInstance(() => A.sx(cow, 'unwrapped'), TypeError);
+                    assertThrewInstance(() => new A(cow), Error);
+                    assertThrewInstance(() => A.gx(cow), TypeError);
+                }
+
+                // Stringify the COW test suite and directly evaluate it in the sandbox.
+                Cu.evalInSandbox('(' + COWTests.toString() + ')()', sandbox);
+
+                // Test that COWed objects passing from content to chrome get unwrapped.
+                function returnCOW() {
+                    return getCOW({
+                        bar: 6
+                    });
+                }
+
+                // eslint-disable-next-line no-unused-vars
+                var unwrapped = Cu.evalInSandbox(
+                    '(' + returnCOW.toString() + ')()',
+                    sandbox
+                );
+
+                ok(true, "passed");
+            });
+        ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_sandboxImport.xhtml b/js/xpconnect/tests/chrome/test_sandboxImport.xhtml
new file mode 100644
index 0000000000..1ae1f02ad7
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_sandboxImport.xhtml
@@ -0,0 +1,37 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=533596
+-->
+<window title="Mozilla Bug 533596"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+      function checkWrapped(obj) {
+          var utils = window.windowUtils;
+          is(utils.getClassName(obj), "Proxy", "right type of wrapper");
+      }
+
+      var sandbox = new Cu.Sandbox("about:blank");
+      sandbox.importFunction(function() { return "PASS"; }, "foo");
+      sandbox.importFunction(function bar() { return "PASS"; });
+      sandbox.importFunction(checkWrapped);
+      is(Cu.evalInSandbox("foo()", sandbox), "PASS", "importFunction works");
+      is(Cu.evalInSandbox("bar()", sandbox), "PASS", "importFunction works");
+      Cu.evalInSandbox("checkWrapped({})", sandbox);
+
+      var importer = sandbox.importFunction;
+      importer(function() { return "PASS"; }, "bar");
+      is(Cu.evalInSandbox("bar()", sandbox), "PASS", "unbound importFunction works");
+      is(typeof this.bar, "undefined", "didn't import into our global");
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_scriptSettings.xhtml b/js/xpconnect/tests/chrome/test_scriptSettings.xhtml
new file mode 100644
index 0000000000..f78b921466
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_scriptSettings.xhtml
@@ -0,0 +1,128 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=937317
+-->
+<window title="Mozilla Bug 937317"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=937317"
+     target="_blank">Mozilla Bug 937317</a>
+  </body>
+
+  <!-- test code goes here -->
+  <iframe src="./file_empty.html"></iframe>
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for the script settings stack. **/
+  SimpleTest.waitForExplicitFinish();
+  SpecialPowers.pushPrefEnv({"set": [["security.allow_eval_with_system_principal",
+                                      true]]});
+  addLoadEvent(function() {
+    const {PromiseUtils} = ChromeUtils.import("resource://gre/modules/PromiseUtils.jsm");
+    let iwin = window[0];
+
+    // Smoketest.
+    is(Cu.getIncumbentGlobal(), window, "smoketest");
+
+    // Calling a cross-compartment non-scripted function changes the
+    // compartment, but not the incumbent script settings object.
+    var sb = new Cu.Sandbox(window, { wantComponents: true });
+    is(sb.Components.utils.getIncumbentGlobal(), window, "cross-compartment sb non-scripted");
+    is(iwin.Components.utils.getIncumbentGlobal(), window, "cross-compartment win non-scripted");
+
+    // If we call a scripted function in the other compartment, that becomes
+    // the incumbent script.
+    function gib() { return Cu.getIncumbentGlobal(); };
+    Cu.evalInSandbox(gib.toSource(), sb);
+    iwin.eval(gib.toSource());
+    is(sb.gib(), sb, "cross-compartment sb scripted");
+    is(iwin.gib(), iwin, "cross-compartment win scripted");
+
+    // Eval-ing top-level script in another component makes that compartment the
+    // incumbent script.
+    is(Cu.evalInSandbox('Components.utils.getIncumbentGlobal()', sb), sb, 'eval sb');
+    is(iwin.eval('Components.utils.getIncumbentGlobal()'), iwin, 'eval iwin');
+
+    // Make sure that the callback mechanism works.
+    function makeCallback(expectedGlobal, deferred, kind) {
+      function cb(incumbentGlobal) {
+        is(incumbentGlobal, expectedGlobal, "Callback got the right incumbent global: " + kind);
+        if (deferred)
+          deferred.resolve();
+      }
+      info("Generated callback: " + kind);
+      return cb;
+    }
+
+    var bound = Cu.getIncumbentGlobal.bind(Cu, makeCallback(window, undefined, "simple bound"));
+    is(bound(), window, "Bound method returns the right global");
+
+    // Callbacks grab the incumbent script at the time of invocation.
+    //
+    // Note - We avoid calling the initial defer |d| so that it's not in-scope for everything below.
+    let initialDefer = PromiseUtils.defer();
+    setTimeout(Cu.getIncumbentGlobal.bind(Cu, makeCallback(window, initialDefer, "same-global setTimeout")), 0);
+    initialDefer.promise.then(function() {
+
+      // Try cross-global setTimeout where |window| is the incumbent script when the callback is created.
+      let d = PromiseUtils.defer();
+      iwin.setTimeout(Cu.getIncumbentGlobal.bind(Cu, makeCallback(window, d, "cross-global setTimeout by |window|")), 0);
+      return d.promise;
+    }).then(function() {
+
+      // Try cross-global setTimeout where |iwin| is the incumbent script when the callback is created.
+      let d = PromiseUtils.defer();
+      iwin.wrappedJSObject.timeoutFun = Cu.getIncumbentGlobal.bind(Cu, makeCallback(iwin, d, "cross-global setTimeout by |iwin|"));
+      iwin.eval('setTimeout(timeoutFun, 0);');
+      return d.promise;
+    }).then(function() {
+
+      // The incumbent script override doesn't take effect if the callback is scripted.
+      let d = PromiseUtils.defer();
+      iwin.wrappedJSObject.timeoutFun2 = Cu.getIncumbentGlobal.bind(Cu, makeCallback(iwin, d, "cross-global setTimeout of scripted function"));
+      iwin.eval('var timeoutFun2Wrapper = function() { timeoutFun2(); }');
+      setTimeout(iwin.wrappedJSObject.timeoutFun2Wrapper, 0);
+      return d.promise;
+    }).then(function() {
+
+      // Try event listeners.
+      let d = PromiseUtils.defer();
+      let body = iwin.document.body;
+      body.addEventListener('click', Cu.getIncumbentGlobal.bind(Cu, makeCallback(window, d, "cross-global event listener")));
+      body.dispatchEvent(new iwin.MouseEvent('click'));
+      return d.promise;
+
+    }).then(function() {
+
+      // Try an event handler set by |iwin|.
+      let d = PromiseUtils.defer();
+      let body = iwin.document.body;
+      iwin.wrappedJSObject.handler = Cu.getIncumbentGlobal.bind(Cu, makeCallback(iwin, d, "cross-global event handler"));
+      iwin.eval('document.body.onmousemove = handler');
+      body.dispatchEvent(new iwin.MouseEvent('mousemove'));
+      return d.promise;
+
+    }).then(function() {
+
+      // Try an event handler compiled by a content attribute.
+      let d = PromiseUtils.defer();
+      let body = iwin.document.body;
+      iwin.wrappedJSObject.innerHandler = Cu.getIncumbentGlobal.bind(Cu, makeCallback(iwin, d, "cross-global compiled event handler"));
+      iwin.eval("document.body.setAttribute('onmouseout', 'innerHandler()')");
+      body.dispatchEvent(new iwin.MouseEvent('mouseout'));
+      return d.promise;
+    }).then(function() {
+
+      SimpleTest.finish();
+    });
+  });
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_scripterror.html b/js/xpconnect/tests/chrome/test_scripterror.html
new file mode 100644
index 0000000000..38cb316467
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_scripterror.html
@@ -0,0 +1,87 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Tests for nsIScriptError</title>
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<div id="log"></div>
+<script>
+function awaitScriptError(fun) {
+  // Use setTimeout in order to prevent throwing from test frame
+  // and to have a clean stack frame.
+  setTimeout(fun, 0)
+
+  return new Promise(resolve => {
+    const observer = {
+      QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+      observe(message) {
+        if (!(message instanceof Ci.nsIScriptError)) {
+          return;
+        }
+
+        Services.console.unregisterListener(observer);
+        resolve(message);
+      }
+    };
+
+    Services.console.registerListener(observer);
+  });
+}
+
+function hasExpectedProperties(message, exception) {
+  is(message.hasException, true, "has exception");
+  is(message.exception, exception, "has correct exception");
+
+  ok(message.stack != null, "has stack");
+  is(message.stack?.source, location.href, "correct stack source")
+
+  is(message.sourceName, location.href, "has correct sourceName/filename");
+  ok(message.lineNumber > 0, "has lineNumber");
+
+  is(message.innerWindowID, window.windowGlobalChild.innerWindowId,
+     "correct innerWindowID");
+}
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({"set": [
+    ["javascript.options.asyncstack_capture_debuggee_only", false],
+  ]});
+
+  const TESTS = [
+    "abc",
+    new Error("foobar"),
+    {foo: "bar"}
+  ];
+
+  for (let test of TESTS) {
+    // First test as regular throw
+    SimpleTest.expectUncaughtException();
+    let message = await awaitScriptError(function testName() {
+        throw test;
+    });
+    hasExpectedProperties(message, test);
+    is(message.isPromiseRejection, false, "not a rejected promise");
+
+    // Now test as uncaught promise rejection
+    message = await awaitScriptError(function testName() {
+        Promise.reject(test);
+    });
+    hasExpectedProperties(message, test);
+    is(message.isPromiseRejection, true, "is a rejected promise");
+
+    // Uncaught rejection from async function
+    message = await awaitScriptError(async function testName() {
+        throw test;
+    });
+    hasExpectedProperties(message, test);
+    is(message.isPromiseRejection, true, "is a rejected promise");
+
+    // Uncaught rejection from then callback
+    message = await awaitScriptError(async function testName() {
+        Promise.resolve().then(() => {
+          throw test;
+        });
+    });
+    hasExpectedProperties(message, test);
+    is(message.isPromiseRejection, true, "is a rejected promise");
+  }
+});
+</script>
diff --git a/js/xpconnect/tests/chrome/test_secureContexts.html b/js/xpconnect/tests/chrome/test_secureContexts.html
new file mode 100644
index 0000000000..956e609d5f
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_secureContexts.html
@@ -0,0 +1,58 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1273687
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1430164</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <iframe id="t" src="https://example.com"></iframe>
+  <iframe id="i" src="http://example.com"></iframe>
+  <script type="application/javascript">
+  /** Test for Bug 1273687 **/
+  SimpleTest.waitForExplicitFinish();
+
+  window.onload = () => {
+    /* globals t, i */
+    runTest(t, true);
+    runTest(i, false);
+
+    // Check we can inherit the system principal
+    var s = new Cu.Sandbox(window, { wantGlobalProperties: ["isSecureContext"] } );
+    s.ok = ok;
+    Cu.evalInSandbox('ok(isSecureContext)', s);
+
+    // Check options insecure works
+    let sb = new Cu.Sandbox('https://www.example.com',
+                            { forceSecureContext: false,
+                              wantGlobalProperties:
+                              ["isSecureContext"]
+                            });
+    ok(!Cu.evalInSandbox('isSecureContext', sb));
+
+    // Check options secure works
+    let sb2 = new Cu.Sandbox('https://www.example.com',
+                            { forceSecureContext: true,
+                              wantGlobalProperties:
+                              ["isSecureContext"]
+                            });
+    ok(Cu.evalInSandbox('isSecureContext', sb2));
+    SimpleTest.finish();
+  };
+
+  // Check dom window inheritance works
+  function runTest(ifr, expectIsSecureContext) {
+    let frameWin = ifr.contentWindow;
+    let s = new Cu.Sandbox(frameWin, { wantGlobalProperties: ["isSecureContext"] });
+    is(expectIsSecureContext, Cu.evalInSandbox('isSecureContext', s));
+
+    // Ensure the implementation of 'wantGlobalProperties' matches the DOM window prototype
+    let s2 = new Cu.Sandbox(frameWin, { sandboxPrototype: frameWin });
+    is(expectIsSecureContext, Cu.evalInSandbox('isSecureContext', s2));
+  }
+  </script>
+</head>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_sharedChromeCompartment.html b/js/xpconnect/tests/chrome/test_sharedChromeCompartment.html
new file mode 100644
index 0000000000..b653f19751
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_sharedChromeCompartment.html
@@ -0,0 +1,63 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1517694
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1517694</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+"use strict";
+
+/** Test for Bug 1517694 **/
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+SimpleTest.waitForExplicitFinish();
+
+function go() {
+    var frame = $('subframe');
+    frame.onload = null;
+
+    var isSameCompartment = Cu.getJSTestingFunctions().isSameCompartment;
+
+    ok(isSameCompartment(window, frame.contentWindow),
+       "System window is in same compartment");
+
+    var sameCompSb = Cu.Sandbox(window);
+    ok(isSameCompartment(window, sameCompSb),
+       "System sandbox is in same compartment");
+
+    var ownCompSb = Cu.Sandbox(window, {freshCompartment: true});
+    ok(!isSameCompartment(window, ownCompSb),
+       "Sandbox created with freshCompartment is in separate compartment");
+
+    // Sandbox created in fresh-compartment sandbox must be in shared
+    // compartment.
+    var sb = Cu.evalInSandbox(`
+      let principal =
+        Cc["@mozilla.org/systemprincipal;1"].getService(Ci.nsIPrincipal);
+      Cu.Sandbox(principal)
+    `, ownCompSb);
+    ok(isSameCompartment(window, sb),
+       "System sandbox created in different compartment is in system compartment");
+
+    ok(isSameCompartment(window, XPCOMUtils),
+       "Object defined in JSM is in same compartment");
+
+    SimpleTest.finish();
+}
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1517694">Mozilla Bug 1517694</a>
+
+<iframe id="subframe" src="file_empty.html" onload="go()"></iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_weakmap_keys_preserved.xhtml b/js/xpconnect/tests/chrome/test_weakmap_keys_preserved.xhtml
new file mode 100644
index 0000000000..c7c5d4369d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_weakmap_keys_preserved.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=673468
+-->
+<window title="Mozilla Bug "
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id="
+     target="_blank">Mozilla Bug 673468</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 673468 **/
+
+  let system = Cc["@mozilla.org/systemprincipal;1"].createInstance();
+  let sandbox = Cu.Sandbox(system);
+  let map = new sandbox.WeakMap();
+  let obj = {};
+  map.set(obj, {});
+
+  Cu.forceGC();
+
+  ok(map.has(obj), "Weakmap still contains our wrapper!");
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_weakmap_keys_preserved2.xhtml b/js/xpconnect/tests/chrome/test_weakmap_keys_preserved2.xhtml
new file mode 100644
index 0000000000..faaaa8b9ac
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_weakmap_keys_preserved2.xhtml
@@ -0,0 +1,80 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=673468
+-->
+<window title="Mozilla Bug "
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a id="testelem" href="https://bugzilla.mozilla.org/show_bug.cgi?id="
+     target="_blank">Mozilla Bug 673468</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+  /** Test for Bug 673468 **/
+  SimpleTest.waitForExplicitFinish();
+  SpecialPowers.DOMWindowUtils.garbageCollect();
+
+  let get_live_dom = function () {
+    return document.getElementById("testelem");
+  };
+
+  let wrappers_as_keys_test = function () {
+    let e = new MessageEvent("foo", { bubbles: false, cancellable: false,
+                                      data: { dummy: document.createXULElement("foo") }});
+    window.eeeevent = e;
+
+    let live_dom = e.data.dummy;
+    let dead_dom = document.createElementNS("http://www.w3.org/1999/xhtml", "div");
+    let dead_child = document.createElementNS("http://www.w3.org/1999/xhtml", "div");
+    dead_dom.appendChild(dead_child);
+    is(dead_dom.children.length, 1, "children have wrong length");
+    let wrappee = {};
+
+    dead_dom.abcxyz = wrappee;
+
+    let system = Cc["@mozilla.org/systemprincipal;1"].createInstance();
+    let sandbox = Cu.Sandbox(system);
+
+    sandbox.wrapper = wrappee;
+    sandbox.value = dead_dom;
+    let map = Cu.evalInSandbox("wm = new WeakMap(); wm.set(wrapper, value); wm", sandbox);
+    sandbox.wrapper = null;
+    sandbox.value = null;
+
+    live_dom.xyzabc = {wrappee, m: map, sb: sandbox};
+
+    let key = ChromeUtils.nondeterministicGetWeakMapKeys(map)[0];
+    let value = map.get(key);
+    is(value.children.length, 1, "children have wrong length");
+  }
+
+  wrappers_as_keys_test();
+
+  let check_wrappers_as_keys = function () {
+    let live_dom = window.eeeevent.data.dummy;
+    let live_map = live_dom.xyzabc.m;
+    is(ChromeUtils.nondeterministicGetWeakMapKeys(live_map).length, 1,
+      "Map should not be empty.");
+    let key = ChromeUtils.nondeterministicGetWeakMapKeys(live_map)[0];
+    let value = live_map.get(key);
+    is(value.children.length, 1, "children have wrong length");
+  }
+
+  Cu.schedulePreciseGC(function () {
+    SpecialPowers.DOMWindowUtils.cycleCollect();
+    SpecialPowers.DOMWindowUtils.garbageCollect();
+
+    check_wrappers_as_keys();
+    SimpleTest.finish();
+  });
+
+  ]]>
+  </script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_weakref.xhtml b/js/xpconnect/tests/chrome/test_weakref.xhtml
new file mode 100644
index 0000000000..21986cbf34
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_weakref.xhtml
@@ -0,0 +1,32 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=484459
+-->
+<window title="Weakrefs"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <iframe type="content" id="ifr">
+    </iframe>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+    SimpleTest.waitForExplicitFinish();
+    var util = window.windowUtils;
+    var weakUtil = Cu.getWeakReference(util);
+    util = null;
+
+    function callback() {
+      ok(weakUtil.get(), "Should still be alive here");
+      SimpleTest.finish();
+    }
+
+    SpecialPowers.exactGC(callback);
+  ]]></script>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_windowProxyDeadWrapper.html b/js/xpconnect/tests/chrome/test_windowProxyDeadWrapper.html
new file mode 100644
index 0000000000..7970c1ae70
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_windowProxyDeadWrapper.html
@@ -0,0 +1,76 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1223372
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1223372</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+/** Test for Bug 1223372 **/
+const {TestUtils} = ChromeUtils.import("resource://testing-common/TestUtils.jsm");
+
+async function go() {
+    SimpleTest.waitForExplicitFinish();
+    await SpecialPowers.pushPrefEnv({"set": [["security.allow_eval_with_system_principal",
+                                             true]]});
+
+    var frame = $('subframe');
+    frame.onload = null;
+
+    var w = frame.contentWindow;
+
+    w.eval("checkDead = function() { return Components.utils.isDeadWrapper(this); };");
+    var checkDead = w.checkDead;
+
+    w.eval("getObject = function() { return {}; }");
+    var getObject = w.getObject;
+
+    ok(!checkDead(), "WindowProxy shouldn't be dead yet");
+
+    // Load a content page in the chrome frame.
+    w.location = "https://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html";
+    tryWindow();
+
+    function tryWindow() {
+        if (w.document.title != 'empty test page') {
+            info("Document not loaded yet - retrying");
+            SimpleTest.executeSoon(tryWindow);
+            return;
+        }
+
+        let winID = w.docShell.outerWindowID;
+        // Remove the frame. This will nuke the WindowProxy wrapper from our chrome
+        // document's global, so evaluating 'this' in it will return a dead wrapper
+        // once the window is destroyed.
+        frame.remove();
+
+        TestUtils.topicObserved("outer-window-nuked", (subject, data) => {
+            let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
+            return id == winID;
+        }).then(() => {
+            ok(checkDead(), "Expected a dead object wrapper");
+
+            // Wrapping the Window should return a dead wrapper now.
+            var global = Cu.getGlobalForObject(getObject());
+            ok(Cu.isDeadWrapper(global),
+               "Expected a dead wrapper when requesting the window's global");
+
+            SimpleTest.finish();
+        });
+    }
+}
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1223372">Mozilla Bug 1223372</a>
+
+<iframe id="subframe" src="./file_empty.html" onload="go()"></iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_wrappers.xhtml b/js/xpconnect/tests/chrome/test_wrappers.xhtml
new file mode 100644
index 0000000000..73c808a9df
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_wrappers.xhtml
@@ -0,0 +1,85 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500931
+-->
+<window title="Mozilla Bug 500931"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=533596"
+     target="_blank">Mozilla Bug 533596</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+
+  /** Test for Bug 533596 **/
+
+  function go() {
+    var win = $('ifr').contentWindow;
+    var utils = window.windowUtils;
+    is(utils.getClassName(window), "Proxy", "our window is wrapped correctly")
+    is(utils.getClassName(location), "Location", "chrome doesn't have location wrappers")
+    is(utils.getClassName(win), "Proxy", "win is an Proxy");
+    is(utils.getClassName(win.location), "Proxy", "deep wrapping works");
+    is(win.location.href, "https://example.org/tests/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html",
+       "can still get strings out");
+
+    var unsafeWin = win.wrappedJSObject;
+    is(utils.getClassName(unsafeWin), "Proxy", "can get a Proxy");
+    is(utils.getClassName(unsafeWin.location), "Proxy", "deep wrapping works");
+
+    Object.defineProperty(unsafeWin, "defprop1", { value: 1, writable: true, enumerable: true, configurable: true });
+    /* TODO (bug 552854): the getter isn't visible in content.
+    function checkWrapper(val) {
+        ok(utils.getClassName(val) == "Proxy", "wrapped properly");
+    }
+    Object.defineProperty(unsafeWin, "defprop2", { set: checkWrapper, enumerable: true, configurable: true });
+    */
+    unsafeWin.run_test(ok, win, unsafeWin);
+
+    win.setTimeout(function() {
+                       is(utils.getClassName(this), "Proxy",
+                          "this is wrapped correctly");
+                       SimpleTest.finish();
+                   }, 0)
+
+   var saw0 = false;
+   for (let i in $('ifr').contentDocument.getElementsByTagName('body')) {
+       if (i === "0")
+           saw0 = true;
+   }
+   ok(saw0, "properly enumerated the 0 value");
+
+   ok(win.XPathEvaluator.toString().includes("XPathEvaluator"),
+      "Can access content window.XPathEvaluator");
+
+   var nativeToString =
+       ("" + Math.sin).replace("sin", "EventTarget");
+   var eventTargetToString = "" + win.EventTarget;
+   ok(eventTargetToString.indexOf(nativeToString) > -1,
+      "Stringifying a DOM interface object should return the same string as " +
+      "stringifying a native function. " + eventTargetToString + " " + nativeToString);
+
+   is(win.XPathResult.NUMBER_TYPE, 1, "can access constants on constructors");
+   is(typeof win.IDBKeyRange.bound, "function", "can access crazy IDBKeyRange static functions");
+
+   // Test getter/setter lookup on Xray wrappers.
+   ok(Object.prototype.__lookupGetter__.call(win.document, 'title'), 'found getter on document');
+   ok(Object.prototype.__lookupGetter__.call(win.document, 'title'), 'found getter on document');
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  ]]></script>
+  <iframe type="content"
+          src="https://example.org/tests/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html"
+          onload="go()"
+          id="ifr">
+  </iframe>
+</window>
diff --git a/js/xpconnect/tests/chrome/test_xrayLargeTypedArray.html b/js/xpconnect/tests/chrome/test_xrayLargeTypedArray.html
new file mode 100644
index 0000000000..dcb0b87380
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_xrayLargeTypedArray.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1674777
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1674777</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://global/skin"/>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+/** Test for Bug 1674777 **/
+
+function go() {
+    SimpleTest.waitForExplicitFinish();
+
+    let win = document.getElementById('ifr').contentWindow;
+
+    const nbytes = 3 * 1024 * 1024 * 1024; // 3 GB.
+    let tarray = new win.Int8Array(nbytes);
+    ok(Cu.isXrayWrapper(tarray), "Should be Xray");
+    is(tarray.length, nbytes, "Length should match");
+    is(tarray.byteLength, nbytes, "byteLength should match");
+
+    // Expect OOM when getting all property names.
+    let ex;
+    try {
+        Object.getOwnPropertyNames(tarray);
+    } catch (e) {
+        ex = e;
+    }
+    is(ex, "out of memory", "Expected OOM");
+
+    SimpleTest.finish();
+}
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1674777">Mozilla Bug 1674777</a>
+
+<iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/chrome/test_xrayToJS.xhtml b/js/xpconnect/tests/chrome/test_xrayToJS.xhtml
new file mode 100644
index 0000000000..fbfa67e61d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_xrayToJS.xhtml
@@ -0,0 +1,1191 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=933681
+-->
+<window title="Mozilla Bug 933681"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=933681"
+     target="_blank">Mozilla Bug 933681</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  /** Test for ES constructors on Xrayed globals. **/
+  SimpleTest.waitForExplicitFinish();
+  let global = Cu.getGlobalForObject.bind(Cu);
+
+  function checkThrows(f, rgxp, msg) {
+    try {
+      f();
+      ok(false, "Should have thrown: " + msg);
+    } catch (e) {
+      ok(true, "Threw as expected: " + msg);
+      ok(rgxp.test(e), "Message correct: " + e);
+    }
+  }
+
+  var { AppConstants } = SpecialPowers.ChromeUtils.import(
+    "resource://gre/modules/AppConstants.jsm"
+  );
+  var isNightlyBuild = AppConstants.NIGHTLY_BUILD;
+  var isReleaseOrBeta = AppConstants.RELEASE_OR_BETA;
+
+  let typedArrayClasses = ['Uint8Array', 'Int8Array', 'Uint16Array', 'Int16Array',
+                           'Uint32Array', 'Int32Array', 'Float32Array', 'Float64Array',
+                           'Uint8ClampedArray'];
+  let errorObjectClasses = ['Error', 'InternalError', 'EvalError', 'RangeError', 'ReferenceError',
+                            'SyntaxError', 'TypeError', 'URIError', 'AggregateError'];
+
+  // A simpleConstructors entry can either be the name of a constructor as a
+  // string, or an object containing the properties `name`, and `args`.
+  // In the former case, the constructor is invoked without any args; in the
+  // latter case, it is invoked with `args` as the arguments list.
+  let simpleConstructors = ['Object', 'Function', 'Array', 'Boolean', 'Date', 'Number',
+                            'String', 'RegExp', 'ArrayBuffer', 'WeakMap', 'WeakSet', 'Map', 'Set',
+                            {name: 'Promise', args: [function(){}]}];
+
+  // All TypedArray constructors can be called with zero arguments.
+  simpleConstructors = simpleConstructors.concat(typedArrayClasses);
+
+  // All Error constructors except AggregateError can be called with zero arguments.
+  simpleConstructors = simpleConstructors.concat(errorObjectClasses.filter(name => {
+    return name !== 'AggregateError';
+  }));
+
+  function go() {
+    window.iwin = document.getElementById('ifr').contentWindow;
+    /* global iwin */
+
+    // Test constructors that can be instantiated with zero arguments, or with
+    // a fixed set of arguments provided using `...rest`.
+    for (let c of simpleConstructors) {
+      var args = [];
+      if (typeof c === 'object') {
+        args = c.args;
+        c = c.name;
+      }
+      ok(iwin[c], "Constructors appear: " + c);
+      is(iwin[c], Cu.unwaiveXrays(iwin.wrappedJSObject[c]),
+         "we end up with the appropriate constructor: " + c);
+      is(Cu.unwaiveXrays(Cu.waiveXrays(new iwin[c](...args)).constructor), iwin[c],
+         "constructor property is set up right: " + c);
+      let expectedProto = Cu.isOpaqueWrapper(new iwin[c](...args)) ?
+        iwin.Object.prototype : iwin[c].prototype;
+      is(Object.getPrototypeOf(new iwin[c](...args)), expectedProto,
+         "prototype is correct: " + c);
+      is(global(new iwin[c](...args)), iwin, "Got the right global: " + c);
+    }
+
+    // Test Object in more detail.
+    var num = new iwin.Object(4);
+    is(Cu.waiveXrays(num).valueOf(), 4, "primitive object construction works");
+    is(global(num), iwin, "correct global for num");
+    var obj = new iwin.Object();
+    obj.foo = 2;
+    var withProto = Cu.unwaiveXrays(Cu.waiveXrays(iwin).Object.create(obj));
+    is(global(withProto), iwin, "correct global for withProto");
+    is(Cu.waiveXrays(withProto).foo, 2, "Inherits properly");
+
+    // Test Function.
+    var primitiveFun = new iwin.Function('return 2');
+    is(global(primitiveFun), iwin, "function construction works");
+    is(primitiveFun(), 2, "basic function works");
+    var doSetFoo = new iwin.Function('arg', 'arg.foo = 2;');
+    is(global(doSetFoo), iwin, "function with args works");
+    try {
+      doSetFoo({});
+      ok(false, "should have thrown while setting property on object");
+    } catch (e) {
+      ok(!!/denied/.test(e), "Threw correctly: " + e);
+    }
+    var factoryFun = new iwin.Function('return {foo: 32}');
+    is(global(factoryFun), iwin, "proper global for factoryFun");
+    is(factoryFun().foo, 32, "factoryFun invokable");
+    is(global(factoryFun()), iwin, "minted objects live in the content scope");
+    testXray('Function', factoryFun, new iwin.Function(), ['length', 'name']);
+    var echoThis = new iwin.Function('return this;');
+    echoThis.wrappedJSObject.bind = 42;
+    var boundEchoThis = echoThis.bind(document);
+    is(boundEchoThis(), document, "bind() works correctly over Xrays");
+    is(global(boundEchoThis), window, "bound functions live in the caller's scope");
+    ok(/return this/.test(echoThis.toSource()), 'toSource works: ' + echoThis.toSource());
+    ok(/return this/.test(echoThis.toString()), 'toString works: ' + echoThis.toString());
+    is(iwin.Function.prototype, Object.getPrototypeOf(echoThis), "Function.prototype works for standard classes");
+    is(echoThis.prototype, undefined, "Function.prototype not visible for non standard constructors");
+    iwin.eval('var foopyFunction = function namedFoopyFunction(a, b, c) {}');
+    var foopyFunction = Cu.unwaiveXrays(Cu.waiveXrays(iwin).foopyFunction);
+    ok(Cu.isXrayWrapper(foopyFunction), "Should be Xrays");
+    is(foopyFunction.name, "namedFoopyFunction", ".name works over Xrays");
+    is(foopyFunction.length, 3, ".length works over Xrays");
+    ok(Object.getOwnPropertyNames(foopyFunction).includes('length'), "Should list length");
+    ok(Object.getOwnPropertyNames(foopyFunction).includes('name'), "Should list name");
+    ok(!Object.getOwnPropertyNames(foopyFunction).includes('prototype'), "Should not list prototype");
+    ok(Object.getOwnPropertyNames(iwin.Array).includes('prototype'), "Should list prototype for standard constructor");
+
+    // Test BoundFunction.
+    iwin.eval('var boundFoopyFunction = foopyFunction.bind(null, 1)');
+    var boundFoopyFunction = Cu.unwaiveXrays(Cu.waiveXrays(iwin).boundFoopyFunction);
+    is(boundFoopyFunction.name, "bound namedFoopyFunction", "bound .name works over Xrays");
+    is(boundFoopyFunction.length, 2, "bound .length works over Xrays");
+    is(JSON.stringify(Object.getOwnPropertyNames(boundFoopyFunction).sort()), '["length","name"]', "Should list length and name");
+    // Mutate .name, it's just a data property.
+    iwin.eval('Object.defineProperty(boundFoopyFunction, "name", {value: "foobar", configurable: true, writable: true});');
+    is(boundFoopyFunction.name, "foobar", "mutated .name works over Xrays");
+    iwin.eval('boundFoopyFunction.name = 123;');
+    is(boundFoopyFunction.name, undefined, "only support string for .name");
+    iwin.eval('delete boundFoopyFunction.name');
+    is(boundFoopyFunction.name, undefined, "deleted .name works over Xrays");
+    // Mutate .length.
+    iwin.eval('Object.defineProperty(boundFoopyFunction, "length", {value: 456, configurable: true, writable: true});');
+    is(boundFoopyFunction.length, 456, "mutated .length works over Xrays");
+    iwin.eval('boundFoopyFunction.length = "bar";');
+    is(boundFoopyFunction.length, undefined, "only support number for .length");
+
+    // Test proxies.
+    var targetObject = new iwin.Object();
+    targetObject.foo = 9;
+    var forwardingProxy = new iwin.Proxy(targetObject, new iwin.Object());
+    is(global(forwardingProxy), iwin, "proxy global correct");
+    is(Cu.waiveXrays(forwardingProxy).foo, 9, "forwards correctly");
+
+    // Test AggregateError.
+    {
+      // AggregateError throws when called without an iterable object as its first argument.
+      let args = [new iwin.Array()];
+
+      ok(iwin.AggregateError, "AggregateError constructor is present");
+      is(iwin.AggregateError, Cu.unwaiveXrays(iwin.wrappedJSObject.AggregateError),
+         "we end up with the appropriate AggregateError constructor");
+      is(Cu.unwaiveXrays(Cu.waiveXrays(new iwin.AggregateError(...args)).constructor), iwin.AggregateError,
+         "AggregateError constructor property is set up right");
+      let expectedProto =  Cu.isOpaqueWrapper(new iwin.AggregateError(...args)) ?
+        iwin.Object.prototype : iwin.AggregateError.prototype;
+      is(Object.getPrototypeOf(new iwin.AggregateError(...args)), expectedProto,
+         "AggregateError prototype is correct");
+      is(global(new iwin.AggregateError(...args)), iwin, "Got the right global for AggregateError");
+    }
+
+    // Test eval.
+    var toEval = "({a: 2, b: {foo: 'bar'}, f: function() { return window; }})";
+    is(global(iwin.eval(toEval)), iwin, "eval creates objects in the correct global");
+    is(iwin.eval(toEval).b.foo, 'bar', "eval-ed object looks right");
+    is(Cu.waiveXrays(iwin.eval(toEval)).f(), Cu.waiveXrays(iwin), "evaled function works right");
+
+    testDate();
+
+    testObject();
+
+    testArray();
+
+    testTypedArrays();
+
+    testErrorObjects();
+
+    testRegExp();
+
+    testPromise();
+
+    testArrayBuffer();
+
+    testMap();
+
+    testSet();
+
+    testWeakMap();
+
+    testWeakSet();
+
+    testProxy();
+
+    testDataView();
+
+    testNumber();
+
+    SimpleTest.finish();
+  }
+
+  // Maintain a static list of the properties that are available on each standard
+  // prototype, so that we make sure to audit any new ones to make sure they're
+  // Xray-safe.
+  //
+  // DO NOT CHANGE WTIHOUT REVIEW FROM AN XPCONNECT PEER.
+  var gPrototypeProperties = {};
+  var gConstructorProperties = {};
+  function constructorProps(arr) {
+    // Some props live on all constructors
+    return arr.concat(["prototype", "length", "name"]);
+  }
+  gPrototypeProperties.Date =
+    ["getTime", "getTimezoneOffset", "getYear", "getFullYear", "getUTCFullYear",
+    "getMonth", "getUTCMonth", "getDate", "getUTCDate", "getDay", "getUTCDay",
+    "getHours", "getUTCHours", "getMinutes", "getUTCMinutes", "getSeconds",
+    "getUTCSeconds", "getMilliseconds", "getUTCMilliseconds", "setTime",
+    "setYear", "setFullYear", "setUTCFullYear", "setMonth", "setUTCMonth",
+    "setDate", "setUTCDate", "setHours", "setUTCHours", "setMinutes",
+    "setUTCMinutes", "setSeconds", "setUTCSeconds", "setMilliseconds",
+    "setUTCMilliseconds", "toUTCString", "toLocaleString",
+    "toLocaleDateString", "toLocaleTimeString", "toDateString", "toTimeString",
+    "toISOString", "toJSON", "toSource", "toString", "valueOf", "constructor",
+    "toGMTString", Symbol.toPrimitive];
+  gConstructorProperties.Date = constructorProps(["UTC", "parse", "now"]);
+  gPrototypeProperties.Object =
+    ["constructor", "toSource", "toString", "toLocaleString", "valueOf",
+     "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable",
+     "__defineGetter__", "__defineSetter__", "__lookupGetter__", "__lookupSetter__",
+     "__proto__"];
+  gConstructorProperties.Object =
+    constructorProps(["setPrototypeOf", "getOwnPropertyDescriptor", "getOwnPropertyDescriptors",
+                      "keys", "is", "defineProperty", "defineProperties", "create",
+                      "getOwnPropertyNames", "getOwnPropertySymbols",
+                      "preventExtensions", "freeze", "fromEntries", "isFrozen", "seal",
+                      "isSealed", "assign", "getPrototypeOf", "values",
+                      "entries", "isExtensible", "hasOwn"]);
+  gPrototypeProperties.Array =
+    ["length", "toSource", "toString", "toLocaleString", "join", "reverse", "sort", "push",
+      "pop", "shift", "unshift", "splice", "concat", "slice", "lastIndexOf", "indexOf",
+      "includes", "forEach", "map", "reduce", "reduceRight", "filter", "some", "every", "find",
+      "findIndex", "copyWithin", "fill", Symbol.iterator, Symbol.unscopables, "entries", "keys",
+      "values", "constructor", "flat", "flatMap", "at", "findLast", "findLastIndex",
+      "toReversed", "toSorted", "toSpliced", "with"];
+  gConstructorProperties.Array =
+    constructorProps(["isArray", "from", "fromAsync", "of", Symbol.species]);
+  for (let c of typedArrayClasses) {
+    gPrototypeProperties[c] = ["constructor", "BYTES_PER_ELEMENT"];
+    gConstructorProperties[c] = constructorProps(["BYTES_PER_ELEMENT"]);
+  }
+  // There is no TypedArray constructor, looks like.
+  is(window.TypedArray, undefined, "If this ever changes, add to this test!");
+  for (let c of errorObjectClasses) {
+      gPrototypeProperties[c] = ["constructor", "name", "message", "stack"];
+      gConstructorProperties[c] = constructorProps([]);
+  }
+  // toString and toSource only live on the parent proto (Error.prototype).
+  gPrototypeProperties.Error.push('toString');
+  gPrototypeProperties.Error.push('toSource');
+
+  gPrototypeProperties.Function =
+    ["constructor", "toSource", "toString", "apply", "call", "bind",
+     "length", "name", "arguments", "caller", Symbol.hasInstance];
+  gConstructorProperties.Function = constructorProps([])
+
+  gPrototypeProperties.RegExp =
+    ["constructor", "toSource", "toString", "compile", "exec", "test",
+     Symbol.match, Symbol.matchAll, Symbol.replace, Symbol.search, Symbol.split,
+     "flags", "dotAll", "global", "hasIndices", "ignoreCase", "multiline", "source", "sticky",
+     "unicode"];
+  gConstructorProperties.RegExp =
+    constructorProps(["input", "lastMatch", "lastParen",
+                      "leftContext", "rightContext", "$1", "$2", "$3", "$4",
+                      "$5", "$6", "$7", "$8", "$9", "$_", "$&", "$+",
+                      "$`", "$'", Symbol.species])
+
+  gPrototypeProperties.Promise =
+    ["constructor", "catch", "then", "finally", Symbol.toStringTag];
+  gConstructorProperties.Promise =
+    constructorProps(["resolve", "reject", "all", "allSettled", "any", "race", Symbol.species]);
+
+  gPrototypeProperties.ArrayBuffer =
+    ["constructor", "byteLength", "slice", Symbol.toStringTag];
+  gConstructorProperties.ArrayBuffer =
+    constructorProps(["isView", Symbol.species]);
+
+  gPrototypeProperties.SharedArrayBuffer = ["constructor", "slice", "byteLength", Symbol.toStringTag];
+  gConstructorProperties.SharedArrayBuffer = constructorProps([Symbol.species]);
+
+  gPrototypeProperties.Map =
+    ["constructor", "size", Symbol.toStringTag, "get", "has", "set", "delete",
+     "keys", "values", "clear", "forEach", "entries", Symbol.iterator];
+  gConstructorProperties.Map =
+    constructorProps([Symbol.species]);
+
+  gPrototypeProperties.Set =
+    ["constructor", "size", Symbol.toStringTag, "has", "add", "delete",
+     "keys", "values", "clear", "forEach", "entries", Symbol.iterator];
+  gConstructorProperties.Set =
+    constructorProps([Symbol.species]);
+
+  gPrototypeProperties.WeakMap =
+    ["constructor", Symbol.toStringTag, "get", "has", "set", "delete"];
+  gConstructorProperties.WeakMap =
+    constructorProps([]);
+
+  gPrototypeProperties.WeakSet =
+    ["constructor", Symbol.toStringTag, "has", "add", "delete"];
+  gConstructorProperties.WeakSet =
+    constructorProps([]);
+
+  gPrototypeProperties.DataView =
+    ["constructor", "buffer", "byteLength", "byteOffset", Symbol.toStringTag,
+     "getInt8", "getUint8", "getInt16", "getUint16",
+     "getInt32", "getUint32", "getFloat32", "getFloat64",
+     "setInt8", "setUint8", "setInt16", "setUint16",
+     "setInt32", "setUint32", "setFloat32", "setFloat64",
+     "getBigInt64", "getBigUint64", "setBigInt64", "setBigUint64"]
+  gConstructorProperties.DataView = constructorProps([]);
+
+  // Sort an array that may contain symbols as well as strings.
+  function sortProperties(arr) {
+    function sortKey(prop) {
+      return typeof prop + ":" + prop.toString();
+    }
+    arr.sort((a, b) => sortKey(a) < sortKey(b) ? -1 : +1);
+  }
+
+  // Sort all the lists so we don't need to mutate them later (or copy them
+  // again to sort them).
+  for (let c of Object.keys(gPrototypeProperties))
+    sortProperties(gPrototypeProperties[c]);
+  for (let c of Object.keys(gConstructorProperties))
+    sortProperties(gConstructorProperties[c]);
+
+  function filterOut(array, props) {
+    return array.filter(p => !props.includes(p));
+  }
+
+  function isTypedArrayClass(classname) {
+    return typedArrayClasses.includes(classname);
+  }
+
+  function propertyIsGetter(obj, name, classname) {
+    return !!Object.getOwnPropertyDescriptor(obj, name).get;
+  }
+
+  function testProtoCallables(protoCallables, xray, xrayProto, localProto) {
+    for (let name of protoCallables) {
+      info("Running tests for property: " + name);
+      // Test both methods and getter properties.
+      function lookupCallable(obj) {
+        let desc = null;
+        do {
+          desc = Object.getOwnPropertyDescriptor(obj, name);
+          if (desc) {
+            break;
+          }
+          obj = Object.getPrototypeOf(obj);
+        } while (obj);
+        return desc ? (desc.get || desc.value) : undefined;
+      };
+      ok(xrayProto.hasOwnProperty(name), `proto should have the property '${name}' as own`);
+      ok(!xray.hasOwnProperty(name), `instance should not have the property '${name}' as own`);
+      let method = lookupCallable(xrayProto);
+      is(typeof method, 'function', "Methods from Xrays are functions");
+      is(global(method), window, "Methods from Xrays are local");
+      ok(method instanceof Function, "instanceof works on methods from Xrays");
+      is(lookupCallable(xrayProto), method, "Holder caching works properly");
+      is(lookupCallable(xray), method, "Proto props resolve on the instance");
+      let local = lookupCallable(localProto);
+      is(method.length, local.length, "Function.length identical");
+      if (!method.length) {
+        is(method.call(xray) + "", local.call(xray) + "",
+           "Xray and local method results stringify identically");
+
+        // If invoking this method returns something non-Xrayable (opaque), the
+        // stringification is going to return [object Object].
+        // This happens for set[@@iterator] and other Iterator objects.
+        let callable = lookupCallable(xray.wrappedJSObject);
+        if (!Cu.isOpaqueWrapper(method.call(xray)) && callable) {
+          is(method.call(xray) + "",
+             callable.call(xray.wrappedJSObject) + "",
+             "Xray and waived method results stringify identically");
+        }
+      }
+    }
+  }
+
+  function testCtorCallables(ctorCallables, xrayCtor, localCtor) {
+    for (let name of ctorCallables) {
+      // Don't try to test Function.prototype, since that is in fact a callable
+      // but doesn't really do the things we expect callables to do here
+      // (e.g. it's in the wrong global, since it gets Xrayed itself).
+      if (name == "prototype" && localCtor.name == "Function") {
+        continue;
+      }
+      info(`Running tests for property: ${localCtor.name}.${name}`);
+      // Test both methods and getter properties.
+      function lookupCallable(obj) {
+        let desc = null;
+        do {
+          desc = Object.getOwnPropertyDescriptor(obj, name);
+          obj = Object.getPrototypeOf(obj);
+        } while (!desc);
+        return desc.get || desc.value;
+      };
+
+      ok(xrayCtor.hasOwnProperty(name), "ctor should have the property as own");
+      let method = lookupCallable(xrayCtor);
+      is(typeof method, 'function', "Methods from ctor Xrays are functions");
+      is(global(method), window, "Methods from ctor Xrays are local");
+      ok(method instanceof Function,
+         "instanceof works on methods from ctor Xrays");
+      is(lookupCallable(xrayCtor), method,
+         "Holder caching works properly on ctors");
+      let local = lookupCallable(localCtor);
+      is(method.length, local.length,
+         "Function.length identical for method from ctor");
+      // Don't try to do the return-value check on Date.now(), since there is
+      // absolutely no reason it should return the same value each time.
+      //
+      // Also don't try to do the return-value check on Regexp.lastMatch and
+      // Regexp["$&"] (which are aliases), because they get state off the global
+      // they live in, as far as I can tell, so testing them over Xrays will be
+      // wrong: on the Xray they will actaully get the lastMatch of _our_
+      // global, not the Xrayed one.
+      if (!method.length &&
+          !(localCtor.name == "Date" && name == "now") &&
+          !(localCtor.name == "RegExp" && (name == "lastMatch" || name == "$&"))) {
+        is(method.call(xrayCtor) + "", local.call(xrayCtor) + "",
+           "Xray and local method results stringify identically on constructors");
+        is(method.call(xrayCtor) + "",
+           lookupCallable(xrayCtor.wrappedJSObject).call(xrayCtor.wrappedJSObject) + "",
+           "Xray and waived method results stringify identically");
+      }
+    }
+  }
+
+  function testXray(classname, xray, xray2, propsToSkip, ctorPropsToSkip = []) {
+    propsToSkip = propsToSkip || [];
+    let xrayProto = Object.getPrototypeOf(xray);
+    let localProto = window[classname].prototype;
+    let desiredProtoProps = Object.getOwnPropertyNames(localProto).sort();
+
+    is(desiredProtoProps.toSource(),
+       gPrototypeProperties[classname].filter(id => typeof id === "string").toSource(),
+       "A property on the " + classname +
+       " prototype has changed! You need a security audit from an XPConnect peer");
+    is(Object.getOwnPropertySymbols(localProto).map(uneval).sort().toSource(),
+       gPrototypeProperties[classname].filter(id => typeof id !== "string").map(uneval).sort().toSource(),
+       "A symbol-keyed property on the " + classname +
+       " prototype has been changed! You need a security audit from an XPConnect peer");
+
+    let protoProps = filterOut(desiredProtoProps, propsToSkip);
+    let protoCallables = protoProps.filter(name => propertyIsGetter(localProto, name, classname) ||
+                                                   typeof localProto[name] == 'function' &&
+                                                   name != 'constructor');
+    ok(!!protoCallables.length, "Need something to test");
+    is(xrayProto, iwin[classname].prototype, "Xray proto is correct");
+    is(xrayProto, xray.__proto__, "Proto accessors agree");
+    var protoProto = classname == "Object" ? null : iwin.Object.prototype;
+    is(Object.getPrototypeOf(xrayProto), protoProto, "proto proto is correct");
+    testProtoCallables(protoCallables, xray, xrayProto, localProto);
+    is(Object.getOwnPropertyNames(xrayProto).sort().toSource(),
+       protoProps.toSource(), "getOwnPropertyNames works");
+    is(Object.getOwnPropertySymbols(xrayProto).map(uneval).sort().toSource(),
+       gPrototypeProperties[classname].filter(id => typeof id !== "string" && !propsToSkip.includes(id))
+         .map(uneval).sort().toSource(),
+       "getOwnPropertySymbols works");
+
+    is(xrayProto.constructor, iwin[classname], "constructor property works");
+
+    xrayProto.expando = 42;
+    is(xray.expando, 42, "Xrayed instances see proto expandos");
+    is(xray2.expando, 42, "Xrayed instances see proto expandos");
+
+    // Now test constructors
+    let localCtor = window[classname];
+    let xrayCtor = xrayProto.constructor;
+    // We already checked that this is the same as iwin[classname]
+
+    let desiredCtorProps =
+        Object.getOwnPropertyNames(localCtor).sort();
+    is(desiredCtorProps.toSource(),
+       gConstructorProperties[classname].filter(id => typeof id === "string").toSource(),
+       "A property on the " + classname +
+       " constructor has changed! You need a security audit from an XPConnect peer");
+    let desiredCtorSymbols =
+        Object.getOwnPropertySymbols(localCtor).map(uneval).sort()
+    is(desiredCtorSymbols.toSource(),
+       gConstructorProperties[classname].filter(id => typeof id !== "string").map(uneval).sort().toSource(),
+       "A symbol-keyed property on the " + classname +
+       " constructor has been changed! You need a security audit from an XPConnect peer");
+
+    let ctorProps = filterOut(desiredCtorProps, ctorPropsToSkip);
+    let ctorSymbols = filterOut(desiredCtorSymbols, ctorPropsToSkip.map(uneval));
+    let ctorCallables = ctorProps.filter(name => propertyIsGetter(localCtor, name, classname) ||
+                                         typeof localCtor[name] == 'function');
+    testCtorCallables(ctorCallables, xrayCtor, localCtor);
+    is(Object.getOwnPropertyNames(xrayCtor).sort().toSource(),
+       ctorProps.toSource(), "getOwnPropertyNames works on Xrayed ctors");
+    is(Object.getOwnPropertySymbols(xrayCtor).map(uneval).sort().toSource(),
+       ctorSymbols.toSource(), "getOwnPropertySymbols works on Xrayed ctors");
+  }
+
+  // We will need arraysEqual and testArrayIterators both in this global scope
+  // and in sandboxes.
+  function arraysEqual(arr1, arr2, reason) {
+    is(arr1.length, arr2.length, `${reason}; lengths should be equal`)
+    for (var i = 0; i < arr1.length; ++i) {
+      if (Array.isArray(arr2[i])) {
+        arraysEqual(arr1[i], arr2[i], `${reason}; item at index ${i}`);
+      } else {
+        is(arr1[i], arr2[i], `${reason}; item at index ${i} should be equal`);
+      }
+    }
+  }
+
+  function testArrayIterators(arrayLike, equivalentArray, reason) {
+    arraysEqual([...arrayLike], equivalentArray, `${reason}; spread operator`);
+    arraysEqual([...arrayLike.entries()], [...equivalentArray.entries()],
+                `${reason}; entries`);
+    arraysEqual([...arrayLike.keys()], [...equivalentArray.keys()],
+                `${reason}; keys`);
+    if (arrayLike.values) {
+      arraysEqual([...arrayLike.values()], equivalentArray,
+                  `${reason}; values`);
+    }
+
+    var forEachCopy = [];
+    arrayLike.forEach(function(arg) { forEachCopy.push(arg); });
+    arraysEqual(forEachCopy, equivalentArray, `${reason}; forEach copy`);
+
+    var everyCopy = [];
+    arrayLike.every(function(arg) { everyCopy.push(arg); return true; });
+    arraysEqual(everyCopy, equivalentArray, `${reason}; every() copy`);
+
+    var filterCopy = [];
+    var filterResult = arrayLike.filter(function(arg) {
+      filterCopy.push(arg);
+      return true;
+    });
+    arraysEqual(filterCopy, equivalentArray, `${reason}; filter copy`);
+    arraysEqual([...filterResult], equivalentArray, `${reason}; filter result`);
+
+    var findCopy = [];
+    arrayLike.find(function(arg) { findCopy.push(arg); return false; });
+    arraysEqual(findCopy, equivalentArray, `${reason}; find() copy`);
+
+    var findIndexCopy = [];
+    arrayLike.findIndex(function(arg) { findIndexCopy.push(arg); return false; });
+    arraysEqual(findIndexCopy, equivalentArray, `${reason}; findIndex() copy`);
+
+    var mapCopy = [];
+    var mapResult = arrayLike.map(function(arg) { mapCopy.push(arg); return arg});
+    arraysEqual(mapCopy, equivalentArray, `${reason}; map() copy`);
+    arraysEqual([...mapResult], equivalentArray, `${reason}; map() result`);
+
+    var reduceCopy = [];
+    arrayLike.reduce(function(_, arg) { reduceCopy.push(arg); }, 0);
+    arraysEqual(reduceCopy, equivalentArray, `${reason}; reduce() copy`);
+
+    var reduceRightCopy = [];
+    arrayLike.reduceRight(function(_, arg) { reduceRightCopy.unshift(arg); }, 0);
+    arraysEqual(reduceRightCopy, equivalentArray, `${reason}; reduceRight() copy`);
+
+    var someCopy = [];
+    arrayLike.some(function(arg) { someCopy.push(arg); return false; });
+    arraysEqual(someCopy, equivalentArray, `${reason}; some() copy`);
+  }
+
+  function testDate() {
+    // toGMTString is handled oddly in the engine. We don't bother to support
+    // it over Xrays.
+    let propsToSkip = ['toGMTString'];
+
+    testXray('Date', new iwin.Date(), new iwin.Date(), propsToSkip);
+
+    // Test the self-hosted toLocaleString.
+    var d = new iwin.Date();
+    isnot(d.toLocaleString, Cu.unwaiveXrays(d.wrappedJSObject.toLocaleString), "Different function identities");
+    is(Cu.getGlobalForObject(d.toLocaleString), window, "Xray global is correct");
+    is(Cu.getGlobalForObject(d.wrappedJSObject.toLocaleString), iwin, "Underlying global is correct");
+    is(d.toLocaleString('de-DE'), d.wrappedJSObject.toLocaleString('de-DE'), "Results match");
+  }
+
+  var uniqueSymbol;
+
+  function testObject() {
+    testXray('Object', Cu.unwaiveXrays(Cu.waiveXrays(iwin).Object.create(new iwin.Object())),
+             new iwin.Object(), []);
+
+    // Construct an object full of tricky things.
+    let symbolProps = '';
+    uniqueSymbol = iwin.eval('var uniqueSymbol = Symbol("uniqueSymbol"); uniqueSymbol');
+    symbolProps = `, [uniqueSymbol]: 43,
+                   [Symbol.for("registrySymbolProp")]: 44`;
+    var trickyObject =
+      iwin.eval(`(function() {
+                 var o = new Object({
+                   primitiveProp: 42, objectProp: { foo: 2 },
+                   xoProp: top, hasOwnProperty: 10,
+                   get getterProp() { return 2; },
+                   set setterProp(x) { },
+                   get getterSetterProp() { return 3; },
+                   set getterSetterProp(x) { },
+                   callableProp: function() { },
+                   nonXrayableProp: new Map()[Symbol.iterator]()
+                   ${symbolProps}
+                 });
+                 Object.defineProperty(o, "nonConfigurableGetterSetterProp",
+                    { get: function() { return 5; }, set: function() {} });
+                 return o;
+                 })()`);
+    testTrickyObject(trickyObject);
+  }
+
+  function testArray() {
+    // The |length| property is generally very weird, especially with respect
+    // to its behavior on the prototype. Array.prototype is actually an Array
+    // instance, and therefore has a vestigial .length. But we don't want to
+    // show that over Xrays, and generally want .length to just appear as an
+    // |own| data property. So we add it to the ignore list here, and check it
+    // separately.
+    //
+    // |Symbol.unscopables| should in principle be exposed, but it is
+    // inconvenient (as it's a data property, unsupported by ClassSpec) and
+    // low value.
+    let propsToSkip = ['length', Symbol.unscopables];
+
+    testXray('Array', new iwin.Array(20), new iwin.Array(), propsToSkip);
+
+    let symbolProps = '';
+    uniqueSymbol = iwin.eval('var uniqueSymbol = Symbol("uniqueSymbol"); uniqueSymbol');
+    symbolProps = `trickyArray[uniqueSymbol] = 43;
+                   trickyArray[Symbol.for("registrySymbolProp")] = 44;`;
+    var trickyArray =
+      iwin.eval(`var trickyArray = [];
+                 trickyArray.primitiveProp = 42;
+                 trickyArray.objectProp = { foo: 2 };
+                 trickyArray.xoProp = top;
+                 trickyArray.hasOwnProperty = 10;
+                 Object.defineProperty(trickyArray, 'getterProp', { get: function() { return 2; }});
+                 Object.defineProperty(trickyArray, 'setterProp', { set: function(x) {}});
+                 Object.defineProperty(trickyArray, 'getterSetterProp', { get: function() { return 3; }, set: function(x) {}, configurable: true});
+                 Object.defineProperty(trickyArray, 'nonConfigurableGetterSetterProp', { get: function() { return 5; }, set: function(x) {}});
+                 trickyArray.callableProp = function() {};
+                 trickyArray.nonXrayableProp = new Map()[Symbol.iterator]();
+                 ${symbolProps}
+                 trickyArray;`);
+
+    // Test indexed access.
+    trickyArray.wrappedJSObject[9] = "some indexed property";
+    is(trickyArray[9], "some indexed property", "indexed properties work correctly over Xrays");
+    is(trickyArray.length, 10, "Length works correctly over Xrays");
+    checkThrows(function() { "use strict"; delete trickyArray.length; }, /config/, "Can't delete non-configurable 'length' property");
+    delete trickyArray[9];
+    is(trickyArray[9], undefined, "Delete works correctly over Xrays");
+    is(trickyArray.wrappedJSObject[9], undefined, "Delete works correctly over Xrays (viewed via waiver)");
+    is(trickyArray.length, 10, "length doesn't change");
+    trickyArray[11] = "some other indexed property";
+    is(trickyArray.length, 12, "length now changes");
+    is(trickyArray.wrappedJSObject[11], "some other indexed property");
+    trickyArray.length = 0;
+    is(trickyArray.length, 0, "Setting length works over Xray");
+    is(trickyArray[11], undefined, "Setting length truncates over Xray");
+    Object.defineProperty(trickyArray, 'length', { configurable: false, enumerable: false, writable: false, value: 0 });
+    trickyArray[1] = "hi";
+    is(trickyArray.length, 0, "Length remains non-writable");
+    is(trickyArray[1], undefined, "Frozen length forbids new properties");
+    is(trickyArray instanceof iwin.Array, true, "instanceof should work across xray wrappers.");
+    testTrickyObject(trickyArray);
+
+    testArrayIterators(new iwin.Array(1, 1, 2, 3, 5), [1, 1, 2, 3, 5]);
+  }
+
+  // Parts of this function are kind of specific to testing Object, but we factor
+  // it out so that we can re-use the trickyObject stuff on Arrays.
+  function testTrickyObject(trickyObject) {
+
+    // Make sure it looks right under the hood.
+    is(trickyObject.wrappedJSObject.getterProp, 2, "Underlying object has getter");
+    is(Cu.unwaiveXrays(trickyObject.wrappedJSObject.xoProp), top, "Underlying object has xo property");
+
+    // Test getOwnPropertyNames.
+    var expectedNames = ['objectProp', 'primitiveProp'];
+    if (trickyObject instanceof iwin.Array)
+      expectedNames.push('length');
+    is(Object.getOwnPropertyNames(trickyObject).sort().toSource(),
+       expectedNames.sort().toSource(), "getOwnPropertyNames should be filtered correctly");
+    var expectedSymbols = [Symbol.for("registrySymbolProp"), uniqueSymbol];
+    is(Object.getOwnPropertySymbols(trickyObject).map(uneval).sort().toSource(),
+       expectedSymbols.map(uneval).sort().toSource(),
+       "getOwnPropertySymbols should be filtered correctly");
+
+    // Test that cloning uses the Xray view.
+    var cloned = Cu.cloneInto(trickyObject, this);
+    is(Object.getOwnPropertyNames(cloned).sort().toSource(),
+       expectedNames.sort().toSource(), "structured clone should use the Xray view");
+    is(Object.getOwnPropertySymbols(cloned).map(uneval).sort().toSource(),
+       "[]", "structured cloning doesn't clone symbol-keyed properties yet");
+
+    // Test iteration and in-place modification. Beware of 'expando', which is the property
+    // we placed on the xray proto.
+    var propCount = 0;
+    for (let prop in trickyObject) {
+      if (prop == 'primitiveProp')
+        trickyObject[prop] = trickyObject[prop] - 10;
+      if (prop != 'expando') {
+        // eslint-disable-next-line no-self-assign
+        trickyObject[prop] = trickyObject[prop];
+      }
+      ++propCount;
+    }
+    is(propCount, 3, "Should iterate the correct number of times");
+
+    // Test Object.keys.
+    is(Object.keys(trickyObject).sort().toSource(),
+       ['objectProp', 'primitiveProp'].toSource(), "Object.keys should be filtered correctly");
+
+    // Test getOwnPropertyDescriptor.
+    is(trickyObject.primitiveProp, 32, "primitive prop works");
+    is(trickyObject.objectProp.foo, 2, "object prop works");
+    is(typeof trickyObject.callableProp, 'undefined', "filtering works correctly");
+    is(Object.getOwnPropertyDescriptor(trickyObject, 'primitiveProp').value, 32, "getOwnPropertyDescriptor works");
+    is(Object.getOwnPropertyDescriptor(trickyObject, 'xoProp'), undefined, "filtering works with getOwnPropertyDescriptor");
+
+    // Test defineProperty.
+
+    trickyObject.primitiveSetByXray = 'fourty two';
+    is(trickyObject.primitiveSetByXray, 'fourty two', "Can set primitive correctly over Xray (ready via Xray)");
+    is(trickyObject.wrappedJSObject.primitiveSetByXray, 'fourty two', "Can set primitive correctly over Xray (ready via Waiver)");
+
+    var newContentObject = iwin.eval('new Object({prop: 99, get getterProp() { return 2; }})');
+    trickyObject.objectSetByXray = newContentObject;
+    is(trickyObject.objectSetByXray.prop, 99, "Can set object correctly over Xray (ready via Xray)");
+    is(trickyObject.wrappedJSObject.objectSetByXray.prop, 99, "Can set object correctly over Xray (ready via Waiver)");
+    checkThrows(function() { trickyObject.rejectedProp = {foo: 33}}, /cross-origin object/,
+                "Should reject privileged object property definition");
+
+    // Test JSON.stringify.
+    var jsonStr = JSON.stringify(newContentObject);
+    ok(/prop/.test(jsonStr), "JSON stringification should work: " + jsonStr);
+
+    // Test deletion.
+    delete newContentObject.prop;
+    ok(!newContentObject.hasOwnProperty('prop'), "Deletion should work");
+    ok(!newContentObject.wrappedJSObject.hasOwnProperty('prop'), "Deletion should forward");
+    delete newContentObject.getterProp;
+    ok(newContentObject.wrappedJSObject.hasOwnProperty('getterProp'), "Deletion be no-op for filtered property");
+
+    // We should be able to overwrite an existing accessor prop and convert it
+    // to a value prop.
+    is(trickyObject.wrappedJSObject.getterSetterProp, 3, "Underlying object has getter");
+    is(trickyObject.getterSetterProp, undefined, "Filtering properly over Xray");
+    trickyObject.getterSetterProp = 'redefined';
+    is(trickyObject.getterSetterProp, 'redefined', "Redefinition works");
+    is(trickyObject.wrappedJSObject.getterSetterProp, 'redefined', "Redefinition forwards");
+
+    // We should NOT be able to overwrite an existing non-configurable accessor
+    // prop, though.
+    is(trickyObject.wrappedJSObject.nonConfigurableGetterSetterProp, 5,
+       "Underlying object has getter");
+    is(trickyObject.nonConfigurableGetterSetterProp, undefined,
+       "Filtering properly over Xray here too");
+    is((trickyObject.nonConfigurableGetterSetterProp = 'redefined'), 'redefined',
+       "Assigning to non-configurable prop should fail silently in non-strict mode");
+    checkThrows(function() {
+      "use strict";
+      trickyObject.nonConfigurableGetterSetterProp = 'redefined';
+    }, /config/, "Should throw when redefining non-configurable prop in strict mode");
+    is(trickyObject.nonConfigurableGetterSetterProp, undefined,
+       "Redefinition should have failed");
+    is(trickyObject.wrappedJSObject.nonConfigurableGetterSetterProp, 5,
+       "Redefinition really should have failed");
+
+    checkThrows(function() { trickyObject.hasOwnProperty = 33; }, /shadow/,
+                "Should reject shadowing of pre-existing inherited properties over Xrays");
+
+    checkThrows(function() { Object.defineProperty(trickyObject, 'rejectedProp', { get() {}}); },
+                /accessor property/, "Should reject accessor property definition");
+  }
+
+  function testTypedArrays() {
+    // We don't invoke testXray with %TypedArray%, because that function isn't
+    // set up to deal with "anonymous" dependent classes (that is, classes not
+    // visible as a global property, which %TypedArray% is not), and fixing it
+    // up is more trouble than it's worth.
+
+    var typedArrayProto = Object.getPrototypeOf(Int8Array.prototype);
+
+    var desiredInheritedProps = Object.getOwnPropertyNames(typedArrayProto).sort();
+    var inheritedProps =
+      filterOut(desiredInheritedProps, ["BYTES_PER_ELEMENT", "constructor"]);
+
+    var inheritedCallables =
+      inheritedProps.filter(name => (propertyIsGetter(typedArrayProto, name) ||
+                                     typeof typedArrayProto[name] === "function") &&
+                                    name !== "constructor");
+
+    for (let c of typedArrayClasses) {
+      var t = new iwin[c](10);
+      checkThrows(function() { t[2]; }, /performant/, "direct property-wise reading of typed arrays forbidden over Xrays");
+      checkThrows(function() { t[2] = 3; }, /performant/, "direct property-wise writing of typed arrays forbidden over Xrays");
+      var wesb = new Cu.Sandbox([iwin], {isWebExtensionContentScript: true});
+      wesb.t = t;
+      wesb.eval('t[2] = 3');
+      is(wesb.eval('t.wrappedJSObject[2]'), 3, "direct property-wise writing of typed arrays allowed for WebExtension content scripts");
+      is(wesb.eval('t[2]'), 3, "direct property-wise reading and writing of typed arrays allowed for WebExtensions content scripts");
+
+      t.wrappedJSObject[2] = 3;
+      is(t.wrappedJSObject[2], 3, "accessing elements over waivers works");
+      t.wrappedJSObject.expando = 'hi';
+      is(t.wrappedJSObject.expando, 'hi', "access expandos over waivers works");
+      is(Cu.cloneInto(t, window)[2], 3, "cloneInto works");
+      is(Cu.cloneInto(t, window).expando, undefined, "cloneInto does not copy expandos");
+      is(Object.getOwnPropertyNames(t).sort().toSource(),
+         '["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]',
+         "Only indexed properties visible over Xrays");
+      Object.defineProperty(t.wrappedJSObject, 'length', {value: 42});
+      is(t.wrappedJSObject.length, 42, "Set tricky expando")
+      is(t.length, 10, "Length accessor works over Xrays")
+      is(t.byteLength, t.length * window[c].prototype.BYTES_PER_ELEMENT, "byteLength accessor works over Xrays")
+
+      // Can create TypedArray from content ArrayBuffer
+      var buffer = new iwin.ArrayBuffer(8);
+      new window[c](buffer);
+
+      var xray = new iwin[c](0);
+      var xrayTypedArrayProto = Object.getPrototypeOf(Object.getPrototypeOf(xray));
+      testProtoCallables(inheritedCallables, new iwin[c](0), xrayTypedArrayProto, typedArrayProto);
+
+      // When testing iterators, make sure to do so from inside our web
+      // extension sandbox, since from chrome we can't poke their indices.  Note
+      // that we have to actually recreate our functions that touch typed array
+      // indices inside the sandbox, not just export them, because otherwise
+      // they'll just run with our principal anyway.
+      //
+      // But we do want to export is(), since we want ours called.
+      wesb.eval(String(arraysEqual));
+      wesb.eval(String(testArrayIterators));
+      Cu.exportFunction(is, wesb,
+                        { defineAs: "is" });
+      wesb.eval('testArrayIterators(t, [0, 0, 3, 0, 0, 0, 0, 0, 0, 0])');
+    }
+  }
+
+  function testErrorObjects() {
+    // We only invoke testXray with Error, because that function isn't set up
+    // to deal with dependent classes and fixing it up is more trouble than
+    // it's worth.
+    testXray('Error', new iwin.Error('some error message'), new iwin.Error());
+
+    // Make sure that the dependent classes have their prototypes set up correctly.
+    for (let c of errorObjectClasses.filter(x => x != "Error")) {
+      var args = ['some message'];
+      if (c === 'AggregateError') {
+        // AggregateError's first argument is the list of aggregated errors.
+        args.unshift(new iwin.Array('error 1', 'error 2'));
+      }
+      var e = new iwin[c](...args);
+      is(Object.getPrototypeOf(e).name, c, "Prototype has correct name");
+      is(Object.getPrototypeOf(Object.getPrototypeOf(e)), iwin.Error.prototype, "Dependent prototype set up correctly");
+      is(e.name, c, "Exception name inherited correctly");
+
+      function testProperty(name, criterion, goodReplacement, faultyReplacement) {
+        ok(criterion(e[name]), name + " property is correct: " + e[name]);
+        e.wrappedJSObject[name] = goodReplacement;
+        is(e[name], goodReplacement, name + " property ok after replacement: " + goodReplacement);
+        e.wrappedJSObject[name] = faultyReplacement;
+        is(e[name], name == 'message' ? "" : undefined, name + " property skipped after suspicious replacement");
+      }
+      testProperty('message', x => x == 'some message', 'some other message', 42);
+      testProperty('fileName', x => x == '', 'otherFilename.html', new iwin.Object());
+      testProperty('columnNumber', x => x == 1, 99, 99.5);
+      testProperty('lineNumber', x => x == 0, 50, 'foo');
+
+      if (c === 'AggregateError') {
+        let {errors} = e;
+        is(errors.length, 2, "errors property has the correct length");
+        is(errors[0], 'error 1', "errors[0] has the correct value");
+        is(errors[1], 'error 2', "errors[1] has the correct value");
+
+        e.wrappedJSObject.errors = 42;
+        is(e.wrappedJSObject.errors, 42, "errors is a plain data property");
+        is(e.errors, 42, "visible over Xrays");
+      }
+
+      // Note - an Exception newed via Xrays is going to have an empty stack given the
+      // current semantics and implementation. This tests the current behavior, but that
+      // may change in bug 1036527 or similar.
+      //
+      // Furthermore, xrays should always return an error's original stack, and
+      // not overwrite it.
+      var stack = e.stack;
+      ok(/^\s*$/.test(stack), "stack property should be correct");
+      e.wrappedJSObject.stack = "not a stack";
+      is(e.stack, stack, "Xrays should never get an overwritten stack property.");
+
+      // Test the .cause property is correctly handled, too.
+      if (isNightlyBuild) {
+        let cause = 'error cause';
+        let options = new iwin.Object();
+        options.cause = cause;
+        args.push(options);
+
+        let e = new iwin[c](...args);
+        is(e.cause, cause);
+
+        e.wrappedJSObject.cause = 42;
+        is(e.wrappedJSObject.cause, 42, "cause is a plain data property");
+        is(e.cause, 42, "visible over Xrays");
+      }
+    }
+  }
+
+  function testRegExp() {
+    // RegExp statics are very weird, and in particular RegExp has static
+    // properties that have to do with the last regexp execution in the global.
+    // Xraying those makes no sense, so we just skip constructor properties for
+    // RegExp xrays.
+    // RegExp[@@species] is affected by above skip, but we don't fix it until
+    // compelling use-case appears, as supporting RegExp[@@species] while
+    // skipping other static properties makes things complicated.
+    let ctorPropsToSkip = ["input", "lastMatch", "lastParen",
+                           "leftContext", "rightContext", "$1", "$2", "$3",
+                           "$4", "$5", "$6", "$7", "$8", "$9", "$_", "$&",
+                           "$+", "$`", "$'", Symbol.species];
+    testXray('RegExp', new iwin.RegExp('foo'), new iwin.RegExp(), [],
+             ctorPropsToSkip);
+
+    // Test the self-hosted |flags| property, toString, and toSource.
+    for (var flags of ["", "g", "i", "m", "y", "gimy"]) {
+      var re = new iwin.RegExp("foo", flags);
+      is(re.flags, re.wrappedJSObject.flags, "Results match");
+
+      isnot(re.toString, Cu.unwaiveXrays(re.wrappedJSObject.toString), "Different function identities");
+      is(Cu.getGlobalForObject(re.toString), window, "Xray global is correct");
+      is(Cu.getGlobalForObject(re.wrappedJSObject.toString), iwin, "Underlying global is correct");
+      is(re.toString(), re.wrappedJSObject.toString(), "Results match");
+
+      isnot(re.toSource, Cu.unwaiveXrays(re.wrappedJSObject.toSource), "Different function identities");
+      is(Cu.getGlobalForObject(re.toSource), window, "Xray global is correct");
+      if (re.wrappedJSObject.toSource) {
+        is(Cu.getGlobalForObject(re.wrappedJSObject.toSource), iwin, "Underlying global is correct");
+        is(re.toSource(), re.wrappedJSObject.toSource(), "Results match");
+      }
+
+      // Test with modified flags accessors
+      iwin.eval(`
+var props = ["global", "ignoreCase", "multiline", "sticky", "source", "unicode"];
+var origDescs = {};
+for (var prop of props) {
+  origDescs[prop] = Object.getOwnPropertyDescriptor(RegExp.prototype, prop);
+  Object.defineProperty(RegExp.prototype, prop, {
+    get: function() {
+      throw new Error("modified accessor is called");
+    }
+  });
+}
+`);
+      try {
+        is(re.flags, flags, "Unmodified flags accessors are called");
+        is(re.toString(), "/foo/" + flags, "Unmodified flags and source accessors are called");
+        is(re.toSource(), "/foo/" + flags, "Unmodified flags and source accessors are called");
+      } finally {
+        iwin.eval(`
+for (var prop of props) {
+  Object.defineProperty(RegExp.prototype, prop, origDescs[prop]);
+}
+`);
+      }
+    }
+  }
+
+  // Note: this is a small set of basic tests. More in-depth tests are located
+  // in test_promise_xrays.html.
+  function testPromise() {
+    testXray('Promise', new iwin.Promise(function(){}), new iwin.Promise(function(){}));
+
+    // Test catch and then.
+    var pr = new iwin.Promise(function(){});
+    isnot(pr.catch, Cu.unwaiveXrays(pr.wrappedJSObject.catch), "Different function identities");
+    is(Cu.getGlobalForObject(pr.catch), window, "Xray global is correct");
+    is(Cu.getGlobalForObject(pr.wrappedJSObject.catch), iwin, "Underlying global is correct");
+
+    isnot(pr.then, Cu.unwaiveXrays(pr.wrappedJSObject.then), "Different function identities");
+    is(Cu.getGlobalForObject(pr.then), window, "Xray global is correct");
+    is(Cu.getGlobalForObject(pr.wrappedJSObject.then), iwin, "Underlying global is correct");
+  }
+
+  function testArrayBuffer() {
+    let constructors = ['ArrayBuffer'];
+
+    for (const c of constructors) {
+      testXray(c, new iwin[c](0), new iwin[c](12));
+
+      var t = new iwin[c](12);
+      is(t.byteLength, 12, `${c} byteLength is correct`);
+
+      is(t.slice(4).byteLength, 8, `${c} byteLength is correct after slicing`);
+      is(Cu.getGlobalForObject(t.slice(4)), iwin, "Slice results lives in the target compartment");
+      is(Object.getPrototypeOf(t.slice(4)), iwin[c].prototype, "Slice results proto lives in target compartment")
+
+      var i32Array = new Int32Array(t);
+      // i32Array is going to be created in the buffer's target compartment,
+      // but usually this is unobservable, because the proto is set to
+      // the current compartment's prototype.
+      // However Xrays ignore the object's proto and claim its proto is
+      // the default proto for that class in the relevant compartment,
+      // so see through this proto hack.
+      todo_is(Object.getPrototypeOf(i32Array), Int32Array.prototype, "Int32Array has correct proto");
+      is(i32Array.length, 3, `Int32Array created from Xray ${c} has the correct length`);
+      is(i32Array.buffer, t, "Int32Array has the correct buffer that we passed in");
+
+      i32Array = new iwin.Int32Array(t);
+      is(Object.getPrototypeOf(i32Array), iwin.Int32Array.prototype, "Xray Int32Array has correct proto");
+      is(i32Array.length, 3, `Xray Int32Array created from Xray ${c} has the correct length`);
+      is(i32Array.buffer, t, "Xray Int32Array has the correct buffer that we passed in");
+
+      t = (new iwin.Int32Array(2)).buffer;
+      is(t.byteLength, 8, `Can access ${c} returned by buffer property`);
+    }
+  }
+
+  function testMap() {
+    testXray('Map', new iwin.Map(), new iwin.Map());
+
+    var t = iwin.eval(`new Map([[1, "a"], [null, "b"]])`);
+    is(t.size, 2, "Map size is correct");
+    is(t.get(1), "a", "Key 1 has the correct value");
+    is(t.get(null), "b", "Key null has the correct value");
+    is(t.has(1), true, "Has Key 1");
+    is(t.set(3, 5).get(3), 5, "Correctly sets key");
+    is(t.delete(null), true, "Key null can be deleted");
+
+    let values = [];
+    t.forEach((value, key) => values.push(value));
+    is(values.toString(), "a,5", "forEach enumerates values correctly");
+
+    t.clear();
+    is(t.size, 0, "Map is empty after calling clear");
+  }
+
+  function testSet() {
+    testXray('Set', new iwin.Set(), new iwin.Set());
+
+    var t = iwin.eval(`new Set([1, null])`);
+    is(t.size, 2, "Set size is correct");
+    is(t.has(1), true, "Contains 1");
+    is(t.has(null), true, "Contains null");
+    is(t.add(5).has(5), true, "Can add value to set");
+    is(t.delete(null), true, "Value null can be deleted");
+
+    let values = [];
+    t.forEach(value => values.push(value));
+    is(values.toString(), "1,5", "forEach enumerates values correctly");
+
+    t.clear();
+    is(t.size, 0, "Set is empty after calling clear");
+  }
+
+  function testWeakMap() {
+    testXray('WeakMap', new iwin.WeakMap(), new iwin.WeakMap());
+
+    var key1 = iwin.eval(`var key1 = {}; key1`);
+    var key2 = iwin.eval(`var key2 = []; key2`);
+    var key3 = iwin.eval(`var key3 = /a/; key3`);
+    var key4 = {};
+    var key5 = [];
+    var t = iwin.eval(`new WeakMap([[key1, "a"], [key2, "b"]])`);
+    is(t.get(key1), "a", "key1 has the correct value");
+    is(t.get(key2), "b", "key2 has the correct value");
+    is(t.has(key1), true, "Has key1");
+    is(t.has(key3), false, "Doesn't have key3");
+    is(t.has(key5), false, "Doesn't have key5");
+    is(t.set(key4, 5).get(key4), 5, "Correctly sets key");
+    is(t.get(key1), "a", "key1 has the correct value after modification");
+    is(t.get(key2), "b", "key2 has the correct value after modification");
+    is(t.delete(key1), true, "key1 can be deleted");
+    is(t.delete(key2), true, "key2 can be deleted");
+    is(t.delete(key3), false, "key3 cannot be deleted");
+    is(t.delete(key4), true, "key4 can be deleted");
+    is(t.delete(key5), false, "key5 cannot be deleted");
+  }
+
+  function testWeakSet() {
+    testXray('WeakSet', new iwin.WeakSet(), new iwin.WeakSet());
+
+    var key1 = iwin.eval(`var key1 = {}; key1`);
+    var key2 = iwin.eval(`var key2 = []; key2`);
+    var key3 = iwin.eval(`var key3 = /a/; key3`);
+    var key4 = {};
+    var key5 = [];
+    var t = iwin.eval(`new WeakSet([key1, key2])`);
+    is(t.has(key1), true, "Has key1");
+    is(t.has(key2), true, "Has key2");
+    is(t.has(key3), false, "Doesn't have key3");
+    is(t.has(key5), false, "Doesn't have key5");
+    is(t.add(key4, 5).has(key4), true, "Can add value to set");
+    is(t.delete(key1), true, "key1 can be deleted");
+    is(t.delete(key2), true, "key2 can be deleted");
+    is(t.delete(key3), false, "key3 cannot be deleted");
+    is(t.delete(key4), true, "key4 can be deleted");
+    is(t.delete(key5), false, "key5 cannot be deleted");
+  }
+
+  function testProxy() {
+    let ProxyCtor = iwin.Proxy;
+    is(Object.getOwnPropertyNames(ProxyCtor).sort().toSource(),
+       ["length", "name"].sort().toSource(),
+       "Xrayed Proxy constructor should not have any properties");
+    is(ProxyCtor.prototype, undefined, "Proxy.prototype should not be set");
+    // Proxy.revocable can safely be exposed, but it is not.
+    // Until it is supported, check that the property is not set.
+    is(ProxyCtor.revocable, undefined, "Proxy.reflect is not set");
+  }
+
+  function testDataView() {
+    testXray('DataView', new iwin.DataView(new iwin.ArrayBuffer(4)),
+             new iwin.DataView(new iwin.ArrayBuffer(8)));
+
+    const versions = [() => iwin.eval(`new DataView(new ArrayBuffer(8))`),
+                      () => new DataView(new iwin.ArrayBuffer(8))];
+
+    for (const constructor of versions) {
+      let t = constructor();
+      is(t.byteLength, 8, `byteLength correct for "${constructor}"`);
+      is(t.byteOffset, 0, `byteOffset correct for "${constructor}"`);
+      is(t.buffer.byteLength, 8, `buffer works for "${constructor}"`);
+
+      const get = ["getInt8", "getUint8", "getInt16", "getUint16",
+                   "getInt32", "getUint32", "getFloat32", "getFloat64"];
+
+      const set = ["setInt8", "setUint8", "setInt16", "setUint16",
+                   "setInt32", "setUint32", "setFloat32", "setFloat64"];
+
+      for (const f of get) {
+        let x = t[f](0);
+        is(x, 0, `${f} is 0 for "${constructor}"`);
+        is(typeof x, 'number', `typeof ${f} is number for "${constructor}"`);
+      }
+
+      for (const f of ["getBigInt64", "getBigUint64"]) {
+        let x = t[f](0);
+        is(x, BigInt(0), `${f} is 0n for "${constructor}"`);
+        is(typeof x, 'bigint', `typeof ${f} is bigint for "${constructor}"`);
+      }
+
+      for (let i = 0; i < set.length; i++) {
+        t[set[i]](0, 13);
+        is(t[get[i]](0), 13, `${get[i]}(0) afer ${set[i]}(0, 13) is 13 for "${constructor}"`);
+      }
+
+      for (const k of ["BigInt64", "BigUint64"]) {
+        t["set" + k](0, BigInt(13));
+        is(t["get" + k](0), BigInt(13), `get${k}(0) afer set${k}(0, 13n) is 13n for "${constructor}"`);
+      }
+    }
+  }
+
+  function testNumber() {
+    // We don't actually support Xrays to Number yet.  This is testing
+    // that case.  If we add such support, we might have to start
+    // using a different non-Xrayed class here, if we can find one.
+    let xrayCtor = iwin.Number;
+    is(Object.getOwnPropertyNames(xrayCtor).sort().toSource(),
+       Object.getOwnPropertyNames(function() {}).sort().toSource(),
+       "We should not have any static properties on a non-Xrayable constructor");
+    is(xrayCtor.noSuchProperty, undefined,
+       "Where did our noSuchProperty property come from?");
+  }
+
+  ]]>
+  </script>
+  <iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/test_xrayic.xhtml b/js/xpconnect/tests/chrome/test_xrayic.xhtml
new file mode 100644
index 0000000000..fd9ab8f7b3
--- /dev/null
+++ b/js/xpconnect/tests/chrome/test_xrayic.xhtml
@@ -0,0 +1,81 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1355109
+-->
+<window title="Mozilla Bug 1355109"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=758415"
+     target="_blank">Mozilla Bug 758415</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+
+  SimpleTest.waitForExplicitFinish();
+
+  // Import our test JSM. We first strip the filename off
+  // the chrome url, then append the jsm filename.
+  var base = /.*\//.exec(window.location.href)[0];
+  ChromeUtils.import(base + "file_expandosharing.jsm");
+
+  // Wait for all child frames to load.
+  var gLoadCount = 0;
+  function frameLoaded() {
+    if (++gLoadCount == window.frames.length)
+      go();
+  }
+
+  function go() {
+    testSandbox(1);
+    testSandbox(100);
+    testSandbox(1000);
+    SimpleTest.finish();
+  }
+
+  function testSandbox(iterations) {
+    // Create an expanded principal sandbox to get xrays with exclusive
+    // expandos.
+    var sandbox = new Cu.Sandbox(["https://test1.example.org",
+                                  "https://test2.example.org"]);
+    sandbox.iframeWindows = new sandbox.Array();
+    for (let iframe of document.getElementsByTagName('iframe')) {
+        sandbox.iframeWindows.push(iframe.contentWindow);
+    }
+    Cu.evalInSandbox(testClassName.toSource(), sandbox);
+    Cu.evalInSandbox(testIC.toSource(), sandbox);
+    is(Cu.evalInSandbox("testIC(" + iterations + ");", sandbox), true, "sandbox test");
+  }
+
+  // This is in a separate function to provide a common source location for ICs.
+  function testClassName(obj, expected) {
+    var className = obj.className;
+    if (className != expected)
+        throw new Error("Got " + className + ", expected " + expected);
+  }
+
+  function testIC(iterations) {
+    for (var i = 0; i < this.iframeWindows.length; i++) {
+      var win = this.iframeWindows[i];
+      var spans = win.document.getElementsByTagName('span');
+      for (var j = 0; j < spans.length; j++) {
+        var span = spans[j];
+        for (var k = 0; k < iterations; k++)
+          testClassName(span, "iamaspan");
+        Object.defineProperty(span, "className", { value: "what" });
+        testClassName(span, "what");
+      }
+    }
+    return true;
+  }
+  ]]>
+  </script>
+  <iframe id="inlineFrame1" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_xrayic.html" />
+  <iframe id="inlineFrame2" onload="frameLoaded();" type="content" src="https://test1.example.org/tests/js/xpconnect/tests/mochitest/file_xrayic.html" />
+</window>
diff --git a/js/xpconnect/tests/chrome/utf8_subscript.js b/js/xpconnect/tests/chrome/utf8_subscript.js
new file mode 100644
index 0000000000..6444273c9d
--- /dev/null
+++ b/js/xpconnect/tests/chrome/utf8_subscript.js
@@ -0,0 +1,5 @@
+// -*- coding: utf-8; indent-tabs-mode: nil -*-
+var str = "𝔘𝔫𝔦𝔠𝔬𝔡𝔢";
+function f() {
+  return 42;
+}
diff --git a/js/xpconnect/tests/chrome/worker_discardSystemSource.js b/js/xpconnect/tests/chrome/worker_discardSystemSource.js
new file mode 100644
index 0000000000..5da32511fa
--- /dev/null
+++ b/js/xpconnect/tests/chrome/worker_discardSystemSource.js
@@ -0,0 +1,6 @@
+function canary() {
+  // eslint-disable-next-line no-unused-vars
+  var someBitOfSource = 42;
+}
+
+postMessage(canary.toString());
diff --git a/js/xpconnect/tests/components/native/moz.build b/js/xpconnect/tests/components/native/moz.build
new file mode 100644
index 0000000000..ba3d227c5b
--- /dev/null
+++ b/js/xpconnect/tests/components/native/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS += [
+    "xpctest_private.h",
+]
+
+UNIFIED_SOURCES += [
+    "xpctest_attributes.cpp",
+    "xpctest_cenums.cpp",
+    "xpctest_esmreturncode.cpp",
+    "xpctest_module.cpp",
+    "xpctest_params.cpp",
+    "xpctest_returncode.cpp",
+]
+
+LOCAL_INCLUDES += [
+    "/xpcom/components",
+]
+
+FINAL_LIBRARY = "xul"
diff --git a/js/xpconnect/tests/components/native/xpctest_attributes.cpp b/js/xpconnect/tests/components/native/xpctest_attributes.cpp
new file mode 100644
index 0000000000..180c1f7606
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_attributes.cpp
@@ -0,0 +1,136 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpctest_private.h"
+
+NS_IMPL_ISUPPORTS(xpcTestObjectReadOnly, nsIXPCTestObjectReadOnly)
+
+xpcTestObjectReadOnly ::xpcTestObjectReadOnly() {
+  boolProperty = true;
+  shortProperty = 32767;
+  longProperty = 2147483647;
+  floatProperty = 5.5f;
+  charProperty = 'X';
+  // timeProperty is PRTime and signed type.
+  // So it has to allow negative value.
+  timeProperty = -1;
+}
+
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetStrReadOnly(char** aStrReadOnly) {
+  if (!aStrReadOnly) return NS_ERROR_NULL_POINTER;
+  *aStrReadOnly = moz_xstrdup("XPConnect Read-Only String");
+  return NS_OK;
+}
+
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetBoolReadOnly(bool* aBoolReadOnly) {
+  *aBoolReadOnly = boolProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetShortReadOnly(
+    int16_t* aShortReadOnly) {
+  *aShortReadOnly = shortProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetLongReadOnly(int32_t* aLongReadOnly) {
+  *aLongReadOnly = longProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetFloatReadOnly(float* aFloatReadOnly) {
+  *aFloatReadOnly = floatProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetCharReadOnly(char* aCharReadOnly) {
+  *aCharReadOnly = charProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadOnly ::GetTimeReadOnly(PRTime* aTimeReadOnly) {
+  *aTimeReadOnly = timeProperty;
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(xpcTestObjectReadWrite, nsIXPCTestObjectReadWrite)
+
+xpcTestObjectReadWrite ::xpcTestObjectReadWrite() {
+  stringProperty = moz_xstrdup("XPConnect Read-Writable String");
+  boolProperty = true;
+  shortProperty = 32767;
+  longProperty = 2147483647;
+  floatProperty = 5.5f;
+  charProperty = 'X';
+  // timeProperty is PRTime and signed type.
+  // So it has to allow negative value.
+  timeProperty = -1;
+}
+
+xpcTestObjectReadWrite ::~xpcTestObjectReadWrite() { free(stringProperty); }
+
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetStringProperty(
+    char** aStringProperty) {
+  if (!aStringProperty) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  *aStringProperty = moz_xstrdup(stringProperty);
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetStringProperty(
+    const char* aStringProperty) {
+  free(stringProperty);
+  stringProperty = moz_xstrdup(aStringProperty);
+  return NS_OK;
+}
+
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetBooleanProperty(
+    bool* aBooleanProperty) {
+  *aBooleanProperty = boolProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetBooleanProperty(
+    bool aBooleanProperty) {
+  boolProperty = aBooleanProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetShortProperty(
+    int16_t* aShortProperty) {
+  *aShortProperty = shortProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetShortProperty(
+    int16_t aShortProperty) {
+  shortProperty = aShortProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetLongProperty(int32_t* aLongProperty) {
+  *aLongProperty = longProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetLongProperty(int32_t aLongProperty) {
+  longProperty = aLongProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetFloatProperty(float* aFloatProperty) {
+  *aFloatProperty = floatProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetFloatProperty(float aFloatProperty) {
+  floatProperty = aFloatProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetCharProperty(char* aCharProperty) {
+  *aCharProperty = charProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetCharProperty(char aCharProperty) {
+  charProperty = aCharProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::GetTimeProperty(PRTime* aTimeProperty) {
+  *aTimeProperty = timeProperty;
+  return NS_OK;
+}
+NS_IMETHODIMP xpcTestObjectReadWrite ::SetTimeProperty(PRTime aTimeProperty) {
+  timeProperty = aTimeProperty;
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/components/native/xpctest_cenums.cpp b/js/xpconnect/tests/components/native/xpctest_cenums.cpp
new file mode 100644
index 0000000000..ae72351b77
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_cenums.cpp
@@ -0,0 +1,67 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* local header for xpconnect tests components */
+
+#include "xpctest_private.h"
+
+NS_IMPL_ISUPPORTS(xpcTestCEnums, nsIXPCTestCEnums)
+
+// If this compiles, we pass. Otherwise, this means that XPIDL bitflag
+// generation is broken.
+xpcTestCEnums::xpcTestCEnums() {
+  static_assert(
+      0 == static_cast<uint32_t>(shouldBe0Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe0Implicit flag");
+  static_assert(
+      1 == static_cast<uint32_t>(shouldBe1Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe1Implicit flag");
+  static_assert(
+      2 == static_cast<uint32_t>(shouldBe2Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe2Implicit flag");
+  static_assert(
+      3 == static_cast<uint32_t>(shouldBe3Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe3Implicit flag");
+  static_assert(
+      5 == static_cast<uint32_t>(shouldBe5Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe5Implicit flag");
+  static_assert(
+      6 == static_cast<uint32_t>(shouldBe6Implicit),
+      "XPIDL bitflag generation did not create correct shouldBe6Implicit flag");
+  static_assert(2 == static_cast<uint32_t>(shouldBe2AgainImplicit),
+                "XPIDL bitflag generation did not create correct "
+                "shouldBe2AgainImplicit flag");
+  static_assert(3 == static_cast<uint32_t>(shouldBe3AgainImplicit),
+                "XPIDL bitflag generation did not create correct "
+                "shouldBe3AgainImplicit flag");
+  static_assert(
+      1 == static_cast<uint32_t>(shouldBe1Explicit),
+      "XPIDL bitflag generation did not create correct shouldBe1Explicit flag");
+  static_assert(
+      2 == static_cast<uint32_t>(shouldBe2Explicit),
+      "XPIDL bitflag generation did not create correct shouldBe2Explicit flag");
+  static_assert(
+      4 == static_cast<uint32_t>(shouldBe4Explicit),
+      "XPIDL bitflag generation did not create correct shouldBe4Explicit flag");
+  static_assert(
+      8 == static_cast<uint32_t>(shouldBe8Explicit),
+      "XPIDL bitflag generation did not create correct shouldBe8Explicit flag");
+  static_assert(12 == static_cast<uint32_t>(shouldBe12Explicit),
+                "XPIDL bitflag generation did not create correct "
+                "shouldBe12Explicit flag");
+}
+
+nsresult xpcTestCEnums::TestCEnumInput(testFlagsExplicit a) {
+  if (a != shouldBe12Explicit) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+nsresult xpcTestCEnums::TestCEnumOutput(testFlagsExplicit* a) {
+  *a = shouldBe8Explicit;
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/components/native/xpctest_esmreturncode.cpp b/js/xpconnect/tests/components/native/xpctest_esmreturncode.cpp
new file mode 100644
index 0000000000..758cab65da
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_esmreturncode.cpp
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpctest_private.h"
+#include "nsComponentManagerUtils.h"
+#include "nsImportModule.h"
+
+NS_IMPL_ISUPPORTS(nsXPCTestESMReturnCodeParent, nsIXPCTestReturnCodeParent)
+
+NS_IMETHODIMP nsXPCTestESMReturnCodeParent::CallChild(int32_t childBehavior,
+                                                      nsresult* _retval) {
+  nsresult rv;
+  nsCOMPtr<nsIXPCTestReturnCodeChild> child(do_ImportESModule(
+      "resource://test/ReturnCodeChild.sys.mjs", "ReturnCodeChild", &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = child->DoIt(childBehavior);
+  *_retval = rv;
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/components/native/xpctest_module.cpp b/js/xpconnect/tests/components/native/xpctest_module.cpp
new file mode 100644
index 0000000000..98ee300e48
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_module.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* module registration and factory code. */
+
+#include "mozilla/GenericFactory.h"
+#include "mozilla/ResultExtensions.h"
+#include "nsComponentManager.h"
+#include "xpctest_private.h"
+
+template <typename T>
+nsresult RegisterFactory(const char* aContractID) {
+  auto constructor = [](REFNSIID aIID, void** aResult) {
+    RefPtr inst = new T();
+    return inst->QueryInterface(aIID, aResult);
+  };
+
+  nsCOMPtr<nsIFactory> factory = new mozilla::GenericFactory(constructor);
+
+  nsID cid;
+  MOZ_TRY(nsID::GenerateUUIDInPlace(cid));
+
+  return nsComponentManagerImpl::gComponentManager->RegisterFactory(
+      cid, aContractID, aContractID, factory);
+}
+
+nsresult xpcTestRegisterComponents() {
+  MOZ_TRY(RegisterFactory<xpcTestObjectReadOnly>(
+      "@mozilla.org/js/xpc/test/native/ObjectReadOnly;1"));
+  MOZ_TRY(RegisterFactory<xpcTestObjectReadWrite>(
+      "@mozilla.org/js/xpc/test/native/ObjectReadWrite;1"));
+  MOZ_TRY(RegisterFactory<nsXPCTestParams>(
+      "@mozilla.org/js/xpc/test/native/Params;1"));
+  MOZ_TRY(RegisterFactory<nsXPCTestReturnCodeParent>(
+      "@mozilla.org/js/xpc/test/native/ReturnCodeParent;1"));
+  MOZ_TRY(RegisterFactory<nsXPCTestESMReturnCodeParent>(
+      "@mozilla.org/js/xpc/test/native/ESMReturnCodeParent;1"));
+  MOZ_TRY(RegisterFactory<xpcTestCEnums>(
+      "@mozilla.org/js/xpc/test/native/CEnums;1"));
+
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/components/native/xpctest_params.cpp b/js/xpconnect/tests/components/native/xpctest_params.cpp
new file mode 100644
index 0000000000..4d1924de05
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_params.cpp
@@ -0,0 +1,413 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpctest_private.h"
+#include "xpctest_interfaces.h"
+#include "mozilla/Casting.h"
+#include "js/Value.h"
+
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIURI.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsXPCTestParams, nsIXPCTestParams)
+
+#define GENERIC_METHOD_IMPL \
+  {                         \
+    *_retval = *b;          \
+    *b = a;                 \
+    return NS_OK;           \
+  }
+
+#define STRING_METHOD_IMPL \
+  {                        \
+    _retval.Assign(b);     \
+    b.Assign(a);           \
+    return NS_OK;          \
+  }
+
+#define SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP)                        \
+  {                                                                 \
+    _retval = std::move(b);                                         \
+    b = a.Clone();                                                  \
+    for (uint32_t i = 0; i < b.Length(); ++i) TAKE_OWNERSHIP(b[i]); \
+    return NS_OK;                                                   \
+  }
+
+#define TAKE_OWNERSHIP_NOOP(val) \
+  {}
+#define TAKE_OWNERSHIP_INTERFACE(val) \
+  { static_cast<nsISupports*>(val)->AddRef(); }
+#define TAKE_OWNERSHIP_STRING(val)  \
+  {                                 \
+    nsDependentCString vprime(val); \
+    val = ToNewCString(vprime);     \
+  }
+#define TAKE_OWNERSHIP_WSTRING(val) \
+  {                                 \
+    nsDependentString vprime(val);  \
+    val = ToNewUnicode(vprime);     \
+  }
+
+// Macro for our buffer-oriented types:
+//   'type' is the type of element that the buffer contains.
+//   'padding' is an offset added to length, allowing us to handle
+//             null-terminated strings.
+//   'TAKE_OWNERSHIP' is one of the macros above.
+#define BUFFER_METHOD_IMPL(type, padding, TAKE_OWNERSHIP)                      \
+  {                                                                            \
+    uint32_t elemSize = sizeof(type);                                          \
+                                                                               \
+    /* Copy b into rv. */                                                      \
+    *rvLength = *bLength;                                                      \
+    *rv = static_cast<type*>(moz_xmalloc(elemSize * (*bLength + padding)));    \
+    memcpy(*rv, *b, elemSize*(*bLength + padding));                            \
+                                                                               \
+    /* Copy a into b. */                                                       \
+    *bLength = aLength;                                                        \
+    free(*b);                                                                  \
+    *b = static_cast<type*>(moz_xmalloc(elemSize * (aLength + padding)));      \
+    memcpy(*b, a, elemSize*(aLength + padding));                               \
+                                                                               \
+    /* We need to take ownership of the data we got from a,                    \
+       since the caller owns it. */                                            \
+    for (unsigned i = 0; i < *bLength + padding; ++i) TAKE_OWNERSHIP((*b)[i]); \
+                                                                               \
+    return NS_OK;                                                              \
+  }
+
+NS_IMETHODIMP nsXPCTestParams::TestBoolean(bool a, bool* b, bool* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestOctet(uint8_t a, uint8_t* b,
+                                         uint8_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestShort(int16_t a, int16_t* b,
+                                         int16_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestLong(int32_t a, int32_t* b,
+                                        int32_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestLongLong(int64_t a, int64_t* b,
+                                            int64_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestUnsignedShort(uint16_t a, uint16_t* b,
+                                                 uint16_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestUnsignedLong(uint32_t a, uint32_t* b,
+                                                uint32_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestUnsignedLongLong(uint64_t a, uint64_t* b,
+                                                    uint64_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestFloat(float a, float* b, float* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestDouble(double a, float* b, double* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestChar(char a, char* b, char* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestString(const char* a, char** b,
+                                          char** _retval) {
+  nsDependentCString aprime(a);
+  nsDependentCString bprime(*b);
+  *_retval = ToNewCString(bprime);
+  *b = ToNewCString(aprime);
+
+  // XPCOM ownership rules dictate that overwritten inout params must be
+  // callee-freed. See https://developer.mozilla.org/en/XPIDL
+  free(const_cast<char*>(bprime.get()));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestWchar(char16_t a, char16_t* b,
+                                         char16_t* _retval) {
+  GENERIC_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestWstring(const char16_t* a, char16_t** b,
+                                           char16_t** _retval) {
+  nsDependentString aprime(a);
+  nsDependentString bprime(*b);
+  *_retval = ToNewUnicode(bprime);
+  *b = ToNewUnicode(aprime);
+
+  // XPCOM ownership rules dictate that overwritten inout params must be
+  // callee-freed. See https://developer.mozilla.org/en/XPIDL
+  free((void*)bprime.get());
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestAString(const nsAString& a, nsAString& b,
+                                           nsAString& _retval) {
+  STRING_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestAUTF8String(const nsACString& a,
+                                               nsACString& b,
+                                               nsACString& _retval) {
+  STRING_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestACString(const nsACString& a, nsACString& b,
+                                            nsACString& _retval) {
+  STRING_METHOD_IMPL;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestJsval(JS::Handle<JS::Value> a,
+                                         JS::MutableHandle<JS::Value> b,
+                                         JS::MutableHandle<JS::Value> _retval) {
+  _retval.set(b);
+  b.set(a);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestShortArray(uint32_t aLength, int16_t* a,
+                                              uint32_t* bLength, int16_t** b,
+                                              uint32_t* rvLength,
+                                              int16_t** rv) {
+  BUFFER_METHOD_IMPL(int16_t, 0, TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestDoubleArray(uint32_t aLength, double* a,
+                                               uint32_t* bLength, double** b,
+                                               uint32_t* rvLength,
+                                               double** rv) {
+  BUFFER_METHOD_IMPL(double, 0, TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestByteArrayOptionalLength(uint8_t* a,
+                                                           uint32_t aLength,
+                                                           uint32_t* rv) {
+  *rv = aLength;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestStringArray(uint32_t aLength, const char** a,
+                                               uint32_t* bLength, char*** b,
+                                               uint32_t* rvLength, char*** rv) {
+  BUFFER_METHOD_IMPL(char*, 0, TAKE_OWNERSHIP_STRING);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestWstringArray(
+    uint32_t aLength, const char16_t** a, uint32_t* bLength, char16_t*** b,
+    uint32_t* rvLength, char16_t*** rv) {
+  BUFFER_METHOD_IMPL(char16_t*, 0, TAKE_OWNERSHIP_WSTRING);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestInterfaceArray(
+    uint32_t aLength, nsIXPCTestInterfaceA** a, uint32_t* bLength,
+    nsIXPCTestInterfaceA*** b, uint32_t* rvLength, nsIXPCTestInterfaceA*** rv) {
+  BUFFER_METHOD_IMPL(nsIXPCTestInterfaceA*, 0, TAKE_OWNERSHIP_INTERFACE);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestJsvalArray(uint32_t aLength, JS::Value* a,
+                                              uint32_t* bLength, JS::Value** b,
+                                              uint32_t* rvLength,
+                                              JS::Value** rv) {
+  BUFFER_METHOD_IMPL(JS::Value, 0, TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestSizedString(uint32_t aLength, const char* a,
+                                               uint32_t* bLength, char** b,
+                                               uint32_t* rvLength, char** rv) {
+  BUFFER_METHOD_IMPL(char, 1, TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestSizedWstring(uint32_t aLength,
+                                                const char16_t* a,
+                                                uint32_t* bLength, char16_t** b,
+                                                uint32_t* rvLength,
+                                                char16_t** rv) {
+  BUFFER_METHOD_IMPL(char16_t, 1, TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestInterfaceIs(const nsIID* aIID, void* a,
+                                               nsIID** bIID, void** b,
+                                               nsIID** rvIID, void** rv) {
+  //
+  // Getting the buffers and ownership right here can be a little tricky.
+  //
+
+  // The interface pointers are heap-allocated, and b has been AddRef'd
+  // by XPConnect for the duration of the call. If we snatch it away from b
+  // and leave no trace, XPConnect won't Release it. Since we also need to
+  // return an already-AddRef'd pointer in rv, we don't need to do anything
+  // special here.
+  *rv = *b;
+
+  // rvIID is out-only, so nobody allocated an IID buffer for us. Do that now,
+  // and store b's IID in the new buffer.
+  *rvIID = static_cast<nsIID*>(moz_xmalloc(sizeof(nsID)));
+  **rvIID = **bIID;
+
+  // Copy the interface pointer from a to b. Since a is in-only, XPConnect will
+  // release it upon completion of the call. AddRef it for b.
+  *b = a;
+  static_cast<nsISupports*>(*b)->AddRef();
+
+  // We already had a buffer allocated for b's IID, so we can re-use it.
+  **bIID = *aIID;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestInterfaceIsArray(
+    uint32_t aLength, const nsIID* aIID, void** a, uint32_t* bLength,
+    nsIID** bIID, void*** b, uint32_t* rvLength, nsIID** rvIID, void*** rv) {
+  // Transfer the IIDs. See the comments in TestInterfaceIs (above) for an
+  // explanation of what we're doing.
+  *rvIID = static_cast<nsIID*>(moz_xmalloc(sizeof(nsID)));
+  **rvIID = **bIID;
+  **bIID = *aIID;
+
+  // The macro is agnostic to the actual interface types, so we can re-use code
+  // here.
+  //
+  // Do this second, since the macro returns.
+  BUFFER_METHOD_IMPL(void*, 0, TAKE_OWNERSHIP_INTERFACE);
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestOutAString(nsAString& o) {
+  o.AssignLiteral("out");
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsXPCTestParams::TestStringArrayOptionalSize(const char** a,
+                                                           uint32_t length,
+                                                           nsACString& out) {
+  out.Truncate();
+  for (uint32_t i = 0; i < length; ++i) {
+    out.Append(a[i]);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestShortSequence(const nsTArray<short>& a, nsTArray<short>& b,
+                                   nsTArray<short>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestDoubleSequence(const nsTArray<double>& a,
+                                    nsTArray<double>& b,
+                                    nsTArray<double>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestInterfaceSequence(
+    const nsTArray<RefPtr<nsIXPCTestInterfaceA>>& a,
+    nsTArray<RefPtr<nsIXPCTestInterfaceA>>& b,
+    nsTArray<RefPtr<nsIXPCTestInterfaceA>>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestAStringSequence(const nsTArray<nsString>& a,
+                                     nsTArray<nsString>& b,
+                                     nsTArray<nsString>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestACStringSequence(const nsTArray<nsCString>& a,
+                                      nsTArray<nsCString>& b,
+                                      nsTArray<nsCString>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestJsvalSequence(const nsTArray<JS::Value>& a,
+                                   nsTArray<JS::Value>& b,
+                                   nsTArray<JS::Value>& _retval) {
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_NOOP);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestSequenceSequence(const nsTArray<nsTArray<short>>& a,
+                                      nsTArray<nsTArray<short>>& b,
+                                      nsTArray<nsTArray<short>>& _retval) {
+  _retval = std::move(b);
+  for (const auto& element : a) {
+    b.AppendElement(element.Clone());
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestInterfaceIsSequence(const nsIID* aIID,
+                                         const nsTArray<void*>& a, nsIID** bIID,
+                                         nsTArray<void*>& b, nsIID** rvIID,
+                                         nsTArray<void*>& _retval) {
+  // Shuffle around our nsIIDs
+  *rvIID = (*bIID)->Clone();
+  *bIID = aIID->Clone();
+
+  // Perform the generic sequence shuffle.
+  SEQUENCE_METHOD_IMPL(TAKE_OWNERSHIP_INTERFACE);
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestOptionalSequence(const nsTArray<uint8_t>& aInArr,
+                                      nsTArray<uint8_t>& aReturnArr) {
+  aReturnArr = aInArr.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::TestOmittedOptionalOut(nsIXPCTestParams* aJSObj,
+                                        nsIURI** aOut) {
+  MOZ_ASSERT(!(*aOut), "Unexpected value received");
+  // Call the js component, to check XPConnect won't crash when passing nullptr
+  // as the optional out parameter, and that the out object is built regardless.
+  nsresult rv;
+  // Invoke it directly passing nullptr.
+  rv = aJSObj->TestOmittedOptionalOut(nullptr, nullptr);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // Also invoke it with a ref pointer.
+  nsCOMPtr<nsIURI> someURI;
+  rv = aJSObj->TestOmittedOptionalOut(nullptr, getter_AddRefs(someURI));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoCString spec;
+  rv = someURI->GetSpec(spec);
+  if (!spec.EqualsLiteral("http://example.com/")) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  someURI.forget(aOut);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPCTestParams::GetTestNaN(double* aResult) {
+  *aResult =
+      BitwiseCast<double>((uint64_t(JSVAL_TAG_OBJECT) << JSVAL_TAG_SHIFT) + 1);
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/components/native/xpctest_private.h b/js/xpconnect/tests/components/native/xpctest_private.h
new file mode 100644
index 0000000000..c5d7bc86cf
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_private.h
@@ -0,0 +1,102 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* local header for xpconnect tests components */
+
+#ifndef xpctest_private_h___
+#define xpctest_private_h___
+
+#include "nsISupports.h"
+#include "nsString.h"
+#include "xpctest_attributes.h"
+#include "xpctest_params.h"
+#include "xpctest_returncode.h"
+#include "xpctest_cenums.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ModuleUtils.h"
+
+nsresult xpcTestRegisterComponents();
+
+class xpcTestObjectReadOnly final : public nsIXPCTestObjectReadOnly {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTOBJECTREADONLY
+  xpcTestObjectReadOnly();
+
+ private:
+  ~xpcTestObjectReadOnly() = default;
+
+  bool boolProperty;
+  int16_t shortProperty;
+  int32_t longProperty;
+  float floatProperty;
+  char charProperty;
+  PRTime timeProperty;
+};
+
+class xpcTestObjectReadWrite final : public nsIXPCTestObjectReadWrite {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTOBJECTREADWRITE
+
+  xpcTestObjectReadWrite();
+
+ private:
+  ~xpcTestObjectReadWrite();
+
+  bool boolProperty;
+  int16_t shortProperty;
+  int32_t longProperty;
+  float floatProperty;
+  char charProperty;
+  char* stringProperty;
+  PRTime timeProperty;
+};
+
+class nsXPCTestParams final : public nsIXPCTestParams {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTPARAMS
+
+  nsXPCTestParams() = default;
+
+ private:
+  ~nsXPCTestParams() = default;
+};
+
+class nsXPCTestReturnCodeParent final : public nsIXPCTestReturnCodeParent {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTRETURNCODEPARENT
+
+  nsXPCTestReturnCodeParent() = default;
+
+ private:
+  ~nsXPCTestReturnCodeParent() = default;
+};
+
+class nsXPCTestESMReturnCodeParent final : public nsIXPCTestReturnCodeParent {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTRETURNCODEPARENT
+
+  nsXPCTestESMReturnCodeParent() = default;
+
+ private:
+  ~nsXPCTestESMReturnCodeParent() = default;
+};
+
+class xpcTestCEnums final : public nsIXPCTestCEnums {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIXPCTESTCENUMS
+
+  xpcTestCEnums();
+
+ private:
+  ~xpcTestCEnums() = default;
+};
+#endif /* xpctest_private_h___ */
diff --git a/js/xpconnect/tests/components/native/xpctest_returncode.cpp b/js/xpconnect/tests/components/native/xpctest_returncode.cpp
new file mode 100644
index 0000000000..3a52f616d9
--- /dev/null
+++ b/js/xpconnect/tests/components/native/xpctest_returncode.cpp
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "xpctest_private.h"
+#include "nsComponentManagerUtils.h"
+#include "nsImportModule.h"
+
+NS_IMPL_ISUPPORTS(nsXPCTestReturnCodeParent, nsIXPCTestReturnCodeParent)
+
+NS_IMETHODIMP nsXPCTestReturnCodeParent::CallChild(int32_t childBehavior,
+                                                   nsresult* _retval) {
+  nsresult rv;
+  nsCOMPtr<nsIXPCTestReturnCodeChild> child(do_ImportModule(
+      "resource://test/ReturnCodeChild.jsm", "ReturnCodeChild", &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = child->DoIt(childBehavior);
+  *_retval = rv;
+  return NS_OK;
+}
diff --git a/js/xpconnect/tests/idl/moz.build b/js/xpconnect/tests/idl/moz.build
new file mode 100644
index 0000000000..8b56f40c21
--- /dev/null
+++ b/js/xpconnect/tests/idl/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPIDL_SOURCES += [
+    "xpctest_attributes.idl",
+    "xpctest_bug809674.idl",
+    "xpctest_cenums.idl",
+    "xpctest_interfaces.idl",
+    "xpctest_params.idl",
+    "xpctest_returncode.idl",
+    "xpctest_utils.idl",
+]
+
+XPIDL_MODULE = "xpctest"
diff --git a/js/xpconnect/tests/idl/xpctest_attributes.idl b/js/xpconnect/tests/idl/xpctest_attributes.idl
new file mode 100644
index 0000000000..9822b24dfb
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_attributes.idl
@@ -0,0 +1,33 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+/*
+ * This defines the interface for a test object.
+ *
+ */
+
+[scriptable, uuid(42fbd9f6-b12d-47ef-b7a1-02d73c11fe53)]
+interface nsIXPCTestObjectReadOnly : nsISupports {
+    readonly attribute string  strReadOnly;
+    readonly attribute boolean boolReadOnly;
+    readonly attribute short   shortReadOnly;
+    readonly attribute long    longReadOnly;
+    readonly attribute float   floatReadOnly;
+    readonly attribute char    charReadOnly;
+    readonly attribute PRTime  timeReadOnly;
+};
+
+[scriptable, uuid(f07529b0-a479-4954-aba5-ab3142c6b1cb)]
+interface nsIXPCTestObjectReadWrite : nsISupports {
+    attribute string  stringProperty;
+    attribute boolean booleanProperty;
+    attribute short   shortProperty;
+    attribute long    longProperty;
+    attribute float   floatProperty;
+    attribute char    charProperty;
+    attribute PRTime  timeProperty;
+};
diff --git a/js/xpconnect/tests/idl/xpctest_bug809674.idl b/js/xpconnect/tests/idl/xpctest_bug809674.idl
new file mode 100644
index 0000000000..1e83e244ec
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_bug809674.idl
@@ -0,0 +1,47 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+/*
+ * Test interface for https://bugzilla.mozilla.org/show_bug.cgi?id=809674 .
+ *
+ * This test makes sure that accessing JS-implemented attributes or methods
+ * marked with [implicit_jscontext] works as expected.
+ *
+ * It also makes sure [optional_argc] is not supported on JS-implemented
+ * methods.
+ */
+
+[scriptable, uuid(2df46559-da21-49bf-b863-0d7b7bbcbc73)]
+interface nsIXPCTestBug809674 : nsISupports {
+    // Various interesting [implicit_jscontext] cases.
+    [implicit_jscontext] unsigned long addArgs(in unsigned long x, in unsigned long y);
+    [implicit_jscontext] unsigned long addSubMulArgs(in unsigned long x, in unsigned long y,
+                                                     out unsigned long subOut,
+                                                     out unsigned long mulOut);
+    [implicit_jscontext] jsval addVals(in jsval x, in jsval y);
+
+    [implicit_jscontext] unsigned long methodNoArgs();
+    [implicit_jscontext] void methodNoArgsNoRetVal();
+
+    // When there are many arguments, the context is passed on the stack on
+    // most platforms.
+    [implicit_jscontext] unsigned long addMany(in unsigned long x1,
+                                               in unsigned long x2,
+                                               in unsigned long x3,
+                                               in unsigned long x4,
+                                               in unsigned long x5,
+                                               in unsigned long x6,
+                                               in unsigned long x7,
+                                               in unsigned long x8);
+
+    // Attributes can use [implicit_jscontext], too.
+    [implicit_jscontext] attribute jsval valProperty;
+    [implicit_jscontext] attribute unsigned long uintProperty;
+
+    // [optional_argc] is not supported.
+    [optional_argc] void methodWithOptionalArgc();
+};
diff --git a/js/xpconnect/tests/idl/xpctest_cenums.idl b/js/xpconnect/tests/idl/xpctest_cenums.idl
new file mode 100644
index 0000000000..70b7f8fae7
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_cenums.idl
@@ -0,0 +1,39 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+/*
+ * This defines the interface for a test object.
+ *
+ */
+
+[scriptable, uuid(6a2f918e-cda2-11e8-bc9a-a34c716d1f2a)]
+interface nsIXPCTestCEnums : nsISupports {
+  const long testConst = 1;
+
+  cenum testFlagsExplicit: 8 {
+    shouldBe1Explicit = 1,
+    shouldBe2Explicit = 2,
+    shouldBe4Explicit = 4,
+    shouldBe8Explicit = 8,
+    shouldBe12Explicit = shouldBe4Explicit | shouldBe8Explicit,
+  };
+
+  cenum testFlagsImplicit: 8 {
+    shouldBe0Implicit,
+    shouldBe1Implicit,
+    shouldBe2Implicit,
+    shouldBe3Implicit,
+    shouldBe5Implicit = 5,
+    shouldBe6Implicit,
+    shouldBe2AgainImplicit = 2,
+    shouldBe3AgainImplicit,
+  };
+
+  void testCEnumInput(in nsIXPCTestCEnums_testFlagsExplicit abc);
+
+  nsIXPCTestCEnums_testFlagsExplicit testCEnumOutput();
+};
diff --git a/js/xpconnect/tests/idl/xpctest_esmreturncode.idl b/js/xpconnect/tests/idl/xpctest_esmreturncode.idl
new file mode 100644
index 0000000000..ac17feda3f
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_esmreturncode.idl
@@ -0,0 +1,45 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test the use of Components.returnCode with system ESM
+ *
+ * This ("parent") interface defines a method that in-turn calls another
+ * ("child") interface implemented in JS, and returns the nsresult from that
+ * child interface.  The child interface manages the return code by way of
+ * Components.returnCode.
+ */
+
+#include "nsISupports.idl"
+
+
+[scriptable, uuid(494f9336-ad06-46ad-bbb4-b0010e27e12d)]
+interface nsIXPCTestESMReturnCodeParent : nsISupports {
+  // Calls the "child" interface with the specified behavior flag.  Returns
+  // the NSRESULT from the child interface.
+  nsresult callChild(in long childBehavior);
+};
+
+[scriptable, uuid(dee07408-75d8-4968-a37c-fe0d48ccd1ac)]
+interface nsIXPCTestESMReturnCodeChild : nsISupports {
+  void doIt(in long behavior);
+
+  // Flags to control that the child does.
+  // child will throw a JS exception
+  const long CHILD_SHOULD_THROW = 0;
+
+  // child will just return normally
+  const long CHILD_SHOULD_RETURN_SUCCESS = 1;
+
+  // child will return after setting Components.returnCode to NS_ERROR_FAILURE
+  const long CHILD_SHOULD_RETURN_RESULTCODE = 2;
+
+  // child will set Components.returnCode to NS_ERROR_UNEXPECTED, then create
+  // a new component that sets Components.returnCode to NS_ERROR_FAILURE.
+  // Our caller should see the NS_ERROR_UNEXPECTED we set rather than the
+  // value set later by the "inner" child.
+  const long CHILD_SHOULD_NEST_RESULTCODES = 3;
+};
diff --git a/js/xpconnect/tests/idl/xpctest_interfaces.idl b/js/xpconnect/tests/idl/xpctest_interfaces.idl
new file mode 100644
index 0000000000..2abc149623
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_interfaces.idl
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Very simple test interfaces.
+ *
+ * This is used by the other test functionality when it needs to play around with
+ * interface pointers.
+ */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(3c8fd2f5-970c-42c6-b5dd-cda1c16dcfd8)]
+interface nsIXPCTestInterfaceA : nsISupports {
+  attribute string name;
+};
+
+[scriptable, uuid(ff528c3a-2410-46de-acaa-449aa6403a33)]
+interface nsIXPCTestInterfaceB : nsISupports {
+  attribute string name;
+};
+
+[scriptable, uuid(401cf1b4-355b-4cee-b7b3-c7973aee49bd)]
+interface nsIXPCTestInterfaceC : nsISupports {
+  attribute long someInteger;
+};
diff --git a/js/xpconnect/tests/idl/xpctest_params.idl b/js/xpconnect/tests/idl/xpctest_params.idl
new file mode 100644
index 0000000000..8bf224507c
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_params.idl
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test pararameter passing and argument conversion.
+ *
+ * Each test method returns the value in 'b', and copies 'a' into 'b'. This lets
+ * us test return values, in params, and inout params (out params should be
+ * covered by the intersection of return values and inout).
+ */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+interface nsIXPCTestInterfaceA;
+interface nsIXPCTestInterfaceB;
+
+[scriptable, uuid(812145c7-9fcc-425e-a878-36ad1b7730b7)]
+interface nsIXPCTestParams : nsISupports {
+
+  // These types correspond to the ones in typelib.py
+  boolean               testBoolean(in boolean a, inout boolean b);
+  octet                 testOctet(in octet a, inout octet b);
+  short                 testShort(in short a, inout short b);
+  long                  testLong(in long a, inout long b);
+  long long             testLongLong(in long long a, inout long long b);
+  unsigned short        testUnsignedShort(in unsigned short a, inout unsigned short b);
+  unsigned long         testUnsignedLong(in unsigned long a, inout unsigned long b);
+  unsigned long long    testUnsignedLongLong(in unsigned long long a, inout unsigned long long b);
+  float                 testFloat(in float a, inout float b);
+  double                testDouble(in double a, inout float b);
+  char                  testChar(in char a, inout char b);
+  string                testString(in string a, inout string b);
+  wchar                 testWchar(in wchar a, inout wchar b);
+  wstring               testWstring(in wstring a, inout wstring b);
+  AString               testAString(in AString a, inout AString b);
+  AUTF8String           testAUTF8String(in AUTF8String a, inout AUTF8String b);
+  ACString              testACString(in ACString a, inout ACString b);
+  jsval                 testJsval(in jsval a, inout jsval b);
+
+  // Test various forms of the Array<T> type.
+  Array<short>          testShortSequence(in Array<short> a, inout Array<short> b);
+  Array<double>         testDoubleSequence(in Array<double> a, inout Array<double> b);
+  Array<nsIXPCTestInterfaceA> testInterfaceSequence(in Array<nsIXPCTestInterfaceA> a, inout Array<nsIXPCTestInterfaceA> b);
+  Array<AString>        testAStringSequence(in Array<AString> a, inout Array<AString> b);
+  Array<ACString>       testACStringSequence(in Array<ACString> a, inout Array<ACString> b);
+  Array<jsval>          testJsvalSequence(in Array<jsval> a, inout Array<jsval> b);
+  Array<Array<short> >  testSequenceSequence(in Array<Array<short> > a, inout Array<Array<short> > b);
+
+  void                  testInterfaceIsSequence(in nsIIDPtr aIID, [iid_is(aIID)] in Array<nsQIResult> a,
+                                                inout nsIIDPtr bIID, [iid_is(bIID)] inout Array<nsQIResult> b,
+                                                out nsIIDPtr rvIID, [retval, iid_is(rvIID)] out Array<nsQIResult> rv);
+
+  // Returns whatever was passed in.
+  Array<uint8_t>        testOptionalSequence([optional] in Array<uint8_t> arr);
+
+  //
+  // Dependent parameters use the same types as above, but are handled much differently.
+  //
+
+  // Test arrays.
+  void                  testShortArray(in unsigned long aLength, [array, size_is(aLength)] in short a,
+                                       inout unsigned long bLength, [array, size_is(bLength)] inout short b,
+                                       out unsigned long rvLength, [retval, array, size_is(rvLength)] out short rv);
+  void                  testDoubleArray(in unsigned long aLength, [array, size_is(aLength)] in double a,
+                                        inout unsigned long bLength, [array, size_is(bLength)] inout double b,
+                                        out unsigned long rvLength, [retval, array, size_is(rvLength)] out double rv);
+  void                  testStringArray(in unsigned long aLength, [array, size_is(aLength)] in string a,
+                                        inout unsigned long bLength, [array, size_is(bLength)] inout string b,
+                                        out unsigned long rvLength, [retval, array, size_is(rvLength)] out string rv);
+  void                  testWstringArray(in unsigned long aLength, [array, size_is(aLength)] in wstring a,
+                                         inout unsigned long bLength, [array, size_is(bLength)] inout wstring b,
+                                         out unsigned long rvLength, [retval, array, size_is(rvLength)] out wstring rv);
+  void                  testInterfaceArray(in unsigned long aLength, [array, size_is(aLength)] in nsIXPCTestInterfaceA a,
+                                           inout unsigned long bLength, [array, size_is(bLength)] inout nsIXPCTestInterfaceA b,
+                                           out unsigned long rvLength, [retval, array, size_is(rvLength)] out nsIXPCTestInterfaceA rv);
+
+  // uint8 array with optional length. Returns array length.
+  unsigned long         testByteArrayOptionalLength([array, size_is(aLength)] in uint8_t a, [optional] in unsigned long aLength);
+
+  // Test sized strings.
+  void                  testSizedString(in unsigned long aLength, [size_is(aLength)] in string a,
+                                        inout unsigned long bLength, [size_is(bLength)] inout string b,
+                                        out unsigned long rvLength, [retval, size_is(rvLength)] out string rv);
+  void                  testSizedWstring(in unsigned long aLength, [size_is(aLength)] in wstring a,
+                                         inout unsigned long bLength, [size_is(bLength)] inout wstring b,
+                                         out unsigned long rvLength, [retval, size_is(rvLength)] out wstring rv);
+
+  // Test iid_is.
+  void                  testInterfaceIs(in nsIIDPtr aIID, [iid_is(aIID)] in nsQIResult a,
+                                        inout nsIIDPtr bIID, [iid_is(bIID)] inout nsQIResult b,
+                                        out nsIIDPtr rvIID, [retval, iid_is(rvIID)] out nsQIResult rv);
+
+  // Test arrays of iid_is. According to khuey we don't use it for anything
+  // in mozilla-central, but calendar stuff depends on it.
+  void                  testInterfaceIsArray(in unsigned long aLength, in nsIIDPtr aIID,
+                                             [array, size_is(aLength), iid_is(aIID)] in nsQIResult a,
+                                             inout unsigned long bLength, inout nsIIDPtr bIID,
+                                             [array, size_is(bLength), iid_is(bIID)] inout nsQIResult b,
+                                             out unsigned long rvLength, out nsIIDPtr rvIID,
+                                             [retval, array, size_is(rvLength), iid_is(rvIID)] out nsQIResult rv);
+
+  // Test arrays of jsvals
+  void                  testJsvalArray(in unsigned long aLength, [array, size_is(aLength)] in jsval a,
+                                       inout unsigned long bLength, [array, size_is(bLength)] inout jsval b,
+                                       out unsigned long rvLength, [retval, array, size_is(rvLength)] out jsval rv);
+
+
+  // Test for out dipper parameters
+  void                 testOutAString(out AString o);
+
+  // Test for optional array size_is.
+  ACString             testStringArrayOptionalSize([array, size_is(aLength)] in string a, [optional] in unsigned long aLength);
+
+  // Test for omitted optional out parameter.
+  void                 testOmittedOptionalOut(in nsIXPCTestParams aJSObj, [optional] out nsIURI aOut);
+
+  readonly attribute double testNaN;
+};
diff --git a/js/xpconnect/tests/idl/xpctest_returncode.idl b/js/xpconnect/tests/idl/xpctest_returncode.idl
new file mode 100644
index 0000000000..5ee6c55479
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_returncode.idl
@@ -0,0 +1,45 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test the use of Components.returnCode
+ *
+ * This ("parent") interface defines a method that in-turn calls another
+ * ("child") interface implemented in JS, and returns the nsresult from that
+ * child interface.  The child interface manages the return code by way of
+ * Components.returnCode.
+ */
+
+#include "nsISupports.idl"
+
+
+[scriptable, uuid(479e4532-95cf-48b8-a99b-8a5881e47138)]
+interface nsIXPCTestReturnCodeParent : nsISupports {
+  // Calls the "child" interface with the specified behavior flag.  Returns
+  // the NSRESULT from the child interface.
+  nsresult callChild(in long childBehavior);
+};
+
+[scriptable, uuid(672cfd34-1fd1-455d-9901-d879fa6fdb95)]
+interface nsIXPCTestReturnCodeChild : nsISupports {
+  void doIt(in long behavior);
+
+  // Flags to control that the child does.
+  // child will throw a JS exception
+  const long CHILD_SHOULD_THROW = 0;
+
+  // child will just return normally
+  const long CHILD_SHOULD_RETURN_SUCCESS = 1;
+
+  // child will return after setting Components.returnCode to NS_ERROR_FAILURE
+  const long CHILD_SHOULD_RETURN_RESULTCODE = 2;
+
+  // child will set Components.returnCode to NS_ERROR_UNEXPECTED, then create
+  // a new component that sets Components.returnCode to NS_ERROR_FAILURE.
+  // Our caller should see the NS_ERROR_UNEXPECTED we set rather than the
+  // value set later by the "inner" child.
+  const long CHILD_SHOULD_NEST_RESULTCODES = 3;
+};
diff --git a/js/xpconnect/tests/idl/xpctest_utils.idl b/js/xpconnect/tests/idl/xpctest_utils.idl
new file mode 100644
index 0000000000..e59814272b
--- /dev/null
+++ b/js/xpconnect/tests/idl/xpctest_utils.idl
@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Utility interfaces for testing.
+ */
+
+#include "nsISupports.idl"
+
+[scriptable, function, uuid(d58a82ab-d8f7-4ca9-9273-b3290d42a0cf)]
+interface nsIXPCTestFunctionInterface : nsISupports {
+  string echo(in string arg);
+};
+
+[scriptable, uuid(1e9cddeb-510d-449a-b152-3c1b5b31d41d)]
+interface nsIXPCTestUtils : nsISupports {
+  nsIXPCTestFunctionInterface doubleWrapFunction(in nsIXPCTestFunctionInterface f);
+};
diff --git a/js/xpconnect/tests/mochitest/bug1681664_helper.js b/js/xpconnect/tests/mochitest/bug1681664_helper.js
new file mode 100644
index 0000000000..14f2289a19
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/bug1681664_helper.js
@@ -0,0 +1 @@
+while (true) {};
diff --git a/js/xpconnect/tests/mochitest/bug500931_helper.html b/js/xpconnect/tests/mochitest/bug500931_helper.html
new file mode 100644
index 0000000000..da268d99d8
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/bug500931_helper.html
@@ -0,0 +1,8 @@
+<html>
+    <head>
+        <title>Inner frame for bug 500931 mochitest</title>
+        <script>x = 42;</script>
+    </head>
+    <body>
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/bug571849_helper.html b/js/xpconnect/tests/mochitest/bug571849_helper.html
new file mode 100644
index 0000000000..234cd57ccf
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/bug571849_helper.html
@@ -0,0 +1,7 @@
+<html>
+    <head>
+    </head>
+    <body>
+        TEXT NODE TEXT NODE
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/bug589028_helper.html b/js/xpconnect/tests/mochitest/bug589028_helper.html
new file mode 100644
index 0000000000..dc56ecbc3c
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/bug589028_helper.html
@@ -0,0 +1,27 @@
+<html>
+    <head>
+        <script>
+        function getMyOption() {
+            return new Option();
+        }
+        function getCallersOption(caller) {
+            return new caller.Option();
+        }
+        function getMyAudio() {
+            return new Audio();
+        }
+        function getCallersAudio(caller) {
+            return new caller.Audio();
+        }
+        function getMyImage() {
+            return new Image();
+        }
+        function getCallersImage(caller) {
+            return new caller.Image();
+        }
+        </script>
+    </head>
+    <body>
+        the iframe
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/bug92773_helper.html b/js/xpconnect/tests/mochitest/bug92773_helper.html
new file mode 100644
index 0000000000..be10dd54ae
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/bug92773_helper.html
@@ -0,0 +1,7 @@
+<html>
+    <head>
+        <script>
+            Object.defineProperty(window, "foo", { get() { alert("FAIL"); } });
+        </script>
+    </head>
+</html>
diff --git a/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html b/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html
new file mode 100644
index 0000000000..a0c1ec87e3
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/chrome_wrappers_helper.html
@@ -0,0 +1,29 @@
+<html>
+    <head>
+        <script>
+            function check_wrapper(ok, wrapper, expected, note) {
+                let { getClassName } = SpecialPowers.unwrap(
+                  SpecialPowers.wrap(window).ChromeUtils
+                );
+                ok(getClassName(wrapper, false) === expected, note);
+            }
+            function run_test(ok, xpcnw, sjow) {
+                // both wrappers should point to our window: XOW
+                check_wrapper(ok, ok, "Proxy", "functions are wrapped properly");
+                check_wrapper(ok, xpcnw, "Proxy", "XPCNWs are transformed correctly");
+                check_wrapper(ok, sjow, "Proxy", "SJOWs are transformed correctly");
+
+                check_wrapper(ok, window.location, "Location",
+                              "same-compartment security wrappers are gone");
+
+                ok(defprop1 === 1, "defprop1 exists");
+                window.defprop1 = 2;
+                ok(defprop1 === 2, "defprop1 is properly writable");
+
+                // defprop2 = {}; disabled because the test doesn't work
+            }
+        </script>
+    </head>
+    <body>
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/class_static_worker.js b/js/xpconnect/tests/mochitest/class_static_worker.js
new file mode 100644
index 0000000000..eb949226ba
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/class_static_worker.js
@@ -0,0 +1,13 @@
+class A {
+  static { this.x = 12; }
+}
+
+
+self.onmessage = function (e) {
+  console.log(e)
+  if (e.data == 'get') {
+    postMessage(A.x);
+    return;
+  }
+  postMessage('Unknown message type.');
+}
+\ No newline at end of file
diff --git a/js/xpconnect/tests/mochitest/file1_bug629227.html b/js/xpconnect/tests/mochitest/file1_bug629227.html
new file mode 100644
index 0000000000..dd12484068
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file1_bug629227.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <script>
+      function doIt() {
+        var doc = window.frames[0].document;
+        var ok = (doc.form1 == doc.getElementById("test1"));
+        window.parent.postMessage(
+          JSON.stringify({ ok: ok,
+                           reason: "Should be able to get named items by name" }),
+                         "*");
+        window.parent.postMessage("finish", "*");
+      }
+
+      window.onmessage = function(ev) {
+        if (ev.data == "start") {
+          doIt();
+        }
+      }
+
+      document.domain = "example.org";
+    </script>
+  </head>
+  <body>
+    <iframe id="subframe"></iframe>
+    <script>
+      document.getElementById("subframe").src =
+        "http://test2.example.org" +
+        location.pathname.replace(/file1_bug629227.html/, "file2_bug629227.html");
+    </script>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file2_bug629227.html b/js/xpconnect/tests/mochitest/file2_bug629227.html
new file mode 100644
index 0000000000..02a0540865
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file2_bug629227.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <script>
+      document.domain = "example.org";
+    </script>
+  </head>
+  <body>
+    <form name="form1" id="test1"></form>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug505915.html b/js/xpconnect/tests/mochitest/file_bug505915.html
new file mode 100644
index 0000000000..5129126914
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug505915.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+Inner frame for testing bug 505915.
+https://bugzilla.mozilla.org/show_bug.cgi?id=505915
+-->
+<head>
+<body onload="parent.postMessage('', '*');">
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug605167.html b/js/xpconnect/tests/mochitest/file_bug605167.html
new file mode 100644
index 0000000000..d5253315b8
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug605167.html
@@ -0,0 +1,7 @@
+<html>
+<body>
+<script>
+  parent.f = function() { return this; };
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug650273.html b/js/xpconnect/tests/mochitest/file_bug650273.html
new file mode 100644
index 0000000000..5fe33e9695
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug650273.html
@@ -0,0 +1,31 @@
+<!-- test by moz_bug_r_a4@yahoo.com -->
+<body onload="a()">
+<script>
+var targetUrl = "http://example.com/";
+var l;
+
+function a() {
+        var o = {};
+        o.toString = function() {
+                l();
+                return "a";
+        };
+        var f = Object.getOwnPropertyDescriptor(Document.prototype, "title").set;
+        setTimeout(f.bind(document), 0, o);
+}
+
+function l() {
+        var l = false;
+        onunload = function() {
+                l = true;
+        };
+        location = targetUrl;
+        do {
+                var r = new XMLHttpRequest();
+                r.open("GET", location.href, false);
+                r.overrideMimeType("text/plain");
+                try { r.send(null); }
+                catch (e) {}
+        } while (!l);
+}
+</script>
diff --git a/js/xpconnect/tests/mochitest/file_bug658560.html b/js/xpconnect/tests/mochitest/file_bug658560.html
new file mode 100644
index 0000000000..411d31ac73
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug658560.html
@@ -0,0 +1,4 @@
+<html>
+    <body>
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug706301.html b/js/xpconnect/tests/mochitest/file_bug706301.html
new file mode 100644
index 0000000000..805449b4aa
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug706301.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <script type="application/javascript">
+      window.addEventListener('message', doContentTest);
+
+      function doContentTest() {
+
+        // This has always worked.
+        var nodelist1 = document.getElementsByTagName('details');
+        Object.getOwnPropertyDescriptor(nodelist1, 'length');
+        ok(nodelist1['length'] == 0, "Content should be able to get the length of " +
+                                     "its own nodelist after calling getOwnPropertyDescriptor.");
+
+        // This is bug 706301.
+        var nodelist2 = document.getElementsByTagName('section');
+        ok(getLengthInChrome(nodelist2), "Chrome should be able to get the length of " +
+                                         "content nodelist after calling getOwnPropertyDescriptor.");
+
+        // All done.
+        finishTestInChrome();
+      }
+    </script>
+  </head>
+  <body>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug720619.html b/js/xpconnect/tests/mochitest/file_bug720619.html
new file mode 100644
index 0000000000..d198ba1fa3
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug720619.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <script>
+            valueOf = function() { return "v"; }
+            toString = function() { return "s"; }
+        </script>
+    </head>
+    <body></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug731471.html b/js/xpconnect/tests/mochitest/file_bug731471.html
new file mode 100644
index 0000000000..fcfb194cb6
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug731471.html
@@ -0,0 +1,5 @@
+<html>
+<body>
+1
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug738244.html b/js/xpconnect/tests/mochitest/file_bug738244.html
new file mode 100644
index 0000000000..a399d9f0e0
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug738244.html
@@ -0,0 +1,10 @@
+<html>
+<body>
+<form name="form1">
+  <input name="input1" />
+  <input name="appendChild" />
+</form>
+<iframe name="frame1">
+</iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug760131.html b/js/xpconnect/tests/mochitest/file_bug760131.html
new file mode 100644
index 0000000000..736732a0a4
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug760131.html
@@ -0,0 +1,23 @@
+<html>
+<div id="target" ontouchstart="alert();"></div>
+<script type="application/javascript">
+
+/** Test for Bug 760131 **/
+
+function accessTouches(evt)
+{
+  var thrown = false;
+  try {
+    var a = evt.touches;
+  } catch (e) {
+    thrown = true;
+  }
+  ok(!thrown, "Unwrapping a TouchList shouldn't throw");
+}
+
+document.getElementById("target").ontouchstart = accessTouches;
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug781476.html b/js/xpconnect/tests/mochitest/file_bug781476.html
new file mode 100644
index 0000000000..745f8818e5
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug781476.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script type="application/javascript">
+function makeEvent() {
+  var evt = new Event("MouseEvents");
+  evt.expando = 42;
+  is(evt.expando, 42, "Expando properly visible in iframe");
+  return evt;
+}
+</script>
+</head>
+<body>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug789713.html b/js/xpconnect/tests/mochitest/file_bug789713.html
new file mode 100644
index 0000000000..4c30fe8275
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug789713.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=789713
+-->
+<head>
+  <meta charset="utf-8">
+</head>
+<body>
+
+<script type="application/javascript">
+
+/** Test for Bug 789713 **/
+
+function go() {
+  var ifr = document.getElementById('ifr');
+  var pass = true;
+  var doc = ifr.contentDocument;
+  var win = ifr.contentWindow;
+
+  var walker = doc.createTreeWalker(doc.body);
+  pass = pass && (walker.root === doc.body);
+  walker.foo = "expando";
+
+  win.bar = "another-expando";
+
+  // First, do the document.domain operation. This shouldn't crash.
+  document.domain = "example.org";
+
+  // Now make sure we can still access properties on "walker".
+  try {
+    walker.root;
+    pass = pass && walker.foo == "expando";
+  } catch (e) {
+    pass = false;
+  }
+
+  // And make sure we can't access properties on "win", because the
+  // document.domain change revoked the access.
+  try {
+    win.bar;
+    pass = false;
+  } catch (e) { pass = pass && /Permission denied/.exec(e.message); }
+  window.parent.postMessage(pass, '*');
+}
+
+</script>
+<iframe id="ifr" src="file_empty.html" onload="go()"></iframe>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug795275.html b/js/xpconnect/tests/mochitest/file_bug795275.html
new file mode 100644
index 0000000000..c3886b8ba8
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug795275.html
@@ -0,0 +1,14 @@
+<html>
+<head>
+<script type="application/javascript">
+  function touchComponents() {
+    Components;
+  }
+  function touchInterfaces() {
+    Components.interfaces;
+  }
+</script>
+</head>
+<body>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug799348.html b/js/xpconnect/tests/mochitest/file_bug799348.html
new file mode 100644
index 0000000000..5800868db0
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug799348.html
@@ -0,0 +1,11 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<script>
+  var foo = window.open('file_empty.html', '', 'width=550, height=420, status=no, resizable=yes, scrollbars=yes, toolbar=no, left=945, top=225');
+</script>
+</head>
+<body>
+</body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/file_bug802557.html b/js/xpconnect/tests/mochitest/file_bug802557.html
new file mode 100644
index 0000000000..39f952bc5b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug802557.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script>
+var gTS = window.location.toString;
+var gGHR = Object.getOwnPropertyDescriptor(window.location, 'href').get;
+function getTests(fromOuter) {
+
+  function loc() {
+    return fromOuter ? window.location : location;
+  }
+  return {
+    getLocationImplicit: function() {
+      return loc() + "";
+    },
+    getLocationExplicit: function() {
+      return loc().toString();
+    },
+    getLocationApply1: function() {
+      return gTS.call(loc());
+    },
+    getLocationApply2: function() {
+      return gTS.apply(loc(), []);
+    },
+    getLocationApply3: function() {
+      return Function.call.apply(gTS, [loc()]);
+    },
+    getHref: function() {
+      return loc().href;
+    },
+    getHrefViaApply: function() {
+      return Function.call.apply(gGHR, [loc()]);
+    },
+  }
+};
+
+function mungeNames(obj, suffix) {
+  var rv = {};
+  Object.getOwnPropertyNames(obj)
+        .forEach(name => rv[name + suffix] = obj[name]);
+  return rv;
+}
+
+function mergeObjects(a, b) {
+  var rv = {};
+  Object.getOwnPropertyNames(a).forEach(name => rv[name] = a[name]);
+  Object.getOwnPropertyNames(b).forEach(name => rv[name] = b[name]);
+  return rv;
+}
+
+function getAllTests() {
+  var innerTests = getTests(false);
+  var outerTests = getTests(true);
+  return mergeObjects(mungeNames(innerTests, '_inner'),
+                      mungeNames(outerTests, '_outer'));
+}
+
+</script>
+</head>
+<body>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_bug860494.html b/js/xpconnect/tests/mochitest/file_bug860494.html
new file mode 100644
index 0000000000..63a7003796
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_bug860494.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+<title></title>
+</head>
+<body>
+<iframe name="top"></iframe>
+<iframe name="parent"></iframe>
+<iframe name="location"></iframe>
+<iframe name="length"></iframe>
+<iframe name="window"></iframe>
+<iframe name="navigator"></iframe>
+<iframe name="alert"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html b/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html
new file mode 100644
index 0000000000..127c479ebe
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html
@@ -0,0 +1,8 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test Cross-Compartment DOM WeakMaps</title>
+</head>
+<body>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_documentdomain.html b/js/xpconnect/tests/mochitest/file_documentdomain.html
new file mode 100644
index 0000000000..784ed269d0
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_documentdomain.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script type="application/javascript">
+
+  function setDomain(domain) {
+    document.domain = domain;
+  }
+
+  function tryToAccess(otherWin) {
+    try {
+      var text = otherWin.document.getElementById('foo').innerHTML;
+      return /Better Late/.exec(text);
+    } catch (e) { return false; }
+  }
+
+  var gRef = null;
+  function storeReference(otherWin) {
+    gRef = otherWin.document.getElementById('foo');
+  }
+
+  function tryToAccessStored() {
+    try {
+      return /Better Late/.exec(gRef.innerHTML);
+    } catch (e) { return false; }
+  }
+
+  function invokingFunctionThrowsSecurityException(name) {
+    try {
+      window[name]();
+      return false;
+    } catch (e) { return /insecure|denied/.test(e); }
+  }
+
+
+</script>
+</head>
+<body>
+<span id="foo">Better Late than Never</span>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_doublewrappedcompartments.html b/js/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
new file mode 100644
index 0000000000..f789a33d76
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_doublewrappedcompartments.html
@@ -0,0 +1,10 @@
+<html>
+    <head>
+        <script>
+            // We want to put an expando on the object, but we want this object
+            // to be wrapped in other compartments. This means that the expando
+            // must implement precreate, which happens (in general) for nodes.
+            // So we just do a cyclic reference to the document body.
+            window.expando = document.documentElement;
+        </script>
+    </head>
diff --git a/js/xpconnect/tests/mochitest/file_empty.html b/js/xpconnect/tests/mochitest/file_empty.html
new file mode 100644
index 0000000000..ebe8e56a68
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_empty.html
@@ -0,0 +1,3 @@
+<!DOCTYPE html>
+<!-- Note: other tests throughout the tree depend on the layout of this, including the title. Don't make big changes without a try run. -->
+<html><head><title>empty test page</title></head><body><span id="text">Nothing to see here</span><iframe name="subframe"></iframe></body></html>
diff --git a/js/xpconnect/tests/mochitest/file_evalInSandbox.html b/js/xpconnect/tests/mochitest/file_evalInSandbox.html
new file mode 100644
index 0000000000..f53aa1166c
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_evalInSandbox.html
@@ -0,0 +1,8 @@
+<html>
+    <body>
+        <script>
+            document.foo = "bar";
+            windowfoo = "windowbar";
+        </script>
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_exnstack.html b/js/xpconnect/tests/mochitest/file_exnstack.html
new file mode 100644
index 0000000000..448e3c0a70
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_exnstack.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <script type="application/javascript">
+    window.doThrow = function(other) {
+      if (other)
+        throwAsOuter(other);
+      else
+        throwAsInner();
+    }
+
+    function throwAsInner() {
+      throw Error('look at me go!');
+    }
+
+    function throwAsOuter(other) {
+      other.doThrow(null);
+    }
+  </script>
+</head>
+<body>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_expandosharing.html b/js/xpconnect/tests/mochitest/file_expandosharing.html
new file mode 100644
index 0000000000..ceb4131bb8
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_expandosharing.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script type="application/javascript">
+  function setup() {
+    // Set up different target objects for expandos, one for each binding type.
+    window.targetWN = window;
+    window.targetDOM = new XMLHttpRequest();
+    window.targetJS = new Date();
+  }
+
+  function placeExpando(name, val, target) {
+    target[name] = val;
+  }
+
+  // If val === null, then we shouldn't have access.
+  function checkExpando(name, val, target, msg) {
+    if (val !== null) {
+      ok(name in target, msg);
+      try {
+        is(target[name], val, "Got the right expando value");
+      } catch(e) { ok(false, "Threw when accessing same-origin expando"); }
+    }
+    else {
+      ok(!(name in target), msg);
+    }
+  }
+
+</script>
+</head>
+<body onload="setup();">
+    <span>Salut, Ma Cherise. ;-)</span>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_matches.html b/js/xpconnect/tests/mochitest/file_matches.html
new file mode 100644
index 0000000000..0dc101b533
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_matches.html
@@ -0,0 +1 @@
+<html><body></body></html>
diff --git a/js/xpconnect/tests/mochitest/file_nodelists.html b/js/xpconnect/tests/mochitest/file_nodelists.html
new file mode 100644
index 0000000000..2195c62ccf
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_nodelists.html
@@ -0,0 +1,7 @@
+<html>
+    <body>
+        <p>
+        <p>
+        <p>
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_wrappers-2.html b/js/xpconnect/tests/mochitest/file_wrappers-2.html
new file mode 100644
index 0000000000..e27b07ed6a
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_wrappers-2.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <script>
+      var obj = {a: 3, next: 1};
+      var to_iterate = Object.create(obj);
+      var enumerate = { 0: 0, "hi": "there" };
+      function func () {};
+      var o = {};
+      var a = [1];
+    </script>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/file_xrayic.html b/js/xpconnect/tests/mochitest/file_xrayic.html
new file mode 100644
index 0000000000..ad06a3118b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/file_xrayic.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+<head>
+<script type="application/javascript">
+  function setup() {
+    // Set up targets for sandbox expandos.
+    window.targetDOM = [document.getElementById("hello"), document.getElementById("there")];
+  }
+</script>
+</head>
+<body onload="setup();">
+<span id="hello" class="iamaspan">Hello</span>
+<span id="there" class="iamaspan">There</span>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/finalizationRegistry_worker.js b/js/xpconnect/tests/mochitest/finalizationRegistry_worker.js
new file mode 100644
index 0000000000..d603cdab38
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/finalizationRegistry_worker.js
@@ -0,0 +1,96 @@
+let holdings1 = [];
+let holdings2 = [];
+let holdings3 = [];
+let holdings4 = [];
+let holdings5 = [];
+
+onmessage = (event) => {
+  switch (event.data) {
+  case 'startTest':
+    startTest();
+    break;
+  case 'checkResults':
+    checkResults();
+    break;
+  default:
+    throw "Unknown message";
+  }
+};
+
+function startTest() {
+  // Registry with no registered objects.
+  let registry1 = new FinalizationRegistry(v => { holdings1.push(v); });
+
+  // Registry with three registered objects.
+  let registry2 = new FinalizationRegistry(v => { holdings2.push(v); });
+  registry2.register({}, 1);
+  registry2.register({}, 2);
+  registry2.register({}, 3);
+
+  // Registry with registered object that is then unregistered.
+  let registry3 = new FinalizationRegistry(v => { holdings3.push(v); });
+  let token3 = {}
+  registry3.register({}, 1, token3);
+  registry3.unregister(token3);
+
+  // Registry with registered object that doesn't die.
+  let registry4 = new FinalizationRegistry(v => { holdings4.push(v); });
+  let object4 = {};
+  registry4.register(object4, 1);
+
+  // Registry observing cyclic JS data structure.
+  let registry5 = new FinalizationRegistry(v => { holdings5.push(v); });
+  registry5.register(makeJSCycle(4), 5);
+
+  const { gc } = getJSTestingFunctions();
+  gc();
+
+  Promise.resolve().then(() => {
+    checkNoCallbacks();
+  });
+
+  postMessage('started');
+}
+
+function checkNoCallbacks() {
+  is(holdings1.length, 0);
+  is(holdings2.length, 0);
+  is(holdings3.length, 0);
+  is(holdings4.length, 0);
+  is(holdings5.length, 0);
+}
+
+function checkResults() {
+  is(holdings1.length, 0);
+
+  let result = holdings2.sort((a, b) => a - b);
+  is(result.length, 3);
+  is(result[0], 1);
+  is(result[1], 2);
+  is(result[2], 3);
+
+  is(holdings3.length, 0);
+  is(holdings4.length, 0);
+
+  is(holdings5.length, 1);
+  is(holdings5[0], 5);
+
+  postMessage('passed');
+}
+
+function is(a, b) {
+  if (a !== b) {
+    throw `Expected ${b} but got ${a}`;
+  }
+}
+
+function makeJSCycle(size) {
+  let first = {};
+  let current = first;
+  for (let i = 0; i < size; i++) {
+    current.next = {};
+    current = current.next;
+  }
+  current.next = first;
+  return first;
+}
diff --git a/js/xpconnect/tests/mochitest/hasinstance/mochitest.ini b/js/xpconnect/tests/mochitest/hasinstance/mochitest.ini
new file mode 100644
index 0000000000..7266b615bb
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/hasinstance/mochitest.ini
@@ -0,0 +1,7 @@
+[DEFAULT]
+prefs =
+  dom.webidl.crosscontext_hasinstance.enabled=false
+support-files =
+  ../file_empty.html
+
+[test_bug870423.html]
diff --git a/js/xpconnect/tests/mochitest/hasinstance/test_bug870423.html b/js/xpconnect/tests/mochitest/hasinstance/test_bug870423.html
new file mode 100644
index 0000000000..9d928cdd63
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/hasinstance/test_bug870423.html
@@ -0,0 +1,58 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=870423
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 870423</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for cross-scope instanceof. **/
+  SimpleTest.waitForExplicitFinish();
+
+  function go() {
+    var sowin = $('soifr').contentWindow;
+    var xowin = $('xoifr').contentWindow;
+    var xosswin = $('xossifr').contentWindow;
+
+    check(window, sowin, 'HTMLBodyElement', function(win) { return win.document.body; });
+    check(window, sowin, 'HTMLDocument', function(win) { return win.document; });
+    check(window, sowin, 'Window', function(win) { return win; });
+    check(window, sowin, 'Location', function(win) { return win.location; });
+
+    ok(!(xowin instanceof Window), "Cross-origin instanceof should fail");
+    ok(!(xowin.location instanceof Location), "Cross-origin instanceof should fail");
+
+    // cross-origin same-site.
+    ok(!(xosswin instanceof Window), "Cross-origin instanceof should fail");
+    ok(!(xosswin.location instanceof Location), "Cross-origin instanceof should fail");
+
+    SimpleTest.finish();
+  }
+
+  function check(win1, win2, constructorName, getInstance) {
+    ok(!(getInstance(win1) instanceof win2[constructorName]),
+       "Cross-Scope instanceof fails: " + constructorName + ", " + win1.location + ", " + win2.location);
+    ok(!(getInstance(win2) instanceof win1[constructorName]),
+       "Cross-Scope instanceof fails: " + constructorName + ", " + win2.location + ", " + win1.location);
+  }
+
+  </script>
+</head>
+<body onload="go();">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=870423">Mozilla Bug 870423</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<iframe id="soifr" src="file_empty.html"></iframe>
+<iframe id="xoifr" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<!-- cross origin, same site -->
+<iframe id="xossifr" src="//test1.mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/inner.html b/js/xpconnect/tests/mochitest/inner.html
new file mode 100644
index 0000000000..8021a55539
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/inner.html
@@ -0,0 +1,7 @@
+<html>
+    <head>
+        <title>Inner frame for bug 39685 mochitest</title>
+    </head>
+    <body onload="x = 4">
+    </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/mochitest.ini b/js/xpconnect/tests/mochitest/mochitest.ini
new file mode 100644
index 0000000000..30536b42e0
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/mochitest.ini
@@ -0,0 +1,178 @@
+[DEFAULT]
+support-files =
+  bug500931_helper.html
+  bug571849_helper.html
+  bug589028_helper.html
+  bug92773_helper.html
+  chrome_wrappers_helper.html
+  file1_bug629227.html
+  file2_bug629227.html
+  file_bug505915.html
+  file_bug605167.html
+  file_bug650273.html
+  file_bug658560.html
+  file_bug706301.html
+  file_bug720619.html
+  file_bug731471.html
+  file_bug738244.html
+  file_bug760131.html
+  file_bug781476.html
+  file_bug789713.html
+  file_bug795275.html
+  file_bug799348.html
+  file_bug802557.html
+  file_bug860494.html
+  file_crosscompartment_weakmap.html
+  file_documentdomain.html
+  file_doublewrappedcompartments.html
+  file_empty.html
+  file_evalInSandbox.html
+  file_exnstack.html
+  file_expandosharing.html
+  file_matches.html
+  file_nodelists.html
+  file_wrappers-2.html
+  file_xrayic.html
+  inner.html
+  test1_bug629331.html
+  test2_bug629331.html
+  finalizationRegistry_worker.js
+  private_field_worker.js
+  class_static_worker.js
+  bug1681664_helper.js
+  shadow_realm_worker.js
+  shadow_realm_module.js
+prefs =
+  javascript.options.weakrefs=true
+  javascript.options.spectre.disable_for_isolated_content=true
+  javascript.options.experimental.enable_new_set_methods=false
+  javascript.options.experimental.shadow_realms=true
+[test_bug384632.html]
+[test_bug390488.html]
+[test_bug393269.html]
+[test_bug396851.html]
+skip-if =
+  http3
+[test_bug428021.html]
+[test_bug446584.html]
+[test_bug462428.html]
+[test_bug478438.html]
+skip-if =
+  http3
+[test_bug500691.html]
+[test_bug505915.html]
+skip-if =
+  http3
+[test_bug560351.html]
+[test_bug585745.html]
+[test_bug589028.html]
+[test_bug601299.html]
+[test_bug605167.html]
+skip-if =
+  http3
+[test_bug618017.html]
+[test_bug623437.html]
+[test_bug628410.html]
+[test_bug628794.html]
+[test_bug629227.html]
+skip-if =
+  http3
+[test_bug629331.html]
+skip-if =
+  http3
+[test_bug636097.html]
+skip-if =
+  http3
+[test_bug650273.html]
+skip-if =
+  http3
+[test_bug655297-1.html]
+[test_bug655297-2.html]
+[test_bug661980.html]
+[test_bug691059.html]
+[test_bug720619.html]
+skip-if =
+  http3
+[test_bug731471.html]
+skip-if = toolkit == "android" && debug
+[test_bug764389.html]
+[test_bug772288.html]
+[test_bug781476.html]
+[test_bug789713.html]
+skip-if =
+  http3
+[test_bug790732.html]
+[test_bug793969.html]
+[test_bug800864.html]
+skip-if =
+  http3
+[test_bug802557.html]
+skip-if =
+  http3
+[test_bug803730.html]
+[test_bug809547.html]
+[test_bug829872.html]
+skip-if =
+  http3
+[test_bug862380.html]
+skip-if =
+  http3
+[test_bug865260.html]
+skip-if =
+  http3
+[test_bug871887.html]
+[test_bug912322.html]
+[test_bug916945.html]
+skip-if =
+  http3
+[test_bug92773.html]
+skip-if =
+  http3
+[test_bug940783.html]
+skip-if =
+  http3
+[test_bug965082.html]
+skip-if =
+  http3
+[test_bug960820.html]
+[test_bug993423.html]
+[test_bug1005806.html]
+[test_bug1094930.html]
+[test_bug1158558.html]
+[test_bug1448048.html]
+[test_bug1681664.html]
+[test_crosscompartment_weakmap.html]
+[test_enable_privilege.html]
+[test_frameWrapping.html]
+# The JS test component we use below is only available in debug builds.
+[test_getWebIDLCaller.html]
+skip-if = (debug == false)
+[test_getweakmapkeys.html]
+[test_isRemoteProxy.html]
+[test_paris_weakmap_keys.html]
+skip-if = (debug == false)
+[test_nukeContentWindow.html]
+[test_sameOriginPolicy.html]
+skip-if =
+  http3
+[test_sandbox_fetch.html]
+  support-files =
+    ../../../../dom/tests/mochitest/fetch/test_fetch_basic.js
+[test_weakmaps.html]
+[test_finalizationRegistry.html]
+[test_finalizationRegistryInWorker.html]
+[test_finalizationRegistry_cleanupSome.html]
+[test_finalizationRegistry_incumbent.html]
+[test_weakRefs.html]
+[test_weakRefs_cross_compartment.html]
+[test_weakRefs_collected_wrapper.html]
+[test_private_field_dom.html]
+[test_private_field_worker.html]
+[test_class_static_block_worker.html]
+skip-if = !nightly_build
+[test_shadowRealm.html]
+# This test has been updated to work with worker modules
+[test_shadowRealm_worker.html]
+skip-if = !nightly_build
+[test_spectre_mitigations.html]
+skip-if = os == "android" # Fission situation on Android is more complicated.
diff --git a/js/xpconnect/tests/mochitest/moz.build b/js/xpconnect/tests/mochitest/moz.build
new file mode 100644
index 0000000000..772ed94cce
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/moz.build
@@ -0,0 +1,7 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+MOCHITEST_MANIFESTS += ["hasinstance/mochitest.ini", "mochitest.ini"]
diff --git a/js/xpconnect/tests/mochitest/private_field_worker.js b/js/xpconnect/tests/mochitest/private_field_worker.js
new file mode 100644
index 0000000000..b822c16248
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/private_field_worker.js
@@ -0,0 +1,21 @@
+class A {
+  #x;
+
+  g(o) {
+    return #x in o;
+  }
+}
+
+let objects = [];
+
+self.onmessage = function (e) {
+  if (e.data === 'allocate') {
+    objects.push(new A);
+    return;
+  }
+  if (e.data == 'count') {
+    postMessage(objects.length);
+    return;
+  }
+  postMessage('Unknown message type.');
+}
+\ No newline at end of file
diff --git a/js/xpconnect/tests/mochitest/shadow_realm_module.js b/js/xpconnect/tests/mochitest/shadow_realm_module.js
new file mode 100644
index 0000000000..35ba80666b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/shadow_realm_module.js
@@ -0,0 +1 @@
+export var x = 1;
diff --git a/js/xpconnect/tests/mochitest/shadow_realm_worker.js b/js/xpconnect/tests/mochitest/shadow_realm_worker.js
new file mode 100644
index 0000000000..c91c9bc30c
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/shadow_realm_worker.js
@@ -0,0 +1,81 @@
+
+var sr = new ShadowRealm();
+var resolve;
+
+var allSettled = new Promise((resolved) => { resolve = resolved });
+
+self.onmessage = async function (e) {
+  try {
+    // Test evaluate
+    if (e.data === 'evaluate') {
+      sr.evaluate("var s = 'PASS set string in realm';")
+      var res = sr.evaluate('s');
+      postMessage(res);
+      return;
+    }
+
+    // If Import works in a worker, then it ought to work in a shadow realm
+    //
+    // See  https://bugzilla.mozilla.org/show_bug.cgi?id=1247687 and
+    //      https://bugzilla.mozilla.org/show_bug.cgi?id=1772162
+    if (e.data == 'import') {
+      var import_worked = false;
+      var importValue_worked = false;
+      var importNested_worked = false;
+      try {
+        var module = await import("./shadow_realm_module.js");
+        if (module.x != 1) {
+          throw "mismatch";
+        }
+        import_worked = true;
+      } catch (e) { }
+
+      try {
+        await sr.importValue("./shadow_realm_module.js", 'x').then((x) => {
+          if (x == 1) { importValue_worked = true; }
+        });
+      } catch (e) { }
+
+      try {
+        sr.evaluate(`
+        var imported = false;
+        import("./shadow_realm_module.js").then((module) => {
+          if (module.x == 1) {
+            imported = true;
+          }
+        });
+        true;
+        `);
+
+        importNested_worked = sr.evaluate("imported");
+      } catch (e) {
+
+      }
+
+      if (importValue_worked == importNested_worked) {
+        postMessage(`PASS: import in workers ${
+          import_worked ? "worked" : "failed"
+        }. importValue, and nested import all ${
+          importValue_worked ? "worked" : "failed"
+        } `);
+        resolve();
+        return;
+      }
+
+      postMessage(`FAIL: importValue ${importValue_worked}, import ${import_worked}, importNested ${importNested_worked}`);
+      resolve();
+      return;
+    }
+
+
+    // Reply back with finish
+    if (e.data == 'finish') {
+      await allSettled;
+      postMessage("finish");
+      return;
+    }
+  } catch (e) {
+    postMessage("FAIL: " + e.message);
+  }
+  postMessage('Unknown message type.');
+}
diff --git a/js/xpconnect/tests/mochitest/test1_bug629331.html b/js/xpconnect/tests/mochitest/test1_bug629331.html
new file mode 100644
index 0000000000..18843e08da
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test1_bug629331.html
@@ -0,0 +1,19 @@
+<body>
+<iframe src="about:blank" id="ifr"></iframe>
+<script>
+/** Test for Bug 629331 **/
+function finish() {
+    parent.postMessage(JSON.stringify({fun: "finish"}), "*");
+}
+
+function is(a, b, description) {
+    parent.postMessage(JSON.stringify({ fun: "is", a: a, b: b, description: description }), "*");
+}
+
+document.domain = "example.org";
+var i = 0;
+is(i, 0, 'i meets starting conditions');
+document.getElementById('ifr').src = 'http://test2.example.org/tests/js/xpconnect/tests/mochitest/test2_bug629331.html';
+</script>
+
+
diff --git a/js/xpconnect/tests/mochitest/test2_bug629331.html b/js/xpconnect/tests/mochitest/test2_bug629331.html
new file mode 100644
index 0000000000..1bcf037398
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test2_bug629331.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+  <head>
+  </head>
+  <body>
+    <script>
+      document.domain = "example.org";
+
+      for (var j = 1; j <= 9; j++) {
+        parent.i = j;
+        var locali = parent.i;
+        parent.is(locali, j, 'step ' + j + ' worked');
+      }
+
+      parent.finish();
+    </script>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug1005806.html b/js/xpconnect/tests/mochitest/test_bug1005806.html
new file mode 100644
index 0000000000..41fe6ee1e6
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug1005806.html
@@ -0,0 +1,27 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1005806
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1005806</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1005806">Mozilla Bug 1005806</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  <input id="ipt"></input>
+</div>
+<pre id="test">
+</pre>
+<script type="application/javascript">
+
+/** Test for Bug 1005806 **/
+is(typeof document.getElementById('ipt').controllers, 'undefined', "Controllers property should not appear for content");
+
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug1094930.html b/js/xpconnect/tests/mochitest/test_bug1094930.html
new file mode 100644
index 0000000000..d303bf2495
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug1094930.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1094930
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1094930</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <iframe id="ifr"></iframe>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1094930">Mozilla Bug 1094930</a>
+<p id="display"></p>
+<script type="application/javascript">
+  SimpleTest.waitForExplicitFinish();
+  class XFoo extends frames[0].HTMLElement {
+    connectedCallback() {
+      ok(true, "connectedCallback was called");
+      SimpleTest.finish();
+    }
+  };
+
+  customElements.define.call(frames[0].customElements, "x-foo", XFoo);
+  frames[0].document.firstChild.appendChild(new XFoo());
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug1158558.html b/js/xpconnect/tests/mochitest/test_bug1158558.html
new file mode 100644
index 0000000000..f5c50d640e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug1158558.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1158558
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1158558</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1158558">Mozilla Bug 1158558</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  <input id="ipt"></input>
+</div>
+<pre id="test">
+</pre>
+<script type="application/javascript">
+
+/** Test for Bug 1158558 **/
+
+// Observers of cycle-collector-begin can be implemented in JS, and
+// thus can end up starting an incremental GC while we're in the middle
+// of a CC slice.
+
+SimpleTest.waitForExplicitFinish();
+
+var observer = {
+  observe: function(subject, topic, data) {
+    SpecialPowers.removeObserver(observer, "cycle-collector-begin");
+    SpecialPowers.Cu.getJSTestingFunctions().startgc(1);
+
+    ok(true, "Do something so the test harness doesn't get angry");
+
+    SimpleTest.finish();
+  }
+};
+
+SpecialPowers.addObserver(observer, "cycle-collector-begin");
+
+SpecialPowers.Cu.forceCC();
+
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug1448048.html b/js/xpconnect/tests/mochitest/test_bug1448048.html
new file mode 100644
index 0000000000..2d58593a6b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug1448048.html
@@ -0,0 +1,33 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1448048
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1448048</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+    /** Test for Bug 1448048 **/
+    var { AppConstants } = SpecialPowers.ChromeUtils.import(
+      "resource://gre/modules/AppConstants.jsm"
+    );
+    if (AppConstants.NIGHTLY_BUILD) {
+      is(typeof Components, "undefined", "Should be no Components shim on Nightly");
+    } else {
+      is(typeof Components, "object", "Should have a components shim on non-Nightly");
+    }
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1448048">Mozilla Bug 1448048</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug1681664.html b/js/xpconnect/tests/mochitest/test_bug1681664.html
new file mode 100644
index 0000000000..685d4aa669
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug1681664.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <title>Test page for bug 1681664</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+    <script>
+      SimpleTest.waitForExplicitFinish()
+      async function init() {
+        var Services = SpecialPowers.Services;
+        var observer = {
+          observe(subject, topic, data) {
+            if (topic === "process-hang-report") {
+              var report = subject.QueryInterface(Ci.nsIHangReport);
+              report.terminateScript();
+              Services.obs.removeObserver(observer, "process-hang-report");
+            }
+          }
+        }
+
+        Services.obs.addObserver(observer, "process-hang-report");
+        try {
+          await import("test_bug1681664_helper.js");
+          result.textContent = "FAIL";
+        } catch (ex) {
+          result.textContent = "PASS";
+        }
+      }
+    </script>
+  </head>
+  <body>
+    <p id="result"></p>
+    <script>
+      (async function() {
+        await init();
+        is(result.textContent, "PASS", "Infinite loop script should not cause browser crash");
+        SimpleTest.finish()
+      })();
+    </script>
+  </body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/test_bug384632.html b/js/xpconnect/tests/mochitest/test_bug384632.html
new file mode 100644
index 0000000000..251ec9b153
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug384632.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=384632
+-->
+<head>
+  <title>Test for Bug 384632</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=384632">Mozilla Bug 384632</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 384632 **/
+var Cc = SpecialPowers.Cc, Ci = SpecialPowers.Ci;
+var propBag = Cc["@mozilla.org/hash-property-bag;1"].createInstance(Ci.nsIWritablePropertyBag);
+var obj = {};
+propBag.setProperty("foopy", obj);
+ok(SpecialPowers.unwrap(propBag.getProperty("foopy")) === obj,
+   "nsIVariant works with regular objects");
+propBag.setProperty("foopy1", external);
+ok(SpecialPowers.unwrap(propBag.getProperty("foopy1")) === external,
+   "nsIVariant works with bizarre objects");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug390488.html b/js/xpconnect/tests/mochitest/test_bug390488.html
new file mode 100644
index 0000000000..ca4bc4024b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug390488.html
@@ -0,0 +1,64 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=390488
+-->
+<head>
+  <title>Test for Bug 390488</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=390488">Mozilla Bug 390488</a>
+<p id="display">
+  <div id="testdiv" onclick="checkForStacks();" style="visibility:hidden">
+  </div>
+</p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for Bug 390488 **/
+  function getStack1() {
+    var func = arguments.callee.caller;
+    var stack = "";
+    for (var i = 1; func && i < 8; i++) {
+      stack += " " + i + ". " + func.name;
+      func = func.caller;
+    }
+    return stack;
+  }
+
+  function getStack2() {
+    var stack = new Error().stack;
+    // Remove the two lines due to calling this
+    return stack.substring(stack.indexOf("\n", stack.indexOf("\n")+1)+1);
+  }
+
+  function simulateClick() {
+    var evt = document.createEvent("MouseEvents");
+    evt.initMouseEvent("click", true, true, window,
+      0, 0, 0, 0, 0, false, false, false, false, 0, null);
+    $("testdiv").dispatchEvent(evt);
+  }
+
+  function matches(s, p, name) {
+    ok(s.match(p) != null,
+      name + " - got " + s + ", expected a string matching " + p);
+  }
+
+  function checkForStacks() {
+    matches(getStack1(), /checkForStacks .* onclick .* simulateClick/,
+            "Stack from walking caller chain should be correct");
+    isnot(getStack2().indexOf("simulateClick@"),  -1,
+          "Stack from |new Error().stack| should include simulateClick");
+  }
+
+  simulateClick();
+</script>
+</pre>
+</body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/test_bug393269.html b/js/xpconnect/tests/mochitest/test_bug393269.html
new file mode 100644
index 0000000000..d69e9ef2d1
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug393269.html
@@ -0,0 +1,46 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=393269
+-->
+<head>
+  <title>Test for Bug 393269</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=393269">Mozilla Bug 393269</a>
+<iframe id="ifr"></iframe>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+(function () {
+    /** Test for Bug 393269 **/
+    var doc = $("ifr").contentDocument;
+    is("UTF-8", doc.characterSet, "control, getting a property");
+    doc.open();
+    try {
+        is("UTF-8", doc.characterSet,
+           "can get a property after 1 document.open")
+    } catch (e) {
+        fail("Shouldn't have thrown: " + e);
+        return;
+    } finally {
+        doc.close();
+    }
+
+    doc.open();
+    try {
+        is("UTF-8", doc.characterSet,
+           "can get a property after 2 document.opens")
+    } catch (e) {
+        fail("Shouldn't have thrown: " + e);
+    } finally {
+        doc.close();
+    }
+})();
+</script>
+</pre>
+</body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/test_bug396851.html b/js/xpconnect/tests/mochitest/test_bug396851.html
new file mode 100644
index 0000000000..dc6bd25d52
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug396851.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=396851
+-->
+<head>
+  <title>Test for Bug 396851</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+
+  <script type="text/javascript">
+  function throws(func, pattern, msg) {
+    try {
+      func();
+      ok(false, msg);
+    } catch (e) {
+      ok(pattern.test(e), `${msg}: Expect exception mathing ${pattern}`);
+    }
+  }
+
+  function go() {
+    var iframe = $("ifr");
+    var win = iframe.contentWindow;
+    throws(() => win.document,
+           /Permission denied/,
+           "Unprivileged code should not be able to access cross-origin document");
+
+    if (SpecialPowers.useRemoteSubframes) {
+      throws(() => win.document,
+             /Permission denied/,
+             "Privileged code should not be able to access cross-process document");
+    } else {
+      ok(SpecialPowers.wrap(win).document != null,
+         "Able to access the cross-origin document");
+    }
+    SimpleTest.finish();
+  }
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=396851">Mozilla Bug 396851</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<script type="text/javascript">
+    SimpleTest.waitForExplicitFinish();
+</script>
+<iframe id="ifr"
+        src="http://example.org/tests/js/xpconnect/tests/mochitest/inner.html"
+        onload="go()">
+</iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug428021.html b/js/xpconnect/tests/mochitest/test_bug428021.html
new file mode 100644
index 0000000000..932dcf7428
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug428021.html
@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=428021
+-->
+<head>
+  <title>Test for Bug 428021</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=428021">Mozilla Bug 428021</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+      /** Test for Bug 428021 **/
+      var rangetter, ransetter;
+      this.__defineGetter__('x', function() { rangetter = true; });
+      this.__defineSetter__('x', function(val) { ransetter = true; });
+
+      var exn;
+      try {
+          e = x;
+          x = false;
+      } catch (e) {
+          exn = e;
+      }
+      ok(!exn, "Exception caught: " + exn);
+      ok(rangetter, "Failed to run getter");
+      ok(ransetter, "Failed to run setter");
+      
+</script>
+</pre>
+</body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/test_bug446584.html b/js/xpconnect/tests/mochitest/test_bug446584.html
new file mode 100644
index 0000000000..09fef92867
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug446584.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=446584
+-->
+<head>
+  <title>Test for Bug 446584</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=446584">Mozilla Bug 446584</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for Bug 446584 **/
+
+function test(val) {
+  try {
+    document.createNodeIterator(document.body,
+                                NodeFilter.SHOW_ALL,
+                                function() { throw val }).nextNode();
+    ok(false, "NodeIterator::nextNode() should have thrown an exception.");
+  } catch (ex) {
+    ok(val === ex, "NodeIterator did not properly forward exception " +
+       val + " of type " + typeof val + ".  Thrown value was " + ex + ".");
+  }
+}
+
+test(0);
+test(1);
+test(3.14);
+test('roses');
+test({});
+test(false);
+test(true);
+test([1,2,3]);
+test(function(){});
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug462428.html b/js/xpconnect/tests/mochitest/test_bug462428.html
new file mode 100644
index 0000000000..a3f7b7c39a
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug462428.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=462428
+-->
+<head>
+  <title>Test for Bug 462428</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=462428">Mozilla Bug 462428</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 462428 **/
+var getter = document.__lookupGetter__('documentElement');
+ok(getter !== undefined, "But able to look it up the normal way");
+ok(!document.hasOwnProperty('documentElement'), "property should still be on the prototype");
+
+var sawProp = false;
+for (var i in document) {
+    if (i === "documentElement") {
+        sawProp = true;
+    }
+}
+
+ok(sawProp, "property should be enumerable");
+
+is(getter.call(document), document.documentElement, "the getter actually works");
+
+Document.prototype.__defineSetter__('documentElement', function() {});
+is(getter.call(document), document.documentElement, "the getter works after defineSetter");
+
+var oldTitle = document.title;
+try {
+    var setter = document.__lookupSetter__('title');
+    setter.call(document, "title 1");
+    is(document.title, "title 1", "the setter is bound correctly");
+} finally {
+    document.title = oldTitle
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug478438.html b/js/xpconnect/tests/mochitest/test_bug478438.html
new file mode 100644
index 0000000000..e64a1e89fb
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug478438.html
@@ -0,0 +1,65 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=478438
+-->
+<head>
+  <title>Test for Bug 478438</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+    function fail(s, e) { ok(false, s + e) }
+    function pass(s, e) { ok(true, s) }
+    (pass.opposite = fail).opposite = pass;
+
+    function test() {
+      if (test.calledAlready)
+        return;
+      test.calledAlready = true;
+
+      var iwin = document.getElementById("f").contentWindow;
+
+      function testOne(fn, onAllow, infinitive) {
+        try { fn(); onAllow("able " + infinitive, "") }
+        catch (e) { onAllow.opposite("unable " + infinitive, ": " + e) }
+      }
+
+      testOne(() => iwin.focus, pass,
+              "to resolve/get allAccess property iwin.focus");
+
+      testOne(() => iwin.focus(), pass,
+              "to call allAccess method iwin.focus");
+
+      testOne(() => iwin.alert, fail,
+              "to resolve/get restricted property iwin.alert");
+
+      testOne(() => iwin.alert(), fail,
+              "to call restricted method iwin.alert");
+
+      testOne(() => iwin.location.toString(), fail,
+              "to call restricted method iwin.location.toString");
+
+      testOne(function() { iwin.location = "http://example.org" }, pass,
+              "to set writable property iwin.location");
+
+      SimpleTest.finish();
+    }
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=478438">Mozilla Bug 478438</a>
+<p id="display"></p>
+<div id="content">
+  <iframe id="f" src="http://example.com" onload="test()"></iframe>
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 478438 **/
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug484107.html b/js/xpconnect/tests/mochitest/test_bug484107.html
new file mode 100644
index 0000000000..38ca7b207b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug484107.html
@@ -0,0 +1,99 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=484107
+-->
+<head>
+  <title>Test for Bug 484107</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=484107">Mozilla Bug 484107</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 484107 **/
+
+  var text = "first group",
+      xpcWin = new XPCSafeJSObjectWrapper(window);
+  function get$1() { return RegExp.$1 };
+
+  function reset() {
+    var match = /(.*)/.exec(text);
+    if (!reset.skipStupidTests) {
+      reset.skipStupidTests = true;
+      ok(match, "No match?");
+      is(match[1], text, "Bad match?");
+      is(text, RegExp.$1, "RegExp.$1 missing?");
+      is(text, get$1(), "RegExp.$1 inaccessible?");
+    }
+  }
+
+  function test_XPC_SJOW_Call() {
+    isnot(text, xpcWin.get$1(), "Able to see RegExp.$1 from wrapped method.");
+    is("", xpcWin.get$1(), "Saw something other than an empty string for " +
+                           "RegExp.$1 from wrapped method.");
+    is(text, window.get$1(), "Unable to see RegExp.$1 from non-wrapped method.");
+  }
+
+  function test_XPC_SJOW_Call_foreign_obj() {
+    var obj = {
+      xpcGet: xpcWin.get$1,
+      rawGet: window.get$1
+    };
+    isnot(text, obj.xpcGet(), "obj.xpcGet() returned matched text.");
+    is("", obj.xpcGet(), "obj.xpcGet() returned something other than the empty string.");
+    is(text, obj.rawGet(), "obj.rawGet() did not return matched text.");
+  }
+
+  function test_XPC_SJOW_toString() {
+    var str = new XPCSafeJSObjectWrapper({
+      toString: function() { return RegExp.$1 }
+    }) + "";
+    isnot(text, str, "toString() returned the matched text.");
+    is("", str, "toString() returned something other than the empty string.");
+  }
+
+  function test_XPC_SJOW_GetOrSetProperty() {
+    window.__defineGetter__("firstMatch", function() { return RegExp.$1 });
+    isnot(text, xpcWin.firstMatch, "Getter xpcWin.firstMatch returned matched text.");
+    is("", xpcWin.firstMatch,
+       "Getter xpcWin.firstMatch returned something other than the empty string.");
+    is(text, window.firstMatch, "Getter window.firstMatch did not return matched text.");
+  }
+
+  function test_XPC_SJOW_Create() {
+    function ctor() {
+      this.match = RegExp.$1;
+      return this; // XXX Why is this necessary?
+    }
+    ctor.prototype.getMatch = function() { return this.match };
+    var xpcCtor = new XPCSafeJSObjectWrapper(ctor),
+        match = (new xpcCtor).getMatch();
+    isnot(text, match, "(new xpcCtor).getMatch() was the matched text.");
+    is("", match, "(new xpcCtor).getMatch() was not the empty string.");
+  }
+
+  var tests = [
+    test_XPC_SJOW_Call,
+    test_XPC_SJOW_Call_foreign_obj,
+    test_XPC_SJOW_toString,
+    test_XPC_SJOW_GetOrSetProperty,
+    test_XPC_SJOW_Create
+  ];
+
+  for (var i = 0; i < tests.length; i++) {
+    reset();
+    tests[i]();
+    is(text, RegExp.$1, "RegExp.$1 was clobbered.");
+  }
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug500691.html b/js/xpconnect/tests/mochitest/test_bug500691.html
new file mode 100644
index 0000000000..2ed127c099
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug500691.html
@@ -0,0 +1,27 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=500691
+-->
+<head>
+  <title>Test for Bug 500691</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=500691">Mozilla Bug 500691</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 500691 **/
+ok(Function === alert.constructor, "alert's constructor is our Function");
+ok(window.Function === alert.constructor, "window.Function is also correct");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug505915.html b/js/xpconnect/tests/mochitest/test_bug505915.html
new file mode 100644
index 0000000000..d5898bc1ed
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug505915.html
@@ -0,0 +1,49 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=505915
+-->
+<head>
+  <title>Test for Bug 505915</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=505915">Mozilla Bug 505915</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 505915 **/
+window.addEventListener("message", function () {
+  ok(false, "should not receive message");
+});
+
+function go() {
+    var ifr = $('ifr');
+    try {
+        // NB: the contentDocument getter now returns null for cross-origin
+        // frames, so use SpecialPowers to get a security wrapper to the document.
+        var xdoc = SpecialPowers.unwrap(SpecialPowers.wrap(ifr).contentDocument)
+        document.createTreeWalker(xdoc, 0, null);
+        ok(false, "should have thrown a security exception");
+    } catch (e) {
+        ok(/TypeError: Document.createTreeWalker: Argument 1 does not implement interface Node/.test(e),
+           "threw a binding exception instead of an invalid child exception");
+    }
+
+    SimpleTest.finish();
+}
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+
+<iframe id="ifr" onload="go();" src="http://test1.mochi.test:8888/"></iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug560351.html b/js/xpconnect/tests/mochitest/test_bug560351.html
new file mode 100644
index 0000000000..263e6850d7
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug560351.html
@@ -0,0 +1,36 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=560351
+-->
+<head>
+  <title>Test for Bug 560351</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=560351">Mozilla Bug 560351</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 560351 **/
+var pass = false;
+try {
+    document.body.__lookupGetter__("lastChild")();
+} catch (e) {
+    pass = true;
+}
+
+</script>
+<script>
+
+ok(pass, "pass was set to true");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug585745.html b/js/xpconnect/tests/mochitest/test_bug585745.html
new file mode 100644
index 0000000000..758aeed30d
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug585745.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=585745
+-->
+<head>
+  <title>Test for Bug 585745</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=585745">Mozilla Bug 585745</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 585745 **/
+
+  var a = document.createElementNS("http://www.w3.org/1998/Math/MathML", 'mrow');
+  var b = document.createElementNS("http://www.w3.org/1999/xhtml", 'span');
+  var htmlProto = Object.getPrototypeOf(b);
+  var mathMLProto = Object.getPrototypeOf(a);
+  // XXXbz once bug 560072 is fixed, we should be able to use
+  // getOwnPropertyDescriptor here.
+  Object.defineProperty(mathMLProto, "style", {
+      get: htmlProto.__lookupGetter__("style"),
+    });
+
+  var threw = false;
+  try {
+    a.style;
+  } catch(e) {
+    threw = true;
+  }
+  is(threw, true,
+     "Getting .style off a mathml element should throw in this case");
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug589028.html b/js/xpconnect/tests/mochitest/test_bug589028.html
new file mode 100644
index 0000000000..2cd0d15ebb
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug589028.html
@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=589028
+-->
+<head>
+  <title>Test for Bug 589028</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=589028">Mozilla Bug 589028</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<script>
+
+/** Test for Bug 589028 **/
+SimpleTest.waitForExplicitFinish();
+var p = 0;
+function go() {
+    var ifr = $('ifr');
+    var ifrwin = ifr.contentWindow;
+    var ifrdoc = ifr.contentDocument;
+
+    o1 = new ifrwin.Option();
+    is(o1.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    o2 = ifrwin.getMyOption();
+    is(o2.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    o3 = ifrwin.getCallersOption(this);
+    is(o3.ownerDocument, document);
+
+    a1 = new ifrwin.Audio();
+    is(a1.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    a2 = ifrwin.getMyAudio();
+    is(a2.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    a3 = ifrwin.getCallersAudio(this);
+    is(a3.ownerDocument, document);
+
+    i1 = new ifrwin.Image();
+    is(i1.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    i2 = ifrwin.getMyImage();
+    is(i2.ownerDocument, ifrdoc, "ownerDocument doesn't match iframe");
+
+    i3 = ifrwin.getCallersImage(this);
+    is(i3.ownerDocument, document);
+
+    SimpleTest.finish();
+}
+
+
+</script>
+</pre>
+<iframe src="bug589028_helper.html" id="ifr" onload="go()"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug601299.html b/js/xpconnect/tests/mochitest/test_bug601299.html
new file mode 100644
index 0000000000..cd726d7974
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug601299.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=601299
+
+Trigger a fastnative from a frameless context.
+-->
+<head>
+  <title>Test for Bug 601299</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body onload="window.setTimeout(RegExp, 0); window.setTimeout(function() { ok(true); SimpleTest.finish(); }, 0);">
+<script>
+SimpleTest.waitForExplicitFinish();
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug605167.html b/js/xpconnect/tests/mochitest/test_bug605167.html
new file mode 100644
index 0000000000..ba625aa805
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug605167.html
@@ -0,0 +1,56 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=505915
+-->
+<head>
+  <title>Test for Bug 505915</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=505915">Mozilla Bug 505915</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 505915 **/
+var url = "file_bug605167.html";
+var targetUrl = "http://example.com";
+var f;
+
+var p = 0;
+function go() {
+        switch (++p) {
+        case 1:
+                frames[0].location = url;
+                break;
+        case 2:
+                frames[0].location = targetUrl;
+                break;
+        case 3:
+                try {
+                    f().cross_origin_property;
+                    ok(false, "should have thrown an exception");
+                } catch (e) {
+                    ok(/Permission denied/.test(e) || /attempt to run compile-and-go script/.test(e),
+                       "threw the correct exception");
+                }
+                SimpleTest.finish();
+                break;
+        }
+}
+
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+
+<iframe id="ifr" onload="go();"></iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug618017.html b/js/xpconnect/tests/mochitest/test_bug618017.html
new file mode 100644
index 0000000000..8bfb428870
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug618017.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=618017
+
+Parsing XML must not override the version.
+-->
+<head>
+  <title>Test for Bug 618017</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+
+<script type='application/javascript'>
+let x = 12;
+function doLetEval() {
+  ok(eval('let x = 13; x') === 13, 'let statement is valid syntax in version 1.7');
+}
+</script>
+
+<script type='application/javascript'>
+doLetEval(); // Call to a function with a different version.
+</script>
+
+</body>
+</html>
+
diff --git a/js/xpconnect/tests/mochitest/test_bug623437.html b/js/xpconnect/tests/mochitest/test_bug623437.html
new file mode 100644
index 0000000000..0cea6f330b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug623437.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=623437
+-->
+<head>
+  <title>Test for Bug 623437</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=623437">Mozilla Bug 623437</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 623437 **/
+    var c = document.createElement("canvas").getContext("2d");
+    var seenArcToFirst;
+    var seenArc = false;
+    var seenArcTo = false;
+    for (var i in c) {
+      if (i == "arc") {
+        seenArc = true;
+        if (!seenArcTo)
+          seenArcToFirst = false;
+      }
+      if (i == "arcTo") {
+        seenArcTo = true;
+        if (!seenArc)
+          seenArcToFirst = true;
+      }
+    }
+    is(seenArc, true, "Should see arc");
+    is(seenArcTo, true, "Should see arcTo");
+    is(seenArcToFirst, true, "Should see arcTo before arc");
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug628410.html b/js/xpconnect/tests/mochitest/test_bug628410.html
new file mode 100644
index 0000000000..2aec713793
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug628410.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=628410
+-->
+<head>
+  <title>Test for Bug 628410</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=628410">Mozilla Bug 628410</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+
+<pre id="test">
+<script type="application/javascript">
+
+window.toString();
+
+if (SpecialPowers.Services.prefs.getBoolPref("extensions.InstallTrigger.enabled") &&
+    SpecialPowers.Services.prefs.getBoolPref("extensions.InstallTriggerImpl.enabled")) {
+  InstallTrigger + "";
+}
+
+console + "";
+ok(true, "Things didn't throw");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug628794.html b/js/xpconnect/tests/mochitest/test_bug628794.html
new file mode 100644
index 0000000000..9cbfe0f436
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug628794.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=585745
+-->
+<head>
+  <title>Test for Bug 585745</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=585745">Mozilla Bug 585745</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 585745 **/
+
+  var a = document.createElementNS("http://www.w3.org/2000/svg", 'svg');
+  var b = document.createElementNS("http://www.w3.org/1999/xhtml", 'span');
+  var htmlProto = Object.getPrototypeOf(b);
+  var svgProto = Object.getPrototypeOf(a);
+  // XXXbz once bug 560072 is fixed, we should be able to use
+  // getOwnPropertyDescriptor here.
+  Object.defineProperty(svgProto, "style", {
+      get: htmlProto.__lookupGetter__("style"),
+    });
+
+  var threw = false;
+  try {
+    a.style;
+  } catch(e) {
+    threw = true;
+  }
+  is(threw, true,
+     "Getting .style off an svg element should throw in this case");
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug629227.html b/js/xpconnect/tests/mochitest/test_bug629227.html
new file mode 100644
index 0000000000..6d01c37ec0
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug629227.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=629227
+-->
+<head>
+  <title>Test for Bug 629227</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=629227">Mozilla Bug 629227</a>
+<p id="display">
+  <iframe id="testTarget"></iframe>
+</p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 629227 **/
+SimpleTest.waitForExplicitFinish();
+
+$("testTarget").src =
+  "http://test1.example.org" +
+  location.pathname.replace(/test_bug629227.html/, "file1_bug629227.html");
+
+window.onmessage = function(ev) {
+  if (ev.data == "finish") {
+    SimpleTest.finish();
+  } else {
+    var data = JSON.parse(ev.data);
+    if ("ok" in data) {
+      ok(data.ok, data.reason);
+    }
+  }
+}
+
+addLoadEvent(function() {
+  $("testTarget").contentWindow.postMessage("start", "*");
+});
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug629331.html b/js/xpconnect/tests/mochitest/test_bug629331.html
new file mode 100644
index 0000000000..17520b187f
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug629331.html
@@ -0,0 +1,37 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=629331
+-->
+<head>
+  <title>Test for Bug 629331</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=629331">Mozilla Bug 629331</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+function handler(event) {
+    var obj = JSON.parse(event.data);
+    if (obj.fun == "finish") {
+        SimpleTest.finish();
+    } else {
+        is(obj.a, obj.b, obj.description);
+    }
+}
+
+window.addEventListener('message', handler);
+
+</script>
+<iframe src="http://test1.example.org/tests/js/xpconnect/tests/mochitest/test1_bug629331.html">
+</iframe>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug636097.html b/js/xpconnect/tests/mochitest/test_bug636097.html
new file mode 100644
index 0000000000..8ae8e4822e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug636097.html
@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=504877
+test by moz_bug_r_a4@yahoo.com
+-->
+<head>
+  <title>Test for Bug 504877</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=504877">Mozilla Bug 504877</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 504877 **/
+SimpleTest.waitForExplicitFinish();
+
+var targetUrl = "http://example.com/";
+var l;
+
+function a() {
+        var r = "FAIL", s;
+        try {
+                s = l.toString();
+        }
+        catch (e) {
+                if (/denied|insecure/.test(e))
+                        r = "PASS";
+                s = e;
+        }
+
+        is(r, "PASS", "should have thrown an exception");
+        SimpleTest.finish();
+}
+
+var p = 0;
+function b() {
+        switch (++p) {
+        case 1:
+                frames[0].location = "about:blank";
+                break;
+        case 2:
+                l = frames[0].location;
+                frames[0].location = targetUrl;
+                break;
+        case 3:
+                a();
+                break;
+        }
+}
+</script>
+
+</pre>
+<iframe onload="b()"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug650273.html b/js/xpconnect/tests/mochitest/test_bug650273.html
new file mode 100644
index 0000000000..18e029982a
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug650273.html
@@ -0,0 +1,42 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=650273
+test by moz_bug_r_a4@yahoo.com
+-->
+<head>
+  <title>Test for Bug 650273</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank"
+href="https://bugzilla.mozilla.org/show_bug.cgi?id=650273">Mozilla Bug 650273</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 504877 **/
+SimpleTest.waitForExplicitFinish();
+var count = 0;
+function done() {
+    if (++count == 2) {
+        try {
+            ok($('ifr').location.host === 'example.com', "shouldn't see this");
+        } catch (e) {
+            ok(true, "navigation successfully happened");
+        }
+        SimpleTest.finish();
+    }
+}
+
+</script>
+
+<iframe id="ifr" src="file_bug650273.html" onload="done()"></iframe>
+
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug655297-1.html b/js/xpconnect/tests/mochitest/test_bug655297-1.html
new file mode 100644
index 0000000000..38ff528c5b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug655297-1.html
@@ -0,0 +1,49 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=655297
+-->
+<head>
+  <title>Test for Bug 655297</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=655297">Mozilla Bug 655297</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+    <form>0</form> <form>1</form> <form>2</form> <form>3</form> <form>4</form>
+    <form>5</form> <form>6</form> <form>7</form> <form>8</form> <form>9</form>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 655297 **/
+
+var map = new WeakMap();
+function f() {
+    var paras = document.getElementsByTagName("form");
+    for (var i = 0; i < paras.length; i++)
+        map.set(paras[i], "ok");
+}
+function g() {
+    var paras = document.getElementsByTagName("form");
+    for (var i = 0; i < paras.length; i++) {
+        if (map.get(paras[i]) != "ok") {
+            return false;
+	}
+    }
+    return true;
+}
+
+f();
+SpecialPowers.forceGC();
+ok(g(), "Failed to keep XPCWrappedNative used as WeakMap key alive.");
+
+</script>
+
+
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug655297-2.html b/js/xpconnect/tests/mochitest/test_bug655297-2.html
new file mode 100644
index 0000000000..67da7964bd
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug655297-2.html
@@ -0,0 +1,49 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=655297
+-->
+<head>
+  <title>Test for Bug 655297</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=655297">Mozilla Bug 655297</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+    <p>0</p> <p>1</p> <p>2</p> <p>3</p> <p>4</p>
+    <p>5</p> <p>6</p> <p>7</p> <p>8</p> <p>9</p>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 655297 **/
+
+var map = new WeakMap();
+function f() {
+    var paras = document.getElementsByTagName("p");
+    for (var i = 0; i < paras.length; i++)
+        map.set(paras[i], "ok");
+}
+function g() {
+    var paras = document.getElementsByTagName("p");
+    for (var i = 0; i < paras.length; i++) {
+        if (map.get(paras[i]) != "ok") {
+            return false;
+	}
+    }
+    return true;
+}
+
+f();
+SpecialPowers.forceGC();
+ok(g(), "Failed to keep XPCWrappedNative used as WeakMap key alive.");
+
+</script>
+
+
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug661980.html b/js/xpconnect/tests/mochitest/test_bug661980.html
new file mode 100644
index 0000000000..afe62559a5
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug661980.html
@@ -0,0 +1,61 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=661980
+-->
+<head>
+  <title>Test for Bug 661980</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=661980">Mozilla Bug 661980</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 661980 **/
+
+// While not currently needed, make this as similar as possible to a real
+// EventTarget just to make sure that we're tripping on the wrapping and
+// nothing else.
+var fakeTarget = {
+  addEventListener: function() {},
+  removeEventListener: function() {},
+  dispatchEvent: function() {}
+}
+
+var mouseevent = document.createEvent("MouseEvent");
+var didThrow = false;
+dump("hello nurse\n");
+try {
+  mouseevent.initMouseEvent("mouseover",
+                            false, false,
+                            window,
+                            1, 2, 3, 4, 5,
+                            false, false, false, false,
+                            0,
+                            fakeTarget);
+}
+catch (ex) {
+  didThrow = true;
+}
+ok(didThrow, "should not be able to implement EventTarget using script");
+
+mouseevent.initMouseEvent("mouseout",
+                          false, false,
+                          window,
+                          1, 2, 3, 4, 5,
+                          false, false, false, false,
+                          0,
+                          document.body);
+is(mouseevent.type, "mouseout",
+   "should able to implement EventTarget using Element");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug691059.html b/js/xpconnect/tests/mochitest/test_bug691059.html
new file mode 100644
index 0000000000..b00da02b0d
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug691059.html
@@ -0,0 +1,59 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=691059
+-->
+<head>
+  <title>Test for Bug 691059</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=691059">Mozilla Bug 691059</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+
+/** Test for Bug 691059 **/
+
+function f() {}
+
+function testEventTarget(obj) {
+  obj.onmouseenter = f;
+  is(obj.onmouseenter, f,
+     "onmouseenter should be settable");
+  obj.onmouseleave = f;
+  is(obj.onmouseleave, f,
+     "onmouseenter should be settable");
+}
+
+function testInterface(obj) {
+  try {
+    obj.prototype.onmouseenter = f;
+    is("onmouseenter" in obj, false,
+       "setting <Interface>.prototype.onmouseenter has no effect on the " +
+       "non-existent <Interface>.onmouseenter");
+    obj.prototype.onmouseleave = f;
+    is("onmouseleave" in obj, false,
+       "setting <Interface>.prototype.onmouseleave has no effect on the " +
+       "non-existent <Interface>.onmouseleave");
+  } catch(ex) {
+    ok(false, ex);
+  }
+}
+
+testEventTarget(window);
+testEventTarget(document);
+testEventTarget(document.documentElement);
+
+testInterface(Document);
+testInterface(HTMLElement);
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug720619.html b/js/xpconnect/tests/mochitest/test_bug720619.html
new file mode 100644
index 0000000000..804ec96d75
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug720619.html
@@ -0,0 +1,55 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=720619
+-->
+<head>
+  <title>Test for Bug 629227</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=720619">Mozilla Bug 720619</a>
+<p id="display">
+  <iframe id="testTarget"></iframe>
+</p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 720619 **/
+SimpleTest.waitForExplicitFinish();
+
+function checkThrows(f, exception) {
+    try {
+        f();
+        ok(false, "should have thrown: " + f);
+    } catch (e) {
+        ok(exception.test(e.toString()), "correctly threw");
+    }
+}
+
+function go() {
+    var loc = $('ifr').contentWindow.location;
+    checkThrows(function() {loc + '';}, /Permission denied/);
+    checkThrows(function() {'' + loc;}, /Permission denied/);
+    checkThrows(function() {String(loc);}, /Permission denied/);
+
+    var win = $('ifr').contentWindow;
+    checkThrows(function() {win + '';}, /Permission denied/);
+    checkThrows(function() {'' + win;}, /Permission denied/);
+    checkThrows(function() {String(win);}, /Permission denied/);
+
+    SimpleTest.finish();
+}
+
+</script>
+
+<iframe id="ifr" onload="go()"
+        src="http://example.org/tests/js/xpconnect/tests/mochitest/file_bug720619.html">
+</iframe>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug731471.html b/js/xpconnect/tests/mochitest/test_bug731471.html
new file mode 100644
index 0000000000..e74b07734a
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug731471.html
@@ -0,0 +1,42 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=731471
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 731471</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body onload="setTimeout(boom, 0);">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=731471">Mozilla Bug 731471</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 731471. This is effectively a crashtest, but it uses window.open, which
+    doesn't work in the crashtest harness. **/
+SimpleTest.waitForExplicitFinish();
+SimpleTest.requestFlakyTimeout("untriaged");
+function boom()
+{
+    w = window.open("file_bug731471.html");
+    setTimeout(function() {
+        w.document.write("2");
+        w.document.close();
+        w.document.write("3 - Done");
+        w.document.close();
+        w.close();
+        ok(true, "Didn't assert!");
+        SimpleTest.finish();
+    }, 400);
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug764389.html b/js/xpconnect/tests/mochitest/test_bug764389.html
new file mode 100644
index 0000000000..6e90dd448b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug764389.html
@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=764389
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 764389</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=764389">Mozilla Bug 764389</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 764389 **/
+
+// This is basically a crash test, but we need to write a mochitest so that it
+// runs with http:// urls instead of file:// urls.
+SimpleTest.waitForExplicitFinish();
+
+function go() {
+  var ifr = document.getElementById('ifr');
+  ifr.contentDocument.open();
+  ok(true, "Didn't crash");
+  ifr.contentDocument.close();
+  SimpleTest.finish();
+}
+
+
+
+</script>
+<iframe id="ifr" onload="go();" src="file_empty.html">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug772288.html b/js/xpconnect/tests/mochitest/test_bug772288.html
new file mode 100644
index 0000000000..5af0f7d2d6
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug772288.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=772288
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 772288</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body onload="doTest()">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=772288">Mozilla Bug 772288</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 772288 **/
+SimpleTest.waitForExplicitFinish();
+
+const Cu = SpecialPowers.Cu;
+
+function doTest() {
+    msg = "AppConstants should be imported on window";
+    try {
+      Cu.import("resource://gre/modules/AppConstants.jsm", window);
+      ok(AppConstants, msg);
+    } catch (ex) {
+      ok(false, msg + " : " + ex);
+    }
+
+    msg = "AppConstants should be imported on myObj";
+    try {
+      var myObj = {};
+      Cu.import("resource://gre/modules/AppConstants.jsm", myObj);
+      ok(myObj.AppConstants, msg);
+    } catch (ex) {
+      ok(false, msg + " : " + ex);
+    }
+
+    SimpleTest.finish();
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug781476.html b/js/xpconnect/tests/mochitest/test_bug781476.html
new file mode 100644
index 0000000000..f9ab40d4d9
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug781476.html
@@ -0,0 +1,36 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=781476
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 781476</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=781476">Mozilla Bug 781476</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 781476 **/
+SimpleTest.waitForExplicitFinish();
+
+function go() {
+  var iwin = document.getElementById('ifr').contentWindow;
+  iwin.is = is;
+  var evt = iwin.makeEvent();
+  is(evt.expando, 42, "Expando properly visible in caller frame");
+  SimpleTest.finish();
+}
+
+
+</script>
+</pre>
+<iframe onload="go();" id="ifr" src="file_bug781476.html"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug789713.html b/js/xpconnect/tests/mochitest/test_bug789713.html
new file mode 100644
index 0000000000..251ecf22c2
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug789713.html
@@ -0,0 +1,39 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=789713
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 789713</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=789713">Mozilla Bug 789713</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+<iframe id="ifr"></iframe>
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 789713 **/
+
+// We can't set document.domain on mochi.test, because it's forbidden to set
+// document.domain to a TLD.
+var ifr = document.getElementById('ifr');
+
+SimpleTest.waitForExplicitFinish();
+ifr.src = window.location.toString().replace("mochi.test:8888", "test1.example.org")
+                                    .replace("test_bug789713", "file_bug789713")
+                                    .split('?')[0];
+window.onmessage = function(message) {
+  ok(message.data, "Test succeeded and didn't crash");
+  SimpleTest.finish();
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug790732.html b/js/xpconnect/tests/mochitest/test_bug790732.html
new file mode 100644
index 0000000000..c702273900
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug790732.html
@@ -0,0 +1,55 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=790732
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 790732</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+async function doTest() {
+  await SpecialPowers.pushPrefEnv({set: [["dom.use_components_shim", true]]})
+
+  // Basic stuff
+  ok(Components, "Components shim exists!");
+  var Ci = Components.interfaces;
+  ok(Ci, "interfaces shim exists!");
+  is(typeof Components.classes, 'undefined', "Shouldn't have a Cc");
+
+  // Check each interface that we shim. We start by checking specific
+  // constants for a couple of interfaces, and then once it's pretty clear that
+  // it's working as intended we just check that the objects themselves are the
+  // same.
+  is(Ci.nsIXMLHttpRequest.HEADERS_RECEIVED, XMLHttpRequest.HEADERS_RECEIVED);
+  is(Ci.nsIDOMNode.DOCUMENT_NODE, Node.DOCUMENT_NODE);
+  is(Ci.nsIDOMKeyEvent, KeyEvent);
+  is(Ci.nsIDOMMouseEvent, MouseEvent);
+  is(Ci.nsIDOMMouseScrollEvent, MouseScrollEvent);
+  is(Ci.nsIDOMMutationEvent, MutationEvent);
+  is(Ci.nsIDOMUIEvent, UIEvent);
+  is(Ci.nsIDOMHTMLMediaElement, HTMLMediaElement);
+  is(Ci.nsIDOMRange, Range);
+  is(Ci.nsIDOMNodeFilter, NodeFilter);
+  is(Ci.nsIDOMXPathResult, XPathResult);
+
+  SimpleTest.finish();
+}
+
+doTest();
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=790732">Mozilla Bug 790732</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+<iframe id="ifr"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug793969.html b/js/xpconnect/tests/mochitest/test_bug793969.html
new file mode 100644
index 0000000000..1d06d65904
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug793969.html
@@ -0,0 +1,53 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=793969
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 793969</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=793969">Mozilla Bug 793969</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 793969 **/
+function checkThrows(f, desc, skipMessageCheck) {
+  try {
+    f();
+    ok(false, "Should have thrown for " + desc);
+  } catch (e) {
+    ok(true, "threw correctly");
+    if (!skipMessageCheck)
+      ok(/denied/.exec(e) ||
+         /can't redefine non-configurable property/.exec(e),
+         "Correctly threw a security exception: " + e);
+  }
+}
+
+// NB: These sets will be no-ops (throw in strict mode) because setting an inherited readonly value prop has those semantics.
+checkThrows(function() { "use strict"; location.valueOf = 'hah'; }, 'Shadow with string', /* skipMessageCheck = */ true);
+checkThrows(function() { "use strict"; location.valueOf = function() { return {a: 'hah'};} }, 'Shadow with function', /* skipMessageCheck = */ true);
+checkThrows(function() { Object.defineProperty(location, 'valueOf', { value: function() { return 'hah'; } }); }, 'defineProperty with value');
+checkThrows(function() { delete location.valueOf; Object.defineProperty(location, 'valueOf', { value: function() { return 'hah'; } }); }, 'delete + defineProperty with value');
+checkThrows(function() { Object.defineProperty(location, 'valueOf', { get: function() { return 'hah'; } }); }, 'defineProperty with getter');
+checkThrows(function() { delete location.valueOf; Object.defineProperty(location, 'valueOf', { get: function() { return 'hah'; } }); }, 'delete + defineProperty with getter');
+
+Object.prototype.valueOf = function() { return 'hah'; };
+is(({}).valueOf(), 'hah', "Shadowing on Object.prototype works for vanilla objects");
+is(location.valueOf(), location, "Shadowing on Object.prototype and Location.prototype doesn't for location objects");
+
+location[Symbol.toPrimitive] = function() { return 'hah'; }
+is(location + "", location.toString(), "Should't be able to shadow with toPrimitive");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug800864.html b/js/xpconnect/tests/mochitest/test_bug800864.html
new file mode 100644
index 0000000000..4acee755f5
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug800864.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=800864
+-->
+<head>
+  <title>Test for Bug 800864</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=800864">Mozilla Bug 800864</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+function checkThrows(f) {
+  try {
+    f();
+    ok(false, "Didn't throw a security exception like we should");
+  } catch(e) {
+    ok(/denied|insecure/.exec(e), "Should throw security exception. Got: " + e);
+  }
+}
+
+function go() {
+  ifr = document.getElementById('ifr');
+  win = ifr.contentWindow;
+  loc = win.location;
+  ifr.onload = check;
+  win.location = 'http://test1.example.com';
+}
+
+function check() {
+  checkThrows(function() { loc.toString(); });
+  checkThrows(function() { loc.valueOf().toString(); });
+  checkThrows(function() { loc.href; });
+  checkThrows(function() { loc + ''; });
+  SimpleTest.finish();
+}
+
+</script>
+</pre>
+</body>
+<iframe id="ifr" onload="go()" src="file_empty.html"></iframe>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug802557.html b/js/xpconnect/tests/mochitest/test_bug802557.html
new file mode 100644
index 0000000000..4479986b8e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug802557.html
@@ -0,0 +1,116 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=802557
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 802557</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 802557 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function checkThrows(fun, desc) {
+    try {
+      fun();
+      ok(false, "Didn't throw when " + desc);
+    } catch(e) {
+      ok(true, "Threw when " + desc + " " + e);
+      ok(/denied|insecure/.exec(e), "Should be security exception");
+    }
+  }
+
+  var loadCount = 0;
+  function go() {
+    ++loadCount;
+    window.ifr = document.getElementById('ifr');
+    window.iWin = ifr.contentWindow;
+
+    if (loadCount == 1) {
+      gLoc = iWin.location;
+      // Note that accessors pulled off Xrays are currently bound. This is bug 658909.
+      // [getter, description, locationObj, bound]
+      gGetters = [[ location.toString, 'toString from LW' ],
+                  [ gLoc.toString, 'toString from XLW' ],
+                  [ Object.__lookupGetter__.call(location, 'href'), 'href getter from LW' ],
+                  [ Object.__lookupGetter__.call(gLoc, 'href'), 'href getter from XLW' ],
+                  [ Object.getOwnPropertyDescriptor(location, 'href').get, 'href getter from location' ],
+                  [ Object.getOwnPropertyDescriptor(gLoc, 'href').get, 'href getter from iWin.location' ],
+                  [ function() { return this + ''; }, 'implicit conversion via [[DefaultValue]]', /* doMessageCheck = */ true ]];
+      gGetters.forEach(function(item) {
+        try {
+          is(item[0].call(location), location.toString(), 'Same-origin LW: ' + item[1]);
+          is(item[0].call(gLoc), gLoc.toString(), 'Same-origin XLW: ' + item[1]);
+        } catch (e) {
+          ok(false, "Threw while applying " + item[1] + " to same-origin location object: " + e);
+        }
+      });
+      ifr.src = "http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html";
+    }
+    else if (loadCount == 2) {
+      gGetters.forEach(function(item) {
+        checkThrows(function() { item[0].call(gLoc); },
+                    'call()ing ' + item[1] + ' after navigation cross-origin');
+      });
+      ifr.src = 'http://mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_bug802557.html';
+    }
+    else if (loadCount == 3) {
+      gTestFunctions = ifr.contentWindow.getAllTests();
+      var win = ifr.contentWindow;
+      for (fun in gTestFunctions)
+         is(gTestFunctions[fun](), win.location.toString(), "allowed via " + fun);
+      win.location = 'http://example.org/tests/js/xpconnect/tests/mochitest/file_bug802557.html';
+    }
+    else if (loadCount == 4) {
+      for (fun in gTestFunctions) {
+        var f = gTestFunctions[fun];
+        checkThrows(f, "calling " + fun);
+      }
+
+      // Verify that URL.prototype.toString can't be applied to Location
+      var threw = false;
+      try {
+        URL.prototype.toString.call(location);
+      } catch (e) {
+        threw = true;
+      }
+      ok(threw,
+         "Should not be able to use URL.prototype.toString on a Location instance");
+  
+      // Verify that URL.prototype.href getter can't be applied to Location
+      threw = false;
+      var reachedTest = false;
+      try {
+        var get = Object.getOwnPropertyDescriptor(URL.prototype, "href").get;
+        is(typeof(get), "function", "Should have an href getter on URL.prototype");
+        var reachedTest = true;
+        get.call(location);
+      } catch (e) {
+        threw = true;
+      }
+      ok(reachedTest,
+         "Should not be able to find URL.prototype.href getter");
+      ok(threw,
+         "Should not be able to use URL.prototype.href getter on a Location instance");
+      SimpleTest.finish();
+    }
+  }
+
+
+
+</script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=802557">Mozilla Bug 802557</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<iframe id="ifr" onload="go();" src="file_empty.html"></iframe>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug803730.html b/js/xpconnect/tests/mochitest/test_bug803730.html
new file mode 100644
index 0000000000..88df8d5477
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug803730.html
@@ -0,0 +1,41 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=803730
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 803730</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=803730">Mozilla Bug 803730</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 803730 **/
+var foo = {
+  isNode: function(obj) {
+    return !!(obj instanceof Node);
+  }
+};
+
+var elem = document.createElement("span");
+var trueCount = 0,
+    falseCount = 0;
+for (var x = 0; x < 100000; x++) {
+  if (foo.isNode(elem))
+    trueCount++;
+  else
+    falseCount++;
+}
+is(falseCount, 0, "elem instanceof Node working correctly.");
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug809547.html b/js/xpconnect/tests/mochitest/test_bug809547.html
new file mode 100644
index 0000000000..17808867d6
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug809547.html
@@ -0,0 +1,42 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=809547
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 809547</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body onload="go()">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=809547">Mozilla Bug 809547</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 809547 **/
+SimpleTest.waitForExplicitFinish();
+var gObj = {};
+function go() {
+  window.location.expando = gObj;
+  is(window.location.expando, gObj, "Expando appears");
+  SimpleTest.executeSoon(finish);
+}
+
+function finish() {
+  SpecialPowers.forceGC();
+  SpecialPowers.forceCC();
+  SpecialPowers.forceGC();
+  SpecialPowers.forceCC();
+  is(window.location.expando, gObj, "Expando preserved");
+  SimpleTest.finish();
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug829872.html b/js/xpconnect/tests/mochitest/test_bug829872.html
new file mode 100644
index 0000000000..07e2a4ca77
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug829872.html
@@ -0,0 +1,52 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=829872
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 829872</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 829872 and Bug 968003 **/
+  SimpleTest.waitForExplicitFinish();
+
+  var gLoadCount = 0;
+  function loaded() {
+    if (++gLoadCount == 3)
+      go();
+  }
+
+  async function check(elem, desc) {
+    is(elem.contentDocument, null, "null cross-origin contentDocument for " + desc);
+    ok(await SpecialPowers.spawn(elem, [], () => this.content.eval('frameElement === null;')),
+       "null cross-origin frameElement for " + desc);
+    if (!(elem instanceof elem.ownerDocument.defaultView.HTMLFrameElement))
+      is(elem.getSVGDocument(), null, "null cross-origin getSVGDocument() for " + desc);
+  }
+
+  async function go() {
+    ok(true, "Starting test");
+    await check($('ifr'), "iframe element");
+    await check($('obj'), "object element");
+    await check($('framesetholder').contentDocument.getElementById('fr'), "frameset frame");
+    SimpleTest.finish();
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=829872">Mozilla Bug 829872</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+<iframe id="ifr" onload="loaded();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<object id="obj" onload="loaded();" data="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></object>
+<iframe id="framesetholder" srcdoc="<html><head></head><frameset cols='100%'><frame id='fr' onload='parent.loaded();' src='http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html' /></frameset></html>"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug862380.html b/js/xpconnect/tests/mochitest/test_bug862380.html
new file mode 100644
index 0000000000..d604e3d05f
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug862380.html
@@ -0,0 +1,54 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=862380
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 862380</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 862380 **/
+  SimpleTest.waitForExplicitFinish();
+  function go() {
+    checkNotEnumerable($('ifr').contentWindow, true);
+    checkNotEnumerable($('ifr').contentWindow.location, false);
+    SimpleTest.finish();
+  }
+
+function checkNotEnumerable(obj, isWindow) {
+    try {
+      const expectedWindow = ["0"];
+      const expectedLocation = [];
+      const expected = isWindow ? expectedWindow : expectedLocation;
+      is(Object.keys(obj).length, expected.length,
+         "Object.keys gives right array length");
+      var actual = [];
+      for (var i in obj)
+        actual.push(i);
+      is(actual.length, expected.length,
+         "Enumeration sees the right number of props");
+      actual.sort();
+      expected.sort();
+      for (var i = 0; i < actual.length; ++i)
+        is(actual[i], expected[i], "Arrays should be the same " + i);
+    } catch (e) {
+      ok(false, "threw: " + e);
+    }
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=862380">Mozilla Bug 862380</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug865260.html b/js/xpconnect/tests/mochitest/test_bug865260.html
new file mode 100644
index 0000000000..b09b488dcd
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug865260.html
@@ -0,0 +1,33 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=865260
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 865260</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 865260 **/
+  SimpleTest.waitForExplicitFinish();
+  function go() {
+    var exn = "nothrow";
+    try { $('ifr').contentWindow['Date']; } catch (e) { exn = e; };
+    ok(!!/denied/.exec(exn), "Threw instead of crashing");
+    SimpleTest.finish();
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=865260">Mozilla Bug 865260</a>
+<p id="display"></p>
+<div id="content">
+<iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug871887.html b/js/xpconnect/tests/mochitest/test_bug871887.html
new file mode 100644
index 0000000000..082b2ae746
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug871887.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=871887
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 871887</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 871887 **/
+  SimpleTest.waitForExplicitFinish();
+
+  // NB: onstart ends up getting invoked twice, for mysterious and potentially-
+  // IE6-related reasons.
+  function checkpoint(invocant) {
+    ok(true, "onstart called");
+    is(invocant, $('llama'), "this-binding is correct");
+    $('llama').loop = 1;
+    $('llama').scrollDelay = 1;
+    $('llama').scrollAmount = 500;
+  }
+
+  function done(invocant) {
+    is(invocant, $('llama'), "this-binding is correct");
+    ok(true, "onfinish called");
+    SimpleTest.finish();
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=871887">Mozilla Bug 871887</a>
+<p id="display"></p>
+<div id="content">
+<marquee id="llama" onstart="checkpoint(this);" onfinish="done(this);">Watch the Llama</marquee>
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug912322.html b/js/xpconnect/tests/mochitest/test_bug912322.html
new file mode 100644
index 0000000000..011c4a8f4e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug912322.html
@@ -0,0 +1,35 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=912322
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 912322</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  var { AppConstants } = SpecialPowers.ChromeUtils.import(
+    "resource://gre/modules/AppConstants.jsm"
+  );
+  // Test window.controllers.
+  if (AppConstants.RELEASE_OR_BETA) {
+    is(typeof window.controllers, 'object', "shimmed controllers should be available to content in beta and release");
+  } else {
+    is(typeof window.controllers, 'undefined', "controllers should not be available to content in Nightly");
+  }
+  is(typeof SpecialPowers.wrap(window).controllers, 'object', "controllers should be available over Xray");
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=912322">Mozilla Bug 912322</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug916945.html b/js/xpconnect/tests/mochitest/test_bug916945.html
new file mode 100644
index 0000000000..01c342eea1
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug916945.html
@@ -0,0 +1,78 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=916945
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 916945</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 916945 **/
+  SimpleTest.waitForExplicitFinish();
+
+  var gLoadCount = 0;
+  function loaded() {
+    if (++gLoadCount == 2)
+      go();
+  }
+  async function go() {
+    // Both same-origin and cross-origin names should be visible if they're set
+    // on the iframe element.
+    ok('winA' in window, "same-origin named access works");
+    ok(winA instanceof winA.Window, "same-origin named access works");
+    ok('winB' in window, "cross-origin named access works when iframe name matches");
+    is(winB.parent, window, "cross-origin named access works when iframe name matches");
+
+    // Setting the 'name' attribute should propagate to the docshell.
+    var ifrB = document.getElementById('ifrB');
+    await SpecialPowers.spawn(ifrB, [], () => {
+      Assert.equal(this.content.name, 'winB',
+                   'initial attribute value propagates to the docshell');
+    });
+
+    ifrB.setAttribute('name', 'foo');
+    await SpecialPowers.spawn(ifrB, [], () => {
+      Assert.equal(this.content.name, 'foo',
+                   'attribute sets propagate to the docshell');
+    });
+    ok('foo' in window, "names are dynamic if updated via setAttribute");
+    is(foo.parent, window, "names are dynamic if updated via setAttribute");
+
+    // Setting window.name on the subframe should not propagate to the attribute.
+    await SpecialPowers.spawn(ifrB, [], () => {
+      this.content.name = "bar";
+    });
+    is(ifrB.getAttribute('name'), 'foo', 'docshell updates dont propagate to the attribute');
+
+    // When the frame element attribute and docshell name don't match, nothing is returned.
+    ok(!('foo' in window), "frame element name not resolved if it doesn't match the docshell");
+    ok(!('bar' in window), "docshell name not resolved if it doesn't match the frame element");
+
+    // This shouldn't assert.
+    function listener() {
+      document.body.appendChild(ifrA);
+      ifrA.name = "";
+    }
+    ifrA.addEventListener("DOMNodeInserted", listener, {once: true});
+    document.body.appendChild(ifrA);
+
+    SimpleTest.finish();
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=916945">Mozilla Bug 916945</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<iframe id="ifrA" name="winA" onload="loaded();" src="file_empty.html"></iframe>
+<iframe id="ifrB" name="winB" onload="loaded();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug92773.html b/js/xpconnect/tests/mochitest/test_bug92773.html
new file mode 100644
index 0000000000..b1172f377e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug92773.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=92773
+-->
+<head>
+  <title>Test for Bug 92773</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=92773">Mozilla Bug 92773</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 92773 **/
+function go() {
+    try {
+        $('ifr').contentWindow.foo;
+        ok(false, "able to access cross-origin getter");
+    } catch (e) {
+        ok(/Permission denied/.exec(e), "unable to access cross-origin getter");
+    }
+
+    SimpleTest.finish();
+}
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+
+<iframe id='ifr'
+        src='http://example.com/tests/js/xpconnect/tests/mochitest/bug92773_helper.html'
+        onload="go()">
+</iframe>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug940783.html b/js/xpconnect/tests/mochitest/test_bug940783.html
new file mode 100644
index 0000000000..0c87e710c1
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug940783.html
@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=940783
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 940783</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 940783 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function checkHistoryThrows(hist) {
+    checkThrows(function() { hist.length; });
+    checkThrows(function() { hist.state; });
+    checkThrows(function() { hist.go(); });
+    checkThrows(function() { hist.back(); });
+    checkThrows(function() { hist.forward(); });
+    checkThrows(function() { hist.pushState({}, "foo"); });
+    checkThrows(function() { hist.replaceState({}, "foo"); });
+
+  }
+
+  window.gLoads = 0;
+  function load() {
+    var iwin = $('ifr').contentWindow;
+    ++gLoads;
+    if (gLoads == 1) {
+      window.gHist = iwin.history;
+      iwin.location = "file_empty.html";
+    } else if (gLoads == 2) {
+      checkHistoryThrows(gHist);
+      window.gHist = iwin.history;
+      iwin.location = "http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html";
+    } else {
+      checkHistoryThrows(gHist);
+      $('ifr').setAttribute('onload', null);
+      SimpleTest.finish();
+    }
+  }
+
+  function checkThrows(fn) {
+    try { fn(); ok(false, "Should have thrown: " + fn.toSource()); }
+    catch (e) { ok(!!/denied|insecure/.exec(e), "Threw correctly: " + e); }
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=940783">Mozilla Bug 940783</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+<iframe id="ifr" onload="load();" src="file_empty.html"></iframe>
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug960820.html b/js/xpconnect/tests/mochitest/test_bug960820.html
new file mode 100644
index 0000000000..7667fde624
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug960820.html
@@ -0,0 +1,56 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=960820
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 960820</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for exception stacks crossing **/
+
+  // Synchronous event dispatch creates a new script entry point. At the time
+  // of this writing, an event listener defined in a Sandbox will cause the
+  // SafeJSContext to be pushed to the cx stack, which differs from the JSContext
+  // associated with this DOM window. So we test both kinds of boundaries.
+  var sb = new SpecialPowers.Cu.Sandbox(SpecialPowers.Services.scriptSecurityManager.getSystemPrincipal());
+  sb.win = window;
+  SpecialPowers.Cu.evalInSandbox("win.document.addEventListener('click', " +
+                                 "function clickHandler() { win.wrappedJSObject.clickCallback(); });", sb);
+  function clickCallback() {
+    var stack = (new Error()).stack;
+    ok(true, "Invoked clickCallback. Stack: " + stack);
+    ok(/clickCallback/.test(stack), "clickCallback should be in the stack");
+    ok(!/clickHandler/.test(stack), "clickHandler should not be in the stack");
+    ok(/dispatchClick/.test(stack), "dispatchClick should be in the stack");
+
+    // Check Components.stack, but first filter through the SpecialPowers junk.
+    var stack = SpecialPowers.wrap(SpecialPowers.Components).stack;
+    while (/testing-common/.test(stack)) {
+      stack = stack.caller;
+    }
+    ok(/clickCallback/.test(stack), "clickCallback should be reachable via Components.stack");
+    ok(/clickHandler/.test(stack.caller), "clickHandler should be reachable via Components.stack");
+    ok(/dispatchClick/.test(stack.caller.caller), "dispatchClick hould be reachable via Components.stack");
+  }
+  function dispatchClick() {
+    document.dispatchEvent(new MouseEvent('click'));
+  }
+  dispatchClick();
+
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=960820">Mozilla Bug 960820</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug965082.html b/js/xpconnect/tests/mochitest/test_bug965082.html
new file mode 100644
index 0000000000..b2320b52c7
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug965082.html
@@ -0,0 +1,39 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=965082
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 965082</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 965082 **/
+  SimpleTest.waitForExplicitFinish();
+
+  function checkThrows(f, msg) {
+    try { f(); ok(false, "Should have thrown: " + msg); }
+    catch (e) { ok(/denied|insecure|can't set prototype/.test(e), "Should throw security exception: " + e + " (" + msg + ")"); }
+  }
+
+  function go() {
+    var protoSetter = Object.getOwnPropertyDescriptor(Object.prototype, '__proto__').set;
+    checkThrows(function() { protoSetter.call(window[0], new Object()); }, "Setting cross-origin Window prototype");
+    checkThrows(function() { protoSetter.call(window[0].location, new Object()); }, "Setting cross-origin Location prototype");
+    SimpleTest.finish();
+  }
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=965082">Mozilla Bug 965082</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<iframe id="ifr" onload="go();" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_bug993423.html b/js/xpconnect/tests/mochitest/test_bug993423.html
new file mode 100644
index 0000000000..dbe4cef3cc
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_bug993423.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=993423
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 993423</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 993423 **/
+  SimpleTest.waitForExplicitFinish();
+
+  var sCallbackInvocations = 0;
+  function callback(handlerIsInXBLScope) {
+    ok(!handlerIsInXBLScope, "Event handler should not be in XBL scope");
+    if (++sCallbackInvocations == 2)
+      SimpleTest.finish();
+  }
+
+  function go() {
+    document.querySelector('use').setAttributeNS('http://www.w3.org/1999/xlink',
+                                                 'href', location.href + '#a');
+  }
+
+  </script>
+</head>
+<body onload="go()";>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=993423">Mozilla Bug 993423</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+<svg>
+  <symbol id="a">
+    <foreignObject>
+    <img src="about:logo" onload="var isInXBL = (function() { return this; })() != window; if (isInXBL) callback = window.wrappedJSObject.callback; callback(isInXBL);">
+    </foreignObject>
+  </symbol>
+  <use />
+</svg>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_class_static_block_worker.html b/js/xpconnect/tests/mochitest/test_class_static_block_worker.html
new file mode 100644
index 0000000000..e3ce063fe9
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_class_static_block_worker.html
@@ -0,0 +1,32 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test class static fields</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      // Make sure static classes parse in regular context too:
+      class B {
+        static { this.x = 12; }
+      }
+      is(B.x, 12, "static block set class value");
+      console.log("script");
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        let worker = new Worker('class_static_worker.js');
+
+        console.log("message")
+        worker.onmessage = function(e) {
+
+          is(e.data, 12, "correctly allocated class-static containing-class in worker");
+          SimpleTest.finish();
+        }
+        worker.postMessage("get");
+        info("Messages posted");
+      }
+      go();
+    </script>
+  </head>
+
+</html>
+\ No newline at end of file
diff --git a/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html b/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html
new file mode 100644
index 0000000000..d7d364fdeb
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html
@@ -0,0 +1,36 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test Cross-Compartment DOM WeakMaps</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<p id="display"></p>
+<script type="application/javascript">
+
+var my_map = new WeakMap();
+
+function setup() {
+  var item = window.frames[0].document.querySelector("body");
+
+  my_map.set(item, "success_string");
+}
+
+function runTest() {
+  setup();
+  SpecialPowers.forceGC();
+  SpecialPowers.forceCC();
+  SpecialPowers.forceGC();
+  SpecialPowers.forceCC();
+  var item = window.frames[0].document.querySelector("body");
+  is(my_map.get(item), "success_string", "Preserve reflectors used cross-compartment as weak map keys.");
+}
+
+</script>
+<iframe src="file_crosscompartment_weakmap.html" onload="runTest()"></iframe>
+
+
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_enable_privilege.html b/js/xpconnect/tests/mochitest/test_enable_privilege.html
new file mode 100644
index 0000000000..03043e9ce6
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_enable_privilege.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <title>Test page for enablePrivilege</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script>
+      function init() {
+        var result = document.getElementById("result");
+        try {
+          /* globals netscape */
+          netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
+          result.textContent = "FAIL";
+        } catch (ex) {
+          result.textContent = "PASS";
+        }
+      }
+    </script>
+  </head>
+  <body>
+    <p id="result"></p>
+    <script>
+      init();
+      is(result.textContent, "PASS", "enablePrivilege should be unavaillable");
+    </script>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_finalizationRegistry.html b/js/xpconnect/tests/mochitest/test_finalizationRegistry.html
new file mode 100644
index 0000000000..9d9a798cdf
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_finalizationRegistry.html
@@ -0,0 +1,168 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test FinalizationRegistry works in the browser</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      let registry1, holdings1;
+      let registry2, holdings2;
+      let registry3, holdings3;
+      let registry4, holdings4;
+      let registry5, holdings5;
+      let registry6, holdings6;
+      let registry7, holdings7;
+      let registry8, holdings8;
+      let registry9, holdings9;
+
+      let object4 = {};
+
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        // Registry with no registered objects.
+        holdings1 = [];
+        registry1 = new FinalizationRegistry(v => { holdings1.push(v); });
+
+        // Registry with three registered objects.
+        holdings2 = [];
+        registry2 = new FinalizationRegistry(v => { holdings2.push(v); });
+        registry2.register({}, 1);
+        registry2.register({}, 2);
+        registry2.register({}, 3);
+
+        // Registry with registered object that is then unregistered.
+        holdings3 = [];
+        registry3 = new FinalizationRegistry(v => { holdings3.push(v); });
+        let token3 = {}
+        registry3.register({}, 1, token3);
+        registry3.unregister(token3);
+
+        // Registry with registered object that doesn't die.
+        holdings4 = [];
+        registry4 = new FinalizationRegistry(v => { holdings4.push(v); });
+        registry4.register(object4, 1);
+
+        // Registry observing cyclic JS data structure.
+        holdings5 = [];
+        registry5 = new FinalizationRegistry(v => { holdings5.push(v); });
+        registry5.register(makeJSCycle(4), 5);
+
+        // Registry observing DOM object without preserved wrappers.
+        holdings6 = [];
+        registry6 = new FinalizationRegistry(v => { holdings6.push(v); });
+        registry6.register(document.createElement("div"), 6);
+
+        // Registry observing DOM object with preserved wrappers.
+        holdings7 = [];
+        registry7 = new FinalizationRegistry(v => { holdings7.push(v); });
+        let object = document.createElement("div");
+        object.someProperty = true;
+        registry7.register(object, 7);
+        object = null;
+
+        // Registry observing reachable DOM object without preserved wrappers.
+        holdings8 = [];
+        registry8 = new FinalizationRegistry(v => { holdings8.push(v); });
+        document.body.appendChild(document.createElement("div"));
+        registry8.register(document.body.lastChild, 8);
+
+        // Registry observing cyclic DOM/JS data structure.
+        holdings9 = [];
+        registry9 = new FinalizationRegistry(v => { holdings9.push(v); });
+        registry9.register(makeDOMCycle(4), 9);
+
+        // Need to run full GC/CC/GC cycle to collect cyclic garbage through DOM
+        // and JS heaps.
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+        SpecialPowers.DOMWindowUtils.cycleCollect();
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+
+        // Microtasks are run before cleanup callbacks.
+        Promise.resolve().then(() => {
+          is(holdings1.length, 0);
+          is(holdings2.length, 0);
+          is(holdings3.length, 0);
+          is(holdings4.length, 0);
+          is(holdings5.length, 0);
+          is(holdings6.length, 0);
+          is(holdings7.length, 0);
+          is(holdings8.length, 0);
+          is(holdings9.length, 0);
+        });
+
+        // setTimeout queues a task which will run after cleanup callbacks.
+        setTimeout(task2, 0);
+      }
+
+      function task2() {
+        is(holdings1.length, 0);
+
+        let result = holdings2.sort((a, b) => a - b);
+        is(result.length, 3);
+        is(result[0], 1);
+        is(result[1], 2);
+        is(result[2], 3);
+
+        is(holdings3.length, 0);
+        is(holdings4.length, 0);
+
+        is(holdings5.length, 1);
+        is(holdings5[0], 5);
+
+        is(holdings6.length, 1);
+        is(holdings6[0], 6);
+
+        is(holdings7.length, 1);
+        is(holdings7[0], 7);
+
+        is(holdings8.length, 0);
+
+        is(holdings9.length, 1);
+        is(holdings9[0], 9);
+
+        document.body.removeChild(document.body.lastChild);
+
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+        SpecialPowers.DOMWindowUtils.cycleCollect();
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+
+        setTimeout(task3, 0);
+      }
+
+      function task3()  {
+        is(holdings8.length, 1);
+        is(holdings8[0], 8);
+
+        SimpleTest.finish();
+      }
+
+      function makeJSCycle(size) {
+        let first = {};
+        let current = first;
+        for (let i = 0; i < size; i++) {
+          current.next = {};
+          current = current.next;
+        }
+        current.next = first;
+        return first;
+      }
+
+      function makeDOMCycle(size) {
+        let first = {};
+        let current = first;
+        for (let i = 0; i < size; i++) {
+          if (i % 2 === 0) {
+            current.next = document.createElement("div");
+          } else {
+            current.next = {};
+          }
+          current = current.next;
+        }
+        current.next = first;
+        return first;
+      }
+    </script>
+  </head>
+  <body onload="go()"></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_finalizationRegistryInWorker.html b/js/xpconnect/tests/mochitest/test_finalizationRegistryInWorker.html
new file mode 100644
index 0000000000..8393781ce1
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_finalizationRegistryInWorker.html
@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test FinalizationRegistry works in workers</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        let worker = new Worker('finalizationRegistry_worker.js');
+
+        worker.onevent = (event) => {
+          console.log(event.message);
+          throw event.error;
+        };
+
+        worker.onmessage = (event) => {
+          switch (event.data) {
+          case 'started':
+            worker.postMessage('checkResults');
+            break;
+
+          case 'passed':
+            ok(true, "Tests passed");
+            SimpleTest.finish();
+            break;
+
+          default:
+            console.log(event.data);
+            break;
+          }
+        };
+
+        worker.postMessage('startTest');
+      }
+    </script>
+  </head>
+  <body onload="go()"></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_finalizationRegistry_cleanupSome.html b/js/xpconnect/tests/mochitest/test_finalizationRegistry_cleanupSome.html
new file mode 100644
index 0000000000..d70cfa7172
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_finalizationRegistry_cleanupSome.html
@@ -0,0 +1,13 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test FinalizationRegistry cleanupSome method is not exposed by default</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      let registry = new FinalizationRegistry(x => 1);
+      is(registry.cleanupSome, undefined,
+         "The cleanupSome method should not be exposed by default");
+    </script>
+  </head>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_finalizationRegistry_incumbent.html b/js/xpconnect/tests/mochitest/test_finalizationRegistry_incumbent.html
new file mode 100644
index 0000000000..8b6c71c9cf
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_finalizationRegistry_incumbent.html
@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test FinalizationRegistry tracks its incumbent global</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      let resolvePromise, rejectPromise;
+
+      async function runTest(global, callback) {
+        let fr = new global.FinalizationRegistry(callback);
+        fr.register({}, undefined);
+
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+
+        let promise = new Promise((resolve, reject) => {
+          resolvePromise = resolve;
+          rejectPromise = reject;
+        });
+
+        return promise;
+      }
+
+      function receiveMessage(event) {
+        resolvePromise(event.source.sourceName);
+      }
+
+      async function go() {
+        // This test uses FinalizationRegistry to trigger a callback and reports
+        // the incumbent global in the callback using postMessage. In all cases
+        // the author function that scheduled the callback is runTest(), so the
+        // incumbent global should be the main window.
+
+        SimpleTest.waitForExplicitFinish();
+
+        window.sourceName = "main";
+        window.addEventListener("message", receiveMessage, false);
+
+        let other = window.frames[0];
+        other.sourceName = "other";
+        other.addEventListener("message", receiveMessage, false);
+
+        is(await runTest(window, v => window.postMessage(v)), "main");
+        is(await runTest(window, window.postMessage.bind(window)), "main");
+        is(await runTest(other, v => other.postMessage(v)), "main");
+        is(await runTest(other, other.postMessage.bind(other)), "main");
+        is(await runTest(window, v => other.postMessage(v)), "main");
+        is(await runTest(window, other.postMessage.bind(other)), "main");
+        is(await runTest(other, v => window.postMessage(v)), "main");
+        is(await runTest(other, window.postMessage.bind(window)), "main");
+
+        SimpleTest.finish();
+      }
+    </script>
+  </head>
+  <body onload="go()">
+    <div style="display: none">
+      <!-- A subframe so we have another global to work with -->
+      <iframe></iframe>
+    </div>
+  </body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_frameWrapping.html b/js/xpconnect/tests/mochitest/test_frameWrapping.html
new file mode 100644
index 0000000000..4c8a6c428c
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_frameWrapping.html
@@ -0,0 +1,37 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+No bug.
+-->
+<head>
+  <title>Test for Bug </title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=">Mozilla Bug </a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** No bug for this test  **/
+
+function go() {
+    var win = frames[0];
+    (function() {
+        var utils = SpecialPowers.getDOMWindowUtils(window);
+        is(utils.getClassName(win), "Proxy", "correctly wrap frame elements");
+     })()
+    SimpleTest.finish();
+}
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+<iframe id="ifr" src="inner.html" onload="go()"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_getWebIDLCaller.html b/js/xpconnect/tests/mochitest/test_getWebIDLCaller.html
new file mode 100644
index 0000000000..22a4ae1c3b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_getWebIDLCaller.html
@@ -0,0 +1,49 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=968335
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 968335</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Cu.getCallerPrincipal (within JS-implemented WebIDL). **/
+
+  SimpleTest.waitForExplicitFinish();
+  SpecialPowers.pushPrefEnv({set: [['dom.expose_test_interfaces', true]]}, go);
+
+
+  function go() {
+    var t = new TestInterfaceJS();
+    is(t.getCallerPrincipal(), location.origin,
+       "Cu.getCallerPrincipal works right within JS-implemented WebIDL");
+
+    try {
+      SpecialPowers.Cu.getWebIDLCallerPrincipal();
+      ok(false, "Should have thrown");
+    } catch (e) {
+      ok(/NOT_AVAILABLE/.test(SpecialPowers.wrap(e)),
+         "API should throw when invoked outside of JS-implemented WebIDL");
+    }
+
+    SimpleTest.finish();
+  }
+
+
+
+
+  </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=968335">Mozilla Bug 968335</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_getweakmapkeys.html b/js/xpconnect/tests/mochitest/test_getweakmapkeys.html
new file mode 100644
index 0000000000..7942d9b945
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_getweakmapkeys.html
@@ -0,0 +1,59 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=688277
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Tests for nondeterministicGetWeakMapKeys</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+  /** Test for Bug 688277 **/
+
+  /* Fail gracefully if junk is passed in. */
+  is(SpecialPowers.nondeterministicGetWeakMapKeys(11), undefined,
+    "nondeterministicGetWeakMapKeys should return undefined for non-objects");
+  is(SpecialPowers.nondeterministicGetWeakMapKeys({}), undefined,
+    "nondeterministicGetWeakMapKeys should return undefined for non-weakmap objects");
+  is(SpecialPowers.nondeterministicGetWeakMapKeys(null), undefined,
+    "nondeterministicGetWeakMapKeys should return undefined for null");
+
+  /* return an empty array for an empty WeakMap */
+  let mempty = new WeakMap();
+  is(SpecialPowers.nondeterministicGetWeakMapKeys(mempty).length, 0,
+    "nondeterministicGetWeakMapKeys should return empty array for empty weakmap");
+
+  /* Test freeing/nonfreeing. */
+  let m = new WeakMap();
+  let liveKeys = new Array();
+
+  let add_elements = function () {
+    let k1 = {};
+    m.set(k1, "live1");
+    liveKeys.push(k1);
+
+    let k2 = {};
+    m.set(k2, "dead1");
+
+    let k = {};
+    m.set(k, k); /* simple cycle */
+  };
+
+  add_elements();
+
+  SpecialPowers.exactGC(function () {
+    let keys = SpecialPowers.nondeterministicGetWeakMapKeys(m);
+    is(liveKeys.length, 1, "Wrong number of live keys.");
+    is(keys.length, 1, "Should have one weak map key.");
+    is(m.get(keys[0]), "live1", "live1 should be live");
+    SimpleTest.finish();
+  });
+
+  SimpleTest.waitForExplicitFinish();
+  </script>
+</head>
+<body>
+<p id="display"></p>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_isRemoteProxy.html b/js/xpconnect/tests/mochitest/test_isRemoteProxy.html
new file mode 100644
index 0000000000..9761fce05b
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_isRemoteProxy.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Tests for Cu.isRemoteProxy</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<script>
+
+async function addFrame(url) {
+  let frame = document.createElement("iframe");
+  frame.src = url;
+  document.body.appendChild(frame);
+
+  await new Promise(resolve => {
+    frame.addEventListener("load", resolve, { once: true });
+  });
+
+  return frame;
+}
+
+add_task(async function() {
+  const { Cu } = SpecialPowers;
+
+  let localFrame = await addFrame("file_empty.html");
+  let remoteFrame = await addFrame(
+    SimpleTest.getTestFileURL("file_empty.html")
+              .replace("mochi.test:8888", "example.com"));
+
+  ok(frames[0] === localFrame.contentWindow, "frames[0] is localFrame");
+  ok(frames[1] === remoteFrame.contentWindow, "frames[1] is remoteFrame");
+
+  ok(!Cu.isRemoteProxy(window), "window is not a remote proxy");
+  ok(!Cu.isRemoteProxy(location), "location is not a remote proxy");
+
+  ok(!Cu.isRemoteProxy(frames[0]), "frames[0] is not a remote proxy");
+  ok(
+    !Cu.isRemoteProxy(frames[0].location),
+    "frames[0].location is not a remote proxy"
+  );
+
+  const { useRemoteSubframes } = SpecialPowers;
+  is(Cu.isRemoteProxy(frames[1]), useRemoteSubframes,
+     "frames[1] is a remote proxy if Fission is enabled");
+  is(Cu.isRemoteProxy(frames[1].location), useRemoteSubframes,
+    "frames[1].location is a remote proxy if Fission is enabled");
+});
+
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_nukeContentWindow.html b/js/xpconnect/tests/mochitest/test_nukeContentWindow.html
new file mode 100644
index 0000000000..0db8749b59
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_nukeContentWindow.html
@@ -0,0 +1,75 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1322273
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1322273</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1322273">Mozilla Bug 1322273</a>
+
+<iframe id="subframe"></iframe>
+
+<script type="application/javascript">
+"use strict";
+
+function waitForWindowDestroyed(winID, callback) {
+  let observer = {
+    observe: function(subject, topic, data) {
+      let id = subject.QueryInterface(SpecialPowers.Ci.nsISupportsPRUint64).data;
+      if (id != winID) {
+        return;
+      }
+      SpecialPowers.removeObserver(observer, "outer-window-nuked");
+      SpecialPowers.executeSoon(callback);
+    }
+  };
+  SpecialPowers.addObserver(observer, "outer-window-nuked");
+}
+
+add_task(async function() {
+  let frame = $('subframe');
+  frame.srcdoc = "foo";
+  await new Promise(resolve => frame.addEventListener("load", resolve, {once: true}));
+
+  let win = frame.contentWindow;
+  let winID = SpecialPowers.wrap(win).docShell.outerWindowID;
+
+  win.eval("obj = {}");
+  win.obj.foo = {bar: "baz"};
+
+  let obj = win.obj;
+
+  let system = SpecialPowers.Services.scriptSecurityManager.getSystemPrincipal()
+  let sandbox = SpecialPowers.Cu.Sandbox(system);
+
+  sandbox.obj = obj;
+
+  let isWrapperDead = SpecialPowers.Cu.evalInSandbox(`(${
+      function isWrapperDead() {
+        return Cu.isDeadWrapper(obj);
+      }
+    })`,
+    sandbox);
+
+  is(isWrapperDead(), false, "Sandbox wrapper for content window should not be dead");
+  is(obj.foo.bar, "baz", "Content wrappers into and out of content window should be alive");
+
+  // Remove the frame, which should nuke the content window.
+  info("Remove the content frame");
+  frame.remove();
+
+  // Give the nuke wrappers task a chance to run.
+  await new Promise(resolve => waitForWindowDestroyed(winID, resolve));
+
+  is(isWrapperDead(), true, "Sandbox wrapper for content window should be dead");
+  is(obj.foo.bar, "baz", "Content wrappers into and out of content window should be alive");
+});
+</script>
+
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_paris_weakmap_keys.html b/js/xpconnect/tests/mochitest/test_paris_weakmap_keys.html
new file mode 100644
index 0000000000..1b786138d4
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_paris_weakmap_keys.html
@@ -0,0 +1,94 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=777385
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Tests for WebIDL objects as weak map keys</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 777385 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  // We wait to run this until the load event because it needs to access an element.
+  function go() {
+
+  let live_map = new WeakMap;
+
+  let get_div_style = function () {
+    return document.getElementById("mydivname").style;
+  }
+
+  let make_live_map = function () {
+    let my_div_style = get_div_style();
+    let div_fail = false;
+    try {
+      live_map.set(my_div_style, 12345);
+    } catch (e) {
+      div_fail = true;
+    }
+    ok(!div_fail, "Using elem.style as a weak map key should not produce an exception.");
+
+    is(live_map.get(get_div_style()), 12345, "Live map should have live style with right value before GC.");
+
+  }
+
+  make_live_map();
+
+  let tf = new TestFunctions;
+
+  let add_non_isupports2 = function () {
+    let testKey = tf.wrapperCachedNonISupportsObject;
+
+    let testFail = false;
+    try {
+      live_map.set(testKey, 23456);
+    } catch (e) {
+      testFail = true;
+    }
+
+    ok(!testFail, "Using a wrapper cached non-nsISupports class as a weak map key should not produce an exception.");
+
+    is(live_map.get(testKey), 23456, "Live map should have wrapper cached non-nsISupports class right value before GC.");
+  }
+
+  add_non_isupports2();
+
+
+  /* Set up for running precise GC/CC then check the results. */
+
+  SpecialPowers.exactGC(function () {
+    SpecialPowers.forceCC();
+    SpecialPowers.forceGC();
+    SpecialPowers.forceGC();
+
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(live_map).length, 2,
+       "Live WebIDL bindings keys should not be removed from a weak map.");
+
+    is(live_map.get(get_div_style()), 12345, "Live weak map should have live style with right value after GC.");
+    is(live_map.get(tf.wrapperCachedNonISupportsObject), 23456,
+       "Live weak map should have live wrapper cached non-nsISupports class with right value after GC.");
+
+    SimpleTest.finish();
+  });
+
+  }
+
+  SimpleTest.waitForExplicitFinish();
+
+  addLoadEvent(function() {
+    SpecialPowers.pushPrefEnv({set: [['dom.expose_test_interfaces', true]]},
+                              go);
+  });
+  </script>
+</head>
+<div></div>
+<div id="mydivname"></div>
+<body>
+<p id="display"></p>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_private_field_dom.html b/js/xpconnect/tests/mochitest/test_private_field_dom.html
new file mode 100644
index 0000000000..4a50c7ca95
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_private_field_dom.html
@@ -0,0 +1,221 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=????
+-->
+
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug ????</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <iframe id="ifr"></iframe>
+</head>
+
+<body>
+  <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1094930">Mozilla Bug 1094930</a>
+  <p id="display"></p>
+  <div id="test_contents">
+    <!-- Extracted from nsHTMLTagList.h -->
+    <applet></applet>
+    <area></area>
+    <audio></audio>
+    <base>
+    </base>
+    <bgsound></bgsound>
+    <blockquote></blockquote>
+
+    <body></body>
+    <br></br>
+    <button></button>
+    <canvas></canvas>
+    <caption></caption>
+    <col>
+    </col>
+    <colgroup></colgroup>
+    <data></data>
+    <datalist></datalist>
+    <del></del>
+    <details></details>
+    <dialog></dialog>
+    <dir></dir>
+    <div></div>
+    <dl></dl>
+    <embed></embed>
+    <fieldset></fieldset>
+    <font></font>
+    <form></form>
+    <frame></frame>
+    <frameset></frameset>
+    <h1></h1>
+    <h2></h2>
+    <h3></h3>
+    <h4></h4>
+    <h5></h5>
+    <h6></h6>
+
+    <head></head>
+    <hr>
+    </hr>
+    <html>
+
+    </html>
+    <iframe></iframe>
+    <img></img>
+    <input></input>
+    <ins></ins>
+    <keygen></keygen>
+    <label></label>
+    <legend></legend>
+    <li></li>
+    <link>
+    </link>
+    <listing></listing>
+    <map></map>
+    <marquee></marquee>
+    <menu></menu>
+    <menuitem>
+    </menuitem>
+    <meta>
+    </meta>
+    <meter></meter>
+    <multicol></multicol>
+    <object></object>
+    <ol></ol>
+    <optgroup></optgroup>
+    <option></option>
+    <output></output>
+    <p></p>
+    <param>
+    </param>
+    <picture></picture>
+    <pre></pre>
+    <progress></progress>
+    <q></q>
+    <script></script>
+    <select></select>
+    <slot></slot>
+    <source>
+    </source>
+    <span></span>
+    <style></style>
+    <summary></summary>
+    <table></table>
+    <tbody></tbody>
+    <td></td>
+    <textarea></textarea>
+    <tfoot></tfoot>
+    <th></th>
+    <thead></thead>
+    <template></template>
+    <time></time>
+    <title></title>
+    <tr></tr>
+    <track>
+    </track>
+    <ul></ul>
+    <video></video>
+    <xmp></xmp>
+  </div>
+  <script type="application/javascript">
+    SimpleTest.waitForExplicitFinish();
+    info("running")
+
+
+    // Because private fields may not be enabled, we construct A via the below eval of an IFFE,
+    // and return early if it syntax errors.
+    var A = undefined;
+    try {
+       A = eval(`(function(){
+                      class Base {
+                          constructor(o) {
+                              return o;
+                          }
+                      }
+
+                      class A extends Base {
+                        #x = 1;
+                        static g(o) {
+                          return o.#x;
+                        }
+                        static s(o, v) {
+                          o.#x = v;
+                        }
+                      }
+                      
+                      return A;
+                  })();`);
+    } catch (e) {
+      is(e instanceof SyntaxError, true, "Threw Syntax Error, Private Fields Not Enabled");
+      is(/private fields are not currently supported/.test(e.message), true, "correct message");
+    }
+
+    if (A instanceof Function) {
+      function assertThrewInstance(f, error) {
+        var threw = true;
+        try {
+          f();
+          threw = false;
+        } catch (e) {
+          // info("Caught " + e.name);
+          is(e instanceof error, true, "Correct Error thrown");
+        }
+        is(threw, true, "Error was thrown");
+      }
+
+      function testNode(node) {
+        info("Testing node " + node.nodeName);
+
+        assertThrewInstance(() => A.g(node), TypeError);
+        assertThrewInstance(() => A.s(node, 'node'), TypeError);
+        // info("Stamping Node");
+        new A(node);
+        // info("Asserting read");
+        is(A.g(node), 1, "correct value read");
+        // info("Setting");
+        A.s(node, 'node');
+        // info("Verifing setter set the value");
+        is(A.g(node), 'node', "updated value read");
+        // info("Verifying we cannot double-init");
+        assertThrewInstance(() => new A(node), TypeError);
+      }
+
+      function testNodeRecursive(node) {
+        testNode(node);
+        for (c of node.children) {
+          testNodeRecursive(c)
+        }
+      }
+
+      const test_contents = document.getElementById('test_contents');
+      testNodeRecursive(test_contents);
+
+      info("Checking Window");
+      // Window itself isn't allowed to host private fields, because it's
+      // a cross-origin object
+      assertThrewInstance(() => A.g(window), TypeError)
+
+      info("Checking Window Prototype Chain")
+      // However, it's prototype chain can.
+      w = Object.getPrototypeOf(window);
+      while (w) {
+        testNode(w);
+        w = Object.getPrototypeOf(w);
+      }
+
+      info("Test Document")
+      testNode(document);
+
+
+      info("Test CSSRuleList")
+      testNode(document.styleSheets[0].cssRules)
+
+      info("Test DOMTokenList")
+      const div = document.createElement('div');
+      testNode(div.classList);
+    }
+    SimpleTest.finish();
+  </script>
+</body>
+
+</html>
+\ No newline at end of file
diff --git a/js/xpconnect/tests/mochitest/test_private_field_worker.html b/js/xpconnect/tests/mochitest/test_private_field_worker.html
new file mode 100644
index 0000000000..68351000c5
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_private_field_worker.html
@@ -0,0 +1,27 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test Private Fields</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        let worker = new Worker('private_field_worker.js');
+
+        var allocated = 0;
+        worker.onmessage = function(e) {
+          is(e.data, allocated, "correctly allocated private field-containing-class");
+          SimpleTest.finish();
+        }
+
+        worker.postMessage("allocate"); allocated++;
+        worker.postMessage("count");
+        info("Messages posted");
+      }
+      go();
+    </script>
+  </head>
+
+</html>
+\ No newline at end of file
diff --git a/js/xpconnect/tests/mochitest/test_sameOriginPolicy.html b/js/xpconnect/tests/mochitest/test_sameOriginPolicy.html
new file mode 100644
index 0000000000..2393e3c24f
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_sameOriginPolicy.html
@@ -0,0 +1,109 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=801576
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 801576</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=801576">Mozilla Bug 801576</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for the same-origin policy. **/
+SimpleTest.waitForExplicitFinish();
+
+function check(obj, prop, allowed, write) {
+  var accessed = false;
+  try {
+    if (write) {
+      try {
+        obj[prop] = 2;
+        accessed = true;
+      } catch (e) {}
+      Object.defineProperty(obj, 'prop', {getter: function() {}, setter: null});
+    }
+    else
+      obj[prop];
+    accessed = true;
+  } catch (e) {}
+  is(accessed, allowed, prop + " is correctly (in)accessible for " + (write ? 'write' : 'read'));
+}
+
+var crossOriginReadableWindowProps = ['blur', 'close', 'closed', 'focus',
+                                      'frames', 'location', 'length',
+                                      'opener', 'parent', 'postMessage',
+                                      'self', 'top', 'window',
+                                      /* indexed and named accessors */
+                                      '0', 'subframe'];
+
+function isCrossOriginReadable(obj, prop) {
+  if (obj == "Window")
+    return crossOriginReadableWindowProps.includes(prop);
+  if (obj == "Location")
+    return prop == 'replace';
+  return false;
+}
+
+function isCrossOriginWritable(obj, prop) {
+  if (obj == "Window")
+    return prop == 'location';
+  if (obj == "Location")
+    return prop == 'href';
+}
+
+// NB: we don't want to succeed with writes, so we only check them when it should be denied.
+function testAll(sameOrigin) {
+  var win = document.getElementById('ifr').contentWindow;
+
+  // Build a list of properties to check from the properties available on our
+  // window.
+  var props = [];
+  for (var prop in window) { props.push(prop); }
+
+  // On android, this appears to be on the window but not on the iframe. It's
+  // not really relevant to this test, so just skip it.
+  if (props.includes('crypto'))
+    props.splice(props.indexOf('crypto'), 1);
+
+  // Add the named grand-child, since that won't appear on our window.
+  props.push('subframe');
+
+  for (var prop of props) {
+    check(win, prop, sameOrigin || isCrossOriginReadable('Window', prop), /* write = */ false);
+    if (!sameOrigin && !isCrossOriginWritable('Window', prop))
+      check(win, prop, false, /* write = */ true);
+  }
+  for (var prop in window.location) {
+    check(win.location, prop, sameOrigin || isCrossOriginReadable('Location', prop));
+    if (!sameOrigin && !isCrossOriginWritable('Location', prop))
+      check(win.location, prop, false, /* write = */ true);
+  }
+}
+
+var loadCount = 0;
+function go() {
+  ++loadCount;
+  if (loadCount == 1) {
+    testAll(true);
+    document.getElementById('ifr').contentWindow.location = 'http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html';
+  }
+  else {
+    is(loadCount, 2);
+    testAll(false);
+    SimpleTest.finish();
+  }
+}
+
+</script>
+</pre>
+<iframe id="ifr" onload="go();" src="file_empty.html"></iframe>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_sandbox_fetch.html b/js/xpconnect/tests/mochitest/test_sandbox_fetch.html
new file mode 100644
index 0000000000..3b6cffed4e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_sandbox_fetch.html
@@ -0,0 +1,54 @@
+<!doctype html>
+<html>
+<head>
+  <title>Fetch in JS Sandbox</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"></link>
+  <script src="test_fetch_basic.js"></script>
+</head>
+<body>
+<script type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+
+function testHttpFetch(url) {
+  info('fetch: ' + url);
+  return fetch(new Request(url, { method: 'GET' }))
+    .then(response => {
+      is(response.status, 200, 'Response is 200');
+      is(response.url, url, 'Response URL matches');
+    });
+}
+
+function runSandboxTest(testFunc, argString) {
+  is(typeof testFunc, 'function');
+  var resolvePromise;
+  var testPromise = new Promise(r => resolvePromise = r);
+  var finishFuncName = 'finish_' + testFunc.name;
+  SpecialPowers.Cu.exportFunction(_ => resolvePromise(), sb,
+                                  { defineAs: finishFuncName });
+  SpecialPowers.Cu.evalInSandbox('(' + testFunc.toString() + ')' +
+                                 '(' + argString + ')' +
+                                 '.then(' + finishFuncName + ');', sb);
+  return testPromise;
+}
+
+var origin = document.location.origin;
+var properties = ['fetch', 'Blob', 'URL'];
+var sb = new SpecialPowers.Cu.Sandbox(origin,
+                                      { wantGlobalProperties: properties });
+
+sb.ok = SpecialPowers.Cu.exportFunction(ok, sb);
+sb.is = SpecialPowers.Cu.exportFunction(is, sb);
+sb.info = SpecialPowers.Cu.exportFunction(info, sb);
+
+Promise.resolve()
+  .then(_ => runSandboxTest(testHttpFetch, '"' + origin + window.location.pathname + '"'))
+  .then(_ => runSandboxTest(testAboutURL))
+  .then(_ => runSandboxTest(testDataURL))
+  .then(_ => runSandboxTest(testSameOriginBlobURL))
+  .then(_ => SimpleTest.finish());
+
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_shadowRealm.html b/js/xpconnect/tests/mochitest/test_shadowRealm.html
new file mode 100644
index 0000000000..311ce68107
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_shadowRealm.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test for ShadowRealms</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <iframe id="ifr"></iframe>
+</head>
+
+<body>
+  <p id="display"></p>
+  <script type="application/javascript">
+    SimpleTest.waitForExplicitFinish();
+    info("running")
+
+    let realm = new ShadowRealm();
+
+    let install = (fun, internal_name) => {
+        let installer = realm.evaluate(`var ${internal_name}; (x) => { ${internal_name} = x}`);
+        installer(fun);
+    }
+
+    install(info, "log");
+    install(is, "is");
+    realm.evaluate(`is(true, true, 'inside realm')`);
+
+    is(realm.evaluate("10"), 10, "ten is ten");
+
+    SimpleTest.finish();
+  </script>
+</body>
+
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_shadowRealm_worker.html b/js/xpconnect/tests/mochitest/test_shadowRealm_worker.html
new file mode 100644
index 0000000000..d26e665f8f
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_shadowRealm_worker.html
@@ -0,0 +1,63 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test for ShadowRealms</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <iframe id="ifr"></iframe>
+</head>
+
+<body>
+  <p id="display"></p>
+  <script type="application/javascript">
+    SimpleTest.waitForExplicitFinish();
+
+    var promise = (async ()=> {
+      var module = await import("./shadow_realm_module.js");
+      is(module.x, 1, "import works outside worker");
+
+      var sr = new ShadowRealm();
+      await sr.importValue("./shadow_realm_module.js", 'x').then((x) => is(x,1, "imported x and got 1"));
+    })();
+
+    promise.then(() => {
+      var worker = new Worker("shadow_realm_worker.js");
+
+      var expected = 0;
+      var recieved = 0;
+
+      function test(str) {
+        worker.postMessage(str);
+        expected++;
+      }
+
+      worker.onmessage = function(e) {
+            console.log("Received Message: "+e.data);
+            recieved++;
+
+            if (e.data == "finish") {
+              is(expected, recieved, "Got the appropriate Number of messages");
+              SimpleTest.finish();
+              return;
+            }
+
+            if (e.data.startsWith("PASS")) {
+              ok(true, e.data);
+              return;
+            }
+
+            ok(false, e.data);
+          };
+
+
+      test("evaluate");
+      test("import");
+
+
+      test("finish");
+  });
+  </script>
+</body>
+
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_spectre_mitigations.html b/js/xpconnect/tests/mochitest/test_spectre_mitigations.html
new file mode 100644
index 0000000000..3797b9af0e
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_spectre_mitigations.html
@@ -0,0 +1,29 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Tests for Spectre mitigations</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<script>
+add_task(async function() {
+  const { Cu } = SpecialPowers;
+  const options = Cu.getJSTestingFunctions().getJitCompilerOptions();
+
+  const testMitigation = function(name) {
+    let val = options[name];
+    ok(val === 0 || val === 1, "must be valid JitOption");
+    is(Boolean(val), !SpecialPowers.useRemoteSubframes, "must be enabled if Fission is disabled");
+  };
+
+  testMitigation("spectre.index-masking");
+  testMitigation("spectre.object-mitigations");
+  testMitigation("spectre.string-mitigations");
+  testMitigation("spectre.value-masking");
+  testMitigation("spectre.jit-to-cxx-calls");
+});
+</script>
+</body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_weakRefs.html b/js/xpconnect/tests/mochitest/test_weakRefs.html
new file mode 100644
index 0000000000..331bb9bb69
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_weakRefs.html
@@ -0,0 +1,80 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test WeakRef works in the browser</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      let wr1, wr2, wr3, wr4;
+
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        // 1. WeakRef with JS target.
+        wr1 = new WeakRef({});
+
+        // 2. WeakRef with DOM object target (without preserved wrapper).
+        wr2 = new WeakRef(document.createElement("div"));
+
+        // 3. WeakRef with DOM object target (with preserved wrapper).
+        let object = document.createElement("div");
+        object.someProperty = true;
+        wr3 = new WeakRef(object);
+        object = null
+
+        // 4. WeakRef with reachable DOM object target without preserved wrapper.
+        document.body.appendChild(document.createElement("div"));
+        wr4 = new WeakRef(document.body.lastChild);
+
+        // WeakRef should keep the target in the current task.
+        isnot(wr1.deref(), undefined, "deref() should return its target.");
+        isnot(wr2.deref(), undefined, "deref() should return its target.");
+        isnot(wr3.deref(), undefined, "deref() should return its target.");
+        isnot(wr4.deref(), undefined, "deref() should return its target.");
+
+        // WeakRef should keep the target until the end of current task, which
+        // includes promise microtasks.
+        Promise.resolve().then(() => {
+          isnot(wr1.deref(), undefined, "deref() should return its target.");
+          isnot(wr2.deref(), undefined, "deref() should return its target.");
+          isnot(wr3.deref(), undefined, "deref() should return its target.");
+          isnot(wr4.deref(), undefined, "deref() should return its target.");
+        });
+
+        // setTimeout will call its callback in a new task.
+        setTimeout(task2, 0);
+      }
+
+      function task2() {
+        // Trigger a full GC/CC/GC cycle to collect WeakRef targets.
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+        SpecialPowers.DOMWindowUtils.cycleCollect();
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+
+        is(wr1.deref(), undefined, "deref() should return undefined.");
+        is(wr2.deref(), undefined, "deref() should return undefined.");
+        is(wr3.deref(), undefined, "deref() should return undefined.");
+        isnot(wr4.deref(), undefined, "deref() should return its target.");
+
+        // setTimeout will call its callback in a new task.
+        setTimeout(task3, 0);
+      }
+
+      function task3() {
+        document.body.removeChild(document.body.lastChild);
+
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+        SpecialPowers.DOMWindowUtils.cycleCollect();
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+
+        is(wr1.deref(), undefined, "deref() should return undefined.");
+        is(wr2.deref(), undefined, "deref() should return undefined.");
+        is(wr3.deref(), undefined, "deref() should return undefined.");
+        is(wr4.deref(), undefined, "deref() should return undefined.");
+
+        SimpleTest.finish();
+      }
+    </script>
+  </head>
+  <body onload="go()"></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_weakRefs_collected_wrapper.html b/js/xpconnect/tests/mochitest/test_weakRefs_collected_wrapper.html
new file mode 100644
index 0000000000..c7af313d96
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_weakRefs_collected_wrapper.html
@@ -0,0 +1,52 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test WeakRefs with DOM wrappers that get cycle collected</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      let weakrefs = [];
+
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        // 1. nsISupports-derived object.
+        let doc = document.implementation.createHTMLDocument();
+        weakrefs.push(new WeakRef(doc));
+
+        // 2. non-nsISupports-derived object.
+        let buffer = new AudioBuffer({length: 1, sampleRate: 8000});
+        weakrefs.push(new WeakRef(buffer));
+
+        // 3. nsISupports non-wrapper-cached object.
+        let image = new ImageData(1, 1);
+        weakrefs.push(new WeakRef(image));
+
+        // 4. non-nsISupports non-wrapper-cached object.
+        let iterator = document.fonts.values();
+        weakrefs.push(new WeakRef(iterator));
+
+        for (let wr of weakrefs) {
+          isnot(wr.deref(), undefined, "Check that live wrapper is returned");
+        }
+
+        // setTimeout will call its callback in a new task.
+        setTimeout(task2, 0);
+      }
+
+      function task2() {
+        // Trigger a GC and CC to collect the DOM objects, but no GC to
+        // collect the wrappers.
+        SpecialPowers.DOMWindowUtils.garbageCollect();
+        SpecialPowers.DOMWindowUtils.cycleCollect();
+
+        for (let wr of weakrefs) {
+          is(wr.deref(), undefined, "Check that stale wrapper is not exposed");
+        }
+
+        SimpleTest.finish();
+      }
+    </script>
+  </head>
+  <body onload="go()"></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_weakRefs_cross_compartment.html b/js/xpconnect/tests/mochitest/test_weakRefs_cross_compartment.html
new file mode 100644
index 0000000000..87e509b535
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_weakRefs_cross_compartment.html
@@ -0,0 +1,68 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>Test WeakRef works when target is in different compartment in the browser</title>
+    <script src="/tests/SimpleTest/SimpleTest.js"></script>
+    <script type="application/javascript">
+      function go() {
+        SimpleTest.waitForExplicitFinish();
+
+        let Cu = SpecialPowers.Cu;
+        let isSameCompartment = Cu.getJSTestingFunctions().isSameCompartment;
+
+        // Open a new window, which will be from different compartment.
+        let win = window.open();
+        is(isSameCompartment(win, window), false,
+           "Test for opeing a window from a different compartment.");
+
+        let wr1, wr2, wr3;
+        {
+          let obj = {};
+
+          // WeakRef and target are both from different compartment.
+          wr1 = new win.WeakRef(new win.Object());
+
+          // WeakRef is same compartment, but target isn't.
+          wr2 = new WeakRef(new win.Object());
+
+          // WeakRef is in different compartment, but target is.
+          wr3 = new win.WeakRef(obj);
+
+          obj = null;
+        }
+
+        // WeakRef should keep the target in the current task.
+        isnot(wr1.deref(), undefined, "wr1.deref() should return its target.");
+        isnot(wr2.deref(), undefined, "wr2.deref() should return its target.");
+        isnot(wr3.deref(), undefined, "we3.deref() should return its target.");
+
+        // Weakref should keep the target until the end of current Job, that
+        // includes microtask(Promise).
+        Promise.resolve().then(() => {
+          isnot(wr1.deref(), undefined,
+                "wr1.deref() should return its target in promise");
+          isnot(wr2.deref(), undefined,
+                "wr2.deref() should return its target in promise");
+          isnot(wr3.deref(), undefined,
+                "wr3.deref() should return its target in promise");
+        });
+
+        // setTimeout will launch a new job and call ClearKeptObjects().
+        setTimeout(() => {
+          // Call gc() forcibly to clear the target of wr.
+          SpecialPowers.DOMWindowUtils.garbageCollect();
+
+          is(wr1.deref(), undefined, "wr1.deref() should return undefined in the new job.");
+          is(wr2.deref(), undefined, "wr2.deref() should return undefined in the new job.");
+          is(wr3.deref(), undefined, "wr3.deref() should return undefined in the new job.");
+
+          win.close();
+          SimpleTest.finish();
+        }, 0);
+      }
+
+    </script>
+  </head>
+  <body onload="go()"></body>
+</html>
diff --git a/js/xpconnect/tests/mochitest/test_weakmaps.html b/js/xpconnect/tests/mochitest/test_weakmaps.html
new file mode 100644
index 0000000000..5e00106fed
--- /dev/null
+++ b/js/xpconnect/tests/mochitest/test_weakmaps.html
@@ -0,0 +1,264 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=668855
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test Cross-Compartment DOM WeakMaps</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+<script type="application/javascript">
+  /** Test for Bug 668855 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+// We wait to run this until the load event because it needs to access an element.
+function go() {
+
+  /* Create a weak reference, with a single-element weak map. */
+  let make_weak_ref = function (obj) {
+    let m = new WeakMap;
+    m.set(obj, {});
+    return m;
+  };
+
+  /* Check to see if a weak reference is dead. */
+  let weak_ref_dead = function (r) {
+    return SpecialPowers.nondeterministicGetWeakMapKeys(r).length == 0;
+  }
+
+  /* Deterministically grab an arbitrary DOM element. */
+  let get_live_dom = function () {
+    let elems = document.getElementsByTagName("a");
+    return elems[0];
+  };
+
+
+  /* Test case from bug 653248, adapted into a standard test.
+
+  This is a dead cycle involving a DOM edge, so the cycle collector can free it.  Keys and
+  values reachable only from XPConnect must be marked gray for this to work, and the cycle collector
+  must know the proper structure of the heap.
+
+  */
+  let make_gray_loop = function () {
+    let map = new WeakMap;
+    let div = document.createElement("div");
+    let key = {};
+    let obj = {m:map, k:key};
+    div.addEventListener("foo", function() {
+      // The code below doesn't matter (it won't run). Just pull a
+      // reference to obj.
+      obj.k = 1;
+      obj.m = "bar";
+    });
+    //div.entrain = {m:map, k:key};  This is not sufficient to cause a leak in Fx9
+    map.set(key, div);
+    return make_weak_ref(map);
+  };
+
+  let weakref = make_gray_loop();
+
+
+  /* Combinations of live and dead gray maps/keys. */
+  let basic_weak_ref = null;
+  let basic_map_weak_ref = null;
+  let black_map = new WeakMap;
+  let black_key = {};
+
+  let basic_unit_tests = function () {
+    let live_dom = get_live_dom();
+    let dead_dom = document.createElement("div");
+    let live_map = new WeakMap;
+    let dead_map = new WeakMap;
+    let live_key = {};
+    let dead_key = {};
+
+    // put the live/dead maps/keys into the appropriate DOM elements
+    live_dom.basic_unit_tests = {m:live_map, k:live_key};
+
+    let obj = {m:dead_map, k:dead_key};
+    // dead_dom.hook = {m:dead_map, k:dead_key};
+    dead_dom.addEventListener("foo", function() {
+      // The code below doesn't matter (it won't run). Just pull a
+      // reference to obj.
+      obj.m = 1;
+      obj.k = "2";
+    });
+
+    // Create a dead value, and a weak ref to it.
+    // The loop keeps dead_dom alive unless the CC is smart enough to kill it.
+    let dead_val = {loop:dead_dom};
+    basic_weak_ref = make_weak_ref(dead_val);
+    basic_map_weak_ref = make_weak_ref(dead_map);
+
+    // set up the actual entries.  most will die.
+    live_map.set(live_key, {my_key:'live_live'});
+    live_map.set(dead_key, dead_val);
+    live_map.set(black_key, {my_key:'live_black'});
+
+    dead_map.set(live_key, dead_val);
+    dead_map.set(dead_key, dead_val);
+    dead_map.set(black_key, dead_val);
+
+    black_map.set(live_key, {my_key:'black_live'});
+    black_map.set(dead_key, dead_val);
+    black_map.set(black_key, {my_key:'black_black'});
+
+  };
+
+  basic_unit_tests();
+
+
+  let check_basic_unit = function () {
+    let live_dom = get_live_dom();
+    let live_map = live_dom.basic_unit_tests.m;
+    let live_key = live_dom.basic_unit_tests.k;
+
+    // check the dead elements
+    ok(weak_ref_dead(basic_weak_ref), "Dead value was kept alive.");
+    ok(weak_ref_dead(basic_map_weak_ref), "Dead map was kept alive.");
+
+    // check the live gray map
+    is(live_map.get(live_key).my_key, 'live_live',
+      "Live key should have the same value in live map.");
+    is(live_map.get(black_key).my_key, 'live_black',
+      "Black key should have the same value in live map.");
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(live_map).length, 2,
+      "Live map should have two entries.");
+
+    // check the live black map
+    is(black_map.get(live_key).my_key, 'black_live',
+      "Live key should have the same value in black map.");
+    is(black_map.get(black_key).my_key, 'black_black',
+      "Black key should have the same value in black map.");
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(black_map).length, 2,
+      "Black map should have two entries.");
+
+  };
+
+
+  /* live gray chained weak map entries, involving the cycle collector. */
+  let chainm = new WeakMap;
+  let num_chains = 5;
+
+  let nested_cc_maps = function () {
+    let dom = get_live_dom();
+    for(let i = 0; i < num_chains; i++) {
+      let k = {count:i};
+      dom.key = k;
+      dom0 = document.createElement("div");
+      chainm.set(k, {d:dom0});
+      dom = document.createElement("div");
+      dom0.appendChild(dom);
+    };
+  };
+
+  let check_nested_cc_maps = function () {
+    let dom = get_live_dom();
+    let all_ok = true;
+    for(let i = 0; i < num_chains; i++) {
+      let k = dom.key;
+      all_ok = all_ok && k.count == i;
+      dom = chainm.get(k).d.firstChild;
+    };
+    ok(all_ok, "Count was invalid on a key in chained weak map entries.");
+  };
+
+  nested_cc_maps();
+
+
+  /* black weak map, chained garbage cycle involving DOM */
+  let garbage_map = new WeakMap;
+
+  let chained_garbage_maps = function () {
+    let dom0 = document.createElement("div");
+    let dom = dom0;
+    for(let i = 0; i < num_chains; i++) {
+      let k = {};
+      dom.key = k;
+      let new_dom = document.createElement("div");
+      garbage_map.set(k, {val_child:new_dom});
+      dom = document.createElement("div");
+      new_dom.appendChild(dom);
+    };
+    // tie the knot
+    dom.appendChild(dom0);
+  };
+
+  chained_garbage_maps();
+
+
+  /* black weak map, chained garbage cycle involving DOM, XPCWN keys */
+  let wn_garbage_map = new WeakMap;
+
+  let wn_chained_garbage_maps = function () {
+    let dom0 = document.createElement("div");
+    let dom = dom0;
+    for(let i = 0; i < num_chains; i++) {
+      let new_dom = document.createElement("div");
+      wn_garbage_map.set(dom, {wn_val_child:new_dom});
+      dom = document.createElement("div");
+      new_dom.appendChild(dom);
+    };
+    // tie the knot
+    dom.appendChild(dom0);
+  };
+
+  wn_chained_garbage_maps();
+
+
+  /* The cycle collector shouldn't remove a live wrapped native key. */
+
+  let wn_live_map = new WeakMap;
+
+  let make_live_map = function () {
+    let live = get_live_dom();
+    wn_live_map.set(live, {});
+    ok(wn_live_map.has(get_live_dom()), "Live map should have live DOM node before GC.");
+  }
+
+  make_live_map();
+
+  // We're out of ideas for unpreservable natives, now that just about
+  // everything is on webidl, so just don't test those.
+
+  /* set up for running precise GC/CC then checking the results */
+
+  SpecialPowers.exactGC(function () {
+    SpecialPowers.forceCC();
+    SpecialPowers.forceGC();
+    SpecialPowers.forceGC();
+
+    ok(weak_ref_dead(weakref), "Garbage gray cycle should be collected.");
+
+    check_nested_cc_maps();
+
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(garbage_map).length, 0, "Chained garbage weak map entries should not leak.");
+
+    check_basic_unit();
+
+    // fixed by Bug 680937
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(wn_garbage_map).length, 0,
+       "Chained garbage WN weak map entries should not leak.");
+
+    // fixed by Bug 680937
+    is(SpecialPowers.nondeterministicGetWeakMapKeys(wn_live_map).length, 1,
+       "Live weak map wrapped native key should not be removed.");
+
+    ok(wn_live_map.has(get_live_dom()), "Live map should have live dom.");
+
+    SimpleTest.finish();
+  });
+
+}
+  </script>
+</head>
+<div></div>
+<div id="mydivname"></div>
+<body onload="go()";>
+<a href="https://bugzilla.mozilla.org/show_bug.cgi?id=668855" target="_blank">Mozilla Bug 668855</a>
+<p id="display"></p>
+</body>
+</html>
diff --git a/js/xpconnect/tests/moz.build b/js/xpconnect/tests/moz.build
new file mode 100644
index 0000000000..c61dc8da02
--- /dev/null
+++ b/js/xpconnect/tests/moz.build
@@ -0,0 +1,21 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+TEST_DIRS += [
+    "mochitest",
+    "chrome",
+    "browser",
+    "components/native",
+]
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    TEST_DIRS += [
+        "idl",
+    ]
+
+XPCSHELL_TESTS_MANIFESTS += [
+    "unit/xpcshell.ini",
+]
diff --git a/js/xpconnect/tests/unit/CatBackgroundTaskRegistrationComponents.manifest b/js/xpconnect/tests/unit/CatBackgroundTaskRegistrationComponents.manifest
new file mode 100644
index 0000000000..7bc3763da9
--- /dev/null
+++ b/js/xpconnect/tests/unit/CatBackgroundTaskRegistrationComponents.manifest
@@ -0,0 +1,4 @@
+category test-cat1 Cat1RegisteredComponent @unit.test.com/cat1-registered-component;1
+category test-cat1 Cat1BackgroundTaskRegisteredComponent @unit.test.com/cat1-backgroundtask-registered-component;1 backgroundtask
+category test-cat1 Cat1BackgroundTaskAlwaysRegisteredComponent @unit.test.com/cat1-backgroundtask-alwaysregistered-component;1 backgroundtask=1
+category test-cat1 Cat1BackgroundTaskNotRegisteredComponent @unit.test.com/cat1-backgroundtask-notregistered-component;1 backgroundtask=0
diff --git a/js/xpconnect/tests/unit/CatRegistrationComponents.manifest b/js/xpconnect/tests/unit/CatRegistrationComponents.manifest
new file mode 100644
index 0000000000..11646b0282
--- /dev/null
+++ b/js/xpconnect/tests/unit/CatRegistrationComponents.manifest
@@ -0,0 +1,2 @@
+category test-cat CatRegisteredComponent @unit.test.com/cat-registered-component;1
+category test-cat CatAppRegisteredComponent @unit.test.com/cat-app-registered-component;1 application={adb42a9a-0d19-4849-bf4d-627614ca19be}
diff --git a/js/xpconnect/tests/unit/ReturnCodeChild.jsm b/js/xpconnect/tests/unit/ReturnCodeChild.jsm
new file mode 100644
index 0000000000..bf74453969
--- /dev/null
+++ b/js/xpconnect/tests/unit/ReturnCodeChild.jsm
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["ReturnCodeChild"];
+
+function xpcWrap(obj, iface) {
+  let ifacePointer = Cc[
+    "@mozilla.org/supports-interface-pointer;1"
+  ].createInstance(Ci.nsISupportsInterfacePointer);
+
+  ifacePointer.data = obj;
+  return ifacePointer.data.QueryInterface(iface);
+}
+
+var ReturnCodeChild = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestReturnCodeChild"]),
+
+  doIt(behaviour) {
+    switch (behaviour) {
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_THROW:
+        throw(new Error("a requested error"));
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_SUCCESS:
+        return;
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_RESULTCODE:
+        Components.returnCode = Cr.NS_ERROR_FAILURE;
+        return;
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_NEST_RESULTCODES:
+        // Use xpconnect to create another instance of *this* component and
+        // call that.  This way we have crossed the xpconnect bridge twice.
+
+        // We set *our* return code early - this should be what is returned
+        // to our caller, even though our "inner" component will set it to
+        // a different value that we will see (but our caller should not)
+        Components.returnCode = Cr.NS_ERROR_UNEXPECTED;
+        // call the child asking it to do the .returnCode set.
+        let sub = xpcWrap(ReturnCodeChild, Ci.nsIXPCTestReturnCodeChild);
+        let childResult = Cr.NS_OK;
+        try {
+          sub.doIt(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_RESULTCODE);
+        } catch (ex) {
+          childResult = ex.result;
+        }
+        // write it to the console so the test can check it.
+        let consoleService = Cc["@mozilla.org/consoleservice;1"]
+                             .getService(Ci.nsIConsoleService);
+        consoleService.logStringMessage("nested child returned " + childResult);
+        return;
+    }
+  }
+};
diff --git a/js/xpconnect/tests/unit/ReturnCodeChild.sys.mjs b/js/xpconnect/tests/unit/ReturnCodeChild.sys.mjs
new file mode 100644
index 0000000000..4d3120da33
--- /dev/null
+++ b/js/xpconnect/tests/unit/ReturnCodeChild.sys.mjs
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function xpcWrap(obj, iface) {
+  let ifacePointer = Cc[
+    "@mozilla.org/supports-interface-pointer;1"
+  ].createInstance(Ci.nsISupportsInterfacePointer);
+
+  ifacePointer.data = obj;
+  return ifacePointer.data.QueryInterface(iface);
+}
+
+export var ReturnCodeChild = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestReturnCodeChild"]),
+
+  doIt(behaviour) {
+    switch (behaviour) {
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_THROW:
+        throw(new Error("a requested error"));
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_SUCCESS:
+        return;
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_RESULTCODE:
+        Components.returnCode = Cr.NS_ERROR_FAILURE;
+        return;
+      case Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_NEST_RESULTCODES:
+        // Use xpconnect to create another instance of *this* component and
+        // call that.  This way we have crossed the xpconnect bridge twice.
+
+        // We set *our* return code early - this should be what is returned
+        // to our caller, even though our "inner" component will set it to
+        // a different value that we will see (but our caller should not)
+        Components.returnCode = Cr.NS_ERROR_UNEXPECTED;
+        // call the child asking it to do the .returnCode set.
+        let sub = xpcWrap(ReturnCodeChild, Ci.nsIXPCTestReturnCodeChild);
+        let childResult = Cr.NS_OK;
+        try {
+          sub.doIt(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_RESULTCODE);
+        } catch (ex) {
+          childResult = ex.result;
+        }
+        // write it to the console so the test can check it.
+        let consoleService = Cc["@mozilla.org/consoleservice;1"]
+                             .getService(Ci.nsIConsoleService);
+        consoleService.logStringMessage("nested child returned " + childResult);
+        return;
+    }
+  }
+};
diff --git a/js/xpconnect/tests/unit/TestBlob.jsm b/js/xpconnect/tests/unit/TestBlob.jsm
new file mode 100644
index 0000000000..7d67963dd6
--- /dev/null
+++ b/js/xpconnect/tests/unit/TestBlob.jsm
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["TestBlob"];
+
+const Assert = {
+  ok(cond, text) {
+    // we don't have the test harness' utilities in this scope, so we need this
+    // little helper. In the failure case, the exception is propagated to the
+    // caller in the main run_test() function, and the test fails.
+    if (!cond)
+      throw "Failed check: " + text;
+  }
+};
+
+var TestBlob = {
+  doTest: function() {
+    // throw if anything goes wrong
+    let testContent = "<a id=\"a\"><b id=\"b\">hey!<\/b><\/a>";
+    // should be able to construct a file
+    var f1 = new Blob([testContent], {"type" : "text/xml"});
+
+    // do some tests
+    Assert.ok(f1 instanceof Blob, "Should be a DOM Blob");
+
+    Assert.ok(!(f1 instanceof File), "Should not be a DOM File");
+
+    Assert.ok(f1.type == "text/xml", "Wrong type");
+
+    Assert.ok(f1.size == testContent.length, "Wrong content size");
+
+    var f2 = new Blob();
+    Assert.ok(f2.size == 0, "Wrong size");
+    Assert.ok(f2.type == "", "Wrong type");
+
+    var threw = false;
+    try {
+      // Needs a valid ctor argument
+      var f2 = new Blob(Date(132131532));
+    } catch (e) {
+      threw = true;
+    }
+    Assert.ok(threw, "Passing a random object should fail");
+
+    return true;
+  },
+};
diff --git a/js/xpconnect/tests/unit/TestFile.jsm b/js/xpconnect/tests/unit/TestFile.jsm
new file mode 100644
index 0000000000..01f07edb7c
--- /dev/null
+++ b/js/xpconnect/tests/unit/TestFile.jsm
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["TestFile"];
+
+const Assert = {
+  ok(cond, text) {
+    // we don't have the test harness' utilities in this scope, so we need this
+    // little helper. In the failure case, the exception is propagated to the
+    // caller in the main run_test() function, and the test fails.
+    if (!cond)
+      throw "Failed check: " + text;
+  }
+};
+
+var TestFile = {
+  doTest: function(cb) {
+    // throw if anything goes wrong
+
+    // find the current directory path
+    var file = Cc["@mozilla.org/file/directory_service;1"]
+               .getService(Ci.nsIProperties)
+               .get("CurWorkD", Ci.nsIFile);
+    file.append("xpcshell.ini");
+
+    // should be able to construct a file
+    var f1, f2;
+    Promise.all([
+      File.createFromFileName(file.path).then(f => { f1 = f; }),
+      File.createFromNsIFile(file).then(f => { f2 = f; }),
+    ])
+    .then(() => {
+      // do some tests
+      Assert.ok(f1 instanceof File, "Should be a DOM File");
+      Assert.ok(f2 instanceof File, "Should be a DOM File");
+
+      Assert.ok(f1.name == "xpcshell.ini", "Should be the right file");
+      Assert.ok(f2.name == "xpcshell.ini", "Should be the right file");
+
+      Assert.ok(f1.type == "", "Should be the right type");
+      Assert.ok(f2.type == "", "Should be the right type");
+    })
+    .then(() => {
+      var threw = false;
+      try {
+        // Needs a ctor argument
+        var f7 = new File();
+      } catch (e) {
+        threw = true;
+      }
+      Assert.ok(threw, "No ctor arguments should throw");
+
+      var threw = false;
+      try {
+        // Needs a valid ctor argument
+        var f7 = new File(Date(132131532));
+      } catch (e) {
+        threw = true;
+      }
+      Assert.ok(threw, "Passing a random object should fail");
+
+      // Directories fail
+      var dir = Cc["@mozilla.org/file/directory_service;1"]
+                  .getService(Ci.nsIProperties)
+                  .get("CurWorkD", Ci.nsIFile);
+      return File.createFromNsIFile(dir)
+    })
+    .then(() => {
+      Assert.ok(false, "Can't create a File object for a directory");
+    }, () => {
+      Assert.ok(true, "Can't create a File object for a directory");
+    })
+    .then(() => {
+      cb(true);
+    });
+  },
+};
diff --git a/js/xpconnect/tests/unit/api_script.js b/js/xpconnect/tests/unit/api_script.js
new file mode 100644
index 0000000000..de4a0a6b59
--- /dev/null
+++ b/js/xpconnect/tests/unit/api_script.js
@@ -0,0 +1,26 @@
+"use strict";
+
+// This is a test script similar to those used by ExtensionAPIs.
+// https://searchfox.org/mozilla-central/source/toolkit/components/extensions/parent
+
+let module3, module4;
+
+// This should work across ESR 102 and Firefox 103+.
+if (ChromeUtils.importESModule) {
+  module3 = ChromeUtils.importESModule("resource://test/esmified-3.sys.mjs");
+  module4 = ChromeUtils.importESModule("resource://test/esmified-4.sys.mjs");
+} else {
+  module3 = ChromeUtils.import("resource://test/esmified-3.jsm");
+  module4 = ChromeUtils.import("resource://test/esmified-4.jsm");
+}
+
+injected3.obj.value += 3;
+module3.obj.value += 3;
+module4.obj.value += 4;
+
+this.testResults = {
+  injected3: injected3.obj.value,
+  module3: module3.obj.value,
+  sameInstance3: injected3 === module3,
+  module4: module4.obj.value,
+};
diff --git a/js/xpconnect/tests/unit/bogus_element_type.jsm b/js/xpconnect/tests/unit/bogus_element_type.jsm
new file mode 100644
index 0000000000..882ca56809
--- /dev/null
+++ b/js/xpconnect/tests/unit/bogus_element_type.jsm
@@ -0,0 +1 @@
+var EXPORTED_SYMBOLS = [{}];
diff --git a/js/xpconnect/tests/unit/bogus_exports_type.jsm b/js/xpconnect/tests/unit/bogus_exports_type.jsm
new file mode 100644
index 0000000000..4b306e4e89
--- /dev/null
+++ b/js/xpconnect/tests/unit/bogus_exports_type.jsm
@@ -0,0 +1 @@
+var EXPORTED_SYMBOLS = "not an array";
diff --git a/js/xpconnect/tests/unit/bug451678_subscript.js b/js/xpconnect/tests/unit/bug451678_subscript.js
new file mode 100644
index 0000000000..72ff49a2d6
--- /dev/null
+++ b/js/xpconnect/tests/unit/bug451678_subscript.js
@@ -0,0 +1,5 @@
+var tags = [];
+function makeTags() {}
+
+// This will be the return value of the script.
+42
diff --git a/js/xpconnect/tests/unit/envChain.jsm b/js/xpconnect/tests/unit/envChain.jsm
new file mode 100644
index 0000000000..c60b032fcc
--- /dev/null
+++ b/js/xpconnect/tests/unit/envChain.jsm
@@ -0,0 +1,20 @@
+var qualified = 10;
+// NOTE: JSM cannot have unqualified name.
+let lexical = 30;
+this.prop = 40;
+
+const funcs = Cu.getJSTestingFunctions();
+const envs = [];
+let env = funcs.getInnerMostEnvironmentObject();
+while (env) {
+  envs.push({
+    type: funcs.getEnvironmentObjectType(env) || "*BackstagePass*",
+    qualified: !!Object.getOwnPropertyDescriptor(env, "qualified"),
+    prop: !!Object.getOwnPropertyDescriptor(env, "prop"),
+    lexical: !!Object.getOwnPropertyDescriptor(env, "lexical"),
+  });
+
+  env = funcs.getEnclosingEnvironmentObject(env);
+}
+
+const EXPORTED_SYMBOLS = ["envs"];
diff --git a/js/xpconnect/tests/unit/envChain_subscript.jsm b/js/xpconnect/tests/unit/envChain_subscript.jsm
new file mode 100644
index 0000000000..473f6eb2d9
--- /dev/null
+++ b/js/xpconnect/tests/unit/envChain_subscript.jsm
@@ -0,0 +1,27 @@
+const target = {};
+Services.scriptloader.loadSubScript(`data:,
+var qualified = 10;
+unqualified = 20;
+let lexical = 30;
+this.prop = 40;
+
+const funcs = Cu.getJSTestingFunctions();
+const envs = [];
+let env = funcs.getInnerMostEnvironmentObject();
+while (env) {
+  envs.push({
+    type: funcs.getEnvironmentObjectType(env) || "*BackstagePass*",
+    qualified: !!Object.getOwnPropertyDescriptor(env, "qualified"),
+    unqualified: !!Object.getOwnPropertyDescriptor(env, "unqualified"),
+    lexical: !!Object.getOwnPropertyDescriptor(env, "lexical"),
+    prop: !!Object.getOwnPropertyDescriptor(env, "prop"),
+  });
+
+  env = funcs.getEnclosingEnvironmentObject(env);
+}
+
+this.ENVS = envs;
+`, target);
+
+const envs = target.ENVS;
+const EXPORTED_SYMBOLS = ["envs"];
diff --git a/js/xpconnect/tests/unit/environment_checkscript.jsm b/js/xpconnect/tests/unit/environment_checkscript.jsm
new file mode 100644
index 0000000000..b4dc452b8e
--- /dev/null
+++ b/js/xpconnect/tests/unit/environment_checkscript.jsm
@@ -0,0 +1,13 @@
+var EXPORTED_SYMBOLS = ["bound"];
+
+var bound = "";
+
+try { void vu; bound += "vu,"; } catch (e) {}
+try { void vq; bound += "vq,"; } catch (e) {}
+try { void vl; bound += "vl,"; } catch (e) {}
+try { void gt; bound += "gt,"; } catch (e) {}
+try { void ed; bound += "ed,"; } catch (e) {}
+try { void ei; bound += "ei,"; } catch (e) {}
+try { void fo; bound += "fo,"; } catch (e) {}
+try { void fi; bound += "fi,"; } catch (e) {}
+try { void fd; bound += "fd,"; } catch (e) {}
diff --git a/js/xpconnect/tests/unit/environment_loadscript.jsm b/js/xpconnect/tests/unit/environment_loadscript.jsm
new file mode 100644
index 0000000000..0e5a0208ae
--- /dev/null
+++ b/js/xpconnect/tests/unit/environment_loadscript.jsm
@@ -0,0 +1,16 @@
+var EXPORTED_SYMBOLS = ["target", "bound"];
+
+var bound = "";
+var target = {};
+Services.scriptloader.loadSubScript("resource://test/environment_script.js", target);
+
+// Check global bindings
+try { void vu; bound += "vu,"; } catch (e) {}
+try { void vq; bound += "vq,"; } catch (e) {}
+try { void vl; bound += "vl,"; } catch (e) {}
+try { void gt; bound += "gt,"; } catch (e) {}
+try { void ed; bound += "ed,"; } catch (e) {}
+try { void ei; bound += "ei,"; } catch (e) {}
+try { void fo; bound += "fo,"; } catch (e) {}
+try { void fi; bound += "fi,"; } catch (e) {}
+try { void fd; bound += "fd,"; } catch (e) {}
diff --git a/js/xpconnect/tests/unit/environment_script.js b/js/xpconnect/tests/unit/environment_script.js
new file mode 100644
index 0000000000..18490541ad
--- /dev/null
+++ b/js/xpconnect/tests/unit/environment_script.js
@@ -0,0 +1,14 @@
+let strict = (function() { return this; })() === undefined;
+
+// Allow this to be used as a JSM
+var EXPORTED_SYMBOLS = [];
+
+if (!strict) vu = 1;                                    // Unqualified Variable
+var vq = 2;                                             // Qualified Variable
+let vl = 3;                                             // Lexical
+this.gt = 4;                                            // Global This
+eval("this.ed = 5");                                    // Direct Eval
+(1,eval)("this.ei = 6");                                // Indirect Eval
+(new Function("this.fo = 7"))();                        // Dynamic Function Object
+if (!strict) (function() { this.fi = 8; })();           // Indirect Function This
+function fd_() { this.fd = 9; }; if (!strict) fd_();    // Direct Function Implicit
diff --git a/js/xpconnect/tests/unit/error_export.sys.mjs b/js/xpconnect/tests/unit/error_export.sys.mjs
new file mode 100644
index 0000000000..7f0f1ec979
--- /dev/null
+++ b/js/xpconnect/tests/unit/error_export.sys.mjs
@@ -0,0 +1,2 @@
+export function something() {
+}
diff --git a/js/xpconnect/tests/unit/error_import.sys.mjs b/js/xpconnect/tests/unit/error_import.sys.mjs
new file mode 100644
index 0000000000..2bbeef5da2
--- /dev/null
+++ b/js/xpconnect/tests/unit/error_import.sys.mjs
@@ -0,0 +1 @@
+import { something } from "./something.sys.mjs";
diff --git a/js/xpconnect/tests/unit/error_other.sys.mjs b/js/xpconnect/tests/unit/error_other.sys.mjs
new file mode 100644
index 0000000000..f6d220f17e
--- /dev/null
+++ b/js/xpconnect/tests/unit/error_other.sys.mjs
@@ -0,0 +1 @@
+a =
diff --git a/js/xpconnect/tests/unit/es6import.js b/js/xpconnect/tests/unit/es6import.js
new file mode 100644
index 0000000000..79d76849fd
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6import.js
@@ -0,0 +1 @@
+export let value = 1;
diff --git a/js/xpconnect/tests/unit/es6module.js b/js/xpconnect/tests/unit/es6module.js
new file mode 100644
index 0000000000..a160895a01
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module.js
@@ -0,0 +1,6 @@
+export let loadCount = 0;
+loadCount++;
+
+export let value = 0;
+import {value as importedValue} from "./es6import.js";
+value = importedValue + 1;
diff --git a/js/xpconnect/tests/unit/es6module_absolute.js b/js/xpconnect/tests/unit/es6module_absolute.js
new file mode 100644
index 0000000000..d74732d296
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_absolute.js
@@ -0,0 +1,4 @@
+import { x as x1 } from "resource://test/es6module_absolute2.js";
+import { x as x2 } from "./es6module_absolute2.js";
+export const absoluteX = x1;
+export const relativeX = x2;
diff --git a/js/xpconnect/tests/unit/es6module_absolute2.js b/js/xpconnect/tests/unit/es6module_absolute2.js
new file mode 100644
index 0000000000..d9d1342a3f
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_absolute2.js
@@ -0,0 +1 @@
+export const x = { value: 10 };
diff --git a/js/xpconnect/tests/unit/es6module_cycle_a.js b/js/xpconnect/tests/unit/es6module_cycle_a.js
new file mode 100644
index 0000000000..62e88d17e2
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_cycle_a.js
@@ -0,0 +1,9 @@
+export const name = "a";
+
+import { name as bName } from "./es6module_cycle_b.js";
+
+export let loaded = true;
+
+export function getValueFromB() {
+  return bName;
+}
diff --git a/js/xpconnect/tests/unit/es6module_cycle_b.js b/js/xpconnect/tests/unit/es6module_cycle_b.js
new file mode 100644
index 0000000000..32725f0f0a
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_cycle_b.js
@@ -0,0 +1,9 @@
+export const name = "b";
+
+import { name as cName } from "./es6module_cycle_c.js";
+
+export let loaded = true;
+
+export function getValueFromC() {
+  return cName;
+}
diff --git a/js/xpconnect/tests/unit/es6module_cycle_c.js b/js/xpconnect/tests/unit/es6module_cycle_c.js
new file mode 100644
index 0000000000..2fd2f6e3eb
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_cycle_c.js
@@ -0,0 +1,9 @@
+export const name = "c";
+
+import { name as aName } from "./es6module_cycle_a.js";
+
+export let loaded = true;
+
+export function getValueFromA() {
+  return aName;
+}
diff --git a/js/xpconnect/tests/unit/es6module_devtoolsLoader.js b/js/xpconnect/tests/unit/es6module_devtoolsLoader.js
new file mode 100644
index 0000000000..30e4f13863
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_devtoolsLoader.js
@@ -0,0 +1 @@
+export const object = { uniqueObjectPerLoader: true };
diff --git a/js/xpconnect/tests/unit/es6module_devtoolsLoader.sys.mjs b/js/xpconnect/tests/unit/es6module_devtoolsLoader.sys.mjs
new file mode 100644
index 0000000000..c7de54c82f
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_devtoolsLoader.sys.mjs
@@ -0,0 +1,29 @@
+export let x = 0;
+
+export function increment() {
+  x++;
+};
+
+import { object } from "resource://test/es6module_devtoolsLoader.js";
+export const importedObject = object;
+
+const importTrue = ChromeUtils.importESModule("resource://test/es6module_devtoolsLoader.js", { loadInDevToolsLoader : true });
+export const importESModuleTrue = importTrue.object;
+
+const importFalse = ChromeUtils.importESModule("resource://test/es6module_devtoolsLoader.js", { loadInDevToolsLoader : false });
+export const importESModuleFalse = importFalse.object;
+
+const importNull = ChromeUtils.importESModule("resource://test/es6module_devtoolsLoader.js", {});
+export const importESModuleNull = importNull.object;
+
+const importNull2 = ChromeUtils.importESModule("resource://test/es6module_devtoolsLoader.js");
+export const importESModuleNull2 = importNull2.object;
+
+const lazy = {};
+ChromeUtils.defineESModuleGetters(lazy, {
+  object: "resource://test/es6module_devtoolsLoader.js",
+});
+
+export function importLazy() {
+  return lazy.object;
+}
diff --git a/js/xpconnect/tests/unit/es6module_devtoolsLoader_only.js b/js/xpconnect/tests/unit/es6module_devtoolsLoader_only.js
new file mode 100644
index 0000000000..4d995c5cfb
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_devtoolsLoader_only.js
@@ -0,0 +1 @@
+export const object = { onlyLoadedFromDevToolsModule: true };
diff --git a/js/xpconnect/tests/unit/es6module_dynamic_import.js b/js/xpconnect/tests/unit/es6module_dynamic_import.js
new file mode 100644
index 0000000000..17a2f41802
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_dynamic_import.js
@@ -0,0 +1,7 @@
+let resolve;
+
+export const result = new Promise(r => { resolve = r; });
+
+import("./es6module_dynamic_import2.js").then(ns => {}, e => {
+  resolve(e);
+});
diff --git a/js/xpconnect/tests/unit/es6module_dynamic_import2.js b/js/xpconnect/tests/unit/es6module_dynamic_import2.js
new file mode 100644
index 0000000000..abc62eff40
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_dynamic_import2.js
@@ -0,0 +1 @@
+export const x = 10;
diff --git a/js/xpconnect/tests/unit/es6module_import_error.js b/js/xpconnect/tests/unit/es6module_import_error.js
new file mode 100644
index 0000000000..e590d0a450
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_import_error.js
@@ -0,0 +1 @@
+import { y } from "./es6module_import_error2.js";
diff --git a/js/xpconnect/tests/unit/es6module_import_error2.js b/js/xpconnect/tests/unit/es6module_import_error2.js
new file mode 100644
index 0000000000..abc62eff40
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_import_error2.js
@@ -0,0 +1 @@
+export const x = 10;
diff --git a/js/xpconnect/tests/unit/es6module_loaded-1.sys.mjs b/js/xpconnect/tests/unit/es6module_loaded-1.sys.mjs
new file mode 100644
index 0000000000..e405565d6f
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_loaded-1.sys.mjs
@@ -0,0 +1 @@
+export function test() {}
diff --git a/js/xpconnect/tests/unit/es6module_loaded-2.sys.mjs b/js/xpconnect/tests/unit/es6module_loaded-2.sys.mjs
new file mode 100644
index 0000000000..e405565d6f
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_loaded-2.sys.mjs
@@ -0,0 +1 @@
+export function test() {}
diff --git a/js/xpconnect/tests/unit/es6module_loaded-3.sys.mjs b/js/xpconnect/tests/unit/es6module_loaded-3.sys.mjs
new file mode 100644
index 0000000000..e405565d6f
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_loaded-3.sys.mjs
@@ -0,0 +1 @@
+export function test() {}
diff --git a/js/xpconnect/tests/unit/es6module_missing_import.js b/js/xpconnect/tests/unit/es6module_missing_import.js
new file mode 100644
index 0000000000..df79b6a0b7
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_missing_import.js
@@ -0,0 +1 @@
+import { name } from "./es6module_not_found2.js";
diff --git a/js/xpconnect/tests/unit/es6module_parse_error.js b/js/xpconnect/tests/unit/es6module_parse_error.js
new file mode 100644
index 0000000000..3128787ba4
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_parse_error.js
@@ -0,0 +1 @@
+this is not valid JS
diff --git a/js/xpconnect/tests/unit/es6module_parse_error_in_import.js b/js/xpconnect/tests/unit/es6module_parse_error_in_import.js
new file mode 100644
index 0000000000..14f057ebe1
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_parse_error_in_import.js
@@ -0,0 +1 @@
+import { name } from "./es6module_parse_error.js";
diff --git a/js/xpconnect/tests/unit/es6module_throws.js b/js/xpconnect/tests/unit/es6module_throws.js
new file mode 100644
index 0000000000..c3ca94b6eb
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_throws.js
@@ -0,0 +1,4 @@
+function throwFunction() {
+  throw new Error("Failing with error foobar");
+}
+throwFunction();
diff --git a/js/xpconnect/tests/unit/es6module_top_level_await.js b/js/xpconnect/tests/unit/es6module_top_level_await.js
new file mode 100644
index 0000000000..7377aacb35
--- /dev/null
+++ b/js/xpconnect/tests/unit/es6module_top_level_await.js
@@ -0,0 +1 @@
+await 1;
diff --git a/js/xpconnect/tests/unit/esm_lazy-1.sys.mjs b/js/xpconnect/tests/unit/esm_lazy-1.sys.mjs
new file mode 100644
index 0000000000..a995420a56
--- /dev/null
+++ b/js/xpconnect/tests/unit/esm_lazy-1.sys.mjs
@@ -0,0 +1,4 @@
+export let X = 10;
+function GetX() {
+  return X;
+}
diff --git a/js/xpconnect/tests/unit/esm_lazy-2.sys.mjs b/js/xpconnect/tests/unit/esm_lazy-2.sys.mjs
new file mode 100644
index 0000000000..49410b6187
--- /dev/null
+++ b/js/xpconnect/tests/unit/esm_lazy-2.sys.mjs
@@ -0,0 +1,4 @@
+export let Y = 20;
+export function AddY(n) {
+  Y += n;
+};
diff --git a/js/xpconnect/tests/unit/esmified-1.sys.mjs b/js/xpconnect/tests/unit/esmified-1.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-1.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-2.sys.mjs b/js/xpconnect/tests/unit/esmified-2.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-2.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-3.sys.mjs b/js/xpconnect/tests/unit/esmified-3.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-3.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-4.sys.mjs b/js/xpconnect/tests/unit/esmified-4.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-4.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-5.sys.mjs b/js/xpconnect/tests/unit/esmified-5.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-5.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-6.sys.mjs b/js/xpconnect/tests/unit/esmified-6.sys.mjs
new file mode 100644
index 0000000000..0f7a1da661
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-6.sys.mjs
@@ -0,0 +1,4 @@
+export let loadCount = 0;
+loadCount++;
+
+export const obj = { value: 10 };
diff --git a/js/xpconnect/tests/unit/esmified-not-exported.sys.mjs b/js/xpconnect/tests/unit/esmified-not-exported.sys.mjs
new file mode 100644
index 0000000000..e4ae8c0815
--- /dev/null
+++ b/js/xpconnect/tests/unit/esmified-not-exported.sys.mjs
@@ -0,0 +1,13 @@
+export var exportedVar = "exported var";
+export function exportedFunction() {
+  return "exported function";
+}
+export let exportedLet = "exported let";
+export const exportedConst = "exported const";
+
+var notExportedVar = "not exported var";
+function notExportedFunction() {
+  return "not exported function";
+}
+let notExportedLet = "not exported let";
+const notExportedConst = "not exported const";
diff --git a/js/xpconnect/tests/unit/file_simple_script.js b/js/xpconnect/tests/unit/file_simple_script.js
new file mode 100644
index 0000000000..af20291400
--- /dev/null
+++ b/js/xpconnect/tests/unit/file_simple_script.js
@@ -0,0 +1 @@
+this.bar = ({foo: "®"});
diff --git a/js/xpconnect/tests/unit/frame.js b/js/xpconnect/tests/unit/frame.js
new file mode 100644
index 0000000000..8b13789179
--- /dev/null
+++ b/js/xpconnect/tests/unit/frame.js
@@ -0,0 +1 @@
+
diff --git a/js/xpconnect/tests/unit/head.js b/js/xpconnect/tests/unit/head.js
new file mode 100644
index 0000000000..ca9a22bee8
--- /dev/null
+++ b/js/xpconnect/tests/unit/head.js
@@ -0,0 +1,15 @@
+"use strict";
+
+// Wraps the given object in an XPConnect wrapper and, if an interface
+// is passed, queries the result to that interface.
+function xpcWrap(obj, iface) {
+  let ifacePointer = Cc[
+    "@mozilla.org/supports-interface-pointer;1"
+  ].createInstance(Ci.nsISupportsInterfacePointer);
+
+  ifacePointer.data = obj;
+  if (iface) {
+    return ifacePointer.data.QueryInterface(iface);
+  }
+  return ifacePointer.data;
+}
diff --git a/js/xpconnect/tests/unit/head_ongc.js b/js/xpconnect/tests/unit/head_ongc.js
new file mode 100644
index 0000000000..146a15eb4f
--- /dev/null
+++ b/js/xpconnect/tests/unit/head_ongc.js
@@ -0,0 +1,35 @@
+var {addDebuggerToGlobal, addSandboxedDebuggerToGlobal} = ChromeUtils.importESModule("resource://gre/modules/jsdebugger.sys.mjs");
+
+const testingFunctions = Cu.getJSTestingFunctions();
+const systemPrincipal = Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
+
+function addTestingFunctionsToGlobal(global) {
+  for (let k in testingFunctions) {
+    global[k] = testingFunctions[k];
+  }
+  global.print = info;
+  global.newGlobal = newGlobal;
+  addDebuggerToGlobal(global);
+}
+
+function newGlobal() {
+  const global = new Cu.Sandbox(systemPrincipal, { freshZone: true });
+  addTestingFunctionsToGlobal(global);
+  return global;
+}
+
+addTestingFunctionsToGlobal(this);
+
+function executeSoon(f) {
+  Services.tm.dispatchToMainThread({ run: f });
+}
+
+// The onGarbageCollection tests don't play well gczeal settings and lead to
+// intermittents.
+if (typeof gczeal == "function") {
+  gczeal(0);
+}
+
+// Make sure to GC before we start the test, so that no zones are scheduled for
+// GC before we start testing onGarbageCollection hooks.
+gc();
diff --git a/js/xpconnect/tests/unit/head_watchdog.js b/js/xpconnect/tests/unit/head_watchdog.js
new file mode 100644
index 0000000000..f977c1f129
--- /dev/null
+++ b/js/xpconnect/tests/unit/head_watchdog.js
@@ -0,0 +1,116 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//
+// Pref management.
+//
+
+var {PromiseTestUtils} = ChromeUtils.importESModule("resource://testing-common/PromiseTestUtils.sys.mjs");
+
+///////////////////
+//
+// Whitelisting these tests.
+// As part of bug 1077403, the shutdown crash should be fixed.
+//
+// These tests may crash intermittently on shutdown if the DOM Promise uncaught
+// rejection observers are still registered when the watchdog operates.
+PromiseTestUtils.thisTestLeaksUncaughtRejectionsAndShouldBeFixed();
+
+var gPrefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+
+function setWatchdogEnabled(enabled) {
+  gPrefs.setBoolPref("dom.use_watchdog", enabled);
+}
+
+function isWatchdogEnabled() {
+  return gPrefs.getBoolPref("dom.use_watchdog");
+}
+
+function setScriptTimeout(seconds) {
+  var oldTimeout = gPrefs.getIntPref("dom.max_script_run_time");
+  gPrefs.setIntPref("dom.max_script_run_time", seconds);
+  return oldTimeout;
+}
+
+//
+// Utilities.
+//
+
+function busyWait(ms) {
+  var start = new Date();
+  while ((new Date()) - start < ms) {}
+}
+
+function do_log_info(aMessage)
+{
+  print("TEST-INFO | " + _TEST_FILE + " | " + aMessage);
+}
+
+// We don't use do_execute_soon, because that inserts a
+// do_test_{pending,finished} pair that gets screwed up when we terminate scripts
+// from the operation callback.
+function executeSoon(fn) {
+  var tm = Cc["@mozilla.org/thread-manager;1"].getService(Ci.nsIThreadManager);
+  tm.dispatchToMainThread({run: fn});
+}
+
+//
+// Asynchronous watchdog diagnostics.
+//
+// When running, the watchdog wakes up every second, and fires the operation
+// callback if the script has been running for >= the minimum script timeout.
+// As such, if the script timeout is 1 second, a script should never be able to
+// run for two seconds or longer without servicing the operation callback.
+// We wait 3 seconds, just to be safe.
+//
+
+function checkWatchdog(expectInterrupt) {
+  var oldTimeout = setScriptTimeout(1);
+  var lastWatchdogWakeup = Cu.getWatchdogTimestamp("WatchdogWakeup");
+
+  return new Promise(resolve => {
+    let inBusyWait = false;
+    setInterruptCallback(function() {
+      // If the watchdog didn't actually trigger the operation callback, ignore
+      // this call. This allows us to test the actual watchdog behavior without
+      // interference from other sites where we trigger the operation callback.
+      if (lastWatchdogWakeup == Cu.getWatchdogTimestamp("WatchdogWakeup")) {
+        return true;
+      }
+      if (!inBusyWait) {
+        Assert.ok(true, "Not in busy wait, ignoring interrupt callback");
+        return true;
+      }
+
+      Assert.ok(expectInterrupt, "Interrupt callback fired");
+      setInterruptCallback(undefined);
+      setScriptTimeout(oldTimeout);
+      // Schedule the promise for resolution before we kill this script.
+      executeSoon(resolve);
+      return false;
+    });
+
+    executeSoon(function() {
+      inBusyWait = true;
+      busyWait(3000);
+      inBusyWait = false;
+      Assert.ok(!expectInterrupt, "Interrupt callback didn't fire");
+      setInterruptCallback(undefined);
+      setScriptTimeout(oldTimeout);
+      resolve();
+    });
+  });
+}
+
+function run_test() {
+
+  // Run async.
+  do_test_pending();
+
+  // Run the async function.
+  testBody().then(() => {
+    do_test_finished();
+  });
+}
+
diff --git a/js/xpconnect/tests/unit/import_stack.jsm b/js/xpconnect/tests/unit/import_stack.jsm
new file mode 100644
index 0000000000..9f12c25566
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack.jsm
@@ -0,0 +1,2 @@
+function test() {}
+var EXPORTED_SYMBOLS = ["test"];
diff --git a/js/xpconnect/tests/unit/import_stack.sys.mjs b/js/xpconnect/tests/unit/import_stack.sys.mjs
new file mode 100644
index 0000000000..e405565d6f
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack.sys.mjs
@@ -0,0 +1 @@
+export function test() {}
diff --git a/js/xpconnect/tests/unit/import_stack_static_1.sys.mjs b/js/xpconnect/tests/unit/import_stack_static_1.sys.mjs
new file mode 100644
index 0000000000..1d2e0452c5
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack_static_1.sys.mjs
@@ -0,0 +1 @@
+import { f2 } from './import_stack_static_2.sys.mjs';
diff --git a/js/xpconnect/tests/unit/import_stack_static_2.sys.mjs b/js/xpconnect/tests/unit/import_stack_static_2.sys.mjs
new file mode 100644
index 0000000000..d6e332e68c
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack_static_2.sys.mjs
@@ -0,0 +1,2 @@
+import { f3 } from './import_stack_static_3.sys.mjs';
+export function f2() {}
diff --git a/js/xpconnect/tests/unit/import_stack_static_3.sys.mjs b/js/xpconnect/tests/unit/import_stack_static_3.sys.mjs
new file mode 100644
index 0000000000..d40df510bf
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack_static_3.sys.mjs
@@ -0,0 +1,2 @@
+import { f4 } from './import_stack_static_4.sys.mjs';
+export function f3() {}
diff --git a/js/xpconnect/tests/unit/import_stack_static_4.sys.mjs b/js/xpconnect/tests/unit/import_stack_static_4.sys.mjs
new file mode 100644
index 0000000000..1bf71d53e9
--- /dev/null
+++ b/js/xpconnect/tests/unit/import_stack_static_4.sys.mjs
@@ -0,0 +1 @@
+export function f4() {}
diff --git a/js/xpconnect/tests/unit/importer.jsm b/js/xpconnect/tests/unit/importer.jsm
new file mode 100644
index 0000000000..e6d2f184e6
--- /dev/null
+++ b/js/xpconnect/tests/unit/importer.jsm
@@ -0,0 +1 @@
+ChromeUtils.import("resource://test/syntax_error.jsm");
+\ No newline at end of file
diff --git a/js/xpconnect/tests/unit/jsm_loaded-1.jsm b/js/xpconnect/tests/unit/jsm_loaded-1.jsm
new file mode 100644
index 0000000000..9f12c25566
--- /dev/null
+++ b/js/xpconnect/tests/unit/jsm_loaded-1.jsm
@@ -0,0 +1,2 @@
+function test() {}
+var EXPORTED_SYMBOLS = ["test"];
diff --git a/js/xpconnect/tests/unit/jsm_loaded-2.jsm b/js/xpconnect/tests/unit/jsm_loaded-2.jsm
new file mode 100644
index 0000000000..9f12c25566
--- /dev/null
+++ b/js/xpconnect/tests/unit/jsm_loaded-2.jsm
@@ -0,0 +1,2 @@
+function test() {}
+var EXPORTED_SYMBOLS = ["test"];
diff --git a/js/xpconnect/tests/unit/jsm_loaded-3.jsm b/js/xpconnect/tests/unit/jsm_loaded-3.jsm
new file mode 100644
index 0000000000..9f12c25566
--- /dev/null
+++ b/js/xpconnect/tests/unit/jsm_loaded-3.jsm
@@ -0,0 +1,2 @@
+function test() {}
+var EXPORTED_SYMBOLS = ["test"];
diff --git a/js/xpconnect/tests/unit/not-esmified-not-exported.jsm b/js/xpconnect/tests/unit/not-esmified-not-exported.jsm
new file mode 100644
index 0000000000..094eab7f92
--- /dev/null
+++ b/js/xpconnect/tests/unit/not-esmified-not-exported.jsm
@@ -0,0 +1,20 @@
+var exportedVar = "exported var";
+function exportedFunction() {
+  return "exported function";
+}
+let exportedLet = "exported let";
+const exportedConst = "exported const";
+
+var notExportedVar = "not exported var";
+function notExportedFunction() {
+  return "not exported function";
+}
+let notExportedLet = "not exported let";
+const notExportedConst = "not exported const";
+
+const EXPORTED_SYMBOLS = [
+  "exportedVar",
+  "exportedFunction",
+  "exportedLet",
+  "exportedConst",
+];
diff --git a/js/xpconnect/tests/unit/recursive_importA.jsm b/js/xpconnect/tests/unit/recursive_importA.jsm
new file mode 100644
index 0000000000..ac763354c4
--- /dev/null
+++ b/js/xpconnect/tests/unit/recursive_importA.jsm
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["foo", "bar"];
+
+function foo() {
+  return "foo";
+}
+
+var bar = {}
+ChromeUtils.import("resource://test/recursive_importB.jsm", bar);
diff --git a/js/xpconnect/tests/unit/recursive_importB.jsm b/js/xpconnect/tests/unit/recursive_importB.jsm
new file mode 100644
index 0000000000..1bf84971b6
--- /dev/null
+++ b/js/xpconnect/tests/unit/recursive_importB.jsm
@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var EXPORTED_SYMBOLS = ["baz", "qux"];
+
+function baz() {
+  return "baz";
+}
+
+var qux = {}
+ChromeUtils.import("resource://test/recursive_importA.jsm", qux);
+
diff --git a/js/xpconnect/tests/unit/syntax_error.jsm b/js/xpconnect/tests/unit/syntax_error.jsm
new file mode 100644
index 0000000000..fca785bcdd
--- /dev/null
+++ b/js/xpconnect/tests/unit/syntax_error.jsm
@@ -0,0 +1 @@
+bogusjs)(
diff --git a/js/xpconnect/tests/unit/test_ComponentEnvironment.js b/js/xpconnect/tests/unit/test_ComponentEnvironment.js
new file mode 100644
index 0000000000..1d2c474ffd
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_ComponentEnvironment.js
@@ -0,0 +1,20 @@
+let tgt = {};
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+const a = ChromeUtils.import("resource://test/environment_script.js", tgt);
+const b = ChromeUtils.import("resource://test/environment_checkscript.jsm", tgt);
+
+const isShared = Cu.getGlobalForObject(a) === Cu.getGlobalForObject(b);
+
+
+// Components should not share namespace
+if (isShared) {
+  todo_check_eq(tgt.bound, "");
+  Assert.equal(tgt.bound, "ei,fo,", "Modules should have no shared non-eval bindings");
+} else {
+  Assert.equal(tgt.bound, "", "Modules should have no shared bindings");
+}
diff --git a/js/xpconnect/tests/unit/test_FrameScriptEnvironment.js b/js/xpconnect/tests/unit/test_FrameScriptEnvironment.js
new file mode 100644
index 0000000000..d02c9900e1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_FrameScriptEnvironment.js
@@ -0,0 +1,46 @@
+let ppmm = Services.ppmm.getChildAt(0);
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+add_task(async function test_bindings() {
+    let {strict, bound} = await new Promise(function(resolve) {
+        // Use a listener to get results from child
+        ppmm.addMessageListener("results", function listener(msg) {
+            ppmm.removeMessageListener("results", listener);
+            resolve(msg.data);
+        });
+
+        // Bind vars in first process script
+        ppmm.loadProcessScript("resource://test/environment_script.js", false);
+
+        // Check visibility in second process script
+        ppmm.loadProcessScript(`data:,
+            let strict = (function() { return this; })() === undefined;
+            var bound = "";
+
+            try { void vu; bound += "vu,"; } catch (e) {}
+            try { void vq; bound += "vq,"; } catch (e) {}
+            try { void vl; bound += "vl,"; } catch (e) {}
+            try { void gt; bound += "gt,"; } catch (e) {}
+            try { void ed; bound += "ed,"; } catch (e) {}
+            try { void ei; bound += "ei,"; } catch (e) {}
+            try { void fo; bound += "fo,"; } catch (e) {}
+            try { void fi; bound += "fi,"; } catch (e) {}
+            try { void fd; bound += "fd,"; } catch (e) {}
+
+            sendAsyncMessage("results", { strict, bound });
+            `, false);
+    });
+
+    // FrameScript loader should share |this| access
+    if (strict) {
+        if (bound != "gt,ed,ei,fo,")
+            throw new Error("Unexpected global binding set - " + bound);
+    } else {
+        if (bound != "gt,ed,ei,fo,fi,fd,")
+            throw new Error("Unexpected global binding set - " + bound);
+    }
+});
diff --git a/js/xpconnect/tests/unit/test_SubscriptLoaderEnvironment.js b/js/xpconnect/tests/unit/test_SubscriptLoaderEnvironment.js
new file mode 100644
index 0000000000..c0a5cf202c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_SubscriptLoaderEnvironment.js
@@ -0,0 +1,38 @@
+let tgt = {};
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+Services.scriptloader.loadSubScript("resource://test/environment_script.js", tgt);
+
+var bound = "";
+var tgt_bound = "";
+
+// Check global bindings
+try { void vu; bound += "vu,"; } catch (e) {}
+try { void vq; bound += "vq,"; } catch (e) {}
+try { void vl; bound += "vl,"; } catch (e) {}
+try { void gt; bound += "gt,"; } catch (e) {}
+try { void ed; bound += "ed,"; } catch (e) {}
+try { void ei; bound += "ei,"; } catch (e) {}
+try { void fo; bound += "fo,"; } catch (e) {}
+try { void fi; bound += "fi,"; } catch (e) {}
+try { void fd; bound += "fd,"; } catch (e) {}
+
+// Check target bindings
+for (var name of ["vu", "vq", "vl", "gt", "ed", "ei", "fo", "fi", "fd"])
+    if (tgt.hasOwnProperty(name))
+        tgt_bound += name + ",";
+
+
+// Expected subscript loader behavior is as follows:
+//  - Qualified vars and |this| access occur on target object
+//  - Lexical vars occur on ExtensibleLexicalEnvironment of target object
+//  - Bareword assignments and global |this| access occur on caller's global
+if (bound != "vu,ei,fo,fi,")
+    throw new Error("Unexpected global binding set - " + bound);
+if (tgt_bound != "vq,gt,ed,fd,")
+    throw new Error("Unexpected target binding set - " + tgt_bound);
diff --git a/js/xpconnect/tests/unit/test_SubscriptLoaderJSMEnvironment.js b/js/xpconnect/tests/unit/test_SubscriptLoaderJSMEnvironment.js
new file mode 100644
index 0000000000..1ae9bc3b74
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_SubscriptLoaderJSMEnvironment.js
@@ -0,0 +1,32 @@
+let tgt_load = {};
+let tgt_check = {};
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+const a = ChromeUtils.import("resource://test/environment_loadscript.jsm", tgt_load);
+const b = ChromeUtils.import("resource://test/environment_checkscript.jsm", tgt_check);
+
+const isShared = Cu.getGlobalForObject(a) === Cu.getGlobalForObject(b);
+
+// Check target bindings
+var tgt_subscript_bound = "";
+for (var name of ["vu", "vq", "vl", "gt", "ed", "ei", "fo", "fi", "fd"])
+    if (tgt_load.target.hasOwnProperty(name))
+        tgt_subscript_bound += name + ",";
+
+// Expected subscript loader behavior is as follows:
+//  - Qualified vars and |this| access occur on target object
+//  - Lexical vars occur on ExtensibleLexicalEnvironment of target object
+//  - Bareword assignments and global |this| access occur on caller's global
+Assert.equal(tgt_load.bound, "vu,ei,fo,fi,", "Should have expected module binding set");
+Assert.equal(tgt_subscript_bound, "vq,gt,ed,fd,", "Should have expected subscript binding set");
+
+// Components should not share namespace
+if (isShared) {
+  todo_check_eq(tgt_check.bound, "");
+  Assert.equal(tgt_check.bound, "ei,fo,", "Modules should have no shared non-eval bindings");
+} else {
+  Assert.equal(tgt_check.bound, "", "Modules should have no shared bindings");
+}
diff --git a/js/xpconnect/tests/unit/test_SubscriptLoaderSandboxEnvironment.js b/js/xpconnect/tests/unit/test_SubscriptLoaderSandboxEnvironment.js
new file mode 100644
index 0000000000..3f4a10a14f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_SubscriptLoaderSandboxEnvironment.js
@@ -0,0 +1,35 @@
+let tgt = Cu.Sandbox(Services.scriptSecurityManager.getSystemPrincipal());
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+Services.scriptloader.loadSubScript("resource://test/environment_script.js", tgt);
+
+var bound = "";
+var tgt_bound = "";
+
+// Check global bindings
+try { void vu; bound += "vu,"; } catch (e) {}
+try { void vq; bound += "vq,"; } catch (e) {}
+try { void vl; bound += "vl,"; } catch (e) {}
+try { void gt; bound += "gt,"; } catch (e) {}
+try { void ed; bound += "ed,"; } catch (e) {}
+try { void ei; bound += "ei,"; } catch (e) {}
+try { void fo; bound += "fo,"; } catch (e) {}
+try { void fi; bound += "fi,"; } catch (e) {}
+try { void fd; bound += "fd,"; } catch (e) {}
+
+// Check target bindings
+for (var name of ["vu", "vq", "vl", "gt", "ed", "ei", "fo", "fi", "fd"])
+    if (tgt.hasOwnProperty(name))
+        tgt_bound += name + ",";
+
+
+// Expected subscript loader behavior with a Sandbox is as follows:
+//  - Lexicals occur on ExtensibleLexicalEnvironment of target
+//  - Everything else occurs on Sandbox global
+if (bound != "")
+    throw new Error("Unexpected global binding set - " + bound);
+if (tgt_bound != "vu,vq,gt,ed,ei,fo,fi,fd,")
+    throw new Error("Unexpected target binding set - " + tgt_bound);
diff --git a/js/xpconnect/tests/unit/test_URLSearchParams.js b/js/xpconnect/tests/unit/test_URLSearchParams.js
new file mode 100644
index 0000000000..fb2d203187
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_URLSearchParams.js
@@ -0,0 +1,12 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["URLSearchParams"] });
+  sb.equal = equal;
+  Cu.evalInSandbox('equal(new URLSearchParams("one=1&two=2").get("one"), "1");',
+                   sb);
+  Cu.importGlobalProperties(["URLSearchParams"]);
+  Assert.equal(new URLSearchParams("one=1&two=2").get("one"), "1");
+}
diff --git a/js/xpconnect/tests/unit/test_allowWaivers.js b/js/xpconnect/tests/unit/test_allowWaivers.js
new file mode 100644
index 0000000000..b5a764e352
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_allowWaivers.js
@@ -0,0 +1,29 @@
+function checkWaivers(from, allowed) {
+  var sb = new Cu.Sandbox('http://example.com');
+  from.test = sb.eval('var o = {prop: 2, f: function() {return 42;}}; o');
+
+  // Make sure that |from| has Xrays to sb.
+  Assert.equal(from.eval('test.prop'), 2);
+  Assert.equal(from.eval('test.f'), undefined);
+
+  // Make sure that waivability works as expected.
+  Assert.equal(from.eval('!!test.wrappedJSObject'), allowed);
+  Assert.equal(from.eval('XPCNativeWrapper.unwrap(test) !== test'), allowed);
+
+  // Make a sandbox with the same principal as |from|, but without any waiver
+  // restrictions, and make sure that the waiver does not transfer.
+  var friend = new Cu.Sandbox(Cu.getObjectPrincipal(from));
+  friend.test = from.test;
+  friend.eval('var waived = test.wrappedJSObject;');
+  Assert.equal(friend.eval('waived.f()'), 42);
+  friend.from = from;
+  friend.eval('from.waived = waived');
+  Assert.equal(from.eval('!!waived.f'), allowed);
+}
+
+function run_test() {
+  checkWaivers(new Cu.Sandbox('http://example.com'), true);
+  checkWaivers(new Cu.Sandbox('http://example.com', {allowWaivers: false}), false);
+  checkWaivers(new Cu.Sandbox(['http://example.com']), true);
+  checkWaivers(new Cu.Sandbox(['http://example.com'], {allowWaivers: false}), false);
+}
diff --git a/js/xpconnect/tests/unit/test_allowedDomains.js b/js/xpconnect/tests/unit/test_allowedDomains.js
new file mode 100644
index 0000000000..bc703a9f6d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_allowedDomains.js
@@ -0,0 +1,41 @@
+function run_test() {
+  var sbMaster = Cu.Sandbox(["http://www.a.com",
+                           "http://www.b.com",
+                           "http://www.d.com"]);
+  var sbSubset = Cu.Sandbox(["http://www.d.com",
+                           "http://www.a.com"]);
+
+  var sbA = Cu.Sandbox("http://www.a.com");
+  var sbB = Cu.Sandbox("http://www.b.com");
+  var sbC = Cu.Sandbox("http://www.c.com");
+
+  sbMaster.objA = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbA);
+  sbMaster.objB = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbB);
+  sbMaster.objC = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbC);
+  sbMaster.objOwn = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbMaster);
+  
+  sbMaster.objSubset = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbSubset);
+  sbA.objMaster = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbMaster);
+  sbSubset.objMaster = Cu.evalInSandbox("var obj = {prop1:200}; obj", sbMaster);
+
+  var ret;
+  ret = Cu.evalInSandbox("objA.prop1", sbMaster);
+  Assert.equal(ret, 200);
+  ret = Cu.evalInSandbox("objB.prop1", sbMaster);
+  Assert.equal(ret, 200);
+  ret = Cu.evalInSandbox("objSubset.prop1", sbMaster);
+  Assert.equal(ret, 200);
+  
+  function evalAndCatch(str, sb) {
+    try {
+      ret = Cu.evalInSandbox(str, sb);
+      Assert.ok(false, "unexpected pass")
+    } catch (e) {    
+      Assert.ok(e.message && e.message.includes("Permission denied to access property"));
+    }  
+  }
+  
+  evalAndCatch("objC.prop1", sbMaster);
+  evalAndCatch("objMaster.prop1", sbA);
+  evalAndCatch("objMaster.prop1", sbSubset);
+}
diff --git a/js/xpconnect/tests/unit/test_allowedDomainsXHR.js b/js/xpconnect/tests/unit/test_allowedDomainsXHR.js
new file mode 100644
index 0000000000..2ed388fb36
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_allowedDomainsXHR.js
@@ -0,0 +1,135 @@
+const { HttpServer } = ChromeUtils.import("resource://testing-common/httpd.js");
+
+var httpserver = new HttpServer();
+var httpserver2 = new HttpServer();
+var httpserver3 = new HttpServer();
+var testpath = "/simple";
+var redirectpath = "/redirect";
+var negativetestpath = "/negative";
+var httpbody = "<?xml version='1.0' ?><root>0123456789</root>";
+
+var sb = Cu.Sandbox(["http://www.example.com",
+                     "http://localhost:4444/redirect",
+                     "http://localhost:4444/simple",
+                     "http://localhost:4446/redirect"],
+                     { wantGlobalProperties: ["XMLHttpRequest"] });
+
+function createXHR(loc, async)
+{
+  var xhr = new XMLHttpRequest();
+  xhr.open("GET", "http://localhost:" + loc, async);
+  return xhr;
+}
+
+function checkResults(xhr)
+{
+  if (xhr.readyState != 4)
+    return false;
+
+  equal(xhr.status, 200);
+  equal(xhr.responseText, httpbody);
+
+  var root_node = xhr.responseXML.getElementsByTagName('root').item(0);
+  equal(root_node.firstChild.data, "0123456789");
+  return true;
+}
+
+var httpServersClosed = 0;
+function finishIfDone()
+{
+  if (++httpServersClosed == 3)
+    do_test_finished();
+}
+
+function run_test()
+{
+  do_get_profile();
+  do_test_pending();
+
+  httpserver.registerPathHandler(testpath, serverHandler);
+  httpserver.registerPathHandler(redirectpath, redirectHandler1);
+  httpserver.start(4444);
+
+  httpserver2.registerPathHandler(negativetestpath, serverHandler);
+  httpserver2.start(4445);
+
+  httpserver3.registerPathHandler(redirectpath, redirectHandler2);
+  httpserver3.start(4446);
+
+  // Test sync XHR sending
+  Cu.evalInSandbox('var createXHR = ' + createXHR.toString(), sb);
+  var res = Cu.evalInSandbox('var sync = createXHR("4444/simple"); sync.send(null); sync', sb);
+  Assert.ok(checkResults(res));
+
+  var principal = res.responseXML.nodePrincipal;
+  Assert.ok(principal.isContentPrincipal);
+  var requestURL = "http://localhost:4444/redirect";
+  Assert.equal(principal.spec, requestURL);
+
+  // negative test sync XHR sending (to ensure that the xhr do not have chrome caps, see bug 779821)
+  try {
+    Cu.evalInSandbox('var createXHR = ' + createXHR.toString(), sb);
+    var res = Cu.evalInSandbox('var sync = createXHR("4445/negative"); sync.send(null); sync', sb);
+    Assert.equal(false, true, "XHR created from sandbox should not have chrome caps");
+  } catch (e) {
+    Assert.ok(true);
+  }
+
+  // Test redirect handling.
+  // This request bounces to server 2 and then back to server 1.  Neither of
+  // these servers support CORS, but if the expanded principal is used as the
+  // triggering principal, this should work.
+  Cu.evalInSandbox('var createXHR = ' + createXHR.toString(), sb);
+  var res = Cu.evalInSandbox('var sync = createXHR("4444/redirect"); sync.send(null); sync', sb);
+  Assert.ok(checkResults(res));
+
+  var principal = res.responseXML.nodePrincipal;
+  Assert.ok(principal.isContentPrincipal);
+  var requestURL = "http://localhost:4444/redirect";
+  Assert.equal(principal.spec, requestURL);
+
+  httpserver2.stop(finishIfDone);
+  httpserver3.stop(finishIfDone);
+
+  // Test async XHR sending
+  sb.finish = function(){
+    httpserver.stop(finishIfDone);
+  }
+
+  // We want to execute checkResults from the scope of the sandbox as well to
+  // make sure that there are no permission errors related to nsEP. For that
+  // we need to clone the function into the sandbox and make a few things
+  // available for it.
+  Cu.evalInSandbox('var checkResults = ' + checkResults.toSource(), sb);
+  sb.equal = equal;
+  sb.httpbody = httpbody;
+
+  function changeListener(event) {
+    if (checkResults(async))
+      finish();
+  }
+
+  var async = Cu.evalInSandbox('var async = createXHR("4444/simple", true);' +
+                               'async.addEventListener("readystatechange", ' +
+                                                       changeListener.toString() + ', false);' +
+                               'async', sb);
+  async.send(null);
+}
+
+function serverHandler(request, response)
+{
+  response.setHeader("Content-Type", "text/xml", false);
+  response.bodyOutputStream.write(httpbody, httpbody.length);
+}
+
+function redirectHandler1(request, response)
+{
+  response.setStatusLine(request.httpVersion, 302, "Found");
+  response.setHeader("Location", "http://localhost:4446/redirect", false);
+}
+
+function redirectHandler2(request, response)
+{
+  response.setStatusLine(request.httpVersion, 302, "Found");
+  response.setHeader("Location", "http://localhost:4444/simple", false);
+}
diff --git a/js/xpconnect/tests/unit/test_attributes.js b/js/xpconnect/tests/unit/test_attributes.js
new file mode 100644
index 0000000000..4fc0acaa91
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_attributes.js
@@ -0,0 +1,103 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var ObjectReadWrite = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestObjectReadWrite"]),
+
+  /* nsIXPCTestObjectReadWrite */
+  stringProperty: "XPConnect Read-Writable String",
+  booleanProperty: true,
+  shortProperty: 32767,
+  longProperty: 2147483647,
+  floatProperty: 5.5,
+  charProperty: "X",
+  // timeProperty is PRTime and signed type.
+  // So it has to allow negative value.
+  timeProperty: -1,
+};
+
+var ObjectReadOnly = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestObjectReadOnly"]),
+
+  /* nsIXPCTestObjectReadOnly */
+  strReadOnly: "XPConnect Read-Only String",
+  boolReadOnly: true,
+  shortReadOnly: 32767,
+  longReadOnly: 2147483647,
+  floatReadOnly: 5.5,
+  charReadOnly: "X",
+  // timeProperty is PRTime and signed type.
+  // So it has to allow negative value.
+  timeReadOnly: -1,
+};
+
+function run_test() {
+  // Load the component manifests.
+  registerXPCTestComponents();
+
+  // Test for each component.
+  test_component_readwrite(Cc["@mozilla.org/js/xpc/test/native/ObjectReadWrite;1"].createInstance());
+  test_component_readwrite(xpcWrap(ObjectReadWrite));
+  test_component_readonly(Cc["@mozilla.org/js/xpc/test/native/ObjectReadOnly;1"].createInstance());
+  test_component_readonly(xpcWrap(ObjectReadOnly));
+}
+
+function test_component_readwrite(obj) {
+  // Instantiate the object.
+  var o = obj.QueryInterface(Ci.nsIXPCTestObjectReadWrite);
+
+  // Test the initial values.
+  Assert.equal("XPConnect Read-Writable String", o.stringProperty);
+  Assert.equal(true, o.booleanProperty);
+  Assert.equal(32767, o.shortProperty);
+  Assert.equal(2147483647, o.longProperty);
+  Assert.ok(5.25 < o.floatProperty && 5.75 > o.floatProperty);
+  Assert.equal("X", o.charProperty);
+  Assert.equal(-1, o.timeProperty);
+
+  // Write new values.
+  o.stringProperty = "another string";
+  o.booleanProperty = false;
+  o.shortProperty = -12345;
+  o.longProperty = 1234567890;
+  o.floatProperty = 10.2;
+  o.charProperty = "Z";
+  o.timeProperty = 1;
+
+  // Test the new values.
+  Assert.equal("another string", o.stringProperty);
+  Assert.equal(false, o.booleanProperty);
+  Assert.equal(-12345, o.shortProperty);
+  Assert.equal(1234567890, o.longProperty);
+  Assert.ok(10.15 < o.floatProperty && 10.25 > o.floatProperty);
+  Assert.equal("Z", o.charProperty);
+  Assert.equal(1, o.timeProperty);
+
+  // Assign values that differ from the expected type to verify conversion.
+
+  function SetAndTestBooleanProperty(newValue, expectedValue) {
+    o.booleanProperty = newValue;
+    Assert.equal(expectedValue, o.booleanProperty);
+  };
+  SetAndTestBooleanProperty(false, false);
+  SetAndTestBooleanProperty(1, true);
+  SetAndTestBooleanProperty(null, false);
+  SetAndTestBooleanProperty("A", true);
+  SetAndTestBooleanProperty(undefined, false);
+  SetAndTestBooleanProperty([], true);
+  SetAndTestBooleanProperty({}, true);
+}
+
+function test_component_readonly(obj) {
+  var o = obj.QueryInterface(Ci.nsIXPCTestObjectReadOnly);
+
+  // Test the initial values.
+  Assert.equal("XPConnect Read-Only String", o.strReadOnly);
+  Assert.equal(true, o.boolReadOnly);
+  Assert.equal(32767, o.shortReadOnly);
+  Assert.equal(2147483647, o.longReadOnly);
+  Assert.ok(5.25 < o.floatReadOnly && 5.75 > o.floatReadOnly);
+  Assert.equal("X", o.charReadOnly);
+  Assert.equal(-1, o.timeReadOnly);
+}
diff --git a/js/xpconnect/tests/unit/test_blob.js b/js/xpconnect/tests/unit/test_blob.js
new file mode 100644
index 0000000000..42f6cf9be8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_blob.js
@@ -0,0 +1,8 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let { TestBlob } = ChromeUtils.import("resource://test/TestBlob.jsm");
+  Assert.ok(TestBlob.doTest());
+}
diff --git a/js/xpconnect/tests/unit/test_blob2.js b/js/xpconnect/tests/unit/test_blob2.js
new file mode 100644
index 0000000000..90d4bdc1c6
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_blob2.js
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+Cu.importGlobalProperties(['Blob', 'File']);
+
+function run_test() {
+  // throw if anything goes wrong
+  let testContent = "<a id=\"a\"><b id=\"b\">hey!<\/b><\/a>";
+  // should be able to construct a file
+  var f1 = new Blob([testContent], {"type" : "text/xml"});
+
+  // do some tests
+  Assert.ok(f1 instanceof Blob, "Should be a DOM Blob");
+
+  Assert.ok(!(f1 instanceof File), "Should not be a DOM File");
+
+  Assert.ok(f1.type == "text/xml", "Wrong type");
+
+  Assert.ok(f1.size == testContent.length, "Wrong content size");
+
+  var f2 = new Blob();
+  Assert.ok(f2.size == 0, "Wrong size");
+  Assert.ok(f2.type == "", "Wrong type");
+
+  var threw = false;
+  try {
+    // Needs a valid ctor argument
+    var f2 = new Blob(Date(132131532));
+  } catch (e) {
+    threw = true;
+  }
+  Assert.ok(threw, "Passing a random object should fail");
+}
diff --git a/js/xpconnect/tests/unit/test_bogus_files.js b/js/xpconnect/tests/unit/test_bogus_files.js
new file mode 100644
index 0000000000..1e8b9f0f2a
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bogus_files.js
@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function test_BrokenFile(path, shouldThrow, expectedName) {
+  var didThrow = false;
+  try {
+    ChromeUtils.import(path);
+  } catch (ex) {
+    var exceptionName = ex.name;
+    print("ex: " + ex + "; name = " + ex.name);
+    didThrow = true;
+  }
+
+  Assert.equal(didThrow, shouldThrow);
+  if (didThrow)
+    Assert.equal(exceptionName, expectedName);
+}
+
+function run_test() {
+  test_BrokenFile("resource://test/bogus_exports_type.jsm", true, "Error");
+
+  test_BrokenFile("resource://test/bogus_element_type.jsm", true, "Error");
+
+  test_BrokenFile("resource://test/non_existing.jsm",
+                  true,
+                  "NS_ERROR_FILE_NOT_FOUND");
+
+  test_BrokenFile("chrome://test/content/test.jsm",
+                  true,
+                  "NS_ERROR_FILE_NOT_FOUND");
+}
diff --git a/js/xpconnect/tests/unit/test_bug1001094.js b/js/xpconnect/tests/unit/test_bug1001094.js
new file mode 100644
index 0000000000..ac06e4c0f3
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1001094.js
@@ -0,0 +1,4 @@
+function run_test() {
+  // Make sure nsJSID implements classinfo.
+  Assert.equal(Components.ID("{a6e2a27f-5521-4b35-8b52-99799a744aee}").equals, Components.ID("{daa47351-7d2e-44a7-b8e3-281802a1eab7}").equals);
+}
diff --git a/js/xpconnect/tests/unit/test_bug1021312.js b/js/xpconnect/tests/unit/test_bug1021312.js
new file mode 100644
index 0000000000..ccb9981b43
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1021312.js
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let sb = new Cu.Sandbox(this);
+  var called = false;
+
+  Cu.exportFunction(function(str) { Assert.ok(/someString/.test(str)); called = true; },
+                    sb, { defineAs: "func" });
+  // Do something weird with the string to make sure that it doesn't get interned.
+  Cu.evalInSandbox("var str = 'someString'; for (var i = 0; i < 10; ++i) str += i;", sb);
+  Cu.evalInSandbox("func(str);", sb);
+  Assert.ok(called);
+}
diff --git a/js/xpconnect/tests/unit/test_bug1033253.js b/js/xpconnect/tests/unit/test_bug1033253.js
new file mode 100644
index 0000000000..e5860833b2
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1033253.js
@@ -0,0 +1,5 @@
+function run_test() {
+  var sb = Cu.Sandbox('http://www.example.com');
+  var f = Cu.evalInSandbox('var f = function() {}; f;', sb);
+  Assert.equal(f.name, "");
+}
diff --git a/js/xpconnect/tests/unit/test_bug1033920.js b/js/xpconnect/tests/unit/test_bug1033920.js
new file mode 100644
index 0000000000..6e85ec4f1d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1033920.js
@@ -0,0 +1,6 @@
+function run_test() {
+  var sb = Cu.Sandbox('http://www.example.com');
+  var o = new sb.Object();
+  o.__proto__ = null;
+  Assert.equal(Object.getPrototypeOf(o), null);
+}
diff --git a/js/xpconnect/tests/unit/test_bug1033927.js b/js/xpconnect/tests/unit/test_bug1033927.js
new file mode 100644
index 0000000000..cd2bb210e7
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1033927.js
@@ -0,0 +1,8 @@
+function run_test() {
+  var sb = Cu.Sandbox('http://www.example.com', { wantGlobalProperties: ['XMLHttpRequest']});
+  var xhr = Cu.evalInSandbox('new XMLHttpRequest()', sb);
+  Assert.equal(xhr[Symbol.toStringTag], "XMLHttpRequest");
+  Assert.equal(xhr.toString(), '[object XMLHttpRequest]');
+  Assert.equal((new sb.Object()).toString(), '[object Object]');
+  Assert.equal(sb.Object.prototype.toString.call(new sb.Uint16Array()), '[object Uint16Array]');
+}
diff --git a/js/xpconnect/tests/unit/test_bug1034262.js b/js/xpconnect/tests/unit/test_bug1034262.js
new file mode 100644
index 0000000000..6bd598bd53
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1034262.js
@@ -0,0 +1,8 @@
+function run_test() {
+  var sb1 = Cu.Sandbox('http://www.example.com', { wantXrays: true });
+  var sb2 = Cu.Sandbox('http://www.example.com', { wantXrays: false });
+  sb2.f = Cu.evalInSandbox('x => typeof x', sb1);
+  Assert.equal(Cu.evalInSandbox('f(dump)', sb2), 'function');
+  Assert.equal(Cu.evalInSandbox('f.call(null, dump)', sb2), 'function');
+  Assert.equal(Cu.evalInSandbox('f.apply(null, [dump])', sb2), 'function');
+}
diff --git a/js/xpconnect/tests/unit/test_bug1081990.js b/js/xpconnect/tests/unit/test_bug1081990.js
new file mode 100644
index 0000000000..80e37ac282
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1081990.js
@@ -0,0 +1,9 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  sb.obj = {};
+  sb.arr = [];
+  sb.fun = function() {};
+  Assert.ok(sb.eval('Object.getPrototypeOf(obj) == null'));
+  Assert.ok(sb.eval('Object.getPrototypeOf(arr) == null'));
+  Assert.ok(sb.eval('Object.getPrototypeOf(fun) == null'));
+}
diff --git a/js/xpconnect/tests/unit/test_bug1110546.js b/js/xpconnect/tests/unit/test_bug1110546.js
new file mode 100644
index 0000000000..04e1add915
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1110546.js
@@ -0,0 +1,4 @@
+function run_test() {
+  var sb = new Cu.Sandbox(null);
+  Assert.ok(Cu.getObjectPrincipal(sb).isNullPrincipal);
+}
diff --git a/js/xpconnect/tests/unit/test_bug1131707.js b/js/xpconnect/tests/unit/test_bug1131707.js
new file mode 100644
index 0000000000..57ade9f8c8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1131707.js
@@ -0,0 +1,20 @@
+function testStrict(sb) {
+  "use strict";
+  Assert.equal(sb.eval("typeof wrappedCtor()"), "string");
+  Assert.equal(sb.eval("typeof new wrappedCtor()"), "object");
+}
+
+function run_test() {
+  var sb = new Cu.Sandbox(null);
+  var dateCtor = sb.Date;
+  sb.wrappedCtor = Cu.exportFunction(function wrapper(val) {
+    "use strict";
+    var constructing = this.constructor == wrapper;
+    return constructing ? new dateCtor(val) : dateCtor(val);
+  }, sb);
+  Assert.equal(typeof Date(), "string");
+  Assert.equal(typeof new Date(), "object");
+  Assert.equal(sb.eval("typeof wrappedCtor()"), "string");
+  Assert.equal(sb.eval("typeof new wrappedCtor()"), "object");
+  testStrict(sb);
+}
diff --git a/js/xpconnect/tests/unit/test_bug1150771.js b/js/xpconnect/tests/unit/test_bug1150771.js
new file mode 100644
index 0000000000..433156d6f5
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1150771.js
@@ -0,0 +1,12 @@
+function run_test() {
+let sandbox1 = new Cu.Sandbox(null);
+let sandbox2 = new Cu.Sandbox(null);
+let arg = Cu.evalInSandbox('({ buf: new ArrayBuffer(2) })', sandbox1);
+
+let clonedArg = Cu.cloneInto(Cu.waiveXrays(arg), sandbox2);
+Assert.equal(typeof Cu.waiveXrays(clonedArg).buf, "object");
+
+clonedArg = Cu.cloneInto(arg, sandbox2);
+Assert.equal(typeof Cu.waiveXrays(clonedArg).buf, "object");
+Assert.equal(Cu.waiveXrays(clonedArg).buf.constructor.name, "ArrayBuffer");
+}
diff --git a/js/xpconnect/tests/unit/test_bug1151385.js b/js/xpconnect/tests/unit/test_bug1151385.js
new file mode 100644
index 0000000000..913050248f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1151385.js
@@ -0,0 +1,9 @@
+function run_test()
+{
+  try {
+    var sandbox = new Cu.Sandbox(null, {"sandboxPrototype" : {}});
+    Assert.ok(false);
+  } catch (e) {
+    Assert.ok(/must subsume sandboxPrototype/.test(e));
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_bug1170311.js b/js/xpconnect/tests/unit/test_bug1170311.js
new file mode 100644
index 0000000000..cdbe62407a
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1170311.js
@@ -0,0 +1,4 @@
+function run_test() {
+  do_check_throws_nsIException(() => Cu.getObjectPrincipal({}).equals(null), "NS_ERROR_ILLEGAL_VALUE");
+  do_check_throws_nsIException(() => Cu.getObjectPrincipal({}).subsumes(null), "NS_ERROR_ILLEGAL_VALUE");
+}
diff --git a/js/xpconnect/tests/unit/test_bug1244222.js b/js/xpconnect/tests/unit/test_bug1244222.js
new file mode 100644
index 0000000000..b907c72033
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1244222.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+var TestUtils = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestUtils"]),
+  doubleWrapFunction(fun) { return fun }
+};
+
+function run_test() {
+  // Generate a CCW to a function.
+  var sb = new Cu.Sandbox(this);
+  sb.eval('function fun(x) { return x; }');
+  Assert.equal(sb.fun("foo"), "foo");
+
+  // Double-wrap the CCW.
+  var utils = xpcWrap(TestUtils, Ci.nsIXPCTestUtils);
+  var doubleWrapped = utils.doubleWrapFunction(sb.fun);
+  Assert.equal(doubleWrapped.echo("foo"), "foo");
+
+  // GC.
+  Cu.forceGC();
+
+  // Make sure it still works.
+  Assert.equal(doubleWrapped.echo("foo"), "foo");
+}
diff --git a/js/xpconnect/tests/unit/test_bug1617527.js b/js/xpconnect/tests/unit/test_bug1617527.js
new file mode 100644
index 0000000000..3db33e60d9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug1617527.js
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let sb1 = new Cu.Sandbox("https://example.org");
+  let throwingFunc = Cu.evalInSandbox("new Function('throw new Error')", sb1);
+  // NOTE: Different origin from the other sandbox.
+  let sb2 = new Cu.Sandbox("https://example.com");
+  Cu.exportFunction(function() {
+    // Call a different-compartment throwing function.
+    throwingFunc();
+  }, sb2, { defineAs: "func" });
+  let threw = Cu.evalInSandbox("var threw; try { func(); threw = false; } catch (e) { threw = true } threw",
+                                sb2);
+  Assert.ok(threw);
+}
diff --git a/js/xpconnect/tests/unit/test_bug267645.js b/js/xpconnect/tests/unit/test_bug267645.js
new file mode 100644
index 0000000000..6196a2165c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug267645.js
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let sb = new Cu.Sandbox("https://example.com",
+                          { wantGlobalProperties: ["DOMException"] });
+  Cu.exportFunction(function() {
+    undefined.foo();
+  }, sb, { defineAs: "func" });
+  // By default, the stacks of things running in a sandbox will contain the
+  // actual evalInSandbox() call location.  To override that, we have to pass an
+  // explicit filename.
+  let threw = Cu.evalInSandbox("var threw; try { func(); threw = false; } catch (e) { globalThis.exn = e; threw = true } threw",
+                                sb, "", "FakeFile");
+  Assert.ok(threw);
+
+  // Check what the sandbox could see from this exception.
+  Assert.ok(!Cu.evalInSandbox("exn.filename", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.fileName", sb), undefined);
+  Assert.ok(!Cu.evalInSandbox("exn.stack", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.message", sb), "An exception was thrown");
+  Assert.equal(Cu.evalInSandbox("exn.name", sb), "InvalidStateError");
+
+  Cu.exportFunction(function() {
+    throw new Error("Hello");
+  }, sb, { defineAs: "func2" });
+  threw = Cu.evalInSandbox("var threw; try { func2(); threw = false; } catch (e) { globalThis.exn = e; threw = true } threw",
+                                sb, "", "FakeFile");
+  Assert.ok(threw);
+  Assert.ok(!Cu.evalInSandbox("exn.filename", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.fileName", sb), undefined);
+  Assert.ok(!Cu.evalInSandbox("exn.stack", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.message", sb), "An exception was thrown");
+  Assert.equal(Cu.evalInSandbox("exn.name", sb), "InvalidStateError");
+
+  let ctor = Cu.evalInSandbox("TypeError", sb);
+  Cu.exportFunction(function() {
+    throw new ctor("Hello");
+  }, sb, { defineAs: "func3" });
+  threw = Cu.evalInSandbox("var threw; try { func3(); threw = false; } catch (e) { globalThis.exn = e; threw = true } threw",
+                                sb, "", "FakeFile");
+  Assert.ok(threw);
+  Assert.ok(!Cu.evalInSandbox("exn.fileName", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.filename", sb), undefined);
+  Assert.ok(!Cu.evalInSandbox("exn.stack", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.message", sb), "Hello");
+  Assert.equal(Cu.evalInSandbox("exn.name", sb), "TypeError");
+
+  ctor = Cu.evalInSandbox("DOMException", sb);
+  Cu.exportFunction(function() {
+    throw new ctor("Goodbye", "InvalidAccessError");
+  }, sb, { defineAs: "func4" });
+  threw = Cu.evalInSandbox("var threw; try { func4(); threw = false; } catch (e) { globalThis.exn = e; threw = true } threw",
+                                sb, "", "FakeFile");
+  Assert.ok(threw);
+  Assert.ok(!Cu.evalInSandbox("exn.filename", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.fileName", sb), undefined);
+  Assert.ok(!Cu.evalInSandbox("exn.stack", sb).includes("/unit/"));
+  Assert.equal(Cu.evalInSandbox("exn.message", sb), "Goodbye");
+  Assert.equal(Cu.evalInSandbox("exn.name", sb), "InvalidAccessError");
+}
diff --git a/js/xpconnect/tests/unit/test_bug408412.js b/js/xpconnect/tests/unit/test_bug408412.js
new file mode 100644
index 0000000000..06321a6f87
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug408412.js
@@ -0,0 +1,12 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+ 
+function run_test() {
+  try {
+    ChromeUtils.import("resource://test/syntax_error.jsm");
+    do_throw("Failed to report any error at all");
+  } catch (e) {
+    Assert.notEqual(/^SyntaxError:/.exec(e + ''), null);
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_bug451678.js b/js/xpconnect/tests/unit/test_bug451678.js
new file mode 100644
index 0000000000..90c18a614c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug451678.js
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  var file = do_get_file("bug451678_subscript.js");
+  var ios = Cc["@mozilla.org/network/io-service;1"]
+              .getService(Ci.nsIIOService);
+  var uri = ios.newFileURI(file);
+  var scriptLoader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
+                       .getService(Ci.mozIJSSubScriptLoader);
+  var srvScope = {};
+  scriptLoader.loadSubScript(uri.spec, srvScope);
+  Assert.ok('makeTags' in srvScope && srvScope.makeTags instanceof Function);
+}
diff --git a/js/xpconnect/tests/unit/test_bug604362.js b/js/xpconnect/tests/unit/test_bug604362.js
new file mode 100644
index 0000000000..7adcfab96c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug604362.js
@@ -0,0 +1,10 @@
+function run_test() {
+  var sp = Cc["@mozilla.org/systemprincipal;1"].
+           createInstance(Ci.nsIPrincipal);
+  var s = Cu.Sandbox(sp);
+  s.a = [];
+  s.Cu = Cu;
+  s.C = Components;
+  s.notEqual = notEqual;
+  Cu.evalInSandbox("notEqual(Cu.import, undefined);", s);
+}
diff --git a/js/xpconnect/tests/unit/test_bug677864.js b/js/xpconnect/tests/unit/test_bug677864.js
new file mode 100644
index 0000000000..f92d15fe66
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug677864.js
@@ -0,0 +1,9 @@
+function check_cl(iface, desc) {
+    Assert.equal(iface.QueryInterface(Ci.nsIClassInfo).classDescription, desc);
+}
+
+function run_test() {
+    check_cl(Ci, 'XPCComponents_Interfaces');
+    check_cl(Cc, 'XPCComponents_Classes');
+    check_cl(Cr, 'XPCComponents_Results');
+}
diff --git a/js/xpconnect/tests/unit/test_bug711404.js b/js/xpconnect/tests/unit/test_bug711404.js
new file mode 100644
index 0000000000..f74b43316c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug711404.js
@@ -0,0 +1,7 @@
+function run_test()
+{
+  var p = Cc["@mozilla.org/hash-property-bag;1"].
+          createInstance(Ci.nsIWritablePropertyBag2);
+  p.setPropertyAsInt64("a", -4000);
+  Assert.notEqual(p.getPropertyAsUint64("a"), -4000);
+}
diff --git a/js/xpconnect/tests/unit/test_bug742444.js b/js/xpconnect/tests/unit/test_bug742444.js
new file mode 100644
index 0000000000..3b8262834f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug742444.js
@@ -0,0 +1,16 @@
+function run_test() {
+  let sb1A = Cu.Sandbox('http://www.example.com');
+  let sb1B = Cu.Sandbox('http://www.example.com');
+  let sb2 = Cu.Sandbox('http://www.example.org');
+  let sbChrome = Cu.Sandbox(this);
+  let obj = new sb1A.Object();
+  sb1B.obj = obj;
+  sb1B.waived = Cu.waiveXrays(obj);
+  sb2.obj = obj;
+  sb2.waived = Cu.waiveXrays(obj);
+  sbChrome.obj = obj;
+  sbChrome.waived = Cu.waiveXrays(obj);
+  Assert.ok(Cu.evalInSandbox('obj === waived', sb1B));
+  Assert.ok(Cu.evalInSandbox('obj === waived', sb2));
+  Assert.ok(Cu.evalInSandbox('obj !== waived', sbChrome));
+}
diff --git a/js/xpconnect/tests/unit/test_bug778409.js b/js/xpconnect/tests/unit/test_bug778409.js
new file mode 100644
index 0000000000..4ca2ea6767
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug778409.js
@@ -0,0 +1,10 @@
+function run_test() {
+  var sb1 = Cu.Sandbox('http://example.com');
+  var sb2 = Cu.Sandbox('http://example.org');
+  var chromeObj = {foo: 2};
+  var sb1obj = Cu.evalInSandbox('new Object()', sb1);
+  chromeObj.__proto__ = sb1obj;
+  sb2.wrapMe = chromeObj;
+  Assert.ok(true, "Didn't crash");
+  Assert.equal(sb2.wrapMe.__proto__, sb1obj, 'proto set correctly');
+}
diff --git a/js/xpconnect/tests/unit/test_bug780370.js b/js/xpconnect/tests/unit/test_bug780370.js
new file mode 100644
index 0000000000..e0da551201
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug780370.js
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=780370 */
+
+// Use a COW to expose a function from a standard prototype, and make we deny
+// access to it.
+
+function run_test()
+{
+  var sb = Cu.Sandbox("http://www.example.com");
+  sb.obj = { foo: 42 };
+  Assert.equal(Cu.evalInSandbox('typeof obj.foo', sb), 'undefined', "COW works as expected");
+  Assert.equal(Cu.evalInSandbox('obj.hasOwnProperty', sb), undefined);
+}
diff --git a/js/xpconnect/tests/unit/test_bug809652.js b/js/xpconnect/tests/unit/test_bug809652.js
new file mode 100644
index 0000000000..6d63c6531f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug809652.js
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=813901 */
+
+const TypedArrays = [ Int8Array, Uint8Array, Int16Array, Uint16Array,
+                      Int32Array, Uint32Array, Float32Array, Float64Array,
+                      Uint8ClampedArray ];
+
+// Make sure that the correct nativecall-y stuff is denied on security wrappers.
+
+function run_test() {
+
+  var sb = new Cu.Sandbox('http://www.example.org');
+  sb.obj = {foo: 2};
+
+  /* Set up some typed arrays. */
+  sb.ab = new ArrayBuffer(8);
+  for (var i = 0; i < 8; ++i)
+    new Uint8Array(sb.ab)[i] = i * 10;
+  sb.ta = [];
+  TypedArrays.forEach(f => sb.ta.push(new f(sb.ab)));
+  sb.dv = new DataView(sb.ab);
+
+  /* Things that should throw. */
+  checkThrows("Object.prototype.__lookupSetter__('__proto__').call(obj, {});", sb);
+  sb.re = /f/;
+  checkThrows("RegExp.prototype.exec.call(re, 'abcdefg').index", sb);
+  sb.d = new Date();
+  checkThrows("Date.prototype.setYear.call(d, 2011)", sb);
+  sb.m = new Map();
+  checkThrows("(new Map()).clear.call(m)", sb);
+  checkThrows("ArrayBuffer.prototype.__lookupGetter__('byteLength').call(ab);", sb);
+  checkThrows("ArrayBuffer.prototype.slice.call(ab, 0);", sb);
+  checkThrows("DataView.prototype.getInt8.call(dv, 0);", sb);
+
+  /* Now that Date is on Xrays, these should all throw. */
+  checkThrows("Date.prototype.getYear.call(d)", sb);
+  checkThrows("Date.prototype.valueOf.call(d)", sb);
+  checkThrows("d.valueOf()", sb);
+  checkThrows("d.toString()", sb);
+
+  /* Typed arrays. */
+  function testForTypedArray(t) {
+    sb.curr = t;
+    sb.currName = t.constructor.name;
+    checkThrows("this[currName].prototype.subarray.call(curr, 0)[0]", sb);
+    checkThrows("(new this[currName]).__lookupGetter__('length').call(curr)", sb);
+    checkThrows("(new this[currName]).__lookupGetter__('buffer').call(curr)", sb);
+    checkThrows("(new this[currName]).__lookupGetter__('byteOffset').call(curr)", sb);
+    checkThrows("(new this[currName]).__lookupGetter__('byteLength').call(curr)", sb);
+  }
+  sb.ta.forEach(testForTypedArray);
+}
+
+function checkThrows(expression, sb) {
+  var result = Cu.evalInSandbox('(function() { try { ' + expression + '; return "allowed"; } catch (e) { return e.toString(); }})();', sb);
+  dump('result: ' + result + '\n\n\n');
+  Assert.ok(!!/denied/.exec(result));
+}
+
diff --git a/js/xpconnect/tests/unit/test_bug809674.js b/js/xpconnect/tests/unit/test_bug809674.js
new file mode 100644
index 0000000000..dee089e759
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug809674.js
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+var Bug809674 = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestBug809674"]),
+
+  /* nsIXPCTestBug809674 */
+  methodWithOptionalArgc() {},
+
+  addArgs(x, y) {
+    return x + y;
+  },
+  addSubMulArgs(x, y, subOut, mulOut) {
+    subOut.value = x - y;
+    mulOut.value = x * y;
+    return x + y;
+  },
+  addVals(x, y) {
+    return x + y;
+  },
+  addMany(x1, x2, x3, x4, x5, x6, x7, x8) {
+    return x1 + x2 + x3 + x4 + x5 + x6 + x7 + x8;
+  },
+
+  methodNoArgs() {
+    return 7;
+  },
+  methodNoArgsNoRetVal() {},
+
+  valProperty: {value: 42},
+  uintProperty: 123,
+};
+
+function run_test() {
+  // XPConnect wrap the object
+  var o = xpcWrap(Bug809674, Ci.nsIXPCTestBug809674);
+
+  // Methods marked [implicit_jscontext].
+
+  Assert.equal(o.addArgs(12, 34), 46);
+
+  var subRes = {}, mulRes = {};
+  Assert.equal(o.addSubMulArgs(9, 7, subRes, mulRes), 16);
+  Assert.equal(subRes.value, 2);
+  Assert.equal(mulRes.value, 63);
+
+  Assert.equal(o.addVals("foo", "x"), "foox");
+  Assert.equal(o.addVals("foo", 1.2), "foo1.2");
+  Assert.equal(o.addVals(1234, "foo"), "1234foo");
+
+  Assert.equal(o.addMany(1, 2, 4, 8, 16, 32, 64, 128), 255);
+
+  Assert.equal(o.methodNoArgs(), 7);
+  Assert.equal(o.methodNoArgsNoRetVal(), undefined);
+
+  // Attributes marked [implicit_jscontext].
+
+  Assert.equal(o.valProperty.value, 42);
+  o.valProperty = o;
+  Assert.equal(o.valProperty, o);
+
+  Assert.equal(o.uintProperty, 123);
+  o.uintProperty++;
+  Assert.equal(o.uintProperty, 124);
+
+  // [optional_argc] is not supported.
+  try {
+    o.methodWithOptionalArgc();
+    Assert.ok(false);
+  } catch (e) {
+    Assert.ok(true);
+    Assert.ok(/optional_argc/.test(e))
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_bug813901.js b/js/xpconnect/tests/unit/test_bug813901.js
new file mode 100644
index 0000000000..433c7872ef
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug813901.js
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=813901 */
+
+// Make sure that we can't inject __exposedProps__ via the proto of a COW-ed object.
+
+function checkThrows(expression, sb, regexp) {
+  var result = Cu.evalInSandbox('(function() { try { ' + expression + '; return "allowed"; } catch (e) { return e.toString(); }})();', sb);
+  dump('result: ' + result + '\n\n\n');
+  Assert.ok(!!regexp.exec(result));
+}
+
+function run_test() {
+
+  var sb = new Cu.Sandbox('http://www.example.org');
+  sb.obj = {foo: 2};
+  checkThrows('obj.foo = 3;', sb, /denied/);
+  Cu.evalInSandbox("var p = {};", sb);
+  sb.obj.__proto__ = sb.p;
+  checkThrows('obj.foo = 4;', sb, /denied/);
+}
diff --git a/js/xpconnect/tests/unit/test_bug845201.js b/js/xpconnect/tests/unit/test_bug845201.js
new file mode 100644
index 0000000000..74253ccaed
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug845201.js
@@ -0,0 +1,18 @@
+function sbTest() {
+  var threw = false;
+  try {
+    for (var x in Components) { }
+    ok(false, "Shouldn't be able to enumerate Components");
+  } catch(e) {
+    ok(true, "Threw appropriately");
+    threw = true;
+  }
+  ok(threw, "Shouldn't have thrown uncatchable exception");
+}
+
+function run_test() {
+  var sb = Cu.Sandbox('http://www.example.com', { wantComponents: true });
+  sb.ok = ok;
+  Cu.evalInSandbox(sbTest.toSource(), sb);
+  Cu.evalInSandbox('sbTest();', sb);
+}
diff --git a/js/xpconnect/tests/unit/test_bug845862.js b/js/xpconnect/tests/unit/test_bug845862.js
new file mode 100644
index 0000000000..41d799803f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug845862.js
@@ -0,0 +1,7 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  Cu.evalInSandbox("this.foo = {}; Object.defineProperty(foo, 'bar', {get: function() {return {};}});", sb);
+  var desc = Object.getOwnPropertyDescriptor(Cu.waiveXrays(sb.foo), 'bar');
+  var b = desc.get();
+  Assert.ok(b != XPCNativeWrapper(b), "results from accessor descriptors are waived");
+}
diff --git a/js/xpconnect/tests/unit/test_bug849730.js b/js/xpconnect/tests/unit/test_bug849730.js
new file mode 100644
index 0000000000..9be55457bf
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug849730.js
@@ -0,0 +1,5 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  sb.arr = [3, 4];
+  Assert.ok(Cu.evalInSandbox('!Array.isArray(arr);', sb));
+}
diff --git a/js/xpconnect/tests/unit/test_bug851895.js b/js/xpconnect/tests/unit/test_bug851895.js
new file mode 100644
index 0000000000..1c3d0f461f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug851895.js
@@ -0,0 +1,9 @@
+function run_test() {
+  // Make sure Components.utils gets its |this| fixed up.
+  var isXrayWrapper = Cu.isXrayWrapper;
+  Assert.ok(!isXrayWrapper({}), "Didn't throw");
+
+  // Even for classes without |this| fixup, make sure that we don't crash.
+  var isSuccessCode = Components.isSuccessCode;
+  try { isSuccessCode(Cr.NS_OK); } catch (e) {};
+}
diff --git a/js/xpconnect/tests/unit/test_bug853709.js b/js/xpconnect/tests/unit/test_bug853709.js
new file mode 100644
index 0000000000..a59d4707bf
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug853709.js
@@ -0,0 +1,30 @@
+function setupChromeSandbox() {
+  this.chromeObj = {a: 2 };
+  this.chromeArr = [4, 2, 1];
+}
+
+function checkDefineThrows(sb, obj, prop, desc) {
+  var result = Cu.evalInSandbox('(function() { try { Object.defineProperty(' + obj + ', "' + prop + '", ' + desc.toSource() + '); return "nothrow"; } catch (e) { return e.toString(); }})();', sb);
+  Assert.notEqual(result, 'nothrow');
+  Assert.ok(!!/denied|prohibited/.exec(result));
+  Assert.ok(result.includes(prop)); // Make sure the prop name is in the error message.
+}
+
+function run_test() {
+  var chromeSB = new Cu.Sandbox(this);
+  var contentSB = new Cu.Sandbox('http://www.example.org');
+  Cu.evalInSandbox('(' + setupChromeSandbox.toSource() + ')()', chromeSB);
+  contentSB.chromeObj = chromeSB.chromeObj;
+  contentSB.chromeArr = chromeSB.chromeArr;
+
+  Assert.equal(Cu.evalInSandbox('chromeObj.a', contentSB), undefined);
+  try {
+    Cu.evalInSandbox('chromeArr[1]', contentSB);
+    Assert.ok(false);
+  } catch (e) { Assert.ok(/denied|insecure/.test(e)); }
+
+  checkDefineThrows(contentSB, 'chromeObj', 'a', {get: function() { return 2; }});
+  checkDefineThrows(contentSB, 'chromeObj', 'a', {configurable: true, get: function() { return 2; }});
+  checkDefineThrows(contentSB, 'chromeObj', 'b', {configurable: true, get: function() { return 2; }, set: function() {}});
+  checkDefineThrows(contentSB, 'chromeArr', '1', {configurable: true, get: function() { return 2; }});
+}
diff --git a/js/xpconnect/tests/unit/test_bug856067.js b/js/xpconnect/tests/unit/test_bug856067.js
new file mode 100644
index 0000000000..b724ba4b18
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug856067.js
@@ -0,0 +1,8 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  let w = Cu.evalInSandbox('var w = new Map()[Symbol.iterator](); w.__proto__ = new Set(); w.foopy = 12; w', sb);
+  Assert.equal(Object.getPrototypeOf(w), sb.Object.prototype);
+  Assert.equal(Object.getOwnPropertyNames(w).length, 0);
+  Assert.equal(w.wrappedJSObject.foopy, 12);
+  Assert.equal(w.foopy, undefined);
+}
diff --git a/js/xpconnect/tests/unit/test_bug867486.js b/js/xpconnect/tests/unit/test_bug867486.js
new file mode 100644
index 0000000000..c053ec27e1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug867486.js
@@ -0,0 +1,8 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com', { wantComponents: true } );
+  Assert.ok(!Cu.evalInSandbox('"Components" in this', sb));
+}
diff --git a/js/xpconnect/tests/unit/test_bug868675.js b/js/xpconnect/tests/unit/test_bug868675.js
new file mode 100644
index 0000000000..7f5e94f83b
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug868675.js
@@ -0,0 +1,29 @@
+function run_test() {
+
+  // Make sure we don't throw for primitive values.
+  var result = "threw";
+  try { result = XPCNativeWrapper.unwrap(2); } catch (e) {}
+  Assert.equal(result, 2);
+  result = "threw";
+  try { result = XPCNativeWrapper(2); } catch (e) {}
+  Assert.equal(result, 2);
+
+  // Make sure we throw when using `new` with primitives.
+  result = null;
+  try { result = new XPCNativeWrapper(2); } catch (e) { result = "catch"; }
+  Assert.equal(result, "catch");
+
+  // Make sure that we can waive on a non-Xrayable object, and that we preserve
+  // transitive waiving behavior.
+  var sb = new Cu.Sandbox('http://www.example.com', { wantGlobalProperties: ["XMLHttpRequest"] });
+  Cu.evalInSandbox('this.xhr = new XMLHttpRequest();', sb);
+  Cu.evalInSandbox('this.jsobj = {mynative: xhr};', sb);
+  Assert.ok(!Cu.isXrayWrapper(XPCNativeWrapper.unwrap(sb.xhr)));
+  Assert.ok(Cu.isXrayWrapper(sb.jsobj.mynative));
+  Assert.ok(!Cu.isXrayWrapper(XPCNativeWrapper.unwrap(sb.jsobj).mynative));
+
+  // Test the new Cu API.
+  var waived = Cu.waiveXrays(sb.xhr);
+  Assert.ok(!Cu.isXrayWrapper(waived));
+  Assert.ok(Cu.isXrayWrapper(Cu.unwaiveXrays(waived)));
+}
diff --git a/js/xpconnect/tests/unit/test_bug872772.js b/js/xpconnect/tests/unit/test_bug872772.js
new file mode 100644
index 0000000000..bfb0d7f4f8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug872772.js
@@ -0,0 +1,33 @@
+function run_test() {
+
+  // Make a content sandbox with an Xrayable object.
+  // NB: We use an nsEP here so that we can have access to Components, but still
+  // have Xray behavior from this scope.
+  var contentSB = new Cu.Sandbox(['http://www.google.com'],
+                                 { wantGlobalProperties: ["XMLHttpRequest"] });
+
+  // Make an XHR in the content sandbox.
+  Cu.evalInSandbox('xhr = new XMLHttpRequest();', contentSB);
+
+  // Make sure that waivers can be set as Xray expandos.
+  var xhr = contentSB.xhr;
+  Assert.ok(Cu.isXrayWrapper(xhr));
+  xhr.unwaivedExpando = xhr;
+  Assert.ok(Cu.isXrayWrapper(xhr.unwaivedExpando));
+  var waived = xhr.wrappedJSObject;
+  Assert.ok(!Cu.isXrayWrapper(waived));
+  xhr.waivedExpando = waived;
+  Assert.ok(!Cu.isXrayWrapper(xhr.waivedExpando));
+
+  // Try the same thing for getters/setters, even though that's kind of
+  // contrived.
+  Cu.evalInSandbox('function f() {}', contentSB);
+  var f = contentSB.f;
+  var fWaiver = Cu.waiveXrays(f);
+  Assert.ok(f != fWaiver);
+  Assert.ok(Cu.unwaiveXrays(fWaiver) === f);
+  Object.defineProperty(xhr, 'waivedAccessors', {get: fWaiver, set: fWaiver});
+  var desc = Object.getOwnPropertyDescriptor(xhr, 'waivedAccessors');
+  Assert.ok(desc.get === fWaiver);
+  Assert.ok(desc.set === fWaiver);
+}
diff --git a/js/xpconnect/tests/unit/test_bug885800.js b/js/xpconnect/tests/unit/test_bug885800.js
new file mode 100644
index 0000000000..8e00b997b1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug885800.js
@@ -0,0 +1,11 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com');
+  var obj = Cu.evalInSandbox('this.obj = {foo: 2}; obj', sb);
+  var chromeSb = new Cu.Sandbox(this);
+  chromeSb.objRef = obj;
+  Assert.equal(Cu.evalInSandbox('objRef.foo', chromeSb), 2);
+  Cu.nukeSandbox(sb);
+  Assert.ok(Cu.isDeadWrapper(obj));
+  // CCWs to nuked wrappers should be considered dead.
+  Assert.ok(Cu.isDeadWrapper(chromeSb.objRef));
+}
diff --git a/js/xpconnect/tests/unit/test_bug930091.js b/js/xpconnect/tests/unit/test_bug930091.js
new file mode 100644
index 0000000000..ef2b7ae253
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug930091.js
@@ -0,0 +1,27 @@
+function checkThrows(fn) {
+  try {
+    fn();
+    ok(false, "Should have thrown");
+  } catch (e) {
+    ok(/denied|insecure|prohibited/.test(e));
+  }
+}
+
+function run_test() {
+  var xosb = new Cu.Sandbox('http://www.example.org');
+  var sb = new Cu.Sandbox('http://www.example.com');
+  sb.ok = ok;
+  sb.fun = function() { ok(false, "Shouldn't ever reach me"); };
+  sb.cow = { foopy: 2 };
+  sb.payload = Cu.evalInSandbox('new Object()', xosb);
+  Cu.evalInSandbox(checkThrows.toSource(), sb);
+  Cu.evalInSandbox('checkThrows(function() { fun(payload); });', sb);
+  Cu.evalInSandbox('checkThrows(function() { Function.prototype.call.call(fun, payload); });', sb);
+  Cu.evalInSandbox('checkThrows(function() { Function.prototype.call.call(fun, null, payload); });', sb);
+  Cu.evalInSandbox('checkThrows(function() { new fun(payload); });', sb);
+  Cu.evalInSandbox('checkThrows(function() { cow.foopy = payload; });', sb);
+  Cu.evalInSandbox('checkThrows(function() { Object.defineProperty(cow, "foopy", { value: payload }); });', sb);
+  // These fail for a different reason, .bind can't access the length/name property on the function.
+  Cu.evalInSandbox('checkThrows(function() { Function.bind.call(fun, null, payload); });', sb);
+  Cu.evalInSandbox('checkThrows(function() { Function.bind.call(fun, payload); });', sb);
+}
diff --git a/js/xpconnect/tests/unit/test_bug976151.js b/js/xpconnect/tests/unit/test_bug976151.js
new file mode 100644
index 0000000000..2e02c3c541
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug976151.js
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  let unprivilegedSb = new Cu.Sandbox('http://www.example.com');
+  function checkOpaqueWrapper(val) {
+    unprivilegedSb.prop = val;
+    try {
+      Cu.evalInSandbox('prop();', sb);
+    } catch (e) {
+      Assert.ok(/denied|insecure|/.test(e));
+    }
+  }
+  let xoSb = new Cu.Sandbox('http://www.example.net');
+  let epSb = new Cu.Sandbox(['http://www.example.com']);
+  checkOpaqueWrapper(eval);
+  checkOpaqueWrapper(xoSb.eval);
+  checkOpaqueWrapper(epSb.eval);
+  checkOpaqueWrapper(Function);
+  checkOpaqueWrapper(xoSb.Function);
+  checkOpaqueWrapper(epSb.Function);
+}
diff --git a/js/xpconnect/tests/unit/test_bug_442086.js b/js/xpconnect/tests/unit/test_bug_442086.js
new file mode 100644
index 0000000000..ad1d8aabaa
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug_442086.js
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Bug 442086 - XPConnect creates doubles without checking for
+//              the INT_FITS_IN_JSVAL case
+
+var types = [
+    'PRUint8',
+    'PRUint16',
+    'PRUint32',
+    'PRUint64',
+    'PRInt16',
+    'PRInt32',
+    'PRInt64',
+    'float',
+    'double'
+];
+
+function run_test()
+{
+  var i;
+  for (i = 0; i < types.length; i++) {
+    var name = types[i];
+    var cls = Cc["@mozilla.org/supports-" + name + ";1"];
+    var ifname = ("nsISupports" + name.charAt(0).toUpperCase() +
+                  name.substring(1));
+    var f = cls.createInstance(Ci[ifname]);
+
+    f.data = 0;
+    switch (f.data) {
+      case 0: /*ok*/ break;
+      default: do_throw("FAILED - bug 442086 (type=" + name + ")");
+    }
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_callFunctionWithAsyncStack.js b/js/xpconnect/tests/unit/test_callFunctionWithAsyncStack.js
new file mode 100644
index 0000000000..75c3fa013e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_callFunctionWithAsyncStack.js
@@ -0,0 +1,28 @@
+function run_test() {
+  if (!Services.prefs.getBoolPref("javascript.options.asyncstack")) {
+    info("Async stacks are disabled.");
+    return;
+  }
+
+  function getAsyncStack() {
+    return Components.stack;
+  }
+
+  // asyncCause may contain non-ASCII characters.
+  let testAsyncCause = "Tes" + String.fromCharCode(355) + "String";
+
+  Cu.callFunctionWithAsyncStack(function asyncCallback() {
+    let stack = Components.stack;
+
+    Assert.equal(stack.name, "asyncCallback");
+    Assert.equal(stack.caller, null);
+    Assert.equal(stack.asyncCause, null);
+
+    Assert.equal(stack.asyncCaller.name, "getAsyncStack");
+    Assert.equal(stack.asyncCaller.asyncCause, testAsyncCause);
+    Assert.equal(stack.asyncCaller.asyncCaller, null);
+
+    Assert.equal(stack.asyncCaller.caller.name, "run_test");
+    Assert.equal(stack.asyncCaller.caller.asyncCause, null);
+  }, getAsyncStack(), testAsyncCause);
+}
diff --git a/js/xpconnect/tests/unit/test_cenums.js b/js/xpconnect/tests/unit/test_cenums.js
new file mode 100644
index 0000000000..6efa8912b1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_cenums.js
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function TestCEnums() {
+}
+
+TestCEnums.prototype = {
+  /* Boilerplate */
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestCEnums"]),
+
+  testCEnumInput: function(input) {
+    if (input != Ci.nsIXPCTestCEnums.shouldBe12Explicit)
+    {
+      throw new Error("Enum values do not match expected value");
+    }
+  },
+
+  testCEnumOutput: function() {
+    return Ci.nsIXPCTestCEnums.shouldBe8Explicit;
+  },
+};
+
+
+function run_test() {
+  // Load the component manifests.
+  registerXPCTestComponents();
+
+  // Test for each component.
+  test_interface_consts();
+  test_component(Cc["@mozilla.org/js/xpc/test/native/CEnums;1"].createInstance());
+  test_component(xpcWrap(new TestCEnums()));
+}
+
+function test_interface_consts() {
+  Assert.equal(Ci.nsIXPCTestCEnums.testConst, 1);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe1Explicit, 1);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe2Explicit, 2);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe4Explicit, 4);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe8Explicit, 8);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe12Explicit, 12);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe1Implicit, 1);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe2Implicit, 2);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe3Implicit, 3);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe5Implicit, 5);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe6Implicit, 6);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe2AgainImplicit, 2);
+  Assert.equal(Ci.nsIXPCTestCEnums.shouldBe3AgainImplicit, 3);
+}
+
+function test_component(obj) {
+  var o = obj.QueryInterface(Ci.nsIXPCTestCEnums);
+  o.testCEnumInput(Ci.nsIXPCTestCEnums.shouldBe12Explicit);
+  o.testCEnumInput(Ci.nsIXPCTestCEnums.shouldBe8Explicit | Ci.nsIXPCTestCEnums.shouldBe4Explicit);
+  var a = o.testCEnumOutput();
+  Assert.equal(a, Ci.nsIXPCTestCEnums.shouldBe8Explicit);
+}
+
diff --git a/js/xpconnect/tests/unit/test_compileScript.js b/js/xpconnect/tests/unit/test_compileScript.js
new file mode 100644
index 0000000000..1baf7ab56e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_compileScript.js
@@ -0,0 +1,99 @@
+"use strict";
+
+const { AddonTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/AddonTestUtils.sys.mjs"
+);
+
+AddonTestUtils.init(this);
+
+add_task(async function() {
+  let scriptUrl = Services.io.newFileURI(do_get_file("file_simple_script.js")).spec;
+
+
+  let script1 = await ChromeUtils.compileScript(scriptUrl, {hasReturnValue: true});
+  let script2 = await ChromeUtils.compileScript(scriptUrl, {hasReturnValue: false});
+
+  equal(script1.url, scriptUrl, "Script URL is correct")
+  equal(script2.url, scriptUrl, "Script URL is correct")
+
+  equal(script1.hasReturnValue, true, "Script hasReturnValue property is correct")
+  equal(script2.hasReturnValue, false, "Script hasReturnValue property is correct")
+
+
+  // Test return-value version.
+
+  let sandbox1 = Cu.Sandbox("http://example.com");
+  let sandbox2 = Cu.Sandbox("http://example.org");
+
+  let obj = script1.executeInGlobal(sandbox1);
+  equal(Cu.getObjectPrincipal(obj).origin, "http://example.com", "Return value origin is correct");
+  equal(obj.foo, "\u00ae", "Return value has the correct charset");
+
+  obj = script1.executeInGlobal(sandbox2);
+  equal(Cu.getObjectPrincipal(obj).origin, "http://example.org", "Return value origin is correct");
+  equal(obj.foo, "\u00ae", "Return value has the correct charset");
+
+
+  // Test no-return-value version.
+
+  sandbox1.bar = null;
+  equal(sandbox1.bar, null);
+
+  obj = script2.executeInGlobal(sandbox1);
+  equal(obj, undefined, "No-return script has no return value");
+
+  equal(Cu.getObjectPrincipal(sandbox1.bar).origin, "http://example.com", "Object value origin is correct");
+  equal(sandbox1.bar.foo, "\u00ae", "Object value has the correct charset");
+
+
+  sandbox2.bar = null;
+  equal(sandbox2.bar, null);
+
+  obj = script2.executeInGlobal(sandbox2);
+  equal(obj, undefined, "No-return script has no return value");
+
+  equal(Cu.getObjectPrincipal(sandbox2.bar).origin, "http://example.org", "Object value origin is correct");
+  equal(sandbox2.bar.foo, "\u00ae", "Object value has the correct charset");
+});
+
+add_task(async function test_syntaxError() {
+  // Generate an artificially large script to force off-main-thread
+  // compilation.
+  let scriptUrl = `data:,${";".repeat(1024 * 1024)}(`;
+
+  await Assert.rejects(
+    ChromeUtils.compileScript(scriptUrl),
+    SyntaxError);
+
+  // Generate a small script to force main thread compilation.
+  scriptUrl = `data:,;(`;
+
+  await Assert.rejects(
+    ChromeUtils.compileScript(scriptUrl),
+    SyntaxError);
+});
+
+/**
+ * Assert that executeInGlobal throws a special exception when the content script throws.
+ * And the content script exception is notified to the console.
+ */
+add_task(async function test_exceptions_in_webconsole() {
+  const scriptUrl = `data:,throw new Error("foo")`;
+  const script = await ChromeUtils.compileScript(scriptUrl);
+  const sandbox = Cu.Sandbox("http://example.com");
+
+  Assert.throws(() => script.executeInGlobal(sandbox),
+    /Error: foo/,
+    "Without reportException set to true, executeInGlobal throws an exception");
+
+  info("With reportException, executeInGlobal doesn't throw, but notifies the console");
+  const { messages } = await AddonTestUtils.promiseConsoleOutput(() => {
+    script.executeInGlobal(sandbox, { reportExceptions: true });
+  });
+
+  info("Wait for the console message related to the content script exception");
+  equal(messages.length, 1, "Got one console message");
+  messages[0].QueryInterface(Ci.nsIScriptError);
+  equal(messages[0].errorMessage, "Error: foo", "We are notified about the plain content script exception via the console");
+  ok(messages[0].stack, "The message has a stack");
+});
diff --git a/js/xpconnect/tests/unit/test_components.js b/js/xpconnect/tests/unit/test_components.js
new file mode 100644
index 0000000000..e019b78f8f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_components.js
@@ -0,0 +1,24 @@
+function run_test() {
+  var sb1 = Cu.Sandbox("http://www.blah.com");
+  var sb2 = Cu.Sandbox(this);
+  var rv;
+
+  // non-chrome accessing chrome Components
+  sb1.C = Components;
+  checkThrows("C.interfaces", sb1);
+  checkThrows("C.utils", sb1);
+  checkThrows("C.classes", sb1);
+
+  // non-chrome accessing own Components: shouldn't exist.
+  Assert.equal(Cu.evalInSandbox("typeof Components", sb1), 'undefined');
+
+  // chrome accessing chrome
+  sb2.C = Components;
+  rv = Cu.evalInSandbox("C.utils", sb2);
+  Assert.equal(rv, Cu);
+}
+
+function checkThrows(expression, sb) {
+  var result = Cu.evalInSandbox('(function() { try { ' + expression + '; return "allowed"; } catch (e) { return e.toString(); }})();', sb);
+  Assert.ok(!!/denied/.exec(result));
+}
diff --git a/js/xpconnect/tests/unit/test_crypto.js b/js/xpconnect/tests/unit/test_crypto.js
new file mode 100644
index 0000000000..228701d182
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_crypto.js
@@ -0,0 +1,28 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  let sb = new Cu.Sandbox('https://www.example.com',
+                          { wantGlobalProperties:
+                            ["crypto", "TextEncoder", "TextDecoder", "isSecureContext"],
+                            forceSecureContext: true,
+                          });
+  sb.ok = ok;
+  Cu.evalInSandbox('ok(this.crypto);', sb);
+  Cu.evalInSandbox('ok(this.crypto.subtle);', sb);
+  sb.equal = equal;
+  let innerPromise = new Promise(r => (sb.test_done = r));
+  Cu.evalInSandbox('crypto.subtle.digest("SHA-256", ' +
+                   '                     new TextEncoder().encode("abc"))' +
+                   '  .then(h => equal(new Uint16Array(h)[0], 30906))' +
+                   '  .then(test_done);', sb);
+
+  Cu.importGlobalProperties(["crypto"]);
+  ok(crypto);
+  ok(crypto.subtle);
+  let outerPromise = crypto.subtle.digest("SHA-256", new TextEncoder().encode("abc"))
+      .then(h => Assert.equal(new Uint16Array(h)[0], 30906));
+
+  do_test_pending();
+  Promise.all([innerPromise, outerPromise]).then(() => do_test_finished());
+}
diff --git a/js/xpconnect/tests/unit/test_css.js b/js/xpconnect/tests/unit/test_css.js
new file mode 100644
index 0000000000..e6635d5293
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_css.js
@@ -0,0 +1,9 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["CSS"] });
+  sb.equal = equal;
+  Cu.evalInSandbox('equal(CSS.escape("$"), "\\\\$");',
+                   sb);
+  Cu.importGlobalProperties(["CSS"]);
+  Assert.equal(CSS.escape("$"), "\\$");
+}
diff --git a/js/xpconnect/tests/unit/test_deepFreezeClone.js b/js/xpconnect/tests/unit/test_deepFreezeClone.js
new file mode 100644
index 0000000000..949b85f551
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_deepFreezeClone.js
@@ -0,0 +1,31 @@
+function checkThrows(f, rgxp) { try { f(); do_check_false(); } catch (e) { Assert.ok(rgxp.test(e)); } }
+
+var o = { foo: 42, bar : { tick: 'tock' } };
+function checkClone(clone, frozen) {
+  var waived = Cu.waiveXrays(clone);
+  function touchFoo() { "use strict"; waived.foo = 12; Assert.equal(waived.foo, 12); }
+  function touchBar() { "use strict"; waived.bar.tick = 'tack'; Assert.equal(waived.bar.tick, 'tack'); }
+  function addProp() { "use strict"; waived.newProp = 100; Assert.equal(waived.newProp, 100); }
+  if (!frozen) {
+    touchFoo();
+    touchBar();
+    addProp();
+  } else {
+    checkThrows(touchFoo, /read-only/);
+    checkThrows(touchBar, /read-only/);
+    checkThrows(addProp, /extensible/);
+  }
+
+  var desc = Object.getOwnPropertyDescriptor(waived, 'foo');
+  Assert.equal(desc.writable, !frozen);
+  Assert.equal(desc.configurable, !frozen);
+  desc = Object.getOwnPropertyDescriptor(waived.bar, 'tick');
+  Assert.equal(desc.writable, !frozen);
+  Assert.equal(desc.configurable, !frozen);
+}
+
+function run_test() {
+  var sb = new Cu.Sandbox(null);
+  checkClone(Cu.waiveXrays(Cu.cloneInto(o, sb)), false);
+  checkClone(Cu.cloneInto(o, sb, { deepFreeze: true }), true);
+}
diff --git a/js/xpconnect/tests/unit/test_defineESModuleGetters.js b/js/xpconnect/tests/unit/test_defineESModuleGetters.js
new file mode 100644
index 0000000000..f7f12de1d9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_defineESModuleGetters.js
@@ -0,0 +1,76 @@
+function assertAccessor(lazy, name) {
+  let desc = Object.getOwnPropertyDescriptor(lazy, name);
+  Assert.equal(typeof desc.get, "function");
+  Assert.equal(desc.get.name, name);
+  Assert.equal(typeof desc.set, "function");
+  Assert.equal(desc.set.name, name);
+  Assert.equal(desc.enumerable, true);
+  Assert.equal(desc.configurable, true);
+}
+
+function assertDataProperty(lazy, name, value) {
+  let desc = Object.getOwnPropertyDescriptor(lazy, name);
+  Assert.equal(desc.value, value);
+  Assert.equal(desc.writable, true);
+  Assert.equal(desc.enumerable, true);
+  Assert.equal(desc.configurable, true);
+}
+
+add_task(function test_getter() {
+  // The property should be defined as getter, and getting it should make it
+  // a data property.
+
+  const lazy = {};
+  ChromeUtils.defineESModuleGetters(lazy, {
+    X: "resource://test/esm_lazy-1.sys.mjs",
+  });
+
+  assertAccessor(lazy, "X");
+
+  Assert.equal(lazy.X, 10);
+  assertDataProperty(lazy, "X", 10);
+});
+
+add_task(function test_setter() {
+  // Setting the value before the first get should result in a data property.
+  const lazy = {};
+  ChromeUtils.defineESModuleGetters(lazy, {
+    X: "resource://test/esm_lazy-1.sys.mjs",
+  });
+
+  assertAccessor(lazy, "X");
+  lazy.X = 20;
+  Assert.equal(lazy.X, 20);
+  assertDataProperty(lazy, "X", 20);
+
+  // The above set shouldn't affect the module's value.
+  const lazy2 = {};
+  ChromeUtils.defineESModuleGetters(lazy2, {
+    X: "resource://test/esm_lazy-1.sys.mjs",
+  });
+
+  Assert.equal(lazy2.X, 10);
+});
+
+add_task(function test_order() {
+  // The change to the exported value should be reflected until it's accessed.
+
+  const lazy = {};
+  ChromeUtils.defineESModuleGetters(lazy, {
+    Y: "resource://test/esm_lazy-2.sys.mjs",
+    AddY: "resource://test/esm_lazy-2.sys.mjs",
+  });
+
+  assertAccessor(lazy, "Y");
+  assertAccessor(lazy, "AddY");
+
+  // The change before getting the value should be reflected.
+  lazy.AddY(2);
+  Assert.equal(lazy.Y, 22);
+  assertDataProperty(lazy, "Y", 22);
+
+  // Change after getting the value shouldn't be reflected.
+  lazy.AddY(2);
+  Assert.equal(lazy.Y, 22);
+  assertDataProperty(lazy, "Y", 22);
+});
diff --git a/js/xpconnect/tests/unit/test_defineModuleGetter.js b/js/xpconnect/tests/unit/test_defineModuleGetter.js
new file mode 100644
index 0000000000..34acceb853
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_defineModuleGetter.js
@@ -0,0 +1,115 @@
+"use strict";
+
+function assertIsGetter(obj, prop) {
+  let desc = Object.getOwnPropertyDescriptor(obj, prop);
+
+  ok(desc, `Property ${prop} exists on object`);
+  equal(typeof desc.get, "function", `Getter function exists for property ${prop}`);
+  equal(typeof desc.set, "function", `Setter function exists for property ${prop}`);
+  equal(desc.enumerable, true, `Property ${prop} is enumerable`);
+  equal(desc.configurable, true, `Property ${prop} is configurable`);
+}
+
+function assertIsValue(obj, prop, value) {
+  let desc = Object.getOwnPropertyDescriptor(obj, prop);
+
+  ok(desc, `Property ${prop} exists on object`);
+
+  ok("value" in desc, `${prop} is a data property`);
+  equal(desc.value, value, `${prop} has the expected value`);
+
+  equal(desc.enumerable, true, `Property ${prop} is enumerable`);
+  equal(desc.configurable, true, `Property ${prop} is configurable`);
+  equal(desc.writable, true, `Property ${prop} is writable`);
+}
+
+add_task(async function() {
+  let temp = {};
+  ChromeUtils.import("resource://gre/modules/AppConstants.jsm", temp);
+
+  let obj = {};
+  let child = Object.create(obj);
+  let sealed = Object.seal(Object.create(obj));
+
+
+  // Test valid import
+
+  ChromeUtils.defineModuleGetter(obj, "AppConstants",
+                                 "resource://gre/modules/AppConstants.jsm");
+
+  assertIsGetter(obj, "AppConstants");
+  equal(child.AppConstants, temp.AppConstants, "Getter works on descendent object");
+  assertIsValue(child, "AppConstants", temp.AppConstants);
+  assertIsGetter(obj, "AppConstants");
+
+  Assert.throws(() => sealed.AppConstants, /Object is not extensible/,
+                "Cannot access lazy getter from sealed object");
+  Assert.throws(() => sealed.AppConstants = null, /Object is not extensible/,
+                "Cannot access lazy setter from sealed object");
+  assertIsGetter(obj, "AppConstants");
+
+  equal(obj.AppConstants, temp.AppConstants, "Getter works on object");
+  assertIsValue(obj, "AppConstants", temp.AppConstants);
+
+
+  // Test overwriting via setter
+
+  child = Object.create(obj);
+
+  ChromeUtils.defineModuleGetter(obj, "AppConstants",
+                                 "resource://gre/modules/AppConstants.jsm");
+
+  assertIsGetter(obj, "AppConstants");
+
+  child.AppConstants = "foo";
+  assertIsValue(child, "AppConstants", "foo");
+  assertIsGetter(obj, "AppConstants");
+
+  obj.AppConstants = "foo";
+  assertIsValue(obj, "AppConstants", "foo");
+
+
+  // Test import missing property
+
+  ChromeUtils.defineModuleGetter(obj, "meh",
+                                 "resource://gre/modules/AppConstants.jsm");
+  assertIsGetter(obj, "meh");
+  equal(obj.meh, undefined, "Missing property returns undefined");
+  assertIsValue(obj, "meh", undefined);
+
+
+  // Test import broken module
+
+  ChromeUtils.defineModuleGetter(obj, "broken",
+                                 "resource://test/bogus_exports_type.jsm");
+  assertIsGetter(obj, "broken");
+
+  let errorPattern = /EXPORTED_SYMBOLS is not an array/;
+  Assert.throws(() => child.broken, errorPattern,
+                "Broken import throws on child");
+  Assert.throws(() => child.broken, errorPattern,
+                "Broken import throws on child again");
+  Assert.throws(() => sealed.broken, errorPattern,
+                "Broken import throws on sealed child");
+  Assert.throws(() => obj.broken, errorPattern,
+                "Broken import throws on object");
+  assertIsGetter(obj, "broken");
+
+
+  // Test import missing module
+
+  ChromeUtils.defineModuleGetter(obj, "missing",
+                                 "resource://test/does_not_exist.jsm");
+  assertIsGetter(obj, "missing");
+
+  Assert.throws(() => obj.missing, /NS_ERROR_FILE_NOT_FOUND/,
+                "missing import throws on object");
+  assertIsGetter(obj, "missing");
+
+
+  // Test overwriting broken import via setter
+
+  assertIsGetter(obj, "broken");
+  obj.broken = "foo";
+  assertIsValue(obj, "broken", "foo");
+});
diff --git a/js/xpconnect/tests/unit/test_envChain_JSM.js b/js/xpconnect/tests/unit/test_envChain_JSM.js
new file mode 100644
index 0000000000..0c5b2e1b80
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_envChain_JSM.js
@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Verify the environment chain for JSM described in
+// js/src/vm/EnvironmentObject.h.
+
+add_task(async function() {
+  const { envs } = ChromeUtils.import("resource://test/envChain.jsm");
+
+  Assert.equal(envs.length, 4);
+
+  let i = 0, env;
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.lexical, true, "lexical must live in the NSLEO");
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticVariablesObject");
+  Assert.equal(env.qualified, true, "qualified var must live in the NSVO");
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, true, "prop var must live in the NSVO");
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "GlobalLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "*BackstagePass*");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+});
diff --git a/js/xpconnect/tests/unit/test_envChain_frameScript.js b/js/xpconnect/tests/unit/test_envChain_frameScript.js
new file mode 100644
index 0000000000..2d877d822f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_envChain_frameScript.js
@@ -0,0 +1,211 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Verify the environment chain for frame scripts described in
+// js/src/vm/EnvironmentObject.h.
+
+const { XPCShellContentUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/XPCShellContentUtils.sys.mjs"
+);
+
+XPCShellContentUtils.init(this);
+
+add_task(async function unique_scope() {
+  const page = await XPCShellContentUtils.loadContentPage("about:blank", {
+    remote: true,
+  });
+
+  const envsPromise = new Promise(resolve => {
+    Services.mm.addMessageListener("unique-envs-result", msg => {
+      resolve(msg.data);
+    });
+  });
+  const sharePromise = new Promise(resolve => {
+    Services.mm.addMessageListener("unique-share-result", msg => {
+      resolve(msg.data);
+    });
+  });
+
+  const runInUniqueScope = true;
+  const runInGlobalScope = !runInUniqueScope;
+
+  Services.mm.loadFrameScript(`data:,
+var unique_qualified = 10;
+unique_unqualified = 20;
+let unique_lexical = 30;
+this.unique_prop = 40;
+
+const funcs = Cu.getJSTestingFunctions();
+const envs = [];
+let env = funcs.getInnerMostEnvironmentObject();
+while (env) {
+  envs.push({
+    type: funcs.getEnvironmentObjectType(env) || "*BackstagePass*",
+    qualified: !!Object.getOwnPropertyDescriptor(env, "unique_qualified"),
+    unqualified: !!Object.getOwnPropertyDescriptor(env, "unique_unqualified"),
+    lexical: !!Object.getOwnPropertyDescriptor(env, "unique_lexical"),
+    prop: !!Object.getOwnPropertyDescriptor(env, "unique_prop"),
+  });
+
+  env = funcs.getEnclosingEnvironmentObject(env);
+}
+
+sendSyncMessage("unique-envs-result", envs);
+`, false, runInGlobalScope);
+
+  Services.mm.loadFrameScript(`data:,
+sendSyncMessage("unique-share-result", {
+  unique_qualified: typeof unique_qualified,
+  unique_unqualified: typeof unique_unqualified,
+  unique_lexical: typeof unique_lexical,
+  unique_prop: this.unique_prop,
+});
+`, false, runInGlobalScope);
+
+  const envs = await envsPromise;
+  const share = await sharePromise;
+
+  Assert.equal(envs.length, 5);
+
+  let i = 0, env;
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, true, "lexical must live in the NSLEO");
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "WithEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, true, "this property must live in the with env");
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticVariablesObject");
+  Assert.equal(env.qualified, true, "qualified var must live in the NSVO");
+  Assert.equal(env.unqualified, true, "unqualified var must live in the NSVO");
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "GlobalLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "*BackstagePass*");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  Assert.equal(share.unique_qualified, "undefined", "qualified var must not be shared");
+  Assert.equal(share.unique_unqualified, "undefined", "unqualified name must not be shared");
+  Assert.equal(share.unique_lexical, "undefined", "lexical must not be shared");
+  Assert.equal(share.unique_prop, 40, "this property must be shared");
+
+  await page.close();
+});
+
+add_task(async function non_unique_scope() {
+  const page = await XPCShellContentUtils.loadContentPage("about:blank", {
+    remote: true,
+  });
+
+  const envsPromise = new Promise(resolve => {
+    Services.mm.addMessageListener("non-unique-envs-result", msg => {
+      resolve(msg.data);
+    });
+  });
+  const sharePromise = new Promise(resolve => {
+    Services.mm.addMessageListener("non-unique-share-result", msg => {
+      resolve(msg.data);
+    });
+  });
+
+  const runInUniqueScope = false;
+  const runInGlobalScope = !runInUniqueScope;
+
+  Services.mm.loadFrameScript(`data:,
+var non_unique_qualified = 10;
+non_unique_unqualified = 20;
+let non_unique_lexical = 30;
+this.non_unique_prop = 40;
+
+const funcs = Cu.getJSTestingFunctions();
+const envs = [];
+let env = funcs.getInnerMostEnvironmentObject();
+while (env) {
+  envs.push({
+    type: funcs.getEnvironmentObjectType(env) || "*BackstagePass*",
+    qualified: !!Object.getOwnPropertyDescriptor(env, "non_unique_qualified"),
+    unqualified: !!Object.getOwnPropertyDescriptor(env, "non_unique_unqualified"),
+    lexical: !!Object.getOwnPropertyDescriptor(env, "non_unique_lexical"),
+    prop: !!Object.getOwnPropertyDescriptor(env, "non_unique_prop"),
+  });
+
+  env = funcs.getEnclosingEnvironmentObject(env);
+}
+
+sendSyncMessage("non-unique-envs-result", envs);
+`, false, runInGlobalScope);
+
+  Services.mm.loadFrameScript(`data:,
+sendSyncMessage("non-unique-share-result", {
+  non_unique_qualified,
+  non_unique_unqualified,
+  non_unique_lexical,
+  non_unique_prop,
+});
+`, false, runInGlobalScope);
+
+  const envs = await envsPromise;
+  const share = await sharePromise;
+
+  Assert.equal(envs.length, 4);
+
+  let i = 0, env;
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, true, "lexical must live in the NSLEO");
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "WithEnvironmentObject");
+  Assert.equal(env.qualified, true, "qualified var must live in the with env");
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, true, "this property must live in the with env");
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "GlobalLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "*BackstagePass*");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, true, "unqualified name must live in the backstage pass");
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  Assert.equal(share.non_unique_qualified, 10, "qualified var must be shared");
+  Assert.equal(share.non_unique_unqualified, 20, "unqualified name must be shared");
+  Assert.equal(share.non_unique_lexical, 30, "lexical must be shared");
+  Assert.equal(share.non_unique_prop, 40, "this property must be shared");
+
+  await page.close();
+});
diff --git a/js/xpconnect/tests/unit/test_envChain_subscript.js b/js/xpconnect/tests/unit/test_envChain_subscript.js
new file mode 100644
index 0000000000..e7774d0d0d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_envChain_subscript.js
@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Verify the environment chain for subscripts described in
+// js/src/vm/EnvironmentObject.h.
+
+add_task(async function() {
+  const target = {};
+  Services.scriptloader.loadSubScript(`data:,
+var qualified = 10;
+unqualified = 20;
+let lexical = 30;
+this.prop = 40;
+
+const funcs = Cu.getJSTestingFunctions();
+const envs = [];
+let env = funcs.getInnerMostEnvironmentObject();
+while (env) {
+  envs.push({
+    type: funcs.getEnvironmentObjectType(env) || "*global*",
+    qualified: !!Object.getOwnPropertyDescriptor(env, "qualified"),
+    unqualified: !!Object.getOwnPropertyDescriptor(env, "unqualified"),
+    lexical: !!Object.getOwnPropertyDescriptor(env, "lexical"),
+    prop: !!Object.getOwnPropertyDescriptor(env, "prop"),
+  });
+
+  env = funcs.getEnclosingEnvironmentObject(env);
+}
+
+this.ENVS = envs;
+`, target);
+
+  const envs = target.ENVS;
+
+  Assert.equal(envs.length, 4);
+
+  let i = 0, env;
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, true, "lexical must live in the NSLEO");
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "WithEnvironmentObject");
+  Assert.equal(env.qualified, true, "qualified var must live in the with env");
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, true, "this property must live in the with env");
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "GlobalLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "*global*");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, true, "unqualified var must live in the global");
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  Assert.equal(target.qualified, 10, "qualified var must be reflected to the target object");
+  Assert.equal(target.prop, 40, "this property must be reflected to the target object");
+});
diff --git a/js/xpconnect/tests/unit/test_envChain_subscript_in_JSM.js b/js/xpconnect/tests/unit/test_envChain_subscript_in_JSM.js
new file mode 100644
index 0000000000..a95806177e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_envChain_subscript_in_JSM.js
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Verify the environment chain for subscripts in JSM described in
+// js/src/vm/EnvironmentObject.h.
+
+add_task(async function() {
+  const { envs } = ChromeUtils.import("resource://test/envChain_subscript.jsm");
+
+  Assert.equal(envs.length, 6);
+
+  let i = 0, env;
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, true, "lexical must live in the NSLEO");
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "WithEnvironmentObject");
+  Assert.equal(env.qualified, true, "qualified var must live in the with env");
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, true, "this property must live in the with env");
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "NonSyntacticVariablesObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, true, "unqualified var must live in the global");
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "GlobalLexicalEnvironmentObject");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+
+  env = envs[i]; i++;
+  Assert.equal(env.type, "*BackstagePass*");
+  Assert.equal(env.qualified, false);
+  Assert.equal(env.unqualified, false);
+  Assert.equal(env.lexical, false);
+  Assert.equal(env.prop, false);
+});
diff --git a/js/xpconnect/tests/unit/test_eventSource.js b/js/xpconnect/tests/unit/test_eventSource.js
new file mode 100644
index 0000000000..8983d852bd
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_eventSource.js
@@ -0,0 +1,6 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+Assert.throws(() => new EventSource('a'),
+              /NS_ERROR_FAILURE/,
+              "This should fail, but not crash, in xpcshell");
diff --git a/js/xpconnect/tests/unit/test_exportFunction.js b/js/xpconnect/tests/unit/test_exportFunction.js
new file mode 100644
index 0000000000..a7b2ca8056
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_exportFunction.js
@@ -0,0 +1,152 @@
+function run_test() {
+  var epsb = new Cu.Sandbox(["http://example.com", "http://example.org"], { wantExportHelpers: true });
+  var subsb = new Cu.Sandbox("http://example.com", { wantGlobalProperties: ["XMLHttpRequest"] });
+  var subsb2 = new Cu.Sandbox("http://example.com", { wantGlobalProperties: ["XMLHttpRequest"] });
+  var xorigsb = new Cu.Sandbox("http://test.com", { wantGlobalProperties: ["XMLHttpRequest"] });
+
+  epsb.subsb = subsb;
+  epsb.xorigsb = xorigsb;
+  epsb.ok = ok;
+  epsb.equal = equal;
+  subsb.ok = ok;
+  subsb.equal = equal;
+
+  // Exporting should work if prinicipal of the source sandbox
+  // subsumes the principal of the target sandbox.
+  Cu.evalInSandbox("(" + function() {
+    var wasCalled = false;
+    this.funToExport = function(expectedThis, a, obj, native, mixed, callback) {
+      equal(arguments.callee.length, 6);
+      equal(a, 42);
+      equal(obj, subsb.tobecloned);
+      equal(obj.cloned, "cloned");
+      equal(native, subsb.native);
+      equal(expectedThis, this);
+      equal(mixed.xrayed, subsb.xrayed);
+      equal(mixed.xrayed2, subsb.xrayed2);
+      if (typeof callback == 'function') {
+        equal(typeof subsb.callback, 'function');
+        equal(callback, subsb.callback);
+        callback();
+      }
+      wasCalled = true;
+    };
+    this.checkIfCalled = function() {
+      ok(wasCalled);
+      wasCalled = false;
+    }
+    exportFunction(funToExport, subsb, { defineAs: "imported", allowCallbacks: true });
+    exportFunction((x) => x, subsb, { defineAs: "echoAllowXO", allowCallbacks: true, allowCrossOriginArguments: true });
+  }.toSource() + ")()", epsb);
+
+  subsb.xrayed = Cu.evalInSandbox("(" + function () {
+      return new XMLHttpRequest();
+  }.toSource() + ")()", subsb2);
+
+  // Exported function should be able to be call from the
+  // target sandbox. Native arguments should be just wrapped
+  // every other argument should be cloned.
+  Cu.evalInSandbox("(" + function () {
+    native = new XMLHttpRequest();
+    xrayed2 = XPCNativeWrapper(new XMLHttpRequest());
+    mixed = { xrayed: xrayed, xrayed2: xrayed2 };
+    tobecloned = { cloned: "cloned" };
+    invokedCallback = false;
+    callback = function() { invokedCallback = true; };
+    imported(this, 42, tobecloned, native, mixed, callback);
+    equal(imported.length, 6);
+    ok(invokedCallback);
+  }.toSource() + ")()", subsb);
+
+  // Invoking an exported function with cross-origin arguments should throw.
+  subsb.xoNative = Cu.evalInSandbox('new XMLHttpRequest()', xorigsb);
+  try {
+    Cu.evalInSandbox('imported(this, xoNative)', subsb);
+    Assert.ok(false);
+  } catch (e) {
+    Assert.ok(/denied|insecure/.test(e));
+  }
+
+  // Callers can opt-out of the above.
+  subsb.xoNative = Cu.evalInSandbox('new XMLHttpRequest()', xorigsb);
+  try {
+    Assert.equal(Cu.evalInSandbox('echoAllowXO(xoNative)', subsb), subsb.xoNative);
+    Assert.ok(true);
+  } catch (e) {
+    Assert.ok(false);
+  }
+
+  // Apply should work and |this| should carry over appropriately.
+  Cu.evalInSandbox("(" + function() {
+    var someThis = {};
+    imported.apply(someThis, [someThis, 42, tobecloned, native, mixed]);
+  }.toSource() + ")()", subsb);
+
+  Cu.evalInSandbox("(" + function() {
+    checkIfCalled();
+  }.toSource() + ")()", epsb);
+
+  // Exporting should throw if principal of the source sandbox does
+  // not subsume the principal of the target.
+  Cu.evalInSandbox("(" + function() {
+    try{
+      exportFunction(function() {}, this.xorigsb, { defineAs: "denied" });
+      ok(false);
+    } catch (e) {
+      ok(e.toString().indexOf('Permission denied') > -1);
+    }
+  }.toSource() + ")()", epsb);
+
+  // Exporting should throw if the principal of the source sandbox does
+  // not subsume the principal of the function.
+  epsb.xo_function = new xorigsb.Function();
+  Cu.evalInSandbox("(" + function() {
+    try{
+      exportFunction(xo_function, this.subsb, { defineAs: "denied" });
+      ok(false);
+    } catch (e) {
+      dump('Exception: ' + e);
+      ok(e.toString().indexOf('Permission denied') > -1);
+    }
+  }.toSource() + ")()", epsb);
+
+  // Let's create an object in the target scope and add privileged
+  // function to it as a property.
+  Cu.evalInSandbox("(" + function() {
+    var newContentObject = createObjectIn(subsb, { defineAs: "importedObject" });
+    exportFunction(funToExport, newContentObject, { defineAs: "privMethod" });
+  }.toSource() + ")()", epsb);
+
+  Cu.evalInSandbox("(" + function () {
+    importedObject.privMethod(importedObject, 42, tobecloned, native, mixed);
+  }.toSource() + ")()", subsb);
+
+  Cu.evalInSandbox("(" + function() {
+    checkIfCalled();
+  }.toSource() + ")()", epsb);
+
+  // exportFunction and createObjectIn should be available from Cu too.
+  var newContentObject = Cu.createObjectIn(subsb, { defineAs: "importedObject2" });
+  var wasCalled = false;
+  Cu.exportFunction(function(arg) { wasCalled = arg.wasCalled; },
+                    newContentObject, { defineAs: "privMethod" });
+
+  Cu.evalInSandbox("(" + function () {
+    importedObject2.privMethod({wasCalled: true});
+  }.toSource() + ")()", subsb);
+
+  // 3rd argument of exportFunction should be optional.
+  Cu.evalInSandbox("(" + function() {
+    subsb.imported2 = exportFunction(funToExport, subsb);
+  }.toSource() + ")()", epsb);
+
+  Cu.evalInSandbox("(" + function () {
+    imported2(this, 42, tobecloned, native, mixed);
+  }.toSource() + ")()", subsb);
+
+  Cu.evalInSandbox("(" + function() {
+    checkIfCalled();
+  }.toSource() + ")()", epsb);
+
+  Assert.ok(wasCalled);
+}
diff --git a/js/xpconnect/tests/unit/test_file.js b/js/xpconnect/tests/unit/test_file.js
new file mode 100644
index 0000000000..ff4589c3f5
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_file.js
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(function() {
+  let { TestFile } = ChromeUtils.import("resource://test/TestFile.jsm");
+  TestFile.doTest(result => {
+    Assert.ok(result);
+    run_next_test();
+  });
+});
diff --git a/js/xpconnect/tests/unit/test_file2.js b/js/xpconnect/tests/unit/test_file2.js
new file mode 100644
index 0000000000..9c72eb4c62
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_file2.js
@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+Cu.importGlobalProperties(['File']);
+
+add_task(async function() {
+  // throw if anything goes wrong
+
+  // find the current directory path
+  var file = Cc["@mozilla.org/file/directory_service;1"]
+             .getService(Ci.nsIProperties)
+             .get("CurWorkD", Ci.nsIFile);
+  file.append("xpcshell.ini");
+
+  // should be able to construct a file
+  var f1 = await File.createFromFileName(file.path);
+  // and with nsIFiles
+  var f2 = await File.createFromNsIFile(file);
+
+  // do some tests
+  Assert.ok(f1 instanceof File, "Should be a DOM File");
+  Assert.ok(f2 instanceof File, "Should be a DOM File");
+
+  Assert.ok(f1.name == "xpcshell.ini", "Should be the right file");
+  Assert.ok(f2.name == "xpcshell.ini", "Should be the right file");
+
+  Assert.ok(f1.type == "", "Should be the right type");
+  Assert.ok(f2.type == "", "Should be the right type");
+
+  var threw = false;
+  try {
+    // Needs a ctor argument
+    var f7 = File();
+  } catch (e) {
+    threw = true;
+  }
+  Assert.ok(threw, "No ctor arguments should throw");
+
+  var threw = false;
+  try {
+    // Needs a valid ctor argument
+    var f7 = File(Date(132131532));
+  } catch (e) {
+    threw = true;
+  }
+  Assert.ok(threw, "Passing a random object should fail");
+
+  var threw = false
+  try {
+    // Directories fail
+    var dir = Cc["@mozilla.org/file/directory_service;1"]
+                .getService(Ci.nsIProperties)
+                .get("CurWorkD", Ci.nsIFile);
+    var f7 = await File.createFromNsIFile(dir)
+  } catch (e) {
+    threw = true;
+  }
+  Assert.ok(threw, "Can't create a File object for a directory");
+});
diff --git a/js/xpconnect/tests/unit/test_fileReader.js b/js/xpconnect/tests/unit/test_fileReader.js
new file mode 100644
index 0000000000..ea86096319
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_fileReader.js
@@ -0,0 +1,12 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["FileReader"] });
+  sb.ok = ok;
+  Cu.evalInSandbox('ok((new FileReader()) instanceof FileReader);',
+                   sb);
+  Cu.importGlobalProperties(["FileReader"]);
+  Assert.ok((new FileReader()) instanceof FileReader);
+}
diff --git a/js/xpconnect/tests/unit/test_function_names.js b/js/xpconnect/tests/unit/test_function_names.js
new file mode 100644
index 0000000000..6eadc1fce7
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_function_names.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function callback() {}
+
+let sandbox = Cu.Sandbox(this);
+let callbackWrapped = Cu.evalInSandbox("(function wrapped() {})", sandbox);
+
+function run_test() {
+  let functions = [
+    [{ notify: callback }, "callback[test_function_names.js]:JS"],
+    [{ notify: { notify: callback } }, "callback[test_function_names.js]:JS"],
+    [callback, "callback[test_function_names.js]:JS"],
+    [function() {}, "run_test/functions<[test_function_names.js]:JS"],
+    [function foobar() {}, "foobar[test_function_names.js]:JS"],
+    [function Δ() {}, "Δ[test_function_names.js]:JS"],
+    [{ notify1: callback, notify2: callback }, "nonfunction:JS"],
+    [{ notify: 10 }, "nonfunction:JS"],
+    [{}, "nonfunction:JS"],
+    [{ notify: callbackWrapped }, "wrapped[test_function_names.js]:JS"],
+  ];
+
+  // Use the observer service so we can get double-wrapped functions.
+  var obs = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
+
+  function observer(subject, topic, data)
+  {
+    let named = subject.QueryInterface(Ci.nsINamed);
+    Assert.equal(named.name, data);
+    dump(`name: ${named.name}\n`);
+  }
+  obs.addObserver(observer, "test-obs-fun", false);
+
+  for (let [f, requiredName] of functions) {
+    obs.notifyObservers(f, "test-obs-fun", requiredName);
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_generateQI.js b/js/xpconnect/tests/unit/test_generateQI.js
new file mode 100644
index 0000000000..d54ed53212
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_generateQI.js
@@ -0,0 +1,29 @@
+"use strict";
+
+add_task(async function test_generateQI() {
+  function checkQI(interfaces, iface) {
+    let obj = {
+      QueryInterface: ChromeUtils.generateQI(interfaces),
+    };
+    equal(obj.QueryInterface(iface), obj,
+         `Correct return value for query to ${iface}`);
+  }
+
+  // Test success scenarios.
+  checkQI([], Ci.nsISupports);
+
+  checkQI([Ci.nsIPropertyBag, "nsIPropertyBag2"], Ci.nsIPropertyBag);
+  checkQI([Ci.nsIPropertyBag, "nsIPropertyBag2"], Ci.nsIPropertyBag2);
+
+  checkQI([Ci.nsIPropertyBag, "nsIPropertyBag2", "nsINotARealInterface"], Ci.nsIPropertyBag2);
+
+  // Non-IID values get stringified, and don't cause any errors as long
+  // as there isn't a non-IID property with the same name on Ci.
+  checkQI([Ci.nsIPropertyBag, "nsIPropertyBag2", null, Object], Ci.nsIPropertyBag2);
+
+  ChromeUtils.generateQI([])(Ci.nsISupports);
+
+  // Test failure scenarios.
+  Assert.throws(() => checkQI([], Ci.nsIPropertyBag),
+                e => e.result == Cr.NS_ERROR_NO_INTERFACE);
+});
diff --git a/js/xpconnect/tests/unit/test_getCallerLocation.js b/js/xpconnect/tests/unit/test_getCallerLocation.js
new file mode 100644
index 0000000000..569d76f8eb
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_getCallerLocation.js
@@ -0,0 +1,86 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+Cu.importGlobalProperties(["ChromeUtils"]);
+
+const {AddonTestUtils} = ChromeUtils.importESModule("resource://testing-common/AddonTestUtils.sys.mjs");
+
+add_task(async function() {
+  const sandbox = Cu.Sandbox("http://example.com/");
+
+  function foo() {
+    return bar();
+  }
+
+  function bar() {
+    return baz();
+  }
+
+  function baz() {
+    return ChromeUtils.getCallerLocation(Cu.getObjectPrincipal(sandbox));
+  }
+
+  Cu.evalInSandbox(`
+    function it() {
+      // Use map() to throw a self-hosted frame on the stack, which we
+      // should filter out.
+      return [0].map(foo)[0];
+    }
+    function thing() {
+      return it();
+    }
+  `, sandbox, undefined, "thing.js");
+
+  Cu.exportFunction(foo, sandbox, {defineAs: "foo"});
+
+  let frame = sandbox.thing();
+
+  equal(frame.source, "thing.js", "Frame source");
+  equal(frame.line, 5, "Frame line");
+  equal(frame.column, 18, "Frame column");
+  equal(frame.functionDisplayName, "it", "Frame function name");
+  equal(frame.parent, null, "Frame parent");
+
+  equal(String(frame), "it@thing.js:5:18\n", "Stringified frame");
+
+
+  // reportError
+
+  let {messages} = await AddonTestUtils.promiseConsoleOutput(() => {
+    Cu.reportError("Meh", frame);
+  });
+
+  let [msg] = messages.filter(m => m.message.includes("Meh"));
+
+  equal(msg.stack, frame, "reportError stack frame");
+  equal(msg.message, '[JavaScript Error: "Meh" {file: "thing.js" line: 5}]\nit@thing.js:5:18\n');
+
+  Assert.throws(() => { Cu.reportError("Meh", {}); },
+                err => err.result == Cr.NS_ERROR_INVALID_ARG,
+                "reportError should throw when passed a non-SavedFrame object");
+
+
+  // createError
+
+  Assert.throws(() => { ChromeUtils.createError("Meh", {}); },
+                err => err.result == Cr.NS_ERROR_INVALID_ARG,
+                "createError should throw when passed a non-SavedFrame object");
+
+  let cloned = Cu.cloneInto(frame, sandbox);
+  let error = ChromeUtils.createError("Meh", cloned);
+
+  equal(String(cloned), String(frame),
+        "Cloning a SavedStack preserves its stringification");
+
+  equal(Cu.getGlobalForObject(error), sandbox,
+        "createError creates errors in the global of the SavedFrame");
+  equal(error.stack, String(cloned),
+        "createError creates errors with the correct stack");
+
+  equal(error.message, "Meh", "Error message");
+  equal(error.fileName, "thing.js", "Error filename");
+  equal(error.lineNumber, 5, "Error line");
+  equal(error.columnNumber, 18, "Error column");
+});
diff --git a/js/xpconnect/tests/unit/test_getObjectPrincipal.js b/js/xpconnect/tests/unit/test_getObjectPrincipal.js
new file mode 100644
index 0000000000..03c6ffce3d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_getObjectPrincipal.js
@@ -0,0 +1,6 @@
+function run_test() {
+  Assert.ok(Cu.getObjectPrincipal({}).isSystemPrincipal);
+  var sb = new Cu.Sandbox('http://www.example.com');
+  Cu.evalInSandbox('var obj = { foo: 42 };', sb);
+  Assert.equal(Cu.getObjectPrincipal(sb.obj).origin, 'http://www.example.com');
+}
diff --git a/js/xpconnect/tests/unit/test_import.js b/js/xpconnect/tests/unit/test_import.js
new file mode 100644
index 0000000000..05c6a52647
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import.js
@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var AppConstants;
+function run_test() {
+  var scope = {};
+  var exports = ChromeUtils.import("resource://gre/modules/AppConstants.jsm", scope);
+  Assert.equal(typeof(scope.AppConstants), "object");
+  Assert.equal(typeof(scope.AppConstants.isPlatformAndVersionAtLeast), "function");
+
+  equal(scope.AppConstants, exports.AppConstants);
+  deepEqual(Object.keys(scope), ["AppConstants"]);
+  deepEqual(Object.keys(exports), ["AppConstants"]);
+
+  exports = ChromeUtils.import("resource://gre/modules/AppConstants.jsm");
+  equal(scope.AppConstants, exports.AppConstants);
+  deepEqual(Object.keys(exports), ["AppConstants"]);
+
+  // access module's global object directly without importing any
+  // symbols
+  Assert.throws(
+    () => ChromeUtils.import("resource://gre/modules/AppConstants.jsm", null),
+    TypeError
+  );
+
+  // import symbols to our global object
+  Assert.equal(typeof(Cu.import), "function");
+  ({AppConstants} = ChromeUtils.import("resource://gre/modules/AppConstants.jsm"));
+  Assert.equal(typeof(AppConstants), "object");
+  Assert.equal(typeof(AppConstants.isPlatformAndVersionAtLeast), "function");
+
+  // try on a new object
+  var scope2 = {};
+  ChromeUtils.import("resource://gre/modules/AppConstants.jsm", scope2);
+  Assert.equal(typeof(scope2.AppConstants), "object");
+  Assert.equal(typeof(scope2.AppConstants.isPlatformAndVersionAtLeast), "function");
+
+  Assert.ok(scope2.AppConstants == scope.AppConstants);
+
+  // try on a new object using the resolved URL
+  var res = Cc["@mozilla.org/network/protocol;1?name=resource"]
+              .getService(Ci.nsIResProtocolHandler);
+  var resURI = Cc["@mozilla.org/network/io-service;1"]
+                 .getService(Ci.nsIIOService)
+                 .newURI("resource://gre/modules/AppConstants.jsm");
+  dump("resURI: " + resURI + "\n");
+  var filePath = res.resolveURI(resURI);
+  var scope3 = {};
+  Assert.throws(
+    () => ChromeUtils.import(filePath, scope3),
+    /SecurityError/, "Expecting file URI not to be imported"
+  );
+
+  // make sure we throw when the second arg is bogus
+  var didThrow = false;
+  try {
+      ChromeUtils.import("resource://gre/modules/AppConstants.jsm", "wrong");
+  } catch (ex) {
+      print("exception (expected): " + ex);
+      didThrow = true;
+  }
+  Assert.ok(didThrow);
+
+  // make sure we throw when the URL scheme is not known
+  var scope4 = {};
+  const wrongScheme = "data:text/javascript,var a = {a:1}";
+  Assert.throws(
+    () => ChromeUtils.import(wrongScheme, scope4),
+    /SecurityError/, "Expecting data URI not to be imported"
+  );
+}
diff --git a/js/xpconnect/tests/unit/test_import_devtools_loader.js b/js/xpconnect/tests/unit/test_import_devtools_loader.js
new file mode 100644
index 0000000000..d7e6fe42f6
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_devtools_loader.js
@@ -0,0 +1,85 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const { addDebuggerToGlobal } = ChromeUtils.importESModule(
+  "resource://gre/modules/jsdebugger.sys.mjs"
+);
+addDebuggerToGlobal(this);
+
+const ESM_URL = "resource://test/es6module_devtoolsLoader.sys.mjs";
+
+// Toggle the following pref to enable Cu.getModuleImportStack()
+if (AppConstants.NIGHTLY_BUILD) {
+  Services.prefs.setBoolPref("browser.startup.record", true);
+  registerCleanupFunction(() => {
+    Services.prefs.clearUserPref("browser.startup.record");
+  });
+}
+
+add_task(async function testDevToolsModuleLoader() {
+  const dbg = new Debugger();
+
+  const sharedGlobal = Cu.getGlobalForObject(Services);
+  const sharedPrincipal = Cu.getObjectPrincipal(sharedGlobal);
+
+  info("Test importing in the regular shared loader");
+  const ns = ChromeUtils.importESModule(ESM_URL);
+  Assert.equal(ns.x, 0);
+  ns.increment();
+  Assert.equal(ns.x, 1);
+  const nsGlobal = Cu.getGlobalForObject(ns);
+  const nsPrincipal = Cu.getObjectPrincipal(nsGlobal);
+  Assert.equal(nsGlobal, sharedGlobal, "Without any parameter, importESModule load in the shared JSM global");
+  Assert.equal(nsPrincipal, sharedPrincipal);
+  Assert.ok(nsPrincipal.isSystemPrincipal);
+  info("Global of ESM loaded in the shared loader can be inspected by the Debugger");
+  dbg.addDebuggee(nsGlobal);
+  Assert.ok(true, "The global is accepted by the Debugger API");
+
+  const ns1 = ChromeUtils.importESModule(ESM_URL, { loadInDevToolsLoader : false });
+  Assert.equal(ns1, ns, "Passing loadInDevToolsLoader=false from the shared JSM global is equivalent to regular importESModule");
+
+  info("Test importing in the devtools loader");
+  const ns2 = ChromeUtils.importESModule(ESM_URL, { loadInDevToolsLoader: true });
+  Assert.equal(ns2.x, 0, "We get a new module instance with a new incremented number");
+  Assert.notEqual(ns2, ns, "We imported a new instance of the module");
+  Assert.notEqual(ns2.importedObject, ns.importedObject, "The two module instances expose distinct objects");
+  Assert.equal(ns2.importESModuleTrue, ns2.importedObject, "When using loadInDevToolsLoader:true from a devtools global, we keep loading in the same loader");
+  Assert.equal(ns2.importESModuleNull, ns2.importedObject, "When having an undefined loadInDevToolsLoader from a devtools global, we keep loading in the same loader");
+  Assert.equal(ns2.importESModuleNull2, ns2.importedObject, "When having no optional argument at all, we keep loading in the same loader");
+  Assert.equal(ns2.importESModuleFalse, ns.importedObject, "When passing an explicit loadInDevToolsLoader:false, we load in the shared global, even from a devtools global");
+  Assert.equal(ns2.importLazy(), ns2.importedObject, "ChromeUtils.defineESModuleGetters imports will follow the contextual loader");
+
+  info("When using the devtools loader, we load in a distinct global, but the same compartment");
+  const ns2Global = Cu.getGlobalForObject(ns2);
+  const ns2Principal = Cu.getObjectPrincipal(ns2Global);
+  Assert.notEqual(ns2Global, sharedGlobal, "The module is loaded in a distinct global");
+  Assert.equal(ns2Principal, sharedPrincipal, "The principal is still the shared system principal");
+  Assert.equal(Cu.getGlobalForObject(ns2.importedObject), ns2Global, "Nested dependencies are also loaded in the same devtools global");
+  Assert.throws(() => dbg.addDebuggee(ns2Global), /TypeError: passing non-debuggable global to addDebuggee/,
+    "Global os ESM loaded in the devtools loader can't be inspected by the Debugee");
+
+  info("Re-import the same module in the devtools loader");
+  const ns3 = ChromeUtils.importESModule(ESM_URL, { loadInDevToolsLoader: true });
+  Assert.equal(ns3, ns2, "We import the exact same module");
+  Assert.equal(ns3.importedObject, ns2.importedObject, "The two module expose the same objects");
+
+  info("Import a module only from the devtools loader");
+  const ns4 = ChromeUtils.importESModule("resource://test/es6module_devtoolsLoader_only.js", { loadInDevToolsLoader: true });
+  const ns4Global = Cu.getGlobalForObject(ns4);
+  Assert.equal(ns4Global, ns2Global, "The module is loaded in the same devtools global");
+
+  // getModuleImportStack only works on nightly builds
+  if (AppConstants.NIGHTLY_BUILD) {
+    info("Assert the behavior of getModuleImportStack on modules loaded in the devtools loader");
+    Assert.ok(Cu.getModuleImportStack(ESM_URL).includes("testDevToolsModuleLoader"));
+    Assert.ok(Cu.getModuleImportStack("resource://test/es6module_devtoolsLoader.js").includes("testDevToolsModuleLoader"));
+    Assert.ok(Cu.getModuleImportStack("resource://test/es6module_devtoolsLoader.js").includes(ESM_URL));
+    // Previous import stack were for module loaded via the shared jsm loader.
+    // Let's also assert that we get stack traces for modules loaded via the devtools loader.
+    Assert.ok(Cu.getModuleImportStack("resource://test/es6module_devtoolsLoader_only.js").includes("testDevToolsModuleLoader"));
+  }
+});
diff --git a/js/xpconnect/tests/unit/test_import_es6_modules.js b/js/xpconnect/tests/unit/test_import_es6_modules.js
new file mode 100644
index 0000000000..9b5659871f
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_es6_modules.js
@@ -0,0 +1,180 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function() {
+  // Test basic import.
+  let ns = ChromeUtils.importESModule("resource://test/es6module.js");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns.value, 2);
+
+  // Test re-import of the same module.
+  let ns2 = ChromeUtils.importESModule("resource://test/es6module.js");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns, ns2);
+
+  // Test imports with absolute and relative URIs return the same thing.
+  let ns3 = ChromeUtils.importESModule("resource://test/es6module_absolute.js");
+  let ns4 = ChromeUtils.importESModule("resource://test/es6module_absolute2.js");
+  Assert.ok(ns3.absoluteX === ns3.relativeX);
+  Assert.ok(ns3.absoluteX === ns4.x);
+
+  // Test load failure.
+  testFailure("resource://test/es6module_not_found.js", {
+    type: "Error",
+    message: "Failed to load resource://test/es6module_not_found.js",
+    fileName: "test_import_es6_modules.js",
+    stack: "testFailure",
+    lineNumber: "*",
+    columnNumber: "*",
+    result: Cr.NS_ERROR_FILE_NOT_FOUND,
+  });
+
+  // Test load failure in import.
+  testFailure("resource://test/es6module_missing_import.js", {
+    type: "Error",
+    message: "Failed to load resource://test/es6module_not_found2.js",
+    fileName: "test_import_es6_modules.js",
+    stack: "testFailure",
+    lineNumber: "*",
+    columnNumber: "*",
+    result: Cr.NS_ERROR_FILE_NOT_FOUND,
+  });
+
+  // Test parse error.
+  testFailure("resource://test/es6module_parse_error.js", {
+    type: "SyntaxError",
+    fileName: "resource://test/es6module_parse_error.js",
+    stack: "testFailure",
+    lineNumber: 1,
+    columnNumber: 5,
+  });
+
+  // Test parse error in import.
+  testFailure("resource://test/es6module_parse_error_in_import.js", {
+    type: "SyntaxError",
+    fileName: "resource://test/es6module_parse_error.js",
+    stack: "testFailure",
+    lineNumber: 1,
+    columnNumber: 5,
+  });
+
+  // Test import error.
+  testFailure("resource://test/es6module_import_error.js", {
+    type: "SyntaxError",
+    fileName: "resource://test/es6module_import_error.js",
+    lineNumber: 1,
+    columnNumber: 9,
+  });
+
+  // Test execution failure.
+  let exception1 = testFailure("resource://test/es6module_throws.js", {
+    type: "Error",
+    message: "foobar",
+    stack: "throwFunction",
+    fileName: "resource://test/es6module_throws.js",
+    lineNumber: 2,
+    columnNumber: 9,
+  });
+
+  // Test re-import throws the same exception.
+  let exception2 = testFailure("resource://test/es6module_throws.js", {
+    type: "Error",
+    message: "foobar",
+    stack: "throwFunction",
+    fileName: "resource://test/es6module_throws.js",
+    lineNumber: 2,
+    columnNumber: 9,
+  });
+  Assert.ok(exception1 === exception2);
+
+  // Test loading cyclic module graph.
+  ns = ChromeUtils.importESModule("resource://test/es6module_cycle_a.js");
+  Assert.ok(ns.loaded);
+  Assert.equal(ns.getValueFromB(), "b");
+  ns = ChromeUtils.importESModule("resource://test/es6module_cycle_b.js");
+  Assert.ok(ns.loaded);
+  Assert.equal(ns.getValueFromC(), "c");
+  ns = ChromeUtils.importESModule("resource://test/es6module_cycle_c.js");
+  Assert.ok(ns.loaded);
+  Assert.equal(ns.getValueFromA(), "a");
+
+  // Test top-level await is not supported.
+  testFailure("resource://test/es6module_top_level_await.js", {
+    type: "SyntaxError",
+    message: "not supported",
+    stack: "testFailure",
+    fileName: "resource://test/es6module_top_level_await.js",
+    lineNumber: 1,
+    columnNumber: 0,
+  });
+
+  // Test dynamic import is not supported.
+  ns = ChromeUtils.importESModule("resource://test/es6module_dynamic_import.js");
+  const e = await ns.result;
+  checkException(e, {
+    type: "TypeError",
+    message: "not supported",
+    fileName: "resource://test/es6module_dynamic_import.js",
+    lineNumber: 5,
+    columnNumber: 1,
+  });
+});
+
+function testFailure(url, expected) {
+  let threw = false;
+  let exception;
+  let importLine, importColumn;
+  try {
+    // Get the line/column for ChromeUtils.importESModule.
+    // lineNumber/columnNumber value with "*" in `expected` points the
+    // line/column.
+    let e = new Error();
+    importLine = e.lineNumber + 3;
+    importColumn = 17;
+    ChromeUtils.importESModule(url);
+  } catch (e) {
+    threw = true;
+    exception = e;
+  }
+
+  Assert.ok(threw, "Error should be thrown");
+
+  checkException(exception, expected, importLine, importColumn);
+
+  return exception;
+}
+
+function checkException(exception, expected, importLine, importColumn) {
+  if ("type" in expected) {
+    Assert.equal(exception.constructor.name, expected.type, "error type");
+  }
+  if ("message" in expected) {
+    Assert.ok(exception.message.includes(expected.message),
+              `Message "${exception.message}" should contain "${expected.message}"`);
+  }
+  if ("stack" in expected) {
+    Assert.ok(exception.stack.includes(expected.stack),
+              `Stack "${exception.stack}" should contain "${expected.stack}"`);
+  }
+  if ("fileName" in expected) {
+    Assert.ok(exception.fileName.includes(expected.fileName),
+              `fileName "${exception.fileName}" should contain "${expected.fileName}"`);
+  }
+  if ("lineNumber" in expected) {
+    let expectedLine = expected.lineNumber;
+    if (expectedLine === "*") {
+      expectedLine = importLine;
+    }
+    Assert.equal(exception.lineNumber, expectedLine, "lineNumber");
+  }
+  if ("columnNumber" in expected) {
+    let expectedColumn = expected.columnNumber;
+    if (expectedColumn === "*") {
+      expectedColumn = importColumn;
+    }
+    Assert.equal(exception.columnNumber, expectedColumn, "columnNumber");
+  }
+  if ("result" in expected) {
+    Assert.equal(exception.result, expected.result, "result");
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_import_fail.js b/js/xpconnect/tests/unit/test_import_fail.js
new file mode 100644
index 0000000000..9ad7fcb072
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_fail.js
@@ -0,0 +1,10 @@
+function run_test()
+{
+  try {
+    ChromeUtils.import("resource://test/importer.jsm");
+    Assert.ok(false, "import should not succeed.");
+  } catch (x) {
+    Assert.notEqual(x.fileName.indexOf("syntax_error.jsm"), -1);
+    Assert.equal(x.lineNumber, 1);
+  }
+}
+\ No newline at end of file
diff --git a/js/xpconnect/tests/unit/test_import_from_sandbox.js b/js/xpconnect/tests/unit/test_import_from_sandbox.js
new file mode 100644
index 0000000000..ddd384a77b
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_from_sandbox.js
@@ -0,0 +1,82 @@
+"use strict";
+
+function makeSandbox() {
+  return Cu.Sandbox(
+    Services.scriptSecurityManager.getSystemPrincipal(),
+    {
+      wantXrays: false,
+      wantGlobalProperties: ["ChromeUtils"],
+      sandboxName: `Sandbox type used for ext-*.js  ExtensionAPI subscripts`,
+    }
+  );
+}
+
+// This test will fail (and should be removed) once the JSM shim is dropped.
+add_task(function test_import_from_sandbox_using_shim() {
+  let sandbox = makeSandbox();
+  Object.assign(sandbox, {
+    injected1: ChromeUtils.import("resource://test/esmified-1.jsm"),
+  });
+
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-2.jsm"), false);
+
+  Services.scriptloader.loadSubScript(
+    `data:,
+      "use strict";
+
+      const shimmed1 = ChromeUtils.import("resource://test/esmified-1.jsm");
+      const shimmed2 = ChromeUtils.import("resource://test/esmified-2.jsm");
+
+      this.testResults = {
+        shimmed1: shimmed1.obj.value,
+        injected1: injected1.obj.value,
+        sameInstance1: injected1 === shimmed1,
+        shimmed2: shimmed2.obj.value,
+      };
+    `,
+    sandbox
+  );
+  let tr = sandbox.testResults;
+
+  Assert.equal(tr.injected1, 10, "Injected esmified-1.mjs has correct value.");
+  Assert.equal(tr.shimmed1, 10, "Shim-imported esmified-1.jsm correct value.");
+  Assert.ok(tr.sameInstance1, "Injected and imported are the same instance.");
+  Assert.equal(tr.shimmed2, 10, "Shim-imported esmified-2.jsm correct value.");
+
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-2.jsm"), true);
+});
+
+// This tests the ESMification transition for extension API scripts.
+add_task(function test_import_from_sandbox_transition() {
+  let sandbox = makeSandbox();
+
+  Object.assign(sandbox, {
+    injected3: ChromeUtils.importESModule("resource://test/esmified-3.sys.mjs"),
+  });
+
+  Services.scriptloader.loadSubScript("resource://test/api_script.js", sandbox);
+  let tr = sandbox.testResults;
+
+  Assert.equal(tr.injected3, 16, "Injected esmified-3.mjs has correct value.");
+  Assert.equal(tr.module3, 16, "Iimported esmified-3.mjs has correct value.");
+  Assert.ok(tr.sameInstance3, "Injected and imported are the same instance.");
+  Assert.equal(tr.module4, 14, "Iimported esmified-4.mjs has correct value.");
+});
+
+// Same as above, just using a PrecompiledScript.
+add_task(async function test_import_from_sandbox_transition() {
+  let sandbox = makeSandbox();
+
+  Object.assign(sandbox, {
+    injected3: ChromeUtils.importESModule("resource://test/esmified-3.sys.mjs"),
+  });
+
+  let script = await ChromeUtils.compileScript("resource://test/api_script.js");
+  script.executeInGlobal(sandbox);
+  let tr = sandbox.testResults;
+
+  Assert.equal(tr.injected3, 22, "Injected esmified-3.mjs has correct value.");
+  Assert.equal(tr.module3, 22, "Iimported esmified-3.mjs has correct value.");
+  Assert.ok(tr.sameInstance3, "Injected and imported are the same instance.");
+  Assert.equal(tr.module4, 18, "Iimported esmified-4.mjs has correct value.");
+});
diff --git a/js/xpconnect/tests/unit/test_import_shim.js b/js/xpconnect/tests/unit/test_import_shim.js
new file mode 100644
index 0000000000..3e265414f8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_shim.js
@@ -0,0 +1,377 @@
+add_task(function test_Cu_import_shim_first() {
+  // Load and cache with shim.
+
+  const exports = {};
+  const global = Components.utils.import(
+    "resource://test/esmified-1.jsm",
+    exports
+  );
+  Assert.equal(global.loadCount, 1);
+  Assert.equal(global.obj.value, 10);
+  Assert.equal(exports.loadCount, 1);
+  Assert.equal(exports.obj.value, 10);
+  Assert.ok(exports.obj === global.obj);
+
+  const ns = ChromeUtils.importESModule("resource://test/esmified-1.sys.mjs");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns.obj.value, 10);
+  Assert.ok(ns.obj === global.obj);
+
+  const exports2 = {};
+  const global2 = Components.utils.import(
+    "resource://test/esmified-1.jsm", exports2
+  );
+  Assert.equal(global2.loadCount, 1);
+  Assert.equal(global2.obj.value, 10);
+  Assert.equal(exports2.loadCount, 1);
+  Assert.equal(exports2.obj.value, 10);
+  Assert.ok(exports2.obj === global2.obj);
+  Assert.ok(exports2.obj === global.obj);
+
+  // Also test with *.js extension.
+  const exports3 = {};
+  const global3 = Components.utils.import(
+    "resource://test/esmified-1.js", exports3
+  );
+  Assert.equal(global3.loadCount, 1);
+  Assert.equal(global3.obj.value, 10);
+  Assert.equal(exports3.loadCount, 1);
+  Assert.equal(exports3.obj.value, 10);
+  Assert.ok(exports3.obj === global3.obj);
+  Assert.ok(exports3.obj === global.obj);
+
+  // Also test with *.jsm.js extension.
+  const exports4 = {};
+  const global4 = Components.utils.import(
+    "resource://test/esmified-1.js", exports4
+  );
+  Assert.equal(global4.loadCount, 1);
+  Assert.equal(global4.obj.value, 10);
+  Assert.equal(exports4.loadCount, 1);
+  Assert.equal(exports4.obj.value, 10);
+  Assert.ok(exports4.obj === global4.obj);
+  Assert.ok(exports4.obj === global.obj);
+});
+
+add_task(function test_Cu_import_no_shim_first() {
+  // Load and cache with importESModule.
+
+  const ns = ChromeUtils.importESModule("resource://test/esmified-2.sys.mjs");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns.obj.value, 10);
+
+  const exports = {};
+  const global = Components.utils.import(
+    "resource://test/esmified-2.jsm", exports
+  );
+  Assert.equal(global.loadCount, 1);
+  Assert.equal(global.obj.value, 10);
+  Assert.equal(exports.loadCount, 1);
+  Assert.equal(exports.obj.value, 10);
+  Assert.ok(exports.obj === global.obj);
+  Assert.ok(ns.obj === global.obj);
+
+  const ns2 = ChromeUtils.importESModule("resource://test/esmified-2.sys.mjs");
+  Assert.equal(ns2.loadCount, 1);
+  Assert.equal(ns2.obj.value, 10);
+});
+
+add_task(function test_ChromeUtils_import_shim_first() {
+  // Load and cache with shim.
+
+  const exports = {};
+  const global = ChromeUtils.import(
+    "resource://test/esmified-3.jsm", exports
+  );
+  Assert.equal(global.loadCount, 1);
+  Assert.equal(global.obj.value, 10);
+  Assert.equal(exports.loadCount, 1);
+  Assert.equal(exports.obj.value, 10);
+  Assert.ok(exports.obj === global.obj);
+
+  const ns = ChromeUtils.importESModule("resource://test/esmified-3.sys.mjs");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns.obj.value, 10);
+  Assert.ok(ns.obj === global.obj);
+
+  const exports2 = {};
+  const global2 = ChromeUtils.import(
+    "resource://test/esmified-3.jsm", exports2
+  );
+  Assert.equal(global2.loadCount, 1);
+  Assert.equal(global2.obj.value, 10);
+  Assert.equal(exports2.loadCount, 1);
+  Assert.equal(exports2.obj.value, 10);
+  Assert.ok(exports2.obj === global2.obj);
+  Assert.ok(exports2.obj === global.obj);
+});
+
+add_task(function test_ChromeUtils_import_no_shim_first() {
+  // Load and cache with importESModule.
+
+  const ns = ChromeUtils.importESModule("resource://test/esmified-4.sys.mjs");
+  Assert.equal(ns.loadCount, 1);
+  Assert.equal(ns.obj.value, 10);
+
+  const exports = {};
+  const global = ChromeUtils.import(
+    "resource://test/esmified-4.jsm", exports
+  );
+  Assert.equal(global.loadCount, 1);
+  Assert.equal(global.obj.value, 10);
+  Assert.equal(exports.loadCount, 1);
+  Assert.equal(exports.obj.value, 10);
+  Assert.ok(exports.obj === global.obj);
+  Assert.ok(ns.obj === global.obj);
+
+  const ns2 = ChromeUtils.importESModule("resource://test/esmified-4.sys.mjs");
+  Assert.equal(ns2.loadCount, 1);
+  Assert.equal(ns2.obj.value, 10);
+});
+
+add_task(function test_ChromeUtils_import_not_exported_no_shim_JSM() {
+  // `exports` properties for not-ESM-ified case.
+
+  const exports = ChromeUtils.import(
+    "resource://test/not-esmified-not-exported.jsm"
+  );
+
+  Assert.equal(exports.exportedVar, "exported var");
+  Assert.equal(exports.exportedFunction(), "exported function");
+  Assert.equal(exports.exportedLet, "exported let");
+  Assert.equal(exports.exportedConst, "exported const");
+  Assert.equal(exports.notExportedVar, undefined);
+  Assert.equal(exports.notExportedFunction, undefined);
+  Assert.equal(exports.notExportedLet, undefined);
+  Assert.equal(exports.notExportedConst, undefined);
+});
+
+add_task(function test_ChromeUtils_import_not_exported_shim() {
+  // `exports` properties for shim case.
+
+  const exports = ChromeUtils.import(
+    "resource://test/esmified-not-exported.jsm"
+  );
+
+  Assert.equal(exports.exportedVar, "exported var");
+  Assert.equal(exports.exportedFunction(), "exported function");
+  Assert.equal(exports.exportedLet, "exported let");
+  Assert.equal(exports.exportedConst, "exported const");
+  Assert.equal(exports.notExportedVar, undefined);
+  Assert.equal(exports.notExportedFunction, undefined);
+  Assert.equal(exports.notExportedLet, undefined);
+  Assert.equal(exports.notExportedConst, undefined);
+});
+
+add_task(function test_ChromeUtils_import_not_exported_no_shim_ESM() {
+  // `exports` properties for ESM-ified case.
+
+  const exports = ChromeUtils.importESModule(
+    "resource://test/esmified-not-exported.sys.mjs"
+  );
+
+  Assert.equal(exports.exportedVar, "exported var");
+  Assert.equal(exports.exportedFunction(), "exported function");
+  Assert.equal(exports.exportedLet, "exported let");
+  Assert.equal(exports.exportedConst, "exported const");
+  Assert.equal(exports.notExportedVar, undefined);
+  Assert.equal(exports.notExportedFunction, undefined);
+  Assert.equal(exports.notExportedLet, undefined);
+  Assert.equal(exports.notExportedConst, undefined);
+});
+
+function testReadProxyOps(global, expectedNames, expectedDesc) {
+  expectedNames.sort();
+
+  // enumerate
+  const names = Object.keys(global).sort();
+  Assert.equal(JSON.stringify(names), JSON.stringify(expectedNames),
+              `enumerate`);
+
+  // has
+  for (const name of expectedNames) {
+    Assert.ok(name in global, `has for ${name}`);
+  }
+
+  // getOwnPropertyDescriptor
+  for (const name of expectedNames) {
+    const desc = Object.getOwnPropertyDescriptor(global, name);
+    Assert.equal(desc.value, global[name]);
+    Assert.equal(desc.writable, expectedDesc.writable,
+                 `writable for ${name}`);
+    Assert.equal(desc.enumerable, expectedDesc.enumerable,
+                 `enumerable for ${name}`);
+    Assert.equal(desc.configurable, expectedDesc.configurable,
+                 `configurable for ${name}`);
+  }
+}
+
+function testWriteProxyOps(global, expectedNames) {
+  // set: no-op
+  for (const name of expectedNames) {
+    const before = global[name];
+    global[name] = -1;
+    Assert.equal(global[name], before, `value after set for ${name}`);
+  }
+
+  // delete: no-op
+  for (const name of expectedNames) {
+    const before = global[name];
+    Assert.ok(!(delete global[name]), `delete result for ${name}`);
+    Assert.equal(global[name], before, `value after delete for ${name}`);
+  }
+}
+
+add_task(function test_Cu_import_not_exported_no_shim_JSM() {
+  // `exports` and `global` properties for not-ESM-ified case.
+  // Not-exported variables should be visible in `global`.
+
+  const exports = {};
+  const global = Components.utils.import(
+    "resource://test/not-esmified-not-exported.jsm",
+    exports
+  );
+
+  Assert.equal(global.exportedVar, "exported var");
+  Assert.equal(global.exportedFunction(), "exported function");
+  Assert.equal(global.exportedLet, "exported let");
+  Assert.equal(global.exportedConst, "exported const");
+  Assert.equal(global.notExportedVar, "not exported var");
+  Assert.equal(global.notExportedFunction(), "not exported function");
+  Assert.equal(global.notExportedLet, "not exported let");
+  Assert.equal(global.notExportedConst, "not exported const");
+
+  const expectedNames = [
+    "EXPORTED_SYMBOLS",
+    "exportedVar",
+    "exportedFunction",
+    "exportedLet",
+    "exportedConst",
+    "notExportedVar",
+    "notExportedFunction",
+    "notExportedLet",
+    "notExportedConst",
+  ];
+
+  testReadProxyOps(global, expectedNames, {
+    writable: false,
+    enumerable: true,
+    configurable: false,
+  });
+  testWriteProxyOps(global, expectedNames);
+
+  Assert.equal(exports.exportedVar, "exported var");
+  Assert.equal(exports.exportedFunction(), "exported function");
+  Assert.equal(exports.exportedLet, "exported let");
+  Assert.equal(exports.exportedConst, "exported const");
+  Assert.equal(exports.notExportedVar, undefined);
+  Assert.equal(exports.notExportedFunction, undefined);
+  Assert.equal(exports.notExportedLet, undefined);
+  Assert.equal(exports.notExportedConst, undefined);
+});
+
+add_task(function test_Cu_import_not_exported_shim() {
+  // `exports` and `global` properties for shim case.
+  // Not-exported variables should be visible in global.
+
+  const exports = {};
+  const global = Components.utils.import(
+    "resource://test/esmified-not-exported.jsm",
+    exports
+  );
+
+  Assert.equal(global.exportedVar, "exported var");
+  Assert.equal(global.exportedFunction(), "exported function");
+  Assert.equal(global.exportedLet, "exported let");
+  Assert.equal(global.exportedConst, "exported const");
+
+  Assert.equal(global.notExportedVar, "not exported var");
+  Assert.equal(global.notExportedFunction(), "not exported function");
+  Assert.equal(global.notExportedLet, "not exported let");
+  Assert.equal(global.notExportedConst, "not exported const");
+
+  const expectedNames = [
+    "exportedVar",
+    "exportedFunction",
+    "exportedLet",
+    "exportedConst",
+    "notExportedVar",
+    "notExportedFunction",
+    "notExportedLet",
+    "notExportedConst",
+  ];
+
+  testReadProxyOps(global, expectedNames, {
+    writable: false,
+    enumerable: true,
+    configurable: false,
+  });
+  testWriteProxyOps(global, expectedNames);
+
+  Assert.equal(exports.exportedVar, "exported var");
+  Assert.equal(exports.exportedFunction(), "exported function");
+  Assert.equal(exports.exportedLet, "exported let");
+  Assert.equal(exports.exportedConst, "exported const");
+  Assert.equal(exports.notExportedVar, undefined);
+  Assert.equal(exports.notExportedFunction, undefined);
+  Assert.equal(exports.notExportedLet, undefined);
+  Assert.equal(exports.notExportedConst, undefined);
+
+  const desc = Object.getOwnPropertyDescriptor(global, "*namespace*");
+  Assert.ok(!desc, `*namespace* special binding should not be exposed`);
+  Assert.equal("*namespace*" in global, false,
+               `*namespace* special binding should not be exposed`);
+  Assert.equal(global["*namespace*"], undefined,
+               `*namespace* special binding should not be exposed`);
+});
+
+add_task(function test_Cu_isModuleLoaded_shim() {
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.js"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm.js"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-5.jsm"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.sys.mjs"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-5.sys.mjs"), false);
+
+  Cu.import("resource://test/esmified-5.jsm", {});
+
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm"), true);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.js"), true);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.jsm.js"), true);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-5.jsm"), true);
+
+  // This is false because Cu.isModuleLoaded does not support ESM directly
+  // (bug 1768819)
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-5.sys.mjs"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-5.sys.mjs"), false);
+});
+
+add_task(function test_Cu_isModuleLoaded_no_shim() {
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.js"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm.js"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.jsm"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.js"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.jsm.js"), false);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.sys.mjs"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.sys.mjs"), false);
+
+  ChromeUtils.importESModule("resource://test/esmified-6.sys.mjs");
+
+  // Regardless of whether the ESM is loaded by shim or not,
+  // query that accesses the ESM-ified module returns the existence of
+  // ESM.
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm"), true);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.js"), true);
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.jsm.js"), true);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.jsm"), true);
+
+  // This is false because shim always use *.jsm.
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.js"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.jsm.js"), false);
+
+  // This is false because Cu.isModuleLoaded does not support ESM directly
+  // (bug 1768819)
+  Assert.equal(Cu.isModuleLoaded("resource://test/esmified-6.sys.mjs"), false);
+  Assert.equal(Cu.loadedModules.includes("resource://test/esmified-6.sys.mjs"), false);
+});
diff --git a/js/xpconnect/tests/unit/test_import_stack.js b/js/xpconnect/tests/unit/test_import_stack.js
new file mode 100644
index 0000000000..2fa35a7502
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_stack.js
@@ -0,0 +1,39 @@
+Services.prefs.setBoolPref("browser.startup.record", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("browser.startup.record");
+});
+
+add_task(function test_JSModule() {
+  const URL = "resource://test/import_stack.jsm";
+  ChromeUtils.import(URL);
+  Assert.ok(Cu.getModuleImportStack(URL).includes("test_JSModule"));
+});
+
+add_task(function test_ESModule() {
+  const URL = "resource://test/import_stack.sys.mjs";
+  ChromeUtils.importESModule(URL);
+  Assert.ok(Cu.getModuleImportStack(URL).includes("test_ESModule"));
+});
+
+add_task(function test_ESModule_static_import() {
+  const URL1 = "resource://test/import_stack_static_1.sys.mjs";
+  const URL2 = "resource://test/import_stack_static_2.sys.mjs";
+  const URL3 = "resource://test/import_stack_static_3.sys.mjs";
+  const URL4 = "resource://test/import_stack_static_4.sys.mjs";
+
+  ChromeUtils.importESModule(URL1);
+
+  Assert.ok(Cu.getModuleImportStack(URL1).includes("test_ESModule_static"));
+
+  Assert.ok(Cu.getModuleImportStack(URL2).includes("test_ESModule_static"));
+  Assert.ok(Cu.getModuleImportStack(URL2).includes(URL1));
+
+  Assert.ok(Cu.getModuleImportStack(URL3).includes("test_ESModule_static"));
+  Assert.ok(Cu.getModuleImportStack(URL3).includes(URL1));
+  Assert.ok(Cu.getModuleImportStack(URL3).includes(URL2));
+
+  Assert.ok(Cu.getModuleImportStack(URL4).includes("test_ESModule_static"));
+  Assert.ok(Cu.getModuleImportStack(URL4).includes(URL1));
+  Assert.ok(Cu.getModuleImportStack(URL4).includes(URL2));
+  Assert.ok(Cu.getModuleImportStack(URL4).includes(URL3));
+});
diff --git a/js/xpconnect/tests/unit/test_import_syntax_error.js b/js/xpconnect/tests/unit/test_import_syntax_error.js
new file mode 100644
index 0000000000..bfdcaf9e04
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_import_syntax_error.js
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+
+add_task(async function() {
+  Assert.throws(
+    () => ChromeUtils.import("resource://test/error_import.sys.mjs"),
+    /use ChromeUtils.importESModule instead/,
+    "Error should be caught and suggest ChromeUtils.importESModule"
+  );
+
+  Assert.throws(
+    () => ChromeUtils.import("resource://test/error_export.sys.mjs"),
+    /use ChromeUtils.importESModule instead/,
+    "Error should be caught and suggest ChromeUtils.importESModule"
+  );
+
+  Assert.throws(
+    () => ChromeUtils.import("resource://test/error_other.sys.mjs"),
+    /expected expression, got end of script/,
+    "Error should be caught but should not suggest ChromeUtils.importESModule"
+  );
+});
diff --git a/js/xpconnect/tests/unit/test_isModuleLoaded.js b/js/xpconnect/tests/unit/test_isModuleLoaded.js
new file mode 100644
index 0000000000..aaf67c13c7
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_isModuleLoaded.js
@@ -0,0 +1,20 @@
+function run_test() {
+  // Existing module.
+  Assert.ok(!Cu.isModuleLoaded("resource://test/jsm_loaded-1.jsm"),
+            "isModuleLoaded returned correct value for non-loaded module");
+  ChromeUtils.import("resource://test/jsm_loaded-1.jsm");
+  Assert.ok(Cu.isModuleLoaded("resource://test/jsm_loaded-1.jsm"),
+            "isModuleLoaded returned true after loading that module");
+  Cu.unload("resource://test/jsm_loaded-1.jsm");
+  Assert.ok(!Cu.isModuleLoaded("resource://test/jsm_loaded-1.jsm"),
+            "isModuleLoaded returned false after unloading that module");
+
+  // Non-existing module
+  Assert.ok(!Cu.isModuleLoaded("resource://gre/modules/non-existing-module.jsm"),
+            "isModuleLoaded returned correct value for non-loaded module");
+  Assert.throws(
+    () => ChromeUtils.import("resource://gre/modules/non-existing-module.jsm"),
+    /NS_ERROR_FILE_NOT_FOUND/,
+    "Should have thrown while trying to load a non existing file"
+  );
+}
diff --git a/js/xpconnect/tests/unit/test_isProxy.js b/js/xpconnect/tests/unit/test_isProxy.js
new file mode 100644
index 0000000000..996aa320b9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_isProxy.js
@@ -0,0 +1,26 @@
+function run_test() {
+  var handler = {
+      get: function(target, name){
+          return name in target?
+              target[name] :
+              37;
+      }
+  };
+
+  var p = new Proxy({}, handler);
+  Assert.ok(Cu.isProxy(p));
+  Assert.ok(!Cu.isProxy({}));
+  Assert.ok(!Cu.isProxy(42));
+
+  sb = new Cu.Sandbox(this,
+                      { wantExportHelpers: true });
+
+  Assert.ok(!Cu.isProxy(sb));
+
+  sb.ok = ok;
+  sb.p = p;
+  Cu.evalInSandbox('ok(isProxy(p));' +
+                   'ok(!isProxy({}));' +
+                   'ok(!isProxy(42));',
+                   sb);
+}
diff --git a/js/xpconnect/tests/unit/test_js_memory_telemetry.js b/js/xpconnect/tests/unit/test_js_memory_telemetry.js
new file mode 100644
index 0000000000..4c44f2e48c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_js_memory_telemetry.js
@@ -0,0 +1,53 @@
+"use strict";
+
+add_task(function test_compartment_realm_counts() {
+  const compsSystem = "MEMORY_JS_COMPARTMENTS_SYSTEM";
+  const compsUser = "MEMORY_JS_COMPARTMENTS_USER";
+  const realmsSystem = "MEMORY_JS_REALMS_SYSTEM";
+  const realmsUser = "MEMORY_JS_REALMS_USER";
+
+  Cu.forceShrinkingGC();
+
+  Services.telemetry.gatherMemory();
+  let snapshot1 = Services.telemetry.getSnapshotForHistograms("main", true).parent;
+
+  // We can't hard code exact counts, but we can check some basic invariants:
+  //
+  // * Compartments must contain at least one realm, so there must be more
+  //   realms than compartments.
+  // * There must be at least one system realm.
+
+  Assert.ok(snapshot1[realmsSystem].sum <= snapshot1[compsSystem].sum,
+            "Number of system compartments can't exceed number of system realms");
+  Assert.ok(snapshot1[realmsUser].sum <= snapshot1[compsUser].sum,
+            "Number of user compartments can't exceed number of user realms");
+  Assert.ok(snapshot1[realmsSystem].sum > 0,
+            "There must be at least one system realm");
+
+  // Now we create a bunch of sandboxes (more than one to be more resilient
+  // against GCs happening in the meantime), so we can check:
+  //
+  // * There are now more realms and user compartments than before. Not system
+  //   compartments, because system realms share a compartment.
+  // * The system compartment contains multiple realms.
+
+  let systemPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
+  let arr = [];
+  for (let i = 0; i < 5; i++) {
+    arr.push(Cu.Sandbox(null));
+    arr.push(Cu.Sandbox(systemPrincipal));
+  }
+
+  Services.telemetry.gatherMemory();
+  let snapshot2 = Services.telemetry.getSnapshotForHistograms("main", true).parent;
+
+  for (let k of [realmsSystem, realmsUser, compsUser]) {
+    Assert.ok(snapshot2[k].sum > snapshot1[k].sum,
+              "There must be more compartments/realms now: " + k);
+  }
+
+  Assert.ok(snapshot2[realmsSystem].sum > snapshot2[compsSystem].sum,
+            "There must be more system realms than system compartments now");
+
+  arr[0].x = 10; // Ensure the JS engine keeps |arr| alive until this point.
+});
diff --git a/js/xpconnect/tests/unit/test_js_weak_references.js b/js/xpconnect/tests/unit/test_js_weak_references.js
new file mode 100644
index 0000000000..2603f24ee2
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_js_weak_references.js
@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=317304 */
+
+function run_test()
+{
+  // Bug 712649: Calling getWeakReference(null) should work.
+  try {
+    var nullWeak = Cu.getWeakReference(null);
+    Assert.ok(nullWeak.get() === null);
+  } catch (e) {
+    Assert.ok(false);
+  }
+
+  var obj = { num: 5, str: 'foo' };
+  var weak = Cu.getWeakReference(obj);
+
+  Assert.ok(weak.get() === obj);
+  Assert.ok(weak.get().num == 5);
+  Assert.ok(weak.get().str == 'foo');
+
+  // Force garbage collection
+  Cu.forceGC();
+
+  // obj still references the object, so it should still be accessible via weak
+  Assert.ok(weak.get() === obj);
+  Assert.ok(weak.get().num == 5);
+  Assert.ok(weak.get().str == 'foo');
+
+  // Clear obj's reference to the object and force garbage collection. To make
+  // sure that there are no instances of obj stored in the registers or on the
+  // native stack and the conservative GC would not find it we force the same
+  // code paths that we used for the initial allocation.
+  obj = { num: 6, str: 'foo2' };
+  var weak2 = Cu.getWeakReference(obj);
+  Assert.ok(weak2.get() === obj);
+
+  Cu.forceGC();
+
+  // The object should have been garbage collected and so should no longer be
+  // accessible via weak
+  Assert.ok(weak.get() === null);
+}
diff --git a/js/xpconnect/tests/unit/test_lazyproxy.js b/js/xpconnect/tests/unit/test_lazyproxy.js
new file mode 100644
index 0000000000..2cf90b339d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_lazyproxy.js
@@ -0,0 +1,113 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This file tests the method defineLazyProxy from XPCOMUtils.sys.mjs.
+ */
+
+const {XPCOMUtils} = ChromeUtils.importESModule("resource://gre/modules/XPCOMUtils.sys.mjs");
+
+add_task(function test_lazy_proxy() {
+  let tmp = {};
+  let realObject = {
+    "prop1": "value1",
+    "prop2": "value2",
+  };
+
+  let evaluated = false;
+  let untrapCalled = false;
+
+  let lazyProxy = XPCOMUtils.defineLazyProxy(
+    tmp,
+    "myLazyProxy",
+
+    // Initiliazer function
+    function init() {
+      evaluated = true;
+      return realObject;
+    },
+
+    // Stub properties
+    {
+      "prop1": "stub"
+    },
+
+    // Untrap callback
+    function untrapCallback(obj) {
+      Assert.equal(obj, realObject, "The underlying object can be obtained in the untrap callback");
+      untrapCalled = true;
+    }
+  );
+
+  // Check that the proxy returned and the one
+  // defined in tmp are the same.
+  //
+  // Note: Assert.strictEqual can't be used here
+  // because it wants to stringify the two objects
+  // compared, which defeats the lazy proxy.
+  Assert.ok(lazyProxy === tmp.myLazyProxy, "Return value and object defined are the same");
+
+  Assert.ok(Cu.isProxy(lazyProxy), "Returned value is in fact a proxy");
+
+  // Check that just using the proxy above didn't
+  // trigger the lazy getter evaluation.
+  Assert.ok(!evaluated, "The lazy proxy hasn't been evaluated yet");
+  Assert.ok(!untrapCalled, "The untrap callback hasn't been called yet");
+
+  // Accessing a stubbed property returns the stub
+  // value and doesn't trigger evaluation.
+  Assert.equal(lazyProxy.prop1, "stub", "Accessing a stubbed property returns the stubbed value");
+
+  Assert.ok(!evaluated, "The access to the stubbed property above didn't evaluate the lazy proxy");
+  Assert.ok(!untrapCalled, "The untrap callback hasn't been called yet");
+
+  // Now the access to another property will trigger
+  // the evaluation, as expected.
+  Assert.equal(lazyProxy.prop2, "value2", "Property access is correctly forwarded to the underlying object");
+
+  Assert.ok(evaluated, "Accessing a non-stubbed property triggered the proxy evaluation");
+  Assert.ok(untrapCalled, "The untrap callback was called");
+
+  // The value of prop1 is now the real value and not the stub value.
+  Assert.equal(lazyProxy.prop1, "value1", "The  value of prop1 is now the real value and not the stub one");
+});
+
+add_task(function test_module_version() {
+  // Test that passing a string instead of an initialization function
+  // makes this behave like a lazy module getter.
+  const TEST_FILE_URI = "resource://test/TestFile.jsm";
+  let underlyingObject;
+
+  Cu.unload(TEST_FILE_URI);
+
+  let lazyProxy = XPCOMUtils.defineLazyProxy(
+    null,
+    "TestFile",
+    TEST_FILE_URI,
+    null, /* no stubs */
+    function untrapCallback(object) {
+      underlyingObject = object;
+    }
+  );
+
+  Assert.ok(!Cu.isModuleLoaded(TEST_FILE_URI), "The NetUtil module was not loaded by the lazy proxy definition");
+
+  // Access the object, which will evaluate the proxy.
+  lazyProxy.foo = "bar";
+
+  // Module was loaded.
+  Assert.ok(Cu.isModuleLoaded(TEST_FILE_URI), "The NetUtil module was loaded");
+
+  let { TestFile } = ChromeUtils.import(TEST_FILE_URI, {});
+
+  // Avoids a gigantic stringification in the logs.
+  Assert.ok(TestFile === underlyingObject, "The module loaded is the same as the one directly obtained by ChromeUtils.import");
+
+  // Proxy correctly passed the setter to the underlying object.
+  Assert.equal(TestFile.foo, "bar", "Proxy correctly passed the setter to the underlying object");
+
+  delete lazyProxy.foo;
+
+  // Proxy correctly passed the delete operation to the underlying object.
+  Assert.ok(!TestFile.hasOwnProperty("foo"), "Proxy correctly passed the delete operation to the underlying object");
+});
diff --git a/js/xpconnect/tests/unit/test_loadedESModules.js b/js/xpconnect/tests/unit/test_loadedESModules.js
new file mode 100644
index 0000000000..00e1059037
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_loadedESModules.js
@@ -0,0 +1,127 @@
+add_task(function test_JSModule() {
+  const URL1 = "resource://test/jsm_loaded-1.jsm";
+  const URL2 = "resource://test/jsm_loaded-2.jsm";
+  const URL3 = "resource://test/jsm_loaded-3.jsm";
+
+  Assert.ok(!Cu.loadedJSModules.includes(URL1));
+  Assert.ok(!Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(!Cu.loadedESModules.includes(URL1));
+  Assert.ok(!Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.import(URL1);
+
+  Assert.ok(Cu.loadedJSModules.includes(URL1));
+  Assert.ok(Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(!Cu.loadedESModules.includes(URL1));
+  Assert.ok(!Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.import(URL2);
+
+  Assert.ok(Cu.loadedJSModules.includes(URL1));
+  Assert.ok(Cu.isJSModuleLoaded(URL1));
+  Assert.ok(Cu.loadedJSModules.includes(URL2));
+  Assert.ok(Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(!Cu.loadedESModules.includes(URL1));
+  Assert.ok(!Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.import(URL3);
+
+  Assert.ok(Cu.loadedJSModules.includes(URL1));
+  Assert.ok(Cu.isJSModuleLoaded(URL1));
+  Assert.ok(Cu.loadedJSModules.includes(URL2));
+  Assert.ok(Cu.isJSModuleLoaded(URL2));
+  Assert.ok(Cu.loadedJSModules.includes(URL3));
+  Assert.ok(Cu.isJSModuleLoaded(URL3));
+  Assert.ok(!Cu.loadedESModules.includes(URL1));
+  Assert.ok(!Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+});
+
+add_task(function test_ESModule() {
+  const URL1 = "resource://test/es6module_loaded-1.sys.mjs";
+  const URL2 = "resource://test/es6module_loaded-2.sys.mjs";
+  const URL3 = "resource://test/es6module_loaded-3.sys.mjs";
+
+  Assert.ok(!Cu.loadedJSModules.includes(URL1));
+  Assert.ok(!Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(!Cu.loadedESModules.includes(URL1));
+  Assert.ok(!Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.importESModule(URL1);
+
+  Assert.ok(!Cu.loadedJSModules.includes(URL1));
+  Assert.ok(!Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(Cu.loadedESModules.includes(URL1));
+  Assert.ok(Cu.isESModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedESModules.includes(URL2));
+  Assert.ok(!Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.importESModule(URL2);
+
+  Assert.ok(!Cu.loadedJSModules.includes(URL1));
+  Assert.ok(!Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(Cu.loadedESModules.includes(URL1));
+  Assert.ok(Cu.isESModuleLoaded(URL1));
+  Assert.ok(Cu.loadedESModules.includes(URL2));
+  Assert.ok(Cu.isESModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedESModules.includes(URL3));
+  Assert.ok(!Cu.isESModuleLoaded(URL3));
+
+  ChromeUtils.importESModule(URL3);
+
+  Assert.ok(!Cu.loadedJSModules.includes(URL1));
+  Assert.ok(!Cu.isJSModuleLoaded(URL1));
+  Assert.ok(!Cu.loadedJSModules.includes(URL2));
+  Assert.ok(!Cu.isJSModuleLoaded(URL2));
+  Assert.ok(!Cu.loadedJSModules.includes(URL3));
+  Assert.ok(!Cu.isJSModuleLoaded(URL3));
+  Assert.ok(Cu.loadedESModules.includes(URL1));
+  Assert.ok(Cu.isESModuleLoaded(URL1));
+  Assert.ok(Cu.loadedESModules.includes(URL2));
+  Assert.ok(Cu.isESModuleLoaded(URL2));
+  Assert.ok(Cu.loadedESModules.includes(URL3));
+  Assert.ok(Cu.isESModuleLoaded(URL3));
+});
diff --git a/js/xpconnect/tests/unit/test_localeCompare.js b/js/xpconnect/tests/unit/test_localeCompare.js
new file mode 100644
index 0000000000..fa98d865e4
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_localeCompare.js
@@ -0,0 +1,6 @@
+function run_test() {
+  Assert.ok("C".localeCompare("D") < 0);
+  Assert.ok("D".localeCompare("C") > 0);
+  Assert.ok("\u010C".localeCompare("D") < 0);
+  Assert.ok("D".localeCompare("\u010C") > 0);
+}
diff --git a/js/xpconnect/tests/unit/test_messageChannel.js b/js/xpconnect/tests/unit/test_messageChannel.js
new file mode 100644
index 0000000000..685aa10e43
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_messageChannel.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function() {
+  let sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["MessageChannel"] });
+  sb.ok = ok;
+  Cu.evalInSandbox('ok((new MessageChannel()) instanceof MessageChannel);',
+                   sb);
+  Cu.evalInSandbox('ok((new MessageChannel()).port1 instanceof MessagePort);',
+                   sb);
+
+  Cu.importGlobalProperties(["MessageChannel"]);
+
+  let mc = new MessageChannel();
+  Assert.ok(mc instanceof MessageChannel);
+  Assert.ok(mc.port1 instanceof MessagePort);
+  Assert.ok(mc.port2 instanceof MessagePort);
+
+  mc.port1.postMessage(42);
+
+  let result = await new Promise(resolve => {
+    mc.port2.onmessage = e => {
+      resolve(e.data);
+    }
+  });
+
+  Assert.equal(result, 42);
+});
diff --git a/js/xpconnect/tests/unit/test_nuke_sandbox.js b/js/xpconnect/tests/unit/test_nuke_sandbox.js
new file mode 100644
index 0000000000..c555121306
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_nuke_sandbox.js
@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=769273 */
+
+const global = this;
+
+function run_test()
+{
+  var ifacePointer = Cc["@mozilla.org/supports-interface-pointer;1"]
+      .createInstance(Ci.nsISupportsInterfacePointer);
+
+  var sb = Cu.Sandbox(global, {wantGlobalProperties: ["ChromeUtils"]});
+  sb.prop = "prop"
+  sb.ifacePointer = ifacePointer
+
+  var refToObjFromSb = Cu.evalInSandbox(`
+    ifacePointer.data = {
+      QueryInterface: ChromeUtils.generateQI([]),
+      wrappedJSObject: {foo: "bar"},
+    };
+
+    var a = {prop2:'prop2'};
+    a
+  `, sb);
+
+  equal(ifacePointer.data.wrappedJSObject.foo, "bar",
+        "Got expected wrapper into sandbox")
+
+  Cu.nukeSandbox(sb);
+  ok(Cu.isDeadWrapper(sb), "sb should be dead");
+  ok(Cu.isDeadWrapper(ifacePointer.data.wrappedJSObject),
+     "Wrapper retrieved via XPConnect should be dead");
+
+  try{
+    sb.prop;
+    Assert.ok(false);
+  } catch (e) {
+    Assert.ok(e.toString().indexOf("can't access dead object") > -1);
+  }
+
+  Cu.isDeadWrapper(refToObjFromSb, "ref to object from sb should be dead");
+  try{
+    refToObjFromSb.prop2;
+    Assert.ok(false);
+  } catch (e) {
+    Assert.ok(e.toString().indexOf("can't access dead object") > -1);
+  }
+}
diff --git a/js/xpconnect/tests/unit/test_nuke_sandbox_event_listeners.js b/js/xpconnect/tests/unit/test_nuke_sandbox_event_listeners.js
new file mode 100644
index 0000000000..2e304a8b72
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_nuke_sandbox_event_listeners.js
@@ -0,0 +1,89 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=1273251
+
+function promiseEvent(target, event) {
+  return new Promise(resolve => {
+    target.addEventListener(event, resolve, {capture: true, once: true});
+  });
+}
+
+add_task(async function() {
+  let principal = Services.scriptSecurityManager
+    .createContentPrincipalFromOrigin("http://example.com/");
+
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+
+  docShell.createAboutBlankContentViewer(principal, principal);
+
+  let window = webnav.document.defaultView;
+  let sandbox = Cu.Sandbox(window, {sandboxPrototype: window});
+
+  function sandboxContent() {
+    window.onload = function SandboxOnLoad() {};
+
+    window.addEventListener("FromTest", () => {
+      window.dispatchEvent(new CustomEvent("FromSandbox"));
+    }, true);
+  }
+
+  Cu.evalInSandbox(`(${sandboxContent})()`, sandbox);
+
+
+  let fromTestPromise = promiseEvent(window, "FromTest");
+  let fromSandboxPromise = promiseEvent(window, "FromSandbox");
+
+  equal(typeof window.onload, "function",
+        "window.onload should contain sandbox event listener");
+  equal(window.onload.name, "SandboxOnLoad",
+        "window.onload have the correct function name");
+
+  info("Dispatch FromTest event");
+  window.dispatchEvent(new window.CustomEvent("FromTest"));
+
+  await fromTestPromise;
+  info("Got event from test");
+
+  await fromSandboxPromise;
+  info("Got response from sandbox");
+
+
+  window.addEventListener("FromSandbox", () => {
+    ok(false, "Got unexpected reply from sandbox");
+  }, true);
+
+  info("Nuke sandbox");
+  Cu.nukeSandbox(sandbox);
+
+
+  info("Dispatch FromTest event");
+  fromTestPromise = promiseEvent(window, "FromTest");
+  window.dispatchEvent(new window.CustomEvent("FromTest"));
+  await fromTestPromise;
+  info("Got event from test");
+
+
+  // Force cycle collection, which should cause our callback reference
+  // to be dropped, and dredge up potential issues there.
+  Cu.forceGC();
+  Cu.forceCC();
+
+  ok(Cu.isDeadWrapper(window.onload),
+     "window.onload should contain a dead wrapper after sandbox is nuked");
+
+  info("Dispatch FromTest event");
+  fromTestPromise = promiseEvent(window, "FromTest");
+  window.dispatchEvent(new window.CustomEvent("FromTest"));
+  await fromTestPromise;
+  info("Got event from test");
+
+  let listeners = Services.els.getListenerInfoFor(window);
+  ok(!listeners.some(info => info.type == "FromTest"),
+     "No 'FromTest' listeners returned for nuked sandbox");
+
+  webnav.close();
+});
diff --git a/js/xpconnect/tests/unit/test_nuke_webextension_wrappers.js b/js/xpconnect/tests/unit/test_nuke_webextension_wrappers.js
new file mode 100644
index 0000000000..34fd0511bc
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_nuke_webextension_wrappers.js
@@ -0,0 +1,71 @@
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=1273251
+
+const {NetUtil} = ChromeUtils.import("resource://gre/modules/NetUtil.jsm");
+ChromeUtils.importESModule("resource://gre/modules/Timer.sys.mjs");
+const {TestUtils} = ChromeUtils.importESModule("resource://testing-common/TestUtils.sys.mjs");
+
+function getWindowlessBrowser(url) {
+  let ssm = Services.scriptSecurityManager;
+
+  let uri = NetUtil.newURI(url);
+
+  let principal = ssm.createContentPrincipal(uri, {});
+
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+
+  docShell.createAboutBlankContentViewer(principal, principal);
+
+  return webnav;
+}
+
+function StubPolicy(id) {
+  return new WebExtensionPolicy({
+    id,
+    mozExtensionHostname: id,
+    baseURL: `file:///{id}`,
+
+    allowedOrigins: new MatchPatternSet([]),
+    localizeCallback(string) {},
+  });
+}
+
+add_task(async function() {
+  let policy = StubPolicy("foo");
+  policy.active = true;
+
+  let webnavA = getWindowlessBrowser("moz-extension://foo/a.html");
+  let webnavB = getWindowlessBrowser("moz-extension://foo/b.html");
+
+  let winA = Cu.waiveXrays(webnavA.document.defaultView);
+  let winB = Cu.waiveXrays(webnavB.document.defaultView);
+
+  winB.winA = winA;
+  winB.eval(`winA.thing = {foo: "bar"};`);
+
+  let getThing = winA.eval(String(() => {
+    try {
+      return thing.foo;
+    } catch (e) {
+      return String(e);
+    }
+  }));
+
+  // Check that the object can be accessed normally before windowB is closed.
+  equal(getThing(), "bar");
+
+  webnavB.close();
+
+  // Wrappers are nuked asynchronously, so wait for that to happen.
+  await TestUtils.topicObserved("inner-window-nuked");
+
+  // Check that it can't be accessed after he window has been closed.
+  let result = getThing();
+  ok(/dead object/.test(result),
+     `Result should show a dead wrapper error: ${result}`);
+
+  webnavA.close();
+
+  policy.active = false;
+});
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-01.js b/js/xpconnect/tests/unit/test_onGarbageCollection-01.js
new file mode 100644
index 0000000000..81ac713865
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-01.js
@@ -0,0 +1,69 @@
+// Test basic usage of onGarbageCollection
+
+const root = newGlobal();
+const dbg = new Debugger();
+const wrappedRoot = dbg.addDebuggee(root)
+
+const NUM_SLICES = root.NUM_SLICES = 10;
+
+let fired = false;
+let slicesFound = 0;
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+dbg.memory.onGarbageCollection = data => {
+  fired = true;
+
+  print("Got onGarbageCollection: " + JSON.stringify(data, null, 2));
+
+  equal(typeof data.reason, "string");
+  equal(typeof data.nonincrementalReason == "string" || data.nonincrementalReason === null,
+        true);
+
+  let lastStartTimestamp = 0;
+  for (let i = 0; i < data.collections.length; i++) {
+    let slice = data.collections[i];
+
+    equal(slice.startTimestamp >= lastStartTimestamp, true);
+    equal(slice.startTimestamp <= slice.endTimestamp, true);
+
+    lastStartTimestamp = slice.startTimestamp;
+  }
+
+  equal(data.collections.length >= 1, true);
+  slicesFound += data.collections.length;
+}
+
+function run_test() {
+  do_test_pending();
+
+  root.eval(
+    `
+    this.allocs = [];
+
+    // GC slices
+    for (var i = 0; i < NUM_SLICES; i++) {
+      this.allocs.push({});
+      gcslice();
+    }
+
+    // Full GC
+    this.allocs.push({});
+    gc();
+    `
+  );
+
+  executeSoon(() => {
+    equal(fired, true, "The GC hook should have fired at least once");
+
+    // NUM_SLICES + 1 full gc + however many were triggered naturally (due to
+    // whatever zealousness setting).
+    print("Found " + slicesFound + " slices");
+    equal(slicesFound >= NUM_SLICES + 1, true);
+
+    do_test_finished();
+  });
+}
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-02.js b/js/xpconnect/tests/unit/test_onGarbageCollection-02.js
new file mode 100644
index 0000000000..fc3bf685ef
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-02.js
@@ -0,0 +1,99 @@
+// Test multiple debuggers, GCs, and zones interacting with each other.
+//
+// Note: when observing both globals, but GC'ing in only one, we don't test that
+// we *didn't* GC in the other zone because GCs are finicky and unreliable. That
+// used to work when this was a jit-test, but in the process of migrating to
+// xpcshell, we lost some amount of reliability and determinism.
+
+const root1 = newGlobal();
+const dbg1 = new Debugger();
+dbg1.addDebuggee(root1)
+
+const root2 = newGlobal();
+const dbg2 = new Debugger();
+dbg2.addDebuggee(root2)
+
+let fired1 = false;
+let fired2 = false;
+dbg1.memory.onGarbageCollection = _ => fired1 = true;
+dbg2.memory.onGarbageCollection = _ => fired2 = true;
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function reset() {
+  fired1 = false;
+  fired2 = false;
+}
+
+function run_test() {
+  do_test_pending();
+
+  gc();
+  executeSoon(() => {
+    reset();
+
+    // GC 1 only
+    root1.eval(`gc(this)`);
+    executeSoon(() => {
+      equal(fired1, true);
+
+      // GC 2 only
+      reset();
+      root2.eval(`gc(this)`);
+      executeSoon(() => {
+        equal(fired2, true);
+
+        // Full GC
+        reset();
+        gc();
+        executeSoon(() => {
+          equal(fired1, true);
+          equal(fired2, true);
+
+          // Full GC with no debuggees
+          reset();
+          dbg1.removeAllDebuggees();
+          dbg2.removeAllDebuggees();
+          gc();
+          executeSoon(() => {
+            equal(fired1, false);
+            equal(fired2, false);
+
+            // One debugger with multiple debuggees in different zones.
+
+            dbg1.addDebuggee(root1);
+            dbg1.addDebuggee(root2);
+
+            // Just debuggee 1
+            reset();
+            root1.eval(`gc(this)`);
+            executeSoon(() => {
+              equal(fired1, true);
+              equal(fired2, false);
+
+              // Just debuggee 2
+              reset();
+              root2.eval(`gc(this)`);
+              executeSoon(() => {
+                equal(fired1, true);
+                equal(fired2, false);
+
+                // All debuggees
+                reset();
+                gc();
+                executeSoon(() => {
+                  equal(fired1, true);
+                  equal(fired2, false);
+                  do_test_finished();
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-03.js b/js/xpconnect/tests/unit/test_onGarbageCollection-03.js
new file mode 100644
index 0000000000..d983e2cd11
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-03.js
@@ -0,0 +1,39 @@
+// Test that the onGarbageCollection hook is not reentrant.
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function run_test() {
+  do_test_pending();
+
+  const root = newGlobal();
+  const dbg = new Debugger();
+  const wrappedRoot = dbg.addDebuggee(root)
+
+  let fired = true;
+  let depth = 0;
+
+  dbg.memory.onGarbageCollection = _ => {
+    fired = true;
+
+    equal(depth, 0);
+    depth++;
+    try {
+      root.eval(`gc()`);
+    } finally {
+      equal(depth, 1);
+      depth--;
+    }
+  }
+
+  root.eval(`gc()`);
+
+  executeSoon(() => {
+    ok(fired);
+    equal(depth, 0);
+    dbg.memory.onGarbageCollection = undefined;
+    do_test_finished();
+  });
+}
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-04.js b/js/xpconnect/tests/unit/test_onGarbageCollection-04.js
new file mode 100644
index 0000000000..72e6d32284
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-04.js
@@ -0,0 +1,72 @@
+// Test that the onGarbageCollection reentrancy guard is on a per Debugger
+// basis. That is if our first Debugger is observing our second Debugger's
+// compartment, and this second Debugger triggers a GC inside its
+// onGarbageCollection hook, the first Debugger's onGarbageCollection hook is
+// still called.
+//
+// This is the scenario we are setting up: top level debugging the `debuggeree`
+// global, which is debugging the `debuggee` global. Then, we trigger the
+// following events:
+//
+//     debuggee gc
+//         |
+//         V
+//     debuggeree's onGarbageCollection
+//         |
+//         V
+//     debuggeree gc
+//         |
+//         V
+//     top level onGarbageCollection
+//
+// Note that the top level's onGarbageCollection hook should be fired, at the
+// same time that we are preventing reentrancy into debuggeree's
+// onGarbageCollection hook.
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function run_test() {
+  do_test_pending();
+
+  const debuggeree = newGlobal();
+  const debuggee = debuggeree.debuggee = newGlobal();
+
+  debuggeree.eval(
+    `
+    var dbg = new Debugger(this.debuggee);
+    var fired = 0;
+    dbg.memory.onGarbageCollection = _ => {
+      fired++;
+      gc(this);
+    };
+    `
+  );
+
+  const dbg = new Debugger(debuggeree);
+  let fired = 0;
+  dbg.memory.onGarbageCollection = _ => {
+    fired++;
+  };
+
+  debuggee.eval(`gc(this)`);
+
+  // Let first onGarbageCollection runnable get run.
+  executeSoon(() => {
+
+    // Let second onGarbageCollection runnable get run.
+    executeSoon(() => {
+
+      // Even though we request GC'ing a single zone, we can't rely on that
+      // behavior and both zones could have been scheduled for gc for both
+      // gc(this) calls.
+      ok(debuggeree.fired >= 1);
+      ok(fired >= 1);
+
+      debuggeree.dbg.removeAllDebuggees();
+      do_test_finished();
+    });
+  });
+}
diff --git a/js/xpconnect/tests/unit/test_onGarbageCollection-05.js b/js/xpconnect/tests/unit/test_onGarbageCollection-05.js
new file mode 100644
index 0000000000..e3b5e5fd9e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_onGarbageCollection-05.js
@@ -0,0 +1,42 @@
+// Test that the onGarbageCollection hook reports its gc cycle's number (aka the
+// major GC number) and that it is monotonically increasing.
+
+const root = newGlobal();
+const dbg = new Debugger();
+const wrappedRoot = dbg.addDebuggee(root)
+
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function run_test() {
+  do_test_pending();
+
+  let numFired = 0;
+  let lastGCCycleNumber = undefined;
+
+  (function loop() {
+    if (numFired == 10) {
+      dbg.memory.onGarbageCollection = undefined;
+      dbg.enabled = false;
+      return void do_test_finished();
+    }
+
+    dbg.memory.onGarbageCollection = data => {
+      print("onGarbageCollection: " + uneval(data));
+
+      if (numFired != 0) {
+        equal(typeof lastGCCycleNumber, "number");
+        equal(data.gcCycleNumber - lastGCCycleNumber, 1);
+      }
+
+      numFired++;
+      lastGCCycleNumber = data.gcCycleNumber;
+
+      executeSoon(loop);
+    };
+
+    root.eval("gc(this)");
+  }());
+}
diff --git a/js/xpconnect/tests/unit/test_params.js b/js/xpconnect/tests/unit/test_params.js
new file mode 100644
index 0000000000..fc986424c6
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_params.js
@@ -0,0 +1,384 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function TestParams() {
+}
+
+/* For once I'm happy that JS is weakly typed. */
+function f(a, b) {
+    var rv = b.value;
+    b.value = a;
+    return rv;
+};
+
+/* Implementation for size_is and iid_is methods. */
+function f_is(aIs, a, bIs, b, rvIs) {
+
+    // Set up the return value and its 'is' parameter.
+    var rv = b.value;
+    rvIs.value = bIs.value;
+
+    // Set up b and its 'is' parameter.
+    b.value = a;
+    bIs.value = aIs;
+
+    return rv;
+}
+
+function f_size_and_iid(aSize, aIID, a, bSize, bIID, b, rvSize, rvIID) {
+
+    // Copy the iids.
+    rvIID.value = bIID.value;
+    bIID.value = aIID;
+
+    // Now that we've reduced the problem to one dependent variable, use f_is.
+    return f_is(aSize, a, bSize, b, rvSize);
+}
+
+TestParams.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestParams"]),
+
+  /* nsIXPCTestParams */
+  testBoolean: f,
+  testOctet: f,
+  testShort: f,
+  testLong: f,
+  testLongLong: f,
+  testUnsignedShort: f,
+  testUnsignedLong: f,
+  testUnsignedLongLong: f,
+  testFloat: f,
+  testDouble: f,
+  testChar: f,
+  testString: f,
+  testWchar: f,
+  testWstring: f,
+  testAString: f,
+  testAUTF8String: f,
+  testACString: f,
+  testJsval: f,
+  testShortSequence: f,
+  testDoubleSequence: f,
+  testAStringSequence: f,
+  testACStringSequence: f,
+  testInterfaceSequence: f,
+  testJsvalSequence: f,
+  testInterfaceIsSequence: f_is,
+  testOptionalSequence: function (arr) { return arr; },
+  testShortArray: f_is,
+  testDoubleArray: f_is,
+  testStringArray: f_is,
+  testByteArrayOptionalLength(arr) { return arr.length; },
+  testWstringArray: f_is,
+  testInterfaceArray: f_is,
+  testJsvalArray: f_is,
+  testSizedString: f_is,
+  testSizedWstring: f_is,
+  testInterfaceIs: f_is,
+  testInterfaceIsArray: f_size_and_iid,
+  testOutAString: function(o) { o.value = "out"; },
+  testStringArrayOptionalSize: function(arr, size) {
+    if (arr.length != size) { throw "bad size passed to test method"; }
+    var rv = "";
+    arr.forEach((x) => rv += x);
+    return rv;
+  },
+  testOmittedOptionalOut(jsObj, o) {
+    if (typeof o != "object" || o.value !== undefined) {
+      throw new Components.Exception(
+        "unexpected value",
+        Cr.NS_ERROR_ILLEGAL_VALUE
+      );
+    }
+    o.value = Cc["@mozilla.org/network/io-service;1"]
+      .getService(Ci.nsIIOService)
+      .newURI("http://example.com/");
+  },
+  testNaN: NaN,
+};
+
+function TestInterfaceA() {}
+TestInterfaceA.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestInterfaceA"]),
+
+  /* nsIXPCTestInterfaceA */
+  name: "TestInterfaceADefaultName"
+};
+
+function TestInterfaceB() {}
+TestInterfaceB.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestInterfaceB"]),
+
+  /* nsIXPCTestInterfaceA */
+  name: "TestInterfaceADefaultName"
+};
+
+function run_test() {
+
+  // Load the component manifests.
+  registerXPCTestComponents();
+
+  // Test for each component.
+  test_component(Cc["@mozilla.org/js/xpc/test/native/Params;1"].createInstance());
+  test_component(xpcWrap(new TestParams()));
+}
+
+function test_component(obj) {
+  var o = obj.QueryInterface(Ci.nsIXPCTestParams);
+
+  // Possible comparator functions.
+  var standardComparator = function(a,b) {return a == b;};
+  var dotEqualsComparator = function(a,b) {return a.equals(b); }
+  var fuzzComparator = function(a,b) {return Math.abs(a - b) < 0.1;};
+  var interfaceComparator = function(a,b) {return a.name == b.name; }
+  var arrayComparator = function(innerComparator) {
+    return function(a,b) {
+      if (a.length != b.length)
+        return false;
+      for (var i = 0; i < a.length; ++i)
+        if (!innerComparator(a[i], b[i]))
+          return false;
+      return true;
+    };
+  };
+
+  // Helper test function - takes the name of test method and two values of
+  // the given type.
+  //
+  // The optional comparator argument can be used for alternative notions of
+  // equality. The comparator should return true on equality.
+  function doTest(name, val1, val2, comparator) {
+    if (!comparator)
+      comparator = standardComparator;
+    var a = val1;
+    var b = {value: val2};
+    var rv = o[name].call(o, a, b);
+    Assert.ok(comparator(rv, val2));
+    Assert.ok(comparator(val1, b.value));
+  };
+
+  function doIsTest(name, val1, val1Is, val2, val2Is, valComparator, isComparator) {
+    if (!isComparator)
+      isComparator = standardComparator;
+    var a = val1;
+    var aIs = val1Is;
+    var b = {value: val2};
+    var bIs = {value: val2Is};
+    var rvIs = {};
+    var rv = o[name].call(o, aIs, a, bIs, b, rvIs);
+    Assert.ok(valComparator(rv, val2));
+    Assert.ok(isComparator(rvIs.value, val2Is));
+    Assert.ok(valComparator(val1, b.value));
+    Assert.ok(isComparator(val1Is, bIs.value));
+  }
+
+  // Special-purpose function for testing arrays of iid_is interfaces, where we
+  // have 2 distinct sets of dependent parameters.
+  function doIs2Test(name, val1, val1Size, val1IID, val2, val2Size, val2IID) {
+    var a = val1;
+    var aSize = val1Size;
+    var aIID = val1IID;
+    var b = {value: val2};
+    var bSize = {value: val2Size};
+    var bIID = {value: val2IID};
+    var rvSize = {};
+    var rvIID = {};
+    var rv = o[name].call(o, aSize, aIID, a, bSize, bIID, b, rvSize, rvIID);
+    Assert.ok(arrayComparator(interfaceComparator)(rv, val2));
+    Assert.ok(standardComparator(rvSize.value, val2Size));
+    Assert.ok(dotEqualsComparator(rvIID.value, val2IID));
+    Assert.ok(arrayComparator(interfaceComparator)(val1, b.value));
+    Assert.ok(standardComparator(val1Size, bSize.value));
+    Assert.ok(dotEqualsComparator(val1IID, bIID.value));
+  }
+
+  // Check that the given call (type mismatch) results in an exception being thrown.
+  function doTypedArrayMismatchTest(name, val1, val1Size, val2, val2Size) {
+    var comparator = arrayComparator(standardComparator);
+    var error = false;
+    try {
+      doIsTest(name, val1, val1Size, val2, val2Size, comparator);
+      
+      // An exception was not thrown as would have been expected.
+      Assert.ok(false);
+    }
+    catch (e) {
+      // An exception was thrown as expected.
+      Assert.ok(true);
+    }
+  }
+
+  // Workaround for bug 687612 (inout parameters broken for dipper types).
+  // We do a simple test of copying a into b, and ignore the rv.
+  function doTestWorkaround(name, val1) {
+    var a = val1;
+    var b = {value: ""};
+    o[name].call(o, a, b);
+    Assert.equal(val1, b.value);
+  }
+
+  // Test all the different types
+  doTest("testBoolean", true, false);
+  doTest("testOctet", 4, 156);
+  doTest("testShort", -456, 1299);
+  doTest("testLong", 50060, -12121212);
+  doTest("testLongLong", 12345, -10000000000);
+  doTest("testUnsignedShort", 1532, 65000);
+  doTest("testUnsignedLong", 0, 4000000000);
+  doTest("testUnsignedLongLong", 215435, 3453492580348535809);
+  doTest("testFloat", 4.9, -11.2, fuzzComparator);
+  doTest("testDouble", -80.5, 15000.2, fuzzComparator);
+  doTest("testChar", "a", "2");
+  doTest("testString", "someString", "another string");
+  doTest("testWstring", "Why wasnt this", "turned on before? ಠ_ಠ");
+  doTest("testWchar", "z", "ア");
+  doTestWorkaround("testAString", "Frosty the ☃ ;-)");
+  doTestWorkaround("testAUTF8String", "We deliver 〠!");
+  doTestWorkaround("testACString", "Just a regular C string.");
+  doTest("testJsval", {aprop: 12, bprop: "str"}, 4.22);
+
+  // Test out dipper parameters, since they're special and we can't really test
+  // inouts.
+  let outAString = {};
+  o.testOutAString(outAString);
+  Assert.equal(outAString.value, "out");
+  try { o.testOutAString(undefined); } catch (e) {} // Don't crash
+  try { o.testOutAString(null); } catch (e) {} // Don't crash
+  try { o.testOutAString("string"); } catch (e) {} // Don't crash
+
+  // Helpers to instantiate various test XPCOM objects.
+  var numAsMade = 0;
+  function makeA() {
+    var a = xpcWrap(new TestInterfaceA(), Ci.nsIXPCTestInterfaceA);
+    a.name = 'testA' + numAsMade++;
+    return a;
+  };
+  var numBsMade = 0;
+  function makeB() {
+    var b = xpcWrap(new TestInterfaceB(), Ci.nsIXPCTestInterfaceB);
+    b.name = 'testB' + numBsMade++;
+    return b;
+  };
+
+  // Test arrays.
+  doIsTest("testShortArray", [2, 4, 6], 3, [1, 3, 5, 7], 4, arrayComparator(standardComparator));
+  doIsTest("testDoubleArray", [-10, -0.5], 2, [1, 3, 1e11, -8e-5 ], 4, arrayComparator(fuzzComparator));
+
+  doIsTest("testStringArray", ["mary", "hat", "hey", "lid", "tell", "lam"], 6,
+                              ["ids", "fleas", "woes", "wide", "has", "know", "!"], 7, arrayComparator(standardComparator));
+  doIsTest("testWstringArray", ["沒有語言", "的偉大嗎?]"], 2,
+                               ["we", "are", "being", "sooo", "international", "right", "now"], 7, arrayComparator(standardComparator));
+  doIsTest("testInterfaceArray", [makeA(), makeA()], 2,
+                                 [makeA(), makeA(), makeA(), makeA(), makeA(), makeA()], 6, arrayComparator(interfaceComparator));
+  doIsTest("testJsvalArray", [{ cheese: 'whiz', apple: 8 }, [1, 5, '3'], /regex/], 3,
+                             ['apple', 2.2e10, 3.3e30, { only: "wheedle", except: {} }], 4, arrayComparator(standardComparator));
+
+  // Test typed arrays and ArrayBuffer aliasing.
+  var arrayBuffer = new ArrayBuffer(16);
+  var int16Array = new Int16Array(arrayBuffer, 2, 3);
+  int16Array.set([-32768, 0, 32767]);
+  doIsTest("testShortArray", int16Array, 3, new Int16Array([1773, -32768, 32767, 7]), 4, arrayComparator(standardComparator));
+  doIsTest("testDoubleArray", new Float64Array([-10, -0.5]), 2, new Float64Array([0, 3.2, 1.0e10, -8.33 ]), 4, arrayComparator(fuzzComparator));
+
+  // Test sized strings.
+  var ssTests = ["Tis not possible, I muttered", "give me back my free hardcore!", "quoth the server:", "4〠4"];
+  doIsTest("testSizedString", ssTests[0], ssTests[0].length, ssTests[1], ssTests[1].length, standardComparator);
+  doIsTest("testSizedWstring", ssTests[2], ssTests[2].length, ssTests[3], ssTests[3].length, standardComparator);
+
+  // Test iid_is.
+  doIsTest("testInterfaceIs", makeA(), Ci['nsIXPCTestInterfaceA'],
+                              makeB(), Ci['nsIXPCTestInterfaceB'],
+                              interfaceComparator, dotEqualsComparator);
+
+  // Test arrays of iids.
+  doIs2Test("testInterfaceIsArray", [makeA(), makeA(), makeA(), makeA(), makeA()], 5, Ci['nsIXPCTestInterfaceA'],
+                                    [makeB(), makeB(), makeB()], 3, Ci['nsIXPCTestInterfaceB']);
+
+  // Test optional array size.
+  Assert.equal(o.testStringArrayOptionalSize(["some", "string", "array"]), "somestringarray");
+
+  // Test incorrect (too big) array size parameter; this should throw NOT_ENOUGH_ELEMENTS.
+  doTypedArrayMismatchTest("testShortArray", new Int16Array([-3, 7, 4]), 4,
+                                             new Int16Array([1, -32, 6]), 3);
+
+  // Test type mismatch (int16 <-> uint16); this should throw BAD_CONVERT_JS.
+  doTypedArrayMismatchTest("testShortArray", new Uint16Array([0, 7, 4, 3]), 4,
+                                             new Uint16Array([1, 5, 6]), 3);
+
+  // Test Sequence<T> types.
+  doTest("testShortSequence", [2, 4, 6], [1, 3, 5, 7], arrayComparator(standardComparator));
+  doTest("testDoubleSequence", [-10, -0.5], [1, 3, 1e11, -8e-5 ], arrayComparator(fuzzComparator));
+  doTest("testACStringSequence", ["mary", "hat", "hey", "lid", "tell", "lam"],
+                                 ["ids", "fleas", "woes", "wide", "has", "know", "!"],
+                                 arrayComparator(standardComparator));
+  doTest("testAStringSequence", ["沒有語言", "的偉大嗎?]"],
+                                ["we", "are", "being", "sooo", "international", "right", "now"],
+                                arrayComparator(standardComparator));
+
+  doTest("testInterfaceSequence", [makeA(), makeA()],
+                                  [makeA(), makeA(), makeA(), makeA(), makeA(), makeA()], arrayComparator(interfaceComparator));
+
+  doTest("testJsvalSequence", [{ cheese: 'whiz', apple: 8 }, [1, 5, '3'], /regex/],
+                              ['apple', 2.2e10, 3.3e30, { only: "wheedle", except: {} }], arrayComparator(standardComparator));
+
+  doIsTest("testInterfaceIsSequence", [makeA(), makeA(), makeA(), makeA(), makeA()], Ci['nsIXPCTestInterfaceA'],
+                                      [makeB(), makeB(), makeB()], Ci['nsIXPCTestInterfaceB'],
+                                      arrayComparator(interfaceComparator), dotEqualsComparator);
+
+  var ret = o.testOptionalSequence();
+  Assert.ok(Array.isArray(ret));
+  Assert.equal(ret.length, 0);
+
+  ret = o.testOptionalSequence([]);
+  Assert.ok(Array.isArray(ret));
+  Assert.equal(ret.length, 0);
+
+  ret = o.testOptionalSequence([1, 2, 3]);
+  Assert.ok(Array.isArray(ret));
+  Assert.equal(ret.length, 3);
+
+  let jsObj = new TestParams();
+  o.testOmittedOptionalOut(jsObj);
+  ret = {};
+  o.testOmittedOptionalOut(jsObj, ret);
+  Assert.equal(ret.value.spec, "http://example.com/")
+
+  // Tests for large ArrayBuffers.
+  var ab = null;
+  try {
+    ab = new ArrayBuffer(4.5 * 1024 * 1024 * 1024); // 4.5 GB.
+  } catch (e) {
+    // Large ArrayBuffers not available (32-bit or disabled).
+  }
+  if (ab) {
+    var uint8 = new Uint8Array(ab);
+
+    // Test length check in JSArray2Native.
+    var ex = null;
+    try {
+      o.testOptionalSequence(uint8);
+    } catch (e) {
+      ex = e;
+    }
+    Assert.ok(ex.message.includes("Could not convert JavaScript argument arg 0"));
+
+    // Test length check for optional length argument in GetArraySizeFromParam.
+    ex = null;
+    try {
+      o.testByteArrayOptionalLength(uint8);
+    } catch (e) {
+      ex = e;
+    }
+    Assert.ok(ex.message.includes("Cannot convert JavaScript object into an array"));
+
+    // Smaller array views on the buffer are fine.
+    uint8 = new Uint8Array(ab, ab.byteLength - 3);
+    uint8[0] = 123;
+    Assert.equal(uint8.byteLength, 3);
+    Assert.equal(o.testOptionalSequence(uint8).toString(), "123,0,0");
+    Assert.equal(o.testByteArrayOptionalLength(uint8), 3);
+  }
+
+  Assert.ok(isNaN(o.testNaN), "Should handle returning NaNs");
+}
diff --git a/js/xpconnect/tests/unit/test_print_stderr.js b/js/xpconnect/tests/unit/test_print_stderr.js
new file mode 100644
index 0000000000..4c2d87ae7a
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_print_stderr.js
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function() {
+  Assert.throws(
+    () => Cu.printStderr(),
+    /Not enough arguments/,
+    "Without argument printStderr throws"
+  );
+
+  const types = ["", "foo", 42, true, null, {foo: "bar"}];
+  types.forEach(type => Cu.printStderr(type));
+});
diff --git a/js/xpconnect/tests/unit/test_private_field_xrays.js b/js/xpconnect/tests/unit/test_private_field_xrays.js
new file mode 100644
index 0000000000..bd37eb44c7
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_private_field_xrays.js
@@ -0,0 +1,58 @@
+'use strict'
+
+ChromeUtils.importESModule("resource://gre/modules/Preferences.sys.mjs");
+
+add_task(async function () {
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+
+  docShell.createAboutBlankContentViewer(null, null);
+
+  let window = webnav.document.defaultView;
+
+  let iframe = window.eval(`
+    iframe = document.createElement("iframe");
+    iframe.id = "iframe"
+    document.body.appendChild(iframe)
+    iframe`);
+
+
+  let unwrapped = Cu.waiveXrays(iframe);
+
+
+  class Base {
+    constructor(o) {
+      return o;
+    }
+  };
+
+
+  class A extends Base {
+    #x = 12;
+    static gx(o) {
+      return o.#x;
+    }
+
+    static sx(o, v) {
+      o.#x = v;
+    }
+  };
+
+  new A(iframe);
+  Assert.equal(A.gx(iframe), 12);
+  A.sx(iframe, 'wrapped');
+
+  // Shouldn't tunnel past xray.
+  Assert.throws(() => A.gx(unwrapped), TypeError);
+  Assert.throws(() => A.sx(unwrapped, 'unwrapped'), TypeError);
+
+  new A(unwrapped);
+  Assert.equal(A.gx(unwrapped), 12);
+  Assert.equal(A.gx(iframe), 'wrapped');
+
+  A.sx(iframe, 'modified');
+  Assert.equal(A.gx(unwrapped), 12);
+  A.sx(unwrapped, 16);
+  Assert.equal(A.gx(iframe), 'modified');
+});
diff --git a/js/xpconnect/tests/unit/test_promise.js b/js/xpconnect/tests/unit/test_promise.js
new file mode 100644
index 0000000000..305e016fb5
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_promise.js
@@ -0,0 +1,7 @@
+function run_test() {
+  sb = new Cu.Sandbox('http://www.example.com');
+  sb.equal = equal;
+  Cu.evalInSandbox('equal(typeof new Promise(function(resolve){resolve();}), "object");',
+                   sb);
+  Assert.equal(typeof new Promise(function(resolve){resolve();}), "object");
+}
diff --git a/js/xpconnect/tests/unit/test_recursive_import.js b/js/xpconnect/tests/unit/test_recursive_import.js
new file mode 100644
index 0000000000..94c6b0b7e9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_recursive_import.js
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+ 
+function run_test() {
+  var scope = {};
+  ChromeUtils.import("resource://test/recursive_importA.jsm", scope);
+
+  // A imported correctly
+  Assert.ok(scope.foo() == "foo");
+
+  // Symbols from B are visible through A
+  Assert.ok(scope.bar.baz() == "baz");
+
+  // Symbols from A are visible through A, B, A.
+  Assert.ok(scope.bar.qux.foo() == "foo");
+}
diff --git a/js/xpconnect/tests/unit/test_reflect_parse.js b/js/xpconnect/tests/unit/test_reflect_parse.js
new file mode 100644
index 0000000000..a96ce0bb61
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_reflect_parse.js
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+({
+  loc:{start:{line:1, column:0}, end:{line:1, column:12}, source:null},
+  type:"Program",
+  body:[
+    {
+      loc:{start:{line:1, column:0}, end:{line:1, column:12}, source:null},
+      type:"ExpressionStatement",
+      expression:{
+        loc:{start:{line:1, column:0}, end:{line:1, column:12}, source:null},
+        type:"Literal",
+        value:"use strict"
+      }
+    }
+  ]
+})
+*/
+
+function run_test() {
+  // Reflect.parse is better tested in js shell; this basically tests its presence.
+  var parseData = Reflect.parse('"use strict"');
+  Assert.equal(parseData.body[0].expression.value, "use strict");
+}
diff --git a/js/xpconnect/tests/unit/test_resolve_dead_promise.js b/js/xpconnect/tests/unit/test_resolve_dead_promise.js
new file mode 100644
index 0000000000..70615b39c0
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_resolve_dead_promise.js
@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=1298597 */
+
+function run_test()
+{
+  var sb = Cu.Sandbox("http://www.blah.com");
+  var resolveFun;
+  var p1 = new sb.Promise((res, rej) => {resolveFun = res});
+  var rejectFun;
+  var p2 = new sb.Promise((res, rej) => {rejectFun = rej});
+  Cu.nukeSandbox(sb);
+  Assert.ok(Cu.isDeadWrapper(sb), "sb should be dead");
+  Assert.ok(Cu.isDeadWrapper(p1), "p1 should be dead");
+  Assert.ok(Cu.isDeadWrapper(p2), "p2 should be dead");
+
+  var exception;
+
+  try{
+    resolveFun(1);
+    Assert.ok(false);
+  } catch (e) {
+    exception = e;
+  }
+  Assert.ok(exception.toString().includes("can't access dead object"),
+            "Resolving dead wrapped promise should throw");
+
+  exception = undefined;
+  try{
+    rejectFun(1);
+    Assert.ok(false);
+  } catch (e) {
+    exception = e;
+  }
+  Assert.ok(exception.toString().includes("can't access dead object"),
+            "Rejecting dead wrapped promise should throw");
+}
diff --git a/js/xpconnect/tests/unit/test_returncode.js b/js/xpconnect/tests/unit/test_returncode.js
new file mode 100644
index 0000000000..de4289c013
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_returncode.js
@@ -0,0 +1,74 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function getConsoleMessages() {
+  let consoleService = Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService);
+  let messages = consoleService.getMessageArray().map((m) => m.toString());
+  // reset ready for the next call.
+  consoleService.reset();
+  return messages;
+}
+
+function run_test() {
+  // Load the component manifests.
+  registerXPCTestComponents();
+
+  // and the tests.
+  test_simple("@mozilla.org/js/xpc/test/native/ReturnCodeParent;1");
+  test_nested("@mozilla.org/js/xpc/test/native/ReturnCodeParent;1");
+
+  test_simple("@mozilla.org/js/xpc/test/native/ESMReturnCodeParent;1");
+  test_nested("@mozilla.org/js/xpc/test/native/ESMReturnCodeParent;1");
+}
+
+function test_simple(contractID) {
+  let parent = Cc[contractID].createInstance(Ci.nsIXPCTestReturnCodeParent);
+  let result;
+
+  // flush existing messages before we start testing.
+  getConsoleMessages();
+
+  // Ask the C++ to call the JS object which will throw.
+  result = parent.callChild(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_THROW);
+  Assert.equal(result, Cr.NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS,
+               "exception caused NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS");
+
+  let messages = getConsoleMessages();
+  Assert.equal(messages.length, 1, "got a console message from the exception");
+  Assert.ok(messages[0].includes("a requested error"), "got the message text");
+
+  // Ask the C++ to call the JS object which will return success.
+  result = parent.callChild(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_SUCCESS);
+  Assert.equal(result, Cr.NS_OK, "success is success");
+
+  Assert.deepEqual(getConsoleMessages(), [], "no messages reported on success.");
+
+  // And finally the point of this test!
+  // Ask the C++ to call the JS object which will use .returnCode
+  result = parent.callChild(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_RETURN_RESULTCODE);
+  Assert.equal(result, Cr.NS_ERROR_FAILURE,
+               "NS_ERROR_FAILURE was seen as the error code.");
+
+  Assert.deepEqual(getConsoleMessages(), [], "no messages reported with .returnCode");
+}
+
+function test_nested(contractID) {
+  let parent = Cc[contractID].createInstance(Ci.nsIXPCTestReturnCodeParent);
+  let result;
+
+  // flush existing messages before we start testing.
+  getConsoleMessages();
+
+  // Ask the C++ to call the "outer" JS object, which will set .returnCode, but
+  // then create and call *another* component which itself sets the .returnCode
+  // to a different value.  This checks the returnCode is correctly saved
+  // across call contexts.
+  result = parent.callChild(Ci.nsIXPCTestReturnCodeChild.CHILD_SHOULD_NEST_RESULTCODES);
+  Assert.equal(result, Cr.NS_ERROR_UNEXPECTED,
+               "NS_ERROR_UNEXPECTED was seen as the error code.");
+  // We expect one message, which is the child reporting what it got as the
+  // return code - which should be NS_ERROR_FAILURE
+  let expected = ["nested child returned " + Cr.NS_ERROR_FAILURE];
+  Assert.deepEqual(getConsoleMessages(), expected, "got the correct sub-error");
+}
diff --git a/js/xpconnect/tests/unit/test_rewrap_dead_wrapper.js b/js/xpconnect/tests/unit/test_rewrap_dead_wrapper.js
new file mode 100644
index 0000000000..10934f550b
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_rewrap_dead_wrapper.js
@@ -0,0 +1,31 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=1354733 */
+
+const global = this;
+
+function run_test()
+{
+  var sb = Cu.Sandbox(global);
+  let obj = new sb.Object();
+  Cu.nukeSandbox(sb);
+
+  ok(Cu.isDeadWrapper(obj), "object should be a dead wrapper");
+
+  // Create a new sandbox to wrap objects for.
+
+  var sb = Cu.Sandbox(global);
+  Cu.evalInSandbox(function echo(val) { return val; },
+                   sb);
+
+  let echoed = sb.echo(obj);
+  ok(Cu.isDeadWrapper(echoed), "Rewrapped object should be a dead wrapper");
+  ok(echoed !== obj, "Rewrapped object should be a new dead wrapper");
+
+  ok(obj === obj, "Dead wrapper object should be equal to itself");
+
+  let liveObj = {};
+  ok(liveObj === sb.echo(liveObj), "Rewrapped live object should be equal to itself");
+}
diff --git a/js/xpconnect/tests/unit/test_rtcIdentityProvider.js b/js/xpconnect/tests/unit/test_rtcIdentityProvider.js
new file mode 100644
index 0000000000..7786691513
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_rtcIdentityProvider.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  let sb = new Cu.Sandbox('https://www.example.com',
+                          { wantGlobalProperties: ['rtcIdentityProvider'] });
+
+  function exerciseInterface() {
+    equal(typeof rtcIdentityProvider, 'object');
+    equal(typeof rtcIdentityProvider.register, 'function');
+    rtcIdentityProvider.register({
+      generateAssertion: function(a, b, c) {
+        return Promise.resolve({
+          idp: { domain: 'example.com' },
+          assertion: JSON.stringify([a, b, c])
+        });
+      },
+      validateAssertion: function(d, e) {
+        return Promise.resolve({
+          identity: 'user@example.com',
+          contents: JSON.stringify([d, e])
+        });
+      }
+    });
+  }
+
+  sb.equal = equal;
+  Cu.evalInSandbox('(' + exerciseInterface.toSource() + ')();', sb);
+  ok(sb.rtcIdentityProvider.hasIdp);
+
+  Cu.importGlobalProperties(['rtcIdentityProvider']);
+  exerciseInterface();
+  ok(rtcIdentityProvider.hasIdp);
+}
diff --git a/js/xpconnect/tests/unit/test_sandbox_DOMException.js b/js/xpconnect/tests/unit/test_sandbox_DOMException.js
new file mode 100644
index 0000000000..04592c6db2
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_sandbox_DOMException.js
@@ -0,0 +1,10 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  var Cu = Components.utils;
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["DOMException"] });
+  sb.notEqual = Assert.notEqual.bind(Assert);
+  Cu.evalInSandbox('notEqual(DOMException, undefined);', sb);
+}
diff --git a/js/xpconnect/tests/unit/test_sandbox_atob.js b/js/xpconnect/tests/unit/test_sandbox_atob.js
new file mode 100644
index 0000000000..a4bd75c13d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_sandbox_atob.js
@@ -0,0 +1,9 @@
+function run_test() {
+  sb = new Cu.Sandbox('http://www.example.com',
+                      { wantGlobalProperties: ["atob", "btoa"] });
+  sb.equal = equal;
+  Cu.evalInSandbox('var dummy = "Dummy test.";' +
+                   'equal(dummy, atob(btoa(dummy)));' +
+                   'equal(btoa("budapest"), "YnVkYXBlc3Q=");',
+                   sb);
+}
diff --git a/js/xpconnect/tests/unit/test_sandbox_metadata.js b/js/xpconnect/tests/unit/test_sandbox_metadata.js
new file mode 100644
index 0000000000..2d0ebe36b0
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_sandbox_metadata.js
@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=898559 */
+
+function run_test()
+{
+  let sandbox = Cu.Sandbox("http://www.blah.com", {
+    metadata: "test metadata",
+  });
+
+  Cu.importGlobalProperties(["XMLHttpRequest"]);
+
+  Assert.equal(Cu.getSandboxMetadata(sandbox), "test metadata");
+
+  sandbox = Cu.Sandbox("http://www.blah.com", {
+    metadata: { foopy: { bar: 2 }, baz: "hi" }
+  });
+
+  let metadata = Cu.getSandboxMetadata(sandbox);
+  Assert.equal(metadata.baz, "hi");
+  Assert.equal(metadata.foopy.bar, 2);
+  metadata.baz = "foo";
+
+  metadata = Cu.getSandboxMetadata(sandbox);
+  Assert.equal(metadata.baz, "foo");
+
+  metadata = { foo: "bar" };
+  Cu.setSandboxMetadata(sandbox, metadata);
+  metadata.foo = "baz";
+  metadata = Cu.getSandboxMetadata(sandbox);
+  Assert.equal(metadata.foo, "bar");
+
+  let thrown = false;
+  let reflector = new XMLHttpRequest();
+
+  try {
+    Cu.setSandboxMetadata(sandbox, { foo: reflector });
+  } catch(e) {
+    thrown = true;
+  }
+
+  Assert.equal(thrown, true);
+
+  sandbox = Cu.Sandbox(this, {
+    metadata: { foopy: { bar: 2 }, baz: "hi" }
+  });
+
+  let inner = Cu.evalInSandbox("Components.utils.Sandbox('http://www.blah.com')", sandbox);
+
+  metadata = Cu.getSandboxMetadata(inner);
+  Assert.equal(metadata.baz, "hi");
+  Assert.equal(metadata.foopy.bar, 2);
+  metadata.baz = "foo";
+}
+
diff --git a/js/xpconnect/tests/unit/test_sandbox_name.js b/js/xpconnect/tests/unit/test_sandbox_name.js
new file mode 100644
index 0000000000..1eaa971a9e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_sandbox_name.js
@@ -0,0 +1,26 @@
+"use strict";
+
+/**
+ * Test that the name of a sandbox contains the name of all principals.
+ */
+function test_sandbox_name() {
+  let names = [
+    "http://example.com/?" + Math.random(),
+    "http://example.org/?" + Math.random()
+  ];
+  let sandbox = Cu.Sandbox(names);
+  let fileName = Cu.evalInSandbox(
+    "(new Error()).fileName",
+    sandbox,
+    "latest" /*js version*/,
+    ""/*file name*/
+  );
+
+  for (let name of names) {
+    Assert.ok(fileName.includes(name), `Name ${name} appears in ${fileName}`);
+  }
+};
+
+function run_test() {
+  test_sandbox_name();
+}
diff --git a/js/xpconnect/tests/unit/test_storage.js b/js/xpconnect/tests/unit/test_storage.js
new file mode 100644
index 0000000000..1ef6b653b5
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_storage.js
@@ -0,0 +1,12 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["storage"] });
+  sb.ok = ok;
+  Cu.evalInSandbox('ok(storage instanceof StorageManager);',
+                   sb);
+  Cu.importGlobalProperties(["storage"]);
+  Assert.ok(storage instanceof StorageManager);
+}
diff --git a/js/xpconnect/tests/unit/test_structuredClone.js b/js/xpconnect/tests/unit/test_structuredClone.js
new file mode 100644
index 0000000000..9ecb51951d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_structuredClone.js
@@ -0,0 +1,33 @@
+function run_test() {
+  var sb = new Cu.Sandbox("http://www.example.com", {
+    wantGlobalProperties: ["structuredClone"],
+  });
+
+  sb.equal = equal;
+
+  sb.testing = Cu.cloneInto({ xyz: 123 }, sb);
+  Cu.evalInSandbox(
+    `
+    equal(structuredClone("abc"), "abc");
+
+    var obj = { a: 1 };
+    obj.self = obj;
+    var clone = structuredClone(obj);
+    equal(clone.a, 1);
+    equal(clone.self, clone);
+
+    var ab = new ArrayBuffer(1);
+    clone = structuredClone(ab, { transfer: [ab] });
+    equal(clone.byteLength, 1);
+    equal(ab.byteLength, 0);
+
+    clone = structuredClone(testing);
+    equal(clone.xyz, 123);
+    `,
+    sb
+  );
+
+  Cu.importGlobalProperties(["structuredClone"]);
+  const clone = structuredClone({ b: 2 });
+  Assert.equal(clone.b, 2);
+}
diff --git a/js/xpconnect/tests/unit/test_subScriptLoader.js b/js/xpconnect/tests/unit/test_subScriptLoader.js
new file mode 100644
index 0000000000..70301f9da4
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_subScriptLoader.js
@@ -0,0 +1,16 @@
+"use strict";
+
+add_task(async function test_executeScriptAfterNuked() {
+  let scriptUrl = Services.io.newFileURI(do_get_file("file_simple_script.js")).spec;
+
+  // Load the script for the first time into a sandbox, and then nuke
+  // that sandbox.
+  let sandbox = Cu.Sandbox(Services.scriptSecurityManager.getSystemPrincipal());
+  Services.scriptloader.loadSubScript(scriptUrl, sandbox);
+  Cu.nukeSandbox(sandbox);
+
+  // Load the script again into a new sandbox, and make sure it
+  // succeeds.
+  sandbox = Cu.Sandbox(Services.scriptSecurityManager.getSystemPrincipal());
+  Services.scriptloader.loadSubScript(scriptUrl, sandbox);
+});
diff --git a/js/xpconnect/tests/unit/test_tearoffs.js b/js/xpconnect/tests/unit/test_tearoffs.js
new file mode 100644
index 0000000000..18b07d1da1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_tearoffs.js
@@ -0,0 +1,115 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function TestInterfaceAll() {}
+TestInterfaceAll.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestInterfaceA",
+                                          "nsIXPCTestInterfaceB",
+                                          "nsIXPCTestInterfaceC"]),
+
+  /* nsIXPCTestInterfaceA / nsIXPCTestInterfaceB */
+  name: "TestInterfaceAllDefaultName",
+
+  /* nsIXPCTestInterfaceC */
+  someInteger: 42
+};
+
+function newWrappedJS() {
+  return xpcWrap(new TestInterfaceAll());
+}
+
+function run_test() {
+  // Shortcut the interfaces we're using.
+  var ifs = {
+    a: Ci['nsIXPCTestInterfaceA'],
+    b: Ci['nsIXPCTestInterfaceB'],
+    c: Ci['nsIXPCTestInterfaceC']
+  };
+
+  // Run through the logic a few times.
+  for (let i = 0; i < 2; ++i)
+    play_with_tearoffs(ifs);
+}
+
+function play_with_tearoffs(ifs) {
+
+  // Allocate a bunch of objects, QI-ed to B.
+  var instances = [];
+  for (var i = 0; i < 300; ++i)
+    instances.push(newWrappedJS().QueryInterface(ifs.b));
+
+  // Nothing to collect.
+  gc();
+
+  // QI them to A.
+  instances.forEach(function(v, i, a) { v.QueryInterface(ifs.a); });
+
+  // QI them to C.
+  instances.forEach(function(v, i, a) { v.QueryInterface(ifs.c); });
+
+  // Check
+  Assert.ok('name' in instances[10], 'Have the prop from A/B');
+  Assert.ok('someInteger' in instances[10], 'Have the prop from C');
+
+  // Grab tearoff reflections for a and b.
+  var aTearOffs = instances.map(function(v, i, a) { return v.nsIXPCTestInterfaceA; } );
+  var bTearOffs = instances.map(function(v, i, a) { return v.nsIXPCTestInterfaceB; } );
+
+  // Check
+  Assert.ok('name' in aTearOffs[1], 'Have the prop from A');
+  Assert.ok(!('someInteger' in aTearOffs[1]), 'Dont have the prop from C');
+
+  // Nothing to collect.
+  gc();
+
+  // Null out every even instance pointer.
+  for (var i = 0; i < instances.length; ++i)
+    if (i % 2 == 0)
+        instances[i] = null;
+
+  // Nothing to collect, since we still have the A and B tearoff reflections.
+  gc();
+
+  // Null out A tearoff reflections that are a multiple of 3.
+  for (var i = 0; i < aTearOffs.length; ++i)
+    if (i % 3 == 0)
+        aTearOffs[i] = null;
+
+  // Nothing to collect, since we still have the B tearoff reflections.
+  gc();
+
+  // Null out B tearoff reflections that are a multiple of 5.
+  for (var i = 0; i < bTearOffs.length; ++i)
+    if (i % 5 == 0)
+        bTearOffs[i] = null;
+
+  // This should collect every 30th object (indices that are multiples of 2, 3, and 5).
+  gc();
+
+  // Kill the b tearoffs entirely.
+  bTearOffs = 0;
+
+  // Collect more.
+  gc();
+
+  // Get C tearoffs.
+  var cTearOffs = instances.map(function(v, i, a) { return v ? v.nsIXPCTestInterfaceC : null; } );
+
+  // Check.
+  Assert.ok(!('name' in cTearOffs[1]), 'Dont have the prop from A');
+  Assert.ok('someInteger' in cTearOffs[1], 'have the prop from C');
+
+  // Null out the a tearoffs.
+  aTearOffs = null;
+
+  // Collect all even indices.
+  gc();
+
+  // Collect all indices.
+  instances = null;
+  gc();
+
+  // Give ourselves a pat on the back. :-)
+  Assert.ok(true, "Got all the way through without crashing!");
+}
diff --git a/js/xpconnect/tests/unit/test_textDecoder.js b/js/xpconnect/tests/unit/test_textDecoder.js
new file mode 100644
index 0000000000..b97aab9f7c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_textDecoder.js
@@ -0,0 +1,11 @@
+function run_test() {
+  sb = new Cu.Sandbox('http://www.example.com',
+                      { wantGlobalProperties: ["TextDecoder", "TextEncoder"] });
+  sb.equal = equal;
+  Cu.evalInSandbox('equal(new TextDecoder().encoding, "utf-8");' +
+                   'equal(new TextEncoder().encoding, "utf-8");',
+                   sb);
+  Cu.importGlobalProperties(["TextDecoder", "TextEncoder"]);
+  Assert.equal(new TextDecoder().encoding, "utf-8");
+  Assert.equal(new TextEncoder().encoding, "utf-8");
+}
diff --git a/js/xpconnect/tests/unit/test_uawidget_scope.js b/js/xpconnect/tests/unit/test_uawidget_scope.js
new file mode 100644
index 0000000000..ede9d656cd
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_uawidget_scope.js
@@ -0,0 +1,56 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+ChromeUtils.importESModule("resource://gre/modules/Timer.sys.mjs");
+const {NetUtil} = ChromeUtils.import("resource://gre/modules/NetUtil.jsm");
+const {TestUtils} = ChromeUtils.importESModule("resource://testing-common/TestUtils.sys.mjs");
+
+function getWindowlessBrowser(url) {
+  let ssm = Services.scriptSecurityManager;
+  let uri = NetUtil.newURI(url);
+  let principal = ssm.createContentPrincipal(uri, {});
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+  docShell.createAboutBlankContentViewer(principal, principal);
+
+  let document = webnav.document;
+  let video = document.createElement("video");
+  document.documentElement.appendChild(video);
+
+  let shadowRoot = video.openOrClosedShadowRoot;
+  ok(shadowRoot, "should have shadowRoot");
+  ok(shadowRoot.isUAWidget(), "ShadowRoot should be a UAWidget");
+  equal(Cu.getGlobalForObject(shadowRoot), Cu.getUAWidgetScope(principal),
+        "shadowRoot should be in UAWidget scope");
+
+  return webnav;
+}
+
+function StubPolicy(id) {
+  return new WebExtensionPolicy({
+    id,
+    mozExtensionHostname: id,
+    baseURL: `file:///{id}`,
+    allowedOrigins: new MatchPatternSet([]),
+    localizeCallback(string) {},
+  });
+}
+
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=1588356
+add_task(async function() {
+  let policy = StubPolicy("foo");
+  policy.active = true;
+
+  let webnav = getWindowlessBrowser("moz-extension://foo/a.html");
+  webnav.close();
+
+  // Wrappers are nuked asynchronously, so wait for that to happen.
+  await TestUtils.topicObserved("inner-window-nuked");
+
+  webnav = getWindowlessBrowser("moz-extension://foo/a.html");
+  webnav.close();
+
+  policy.active = false;
+});
diff --git a/js/xpconnect/tests/unit/test_uninitialized_lexical.js b/js/xpconnect/tests/unit/test_uninitialized_lexical.js
new file mode 100644
index 0000000000..f5f2f254ee
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_uninitialized_lexical.js
@@ -0,0 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+Assert.throws(() => ChromeUtils.import("resource://test/uninitialized_lexical.jsm"),
+              /Symbol 'foo' accessed before initialization/,
+              "Uninitialized lexicals result in an exception");
diff --git a/js/xpconnect/tests/unit/test_unload.js b/js/xpconnect/tests/unit/test_unload.js
new file mode 100644
index 0000000000..13e2e0c63e
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_unload.js
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+  var scope1 = {};
+  var exports1 = ChromeUtils.import("resource://test/TestBlob.jsm", scope1);
+
+  var scope2 = {};
+  var exports2 = ChromeUtils.import("resource://test/TestBlob.jsm", scope2);
+
+  Assert.ok(exports1 === exports2);
+  Assert.ok(scope1.TestBlob === scope2.TestBlob);
+
+  Cu.unload("resource://test/TestBlob.jsm");
+
+  var scope3 = {};
+  var exports3 = ChromeUtils.import("resource://test/TestBlob.jsm", scope3);
+
+  Assert.equal(false, exports1 === exports3);
+  Assert.equal(false, scope1.TestBlob === scope3.TestBlob);
+
+  // When the jsm was unloaded, the value of all its global's properties were
+  // set to undefined. While it must be safe (not crash) to call into the
+  // module, we expect it to throw an error (e.g., when trying to use Ci).
+  try { scope1.TestBlob.doTest(() => {}); } catch (e) {}
+  try { scope3.TestBlob.doTest(() => {}); } catch (e) {}
+}
diff --git a/js/xpconnect/tests/unit/test_url.js b/js/xpconnect/tests/unit/test_url.js
new file mode 100644
index 0000000000..0f912d12e9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_url.js
@@ -0,0 +1,9 @@
+function run_test() {
+  var sb = new Cu.Sandbox('http://www.example.com',
+                          { wantGlobalProperties: ["URL"] });
+  sb.equal = equal;
+  Cu.evalInSandbox('equal(new URL("http://www.example.com").host, "www.example.com");',
+                   sb);
+  Cu.importGlobalProperties(["URL"]);
+  Assert.equal(new URL("http://www.example.com").host, "www.example.com");
+}
diff --git a/js/xpconnect/tests/unit/test_want_components.js b/js/xpconnect/tests/unit/test_want_components.js
new file mode 100644
index 0000000000..1c203c3e9d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_want_components.js
@@ -0,0 +1,16 @@
+function run_test() {
+  var sb;
+
+  sb = Cu.Sandbox(this, {wantComponents: false});
+  Assert.equal(Cu.evalInSandbox("this.Components", sb), undefined);
+  Assert.equal(Cu.evalInSandbox("this.Services", sb), undefined);
+
+  sb = Cu.Sandbox(this, {wantComponents: true});
+  Assert.equal(Cu.evalInSandbox("typeof this.Components", sb), "object");
+  Assert.equal(Cu.evalInSandbox("typeof this.Services", sb), "object");
+
+  // wantComponents defaults to true.
+  sb = Cu.Sandbox(this, {});
+  Assert.equal(Cu.evalInSandbox("typeof this.Components", sb), "object");
+  Assert.equal(Cu.evalInSandbox("typeof this.Services", sb), "object");
+}
diff --git a/js/xpconnect/tests/unit/test_watchdog_default.js b/js/xpconnect/tests/unit/test_watchdog_default.js
new file mode 100644
index 0000000000..4634184f3c
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_watchdog_default.js
@@ -0,0 +1,9 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function testBody() {
+  // Check that we properly implement whatever behavior is specified by the
+  // default profile for this configuration.
+  return checkWatchdog(isWatchdogEnabled());
+}
diff --git a/js/xpconnect/tests/unit/test_watchdog_disable.js b/js/xpconnect/tests/unit/test_watchdog_disable.js
new file mode 100644
index 0000000000..926edf2ffa
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_watchdog_disable.js
@@ -0,0 +1,8 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function testBody() {
+  setWatchdogEnabled(false);
+  return checkWatchdog(false);
+}
diff --git a/js/xpconnect/tests/unit/test_watchdog_enable.js b/js/xpconnect/tests/unit/test_watchdog_enable.js
new file mode 100644
index 0000000000..f39757dfae
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_watchdog_enable.js
@@ -0,0 +1,8 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function testBody() {
+  setWatchdogEnabled(true);
+  return checkWatchdog(true);
+}
diff --git a/js/xpconnect/tests/unit/test_watchdog_hibernate.js b/js/xpconnect/tests/unit/test_watchdog_hibernate.js
new file mode 100644
index 0000000000..119cc095e2
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_watchdog_hibernate.js
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+async function testBody() {
+
+  setWatchdogEnabled(true);
+
+  // It's unlikely that we've ever hibernated at this point, but the timestamps
+  // default to 0, so this should always be true.
+  var now = Date.now() * 1000;
+  var startHibernation = Cu.getWatchdogTimestamp("WatchdogHibernateStart");
+  var stopHibernation = Cu.getWatchdogTimestamp("WatchdogHibernateStop");
+  do_log_info("Pre-hibernation statistics:");
+  do_log_info("now: " + now / 1000000);
+  do_log_info("startHibernation: " + startHibernation / 1000000);
+  do_log_info("stopHibernation: " + stopHibernation / 1000000);
+  Assert.less(startHibernation, now, "startHibernation ok");
+  Assert.less(stopHibernation, now, "stopHibernation ok");
+
+  // When the watchdog runs, it hibernates if there's been no activity for the
+  // last 2 seconds, otherwise it sleeps for 1 second. As such, given perfect
+  // scheduling, we should never have more than 3 seconds of inactivity without
+  // hibernating. To add some padding for automation, we mandate that hibernation
+  // must begin between 2 and 5 seconds from now.
+
+  // Sleep for 10 seconds. Note: we don't use nsITimer here because then we may run
+  // arbitrary (idle) events involving script before it fires.
+  simulateNoScriptActivity(10);
+
+  busyWait(1000); // Give the watchdog time to wake up on the condvar.
+  var stateChange = Cu.getWatchdogTimestamp("ContextStateChange");
+  startHibernation = Cu.getWatchdogTimestamp("WatchdogHibernateStart");
+  stopHibernation = Cu.getWatchdogTimestamp("WatchdogHibernateStop");
+  do_log_info("Post-hibernation statistics:");
+  do_log_info("stateChange: " + stateChange / 1000000);
+  do_log_info("startHibernation: " + startHibernation / 1000000);
+  do_log_info("stopHibernation: " + stopHibernation / 1000000);
+  // XPCOM timers, JS times, and PR_Now() are apparently not directly
+  // comparable, as evidenced by certain seemingly-impossible timing values
+  // that occasionally get logged in windows automation. We're really just
+  // making sure this behavior is roughly as expected on the macro scale,
+  // so we add a 1 second fuzz factor here.
+  const FUZZ_FACTOR = 1 * 1000 * 1000;
+  Assert.greater(stateChange, now + 10*1000*1000 - FUZZ_FACTOR, "stateChange ok");
+  Assert.greater(startHibernation, now + 2*1000*1000 - FUZZ_FACTOR, "startHibernation ok");
+  Assert.less(startHibernation, now + 5*1000*1000 + FUZZ_FACTOR, "startHibernation ok");
+  Assert.greater(stopHibernation, now + 10*1000*1000 - FUZZ_FACTOR, "stopHibernation ok");
+}
diff --git a/js/xpconnect/tests/unit/test_watchdog_toggle.js b/js/xpconnect/tests/unit/test_watchdog_toggle.js
new file mode 100644
index 0000000000..6f43a8b876
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_watchdog_toggle.js
@@ -0,0 +1,10 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function testBody() {
+  var defaultBehavior = isWatchdogEnabled();
+  setWatchdogEnabled(!defaultBehavior);
+  setWatchdogEnabled(defaultBehavior);
+  return checkWatchdog(defaultBehavior);
+}
diff --git a/js/xpconnect/tests/unit/test_weak_keys.js b/js/xpconnect/tests/unit/test_weak_keys.js
new file mode 100644
index 0000000000..58e3237bd8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_weak_keys.js
@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=1165807 */
+
+function run_test()
+{
+  var bunnies = new String("bunnies");
+  var lizards = new String("lizards");
+
+  var weakset = new WeakSet([bunnies, lizards]);
+  var weakmap = new WeakMap();
+  weakmap.set(bunnies, 23);
+  weakmap.set(lizards, "oh no");
+
+  var keys = ChromeUtils.nondeterministicGetWeakMapKeys(bunnies);
+  equal(keys, undefined, "test nondeterministicGetWeakMapKeys on non-WeakMap");
+
+  keys = ChromeUtils.nondeterministicGetWeakMapKeys(weakmap);
+  equal(keys.length, 2, "length of nondeterministicGetWeakMapKeys");
+  equal(weakmap.get(bunnies), 23, "check bunnies in weakmap");
+  equal(weakmap.get(lizards), "oh no", "check lizards in weakmap");
+
+  keys = ChromeUtils.nondeterministicGetWeakSetKeys(bunnies);
+  equal(keys, undefined, "test nondeterministicGetWeakSetKeys on non-WeakMap");
+
+  keys = ChromeUtils.nondeterministicGetWeakSetKeys(weakset);
+  equal(keys.length, 2, "length of nondeterministicGetWeakSetKeys");
+  ok(weakset.has(bunnies), "check bunnies in weakset");
+  ok(weakset.has(lizards), "check lizards in weakset");
+
+  bunnies = null;
+  keys = null;
+
+  Cu.forceGC();
+
+  keys = ChromeUtils.nondeterministicGetWeakMapKeys(weakmap);
+  equal(keys.length, 1, "length of nondeterministicGetWeakMapKeys after GC");
+  equal(weakmap.get(lizards), "oh no", "check lizards still in weakmap");
+
+  keys = ChromeUtils.nondeterministicGetWeakSetKeys(weakset);
+  equal(keys.length, 1, "length of nondeterministicGetWeakSetKeys after GC");
+  ok(weakset.has(lizards), "check lizards still in weakset");
+}
diff --git a/js/xpconnect/tests/unit/test_wrapped_js_enumerator.js b/js/xpconnect/tests/unit/test_wrapped_js_enumerator.js
new file mode 100644
index 0000000000..5a366ba25d
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_wrapped_js_enumerator.js
@@ -0,0 +1,71 @@
+"use strict";
+
+// Tests that JS iterators are automatically wrapped into
+// equivalent nsISimpleEnumerator objects.
+
+const Variant = Components.Constructor("@mozilla.org/variant;1",
+                                       "nsIWritableVariant",
+                                       "setFromVariant");
+const SupportsInterfacePointer = Components.Constructor(
+  "@mozilla.org/supports-interface-pointer;1", "nsISupportsInterfacePointer");
+
+function wrapEnumerator1(iter) {
+  var ip = SupportsInterfacePointer();
+  ip.data = iter;
+  return ip.data.QueryInterface(Ci.nsISimpleEnumerator);
+}
+
+function wrapEnumerator2(iter) {
+  var ip = SupportsInterfacePointer();
+  ip.data = {
+    QueryInterface: ChromeUtils.generateQI(["nsIFilePicker"]),
+    get files() {
+      return iter;
+    },
+  };
+  return ip.data.QueryInterface(Ci.nsIFilePicker).files;
+}
+
+
+function enumToArray(iter) {
+  let result = [];
+  while (iter.hasMoreElements()) {
+    result.push(iter.getNext().QueryInterface(Ci.nsIVariant));
+  }
+  return result;
+}
+
+add_task(async function test_wrapped_js_enumerator() {
+  let array = [1, 2, 3, 4];
+
+  for (let wrapEnumerator of [wrapEnumerator1, wrapEnumerator2]) {
+    // Test a plain JS iterator. This should automatically be wrapped into
+    // an equivalent nsISimpleEnumerator.
+    {
+      let iter = wrapEnumerator(array.values());
+      let result = enumToArray(iter);
+
+      deepEqual(result, array, "Got correct result");
+    }
+
+    // Test an object with a QueryInterface method, which implements
+    // nsISimpleEnumerator. This should be wrapped and used directly.
+    {
+      let obj = {
+        QueryInterface: ChromeUtils.generateQI(["nsISimpleEnumerator"]),
+        _idx: 0,
+        hasMoreElements() {
+          return this._idx < array.length;
+        },
+        getNext() {
+          return Variant(array[this._idx++]);
+        },
+      };
+
+      let iter = wrapEnumerator(obj);
+      let result = enumToArray(iter);
+
+      deepEqual(result, array, "Got correct result");
+    }
+  }
+});
diff --git a/js/xpconnect/tests/unit/test_xpcomutils.js b/js/xpconnect/tests/unit/test_xpcomutils.js
new file mode 100644
index 0000000000..90605c4ca8
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xpcomutils.js
@@ -0,0 +1,275 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 4 -*-
+ * vim: sw=4 ts=4 sts=4 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file tests the methods on XPCOMUtils.sys.mjs.
+ * Also on ComponentUtils.jsm. Which is deprecated.
+ */
+
+const {AppConstants} = ChromeUtils.importESModule("resource://gre/modules/AppConstants.sys.mjs");
+const {ComponentUtils} = ChromeUtils.importESModule("resource://gre/modules/ComponentUtils.sys.mjs");
+const {Preferences} = ChromeUtils.importESModule("resource://gre/modules/Preferences.sys.mjs");
+const {XPCOMUtils} = ChromeUtils.importESModule("resource://gre/modules/XPCOMUtils.sys.mjs");
+
+////////////////////////////////////////////////////////////////////////////////
+//// Tests
+
+add_test(function test_generateQI_string_names()
+{
+    var x = {
+        QueryInterface: ChromeUtils.generateQI([
+            "nsIClassInfo",
+            "nsIObserver"
+        ])
+    };
+
+    try {
+        x.QueryInterface(Ci.nsIClassInfo);
+    } catch(e) {
+        do_throw("Should QI to nsIClassInfo");
+    }
+    try {
+        x.QueryInterface(Ci.nsIObserver);
+    } catch(e) {
+        do_throw("Should QI to nsIObserver");
+    }
+    try {
+        x.QueryInterface(Ci.nsIObserverService);
+        do_throw("QI should not have succeeded!");
+    } catch(e) {}
+    run_next_test();
+});
+
+add_test(function test_defineLazyGetter()
+{
+    let accessCount = 0;
+    let obj = {
+      inScope: false
+    };
+    const TEST_VALUE = "test value";
+    XPCOMUtils.defineLazyGetter(obj, "foo", function() {
+        accessCount++;
+        this.inScope = true;
+        return TEST_VALUE;
+    });
+    Assert.equal(accessCount, 0);
+
+    // Get the property, making sure the access count has increased.
+    Assert.equal(obj.foo, TEST_VALUE);
+    Assert.equal(accessCount, 1);
+    Assert.ok(obj.inScope);
+
+    // Get the property once more, making sure the access count has not
+    // increased.
+    Assert.equal(obj.foo, TEST_VALUE);
+    Assert.equal(accessCount, 1);
+    run_next_test();
+});
+
+
+add_test(function test_defineLazyServiceGetter()
+{
+    let obj = { };
+    XPCOMUtils.defineLazyServiceGetter(obj, "service",
+                                       "@mozilla.org/consoleservice;1",
+                                       "nsIConsoleService");
+    let service = Cc["@mozilla.org/consoleservice;1"].
+                  getService(Ci.nsIConsoleService);
+
+    // Check that the lazy service getter and the actual service have the same
+    // properties.
+    for (let prop in obj.service)
+        Assert.ok(prop in service);
+    for (let prop in service)
+        Assert.ok(prop in obj.service);
+    run_next_test();
+});
+
+
+add_test(function test_defineLazyPreferenceGetter()
+{
+    const PREF = "xpcomutils.test.pref";
+
+    let obj = {};
+    XPCOMUtils.defineLazyPreferenceGetter(obj, "pref", PREF, "defaultValue");
+
+
+    equal(obj.pref, "defaultValue", "Should return the default value before pref is set");
+
+    Preferences.set(PREF, "currentValue");
+
+
+    info("Create second getter on new object");
+
+    obj = {};
+    XPCOMUtils.defineLazyPreferenceGetter(obj, "pref", PREF, "defaultValue");
+
+
+    equal(obj.pref, "currentValue", "Should return the current value on initial read when pref is already set");
+
+    Preferences.set(PREF, "newValue");
+
+    equal(obj.pref, "newValue", "Should return new value after preference change");
+
+    Preferences.set(PREF, "currentValue");
+
+    equal(obj.pref, "currentValue", "Should return new value after second preference change");
+
+
+    Preferences.reset(PREF);
+
+    equal(obj.pref, "defaultValue", "Should return default value after pref is reset");
+
+    obj = {};
+    XPCOMUtils.defineLazyPreferenceGetter(obj, "pref", PREF, "a,b",
+                                          null, value => value.split(","));
+
+    deepEqual(obj.pref, ["a", "b"], "transform is applied to default value");
+
+    Preferences.set(PREF, "x,y,z");
+    deepEqual(obj.pref, ["x", "y", "z"], "transform is applied to updated value");
+
+    Preferences.reset(PREF);
+    deepEqual(obj.pref, ["a", "b"], "transform is applied to reset default");
+
+    if (AppConstants.DEBUG) {
+      // Need to use a 'real' pref so it will have a valid prefType
+      obj = {};
+      Assert.throws(
+        () => XPCOMUtils.defineLazyPreferenceGetter(obj, "pref", "javascript.enabled", 1),
+        /Default value does not match preference type/,
+        "Providing a default value of a different type than the preference throws an exception"
+      );
+    }
+
+    run_next_test();
+});
+
+
+add_test(function test_categoryRegistration()
+{
+  const CATEGORY_NAME = "test-cat";
+  const XULAPPINFO_CONTRACTID = "@mozilla.org/xre/app-info;1";
+  const XULAPPINFO_CID = Components.ID("{fc937916-656b-4fb3-a395-8c63569e27a8}");
+
+  // Create a fake app entry for our category registration apps filter.
+  let { newAppInfo } = ChromeUtils.importESModule("resource://testing-common/AppInfo.sys.mjs");
+  let XULAppInfo = newAppInfo({
+    name: "catRegTest",
+    ID: "{adb42a9a-0d19-4849-bf4d-627614ca19be}",
+    version: "1",
+    platformVersion: "",
+  });
+  let XULAppInfoFactory = {
+    createInstance: function (iid) {
+      return XULAppInfo.QueryInterface(iid);
+    }
+  };
+  let registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+  registrar.registerFactory(
+    XULAPPINFO_CID,
+    "XULAppInfo",
+    XULAPPINFO_CONTRACTID,
+    XULAppInfoFactory
+  );
+
+  // Load test components.
+  do_load_manifest("CatRegistrationComponents.manifest");
+
+  const expectedEntries = new Map([
+    ["CatRegisteredComponent", "@unit.test.com/cat-registered-component;1"],
+    ["CatAppRegisteredComponent", "@unit.test.com/cat-app-registered-component;1"],
+  ]);
+
+  // Verify the correct entries are registered in the "test-cat" category.
+  for (let {entry, value} of Services.catMan.enumerateCategory(CATEGORY_NAME)) {
+    ok(expectedEntries.has(entry), `${entry} is expected`);
+    Assert.equal(value, expectedEntries.get(entry), "${entry} has correct value.");
+    expectedEntries.delete(entry);
+  }
+  Assert.deepEqual(
+    Array.from(expectedEntries.keys()),
+    [],
+    "All expected entries have been deleted."
+  );
+  run_next_test();
+});
+
+add_test(function test_categoryBackgroundTaskRegistration()
+{
+  const CATEGORY_NAME = "test-cat1";
+
+  // Note that this test should succeed whether or not MOZ_BACKGROUNDTASKS is
+  // defined.  If it's defined, there's no active task so the `backgroundtask`
+  // directive is processed, dropped, and always succeeds.  If it's not defined,
+  // then the `backgroundtask` directive is processed and ignored.
+
+  // Load test components.
+  do_load_manifest("CatBackgroundTaskRegistrationComponents.manifest");
+
+  let expectedEntriesList = [
+    ["Cat1RegisteredComponent", "@unit.test.com/cat1-registered-component;1"],
+    ["Cat1BackgroundTaskNotRegisteredComponent", "@unit.test.com/cat1-backgroundtask-notregistered-component;1"],
+  ];
+  if (!AppConstants.MOZ_BACKGROUNDTASKS) {
+    expectedEntriesList.push(...[
+      ["Cat1BackgroundTaskRegisteredComponent", "@unit.test.com/cat1-backgroundtask-registered-component;1"],
+      ["Cat1BackgroundTaskAlwaysRegisteredComponent", "@unit.test.com/cat1-backgroundtask-alwaysregistered-component;1"],
+    ]);
+  }
+  const expectedEntries = new Map(expectedEntriesList);
+
+  // Verify the correct entries are registered in the "test-cat" category.
+  for (let {entry, value} of Services.catMan.enumerateCategory(CATEGORY_NAME)) {
+    ok(expectedEntries.has(entry), `${entry} is expected`);
+    Assert.equal(value, expectedEntries.get(entry), "Verify that the value is correct in the expected entries.");
+    expectedEntries.delete(entry);
+  }
+  Assert.deepEqual(
+    Array.from(expectedEntries.keys()),
+    [],
+    "All expected entries have been deleted."
+  );
+  run_next_test();
+});
+
+add_test(function test_generateSingletonFactory()
+{
+  const XPCCOMPONENT_CONTRACTID = "@mozilla.org/singletonComponentTest;1";
+  const XPCCOMPONENT_CID = Components.ID("{31031c36-5e29-4dd9-9045-333a5d719a3e}");
+
+  function XPCComponent() {}
+  XPCComponent.prototype = {
+    classID: XPCCOMPONENT_CID,
+    QueryInterface: ChromeUtils.generateQI([])
+  };
+  let registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+  registrar.registerFactory(
+    XPCCOMPONENT_CID,
+    "XPCComponent",
+    XPCCOMPONENT_CONTRACTID,
+    ComponentUtils.generateSingletonFactory(XPCComponent)
+  );
+
+  // First, try to instance the component.
+  let instance = Cc[XPCCOMPONENT_CONTRACTID].createInstance(Ci.nsISupports);
+  // Try again, check that it returns the same instance as before.
+  Assert.equal(instance,
+               Cc[XPCCOMPONENT_CONTRACTID].createInstance(Ci.nsISupports));
+  // Now, for sanity, check that getService is also returning the same instance.
+  Assert.equal(instance,
+               Cc[XPCCOMPONENT_CONTRACTID].getService(Ci.nsISupports));
+
+  run_next_test();
+});
+
+////////////////////////////////////////////////////////////////////////////////
+//// Test Runner
+
+function run_test()
+{
+  run_next_test();
+}
diff --git a/js/xpconnect/tests/unit/test_xpcwn_instanceof.js b/js/xpconnect/tests/unit/test_xpcwn_instanceof.js
new file mode 100644
index 0000000000..96268fd0b4
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xpcwn_instanceof.js
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Tests for custom `instanceof` behavior via XPC_SCRIPTABLE_WANT_HASINSTANCE.
+
+add_task(function id_instanceof() {
+  // ID objects are instances of Components.ID.
+  let id = Components.ID("{f2f5c784-7f6c-43f5-81b0-45ff32c312b1}");
+  Assert.equal(id instanceof Components.ID, true);
+  Assert.equal({} instanceof Components.ID, false);
+  Assert.equal(null instanceof Components.ID, false);
+
+  // Components.ID has a Symbol.hasInstance function.
+  let desc = Object.getOwnPropertyDescriptor(Components.ID, Symbol.hasInstance);
+  Assert.equal(typeof desc, "object");
+  Assert.equal(typeof desc.value, "function");
+
+  // Test error handling when calling this function with unexpected values.
+  Assert.throws(() => desc.value.call(null), /At least 1 argument required/);
+  Assert.throws(() => desc.value.call(null, 1), /unexpected this value/);
+  Assert.throws(() => desc.value.call({}, {}), /NS_ERROR_XPC_BAD_OP_ON_WN_PROTO/);
+});
diff --git a/js/xpconnect/tests/unit/test_xpcwn_tamperproof.js b/js/xpconnect/tests/unit/test_xpcwn_tamperproof.js
new file mode 100644
index 0000000000..62d57533fa
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xpcwn_tamperproof.js
@@ -0,0 +1,180 @@
+// Test that it's not possible to create expando properties on XPCWNs.
+// See <https://bugzilla.mozilla.org/show_bug.cgi?id=1143810#c5>.
+
+function TestInterfaceAll() {}
+TestInterfaceAll.prototype = {
+  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestInterfaceA",
+                                          "nsIXPCTestInterfaceB",
+                                          "nsIXPCTestInterfaceC"]),
+
+  /* nsIXPCTestInterfaceA / nsIXPCTestInterfaceB */
+  name: "TestInterfaceAllDefaultName",
+
+  /* nsIXPCTestInterfaceC */
+  someInteger: 42
+};
+
+function check_throws(f) {
+  try {
+    f();
+  } catch (exc) {
+    return;
+  }
+  throw new TypeError("Expected exception, no exception thrown");
+}
+
+/*
+ * Test that XPCWrappedNative objects do not permit expando properties to be created.
+ *
+ * This function is called twice. The first time, realObj is an nsITimer XPCWN
+ * and accessObj === realObj.
+ *
+ * The second time, accessObj is a scripted proxy with realObj as its target.
+ * So the second time we are testing that scripted proxies don't magically
+ * bypass whatever mechanism enforces the expando policy on XPCWNs.
+ */
+function test_tamperproof(realObj, accessObj, {method, constant, attribute}) {
+  // Assignment can't create an expando property.
+  check_throws(function () { accessObj.expando = 14; });
+  Assert.equal(false, "expando" in realObj);
+
+  // Strict assignment throws.
+  check_throws(function () { "use strict"; accessObj.expando = 14; });
+  Assert.equal(false, "expando" in realObj);
+
+  // Assignment to an inherited method name doesn't work either.
+  check_throws(function () { accessObj.hasOwnProperty = () => "lies"; });
+  check_throws(function () { "use strict"; accessObj.hasOwnProperty = () => "lies"; });
+  Assert.ok(!realObj.hasOwnProperty("hasOwnProperty"));
+
+  // Assignment to a method name doesn't work either.
+  let originalMethod;
+  if (method) {
+    originalMethod = accessObj[method];
+    accessObj[method] = "nope";  // non-writable data property, no exception in non-strict code
+    check_throws(function () { "use strict"; accessObj[method] = "nope"; });
+    Assert.ok(realObj[method] === originalMethod);
+  }
+
+  // A constant is the same thing.
+  let originalConstantValue;
+  if (constant) {
+    originalConstantValue = accessObj[constant];
+    accessObj[constant] = "nope";
+    Assert.equal(realObj[constant], originalConstantValue);
+    check_throws(function () { "use strict"; accessObj[constant] = "nope"; });
+    Assert.equal(realObj[constant], originalConstantValue);
+  }
+
+  // Assignment to a readonly accessor property with no setter doesn't work either.
+  let originalAttributeDesc;
+  if (attribute) {
+    originalAttributeDesc = Object.getOwnPropertyDescriptor(realObj, attribute);
+    Assert.ok("set" in originalAttributeDesc);
+    Assert.ok(originalAttributeDesc.set === undefined);
+
+    accessObj[attribute] = "nope";  // accessor property with no setter: no exception in non-strict code
+    check_throws(function () { "use strict"; accessObj[attribute] = "nope"; });
+
+    let desc = Object.getOwnPropertyDescriptor(realObj, attribute);
+    Assert.ok("set" in desc);
+    Assert.equal(originalAttributeDesc.get, desc.get);
+    Assert.equal(undefined, desc.set);
+  }
+
+  // Reflect.set doesn't work either.
+  if (method) {
+    Assert.ok(!Reflect.set({}, method, "bad", accessObj));
+    Assert.equal(realObj[method], originalMethod);
+  }
+  if (attribute) {
+    Assert.ok(!Reflect.set({}, attribute, "bad", accessObj));
+    Assert.equal(originalAttributeDesc.get, Object.getOwnPropertyDescriptor(realObj, attribute).get);
+  }
+
+  // Object.defineProperty can't do anything either.
+  let names = ["expando"];
+  if (method) names.push(method);
+  if (constant) names.push(constant);
+  if (attribute) names.push(attribute);
+  for (let name of names) {
+    let originalDesc = Object.getOwnPropertyDescriptor(realObj, name);
+    check_throws(function () {
+      Object.defineProperty(accessObj, name, {configurable: true});
+    });
+    check_throws(function () {
+      Object.defineProperty(accessObj, name, {writable: true});
+    });
+    check_throws(function () {
+      Object.defineProperty(accessObj, name, {get: function () { return "lies"; }});
+    });
+    check_throws(function () {
+      Object.defineProperty(accessObj, name, {value: "bad"});
+    });
+    let desc = Object.getOwnPropertyDescriptor(realObj, name);
+    if (originalDesc === undefined) {
+      Assert.equal(undefined, desc);
+    } else {
+      Assert.equal(originalDesc.configurable, desc.configurable);
+      Assert.equal(originalDesc.enumerable, desc.enumerable);
+      Assert.equal(originalDesc.writable, desc.writable);
+      Assert.equal(originalDesc.value, desc.value);
+      Assert.equal(originalDesc.get, desc.get);
+      Assert.equal(originalDesc.set, desc.set);
+    }
+  }
+
+  // Existing properties can't be deleted.
+  if (method) {
+    Assert.equal(false, delete accessObj[method]);
+    check_throws(function () { "use strict"; delete accessObj[method]; });
+    Assert.equal(realObj[method], originalMethod);
+  }
+  if (constant) {
+    Assert.equal(false, delete accessObj[constant]);
+    check_throws(function () { "use strict"; delete accessObj[constant]; });
+    Assert.equal(realObj[constant], originalConstantValue);
+  }
+  if (attribute) {
+    Assert.equal(false, delete accessObj[attribute]);
+    check_throws(function () { "use strict"; delete accessObj[attribute]; });
+    desc = Object.getOwnPropertyDescriptor(realObj, attribute);
+    Assert.equal(originalAttributeDesc.get, desc.get);
+  }
+}
+
+function test_twice(obj, options) {
+  test_tamperproof(obj, obj, options);
+
+  let handler = {
+    getPrototypeOf(t) {
+      return new Proxy(Object.getPrototypeOf(t), handler);
+    }
+  };
+  test_tamperproof(obj, new Proxy(obj, handler), options);
+}
+
+function run_test() {
+  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+  test_twice(timer, {
+    method: "init",
+    constant: "TYPE_ONE_SHOT",
+    attribute: "callback"
+  });
+
+  let cmdline = Cu.createCommandLine([], null, Ci.nsICommandLine.STATE_INITIAL_LAUNCH);
+  test_twice(cmdline, {});
+
+  test_twice(Object.getPrototypeOf(cmdline), {
+    method: "getArgument",
+    constant: "STATE_INITIAL_LAUNCH",
+    attribute: "length"
+  });
+
+  // Test a tearoff object.
+  let b = xpcWrap(new TestInterfaceAll(), Ci.nsIXPCTestInterfaceB);
+  let tearoff = b.nsIXPCTestInterfaceA;
+  test_twice(tearoff, {
+    method: "QueryInterface"
+  });
+}
diff --git a/js/xpconnect/tests/unit/test_xray_SavedFrame-02.js b/js/xpconnect/tests/unit/test_xray_SavedFrame-02.js
new file mode 100644
index 0000000000..e9b5752044
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_SavedFrame-02.js
@@ -0,0 +1,71 @@
+// Test calling SavedFrame getters across wrappers from privileged and
+// un-privileged globals.
+
+const {addDebuggerToGlobal} = ChromeUtils.importESModule("resource://gre/modules/jsdebugger.sys.mjs");
+addDebuggerToGlobal(globalThis);
+
+const lowP = Services.scriptSecurityManager.createNullPrincipal({});
+const highP = Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
+
+const low  = new Cu.Sandbox(lowP);
+const high = new Cu.Sandbox(highP);
+
+function run_test() {
+  // Privileged compartment accessing unprivileged stack.
+  high.stack = getSavedFrameInstanceFromSandbox(low);
+  Cu.evalInSandbox("this.parent = stack.parent", high);
+  Cu.evalInSandbox("this.asyncParent = stack.asyncParent", high);
+  Cu.evalInSandbox("this.source = stack.source", high);
+  Cu.evalInSandbox("this.functionDisplayName = stack.functionDisplayName", high);
+
+  // Un-privileged compartment accessing privileged stack.
+  low.stack = getSavedFrameInstanceFromSandbox(high);
+  try {
+    Cu.evalInSandbox("this.parent = stack.parent", low);
+  } catch (e) { }
+  try {
+    Cu.evalInSandbox("this.asyncParent = stack.asyncParent", low);
+  } catch (e) { }
+  try {
+    Cu.evalInSandbox("this.source = stack.source", low);
+  } catch (e) { }
+  try {
+    Cu.evalInSandbox("this.functionDisplayName = stack.functionDisplayName", low);
+  } catch (e) { }
+
+  // Privileged compartment accessing privileged stack.
+  let stack = getSavedFrameInstanceFromSandbox(high);
+  let parent = stack.parent;
+  let asyncParent = stack.asyncParent;
+  let source = stack.source;
+  let functionDisplayName = stack.functionDisplayName;
+
+  ok(true, "Didn't crash");
+}
+
+// Get a SavedFrame instance from inside the given sandbox.
+//
+// We can't use Cu.getJSTestingFunctions().saveStack() because Cu isn't
+// available to sandboxes that don't have the system principal. The easiest way
+// to get the SavedFrame is to use the Debugger API to track allocation sites
+// and then do an allocation.
+function getSavedFrameInstanceFromSandbox(sandbox) {
+  const dbg = new Debugger(sandbox);
+
+  dbg.memory.trackingAllocationSites = true;
+  Cu.evalInSandbox("(function iife() { return new RegExp }())", sandbox);
+  const allocs = dbg.memory.drainAllocationsLog().filter(e => e.class === "RegExp");
+  dbg.memory.trackingAllocationSites = false;
+
+  ok(allocs[0], "We should observe the allocation");
+  const { frame } = allocs[0];
+
+  if (sandbox !== high) {
+    ok(Cu.isXrayWrapper(frame), "`frame` should be an xray...");
+    equal(Object.prototype.toString.call(Cu.waiveXrays(frame)),
+          "[object SavedFrame]",
+          "...and that xray should wrap a SavedFrame");
+  }
+
+  return frame;
+}
diff --git a/js/xpconnect/tests/unit/test_xray_SavedFrame.js b/js/xpconnect/tests/unit/test_xray_SavedFrame.js
new file mode 100644
index 0000000000..85c91a2aa1
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_SavedFrame.js
@@ -0,0 +1,104 @@
+// Bug 1117242: Test calling SavedFrame getters from globals that don't subsume
+// that frame's principals.
+
+const {addDebuggerToGlobal} = ChromeUtils.importESModule("resource://gre/modules/jsdebugger.sys.mjs");
+addDebuggerToGlobal(globalThis);
+
+const lowP = Services.scriptSecurityManager.createNullPrincipal({});
+const midP = [lowP, "http://other.com"];
+const highP = Cc["@mozilla.org/systemprincipal;1"].createInstance(Ci.nsIPrincipal);
+
+const low  = new Cu.Sandbox(lowP);
+const mid  = new Cu.Sandbox(midP);
+const high = new Cu.Sandbox(highP);
+
+function run_test() {
+  // Test that the priveleged view of a SavedFrame from a subsumed compartment
+  // is the same view that the subsumed compartment gets. Create the following
+  // chain of function calls (with some intermediate system-principaled frames
+  // due to implementation):
+  //
+  //     low.lowF -> mid.midF -> high.highF -> high.saveStack
+  //
+  // Where high.saveStack gets monkey patched to create stacks in each of our
+  // sandboxes.
+
+  Cu.evalInSandbox("function highF() { return saveStack(); }", high);
+
+  mid.highF = () => high.highF();
+  Cu.evalInSandbox("function midF() { return highF(); }", mid);
+
+  low.midF = () => mid.midF();
+  Cu.evalInSandbox("function lowF() { return midF(); }", low);
+
+  const expected = [
+    {
+      sandbox: low,
+      frames: ["lowF"],
+    },
+    {
+      sandbox: mid,
+      frames: ["midF", "lowF"],
+    },
+    {
+      sandbox: high,
+      frames: ["getSavedFrameInstanceFromSandbox",
+               "saveStack",
+               "highF",
+               "run_test/mid.highF",
+               "midF",
+               "run_test/low.midF",
+               "lowF",
+               "run_test",
+               "_execute_test",
+               null],
+    }
+  ];
+
+  for (let { sandbox, frames } of expected) {
+    high.saveStack = function saveStack() {
+      return getSavedFrameInstanceFromSandbox(sandbox);
+    };
+
+    const xrayStack = low.lowF();
+    equal(xrayStack.functionDisplayName, "getSavedFrameInstanceFromSandbox",
+          "Xrays should always be able to see everything.");
+
+    let waived = Cu.waiveXrays(xrayStack);
+    do {
+      ok(frames.length,
+         "There should still be more expected frames while we have actual frames.");
+      equal(waived.functionDisplayName, frames.shift(),
+            "The waived wrapper should give us the stack's compartment's view.");
+      waived = waived.parent;
+    } while (waived);
+  }
+}
+
+// Get a SavedFrame instance from inside the given sandbox.
+//
+// We can't use Cu.getJSTestingFunctions().saveStack() because Cu isn't
+// available to sandboxes that don't have the system principal. The easiest way
+// to get the SavedFrame is to use the Debugger API to track allocation sites
+// and then do an allocation.
+function getSavedFrameInstanceFromSandbox(sandbox) {
+  const dbg = new Debugger(sandbox);
+
+  dbg.memory.trackingAllocationSites = true;
+  Cu.evalInSandbox("new Object", sandbox);
+  const allocs = dbg.memory.drainAllocationsLog();
+  dbg.memory.trackingAllocationSites = false;
+
+  ok(allocs[0], "We should observe the allocation");
+  const { frame } = allocs[0];
+
+  if (sandbox !== high) {
+    ok(Cu.isXrayWrapper(frame), "`frame` should be an xray...");
+    equal(Object.prototype.toString.call(Cu.waiveXrays(frame)),
+          "[object SavedFrame]",
+          "...and that xray should wrap a SavedFrame");
+  }
+
+  return frame;
+}
+
diff --git a/js/xpconnect/tests/unit/test_xray_instanceof.js b/js/xpconnect/tests/unit/test_xray_instanceof.js
new file mode 100644
index 0000000000..950d7c0060
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_instanceof.js
@@ -0,0 +1,206 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(function instanceof_xrays() {
+  let sandbox = Cu.Sandbox(null);
+  Cu.evalInSandbox(`
+    this.proxy = new Proxy([], {
+      getPrototypeOf() {
+        return Date.prototype;
+      },
+    });
+
+    this.inheritedProxy = Object.create(this.proxy);
+
+    this.FunctionProxy = new Proxy(function() {}, {});
+    this.functionProxyInstance = new this.FunctionProxy();
+
+    this.CustomClass = class {};
+    this.customClassInstance = new this.CustomClass();
+  `, sandbox);
+
+  {
+    // Sanity check that instanceof still works with standard constructors when xrays are present.
+    Assert.ok(Cu.evalInSandbox(`new Date()`, sandbox) instanceof sandbox.Date,
+              "async function result in sandbox instanceof sandbox.Date");
+    Assert.ok(new sandbox.Date() instanceof sandbox.Date,
+              "sandbox.Date() instanceof sandbox.Date");
+
+    Assert.ok(sandbox.CustomClass instanceof sandbox.Function,
+              "Class constructor instanceof sandbox.Function");
+    Assert.ok(sandbox.CustomClass instanceof sandbox.Object,
+              "Class constructor instanceof sandbox.Object");
+
+    // Both operands must have the same kind of Xray vision.
+    Assert.equal(Cu.waiveXrays(sandbox.CustomClass) instanceof sandbox.Function, false,
+                 "Class constructor with waived xrays instanceof sandbox.Function");
+    Assert.equal(Cu.waiveXrays(sandbox.CustomClass) instanceof sandbox.Object, false,
+                 "Class constructor with waived xrays instanceof sandbox.Object");
+  }
+
+  {
+    let {proxy} = sandbox;
+    Assert.equal(proxy instanceof sandbox.Date, false,
+                 "instanceof should ignore the proxy trap");
+    Assert.equal(proxy instanceof sandbox.Array, false,
+                 "instanceof should ignore the proxy target");
+    Assert.equal(Cu.waiveXrays(proxy) instanceof sandbox.Date, false,
+                 "instanceof should ignore the proxy trap despite the waived xrays on the proxy");
+    Assert.equal(Cu.waiveXrays(proxy) instanceof sandbox.Array, false,
+                 "instanceof should ignore the proxy target despite the waived xrays on the proxy");
+
+    Assert.ok(proxy instanceof Cu.waiveXrays(sandbox.Date),
+              "instanceof should trigger the proxy trap after waiving Xrays on the constructor");
+    Assert.equal(proxy instanceof Cu.waiveXrays(sandbox.Array), false,
+                 "instanceof should trigger the proxy trap after waiving Xrays on the constructor");
+
+    Assert.ok(Cu.waiveXrays(proxy) instanceof Cu.waiveXrays(sandbox.Date),
+              "instanceof should trigger the proxy trap after waiving both Xrays");
+  }
+
+
+  {
+    let {inheritedProxy} = sandbox;
+    Assert.equal(inheritedProxy instanceof sandbox.Date, false,
+                 "instanceof should ignore the inherited proxy trap");
+    Assert.equal(Cu.waiveXrays(inheritedProxy) instanceof sandbox.Date, false,
+                 "instanceof should ignore the inherited proxy trap despite the waived xrays on the proxy");
+
+    Assert.ok(inheritedProxy instanceof Cu.waiveXrays(sandbox.Date),
+              "instanceof should trigger the inherited proxy trap after waiving Xrays on the constructor");
+
+    Assert.ok(Cu.waiveXrays(inheritedProxy) instanceof Cu.waiveXrays(sandbox.Date),
+              "instanceof should trigger the inherited proxy trap after waiving both Xrays");
+  }
+
+  {
+    let {FunctionProxy, functionProxyInstance} = sandbox;
+
+    // Ideally, the next two test cases should both throw "... not a function".
+    // However, because the opaque XrayWrapper does not override isCallable, an
+    // opaque XrayWrapper is still considered callable if the proxy target is,
+    // and "instanceof" will try to look up the prototype of the wrapper (and
+    // fail because opaque XrayWrappers hide the properties).
+    Assert.throws(
+      () => functionProxyInstance instanceof FunctionProxy,
+      /'prototype' property of FunctionProxy is not an object/,
+      "Opaque constructor proxy should be hidden by Xrays");
+    Assert.throws(
+      () => functionProxyInstance instanceof sandbox.proxy,
+      /sandbox.proxy is not a function/,
+      "Opaque non-constructor proxy should be hidden by Xrays");
+
+    Assert.ok(functionProxyInstance instanceof Cu.waiveXrays(FunctionProxy),
+              "instanceof should get through the proxy after waiving Xrays on the constructor proxy");
+    Assert.ok(Cu.waiveXrays(functionProxyInstance) instanceof Cu.waiveXrays(FunctionProxy),
+              "instanceof should get through the proxy after waiving both Xrays");
+  }
+
+  {
+    let {CustomClass, customClassInstance} = sandbox;
+    // Under Xray vision, every JS object is either a plain object or array.
+    // Prototypical inheritance is invisible when the constructor is wrapped.
+    Assert.throws(
+      () => customClassInstance instanceof CustomClass,
+      /TypeError: 'prototype' property of CustomClass is not an object/,
+      "instanceof on a custom JS class with xrays should fail");
+    Assert.ok(customClassInstance instanceof Cu.waiveXrays(CustomClass),
+              "instanceof should see the true prototype of CustomClass after waiving Xrays on the class");
+    Assert.ok(Cu.waiveXrays(customClassInstance) instanceof Cu.waiveXrays(CustomClass),
+              "instanceof should see the true prototype of CustomClass after waiving Xrays");
+  }
+});
+
+add_task(function instanceof_dom_xrays_hasInstance() {
+  const principal = Services.scriptSecurityManager.createNullPrincipal({});
+  const webnav = Services.appShell.createWindowlessBrowser(false);
+  webnav.docShell.createAboutBlankContentViewer(principal, principal);
+  let window = webnav.document.defaultView;
+
+  let sandbox = Cu.Sandbox(principal);
+  sandbox.DOMObjectWithHasInstance = window.document;
+  Cu.evalInSandbox(`
+    this.DOMObjectWithHasInstance[Symbol.hasInstance] = function() {
+      return true;
+    };
+    this.ObjectWithHasInstance = {
+      [Symbol.hasInstance](v) {
+        v.throwsIfVCannotBeAccessed;
+        return true;
+      },
+    };
+  `, sandbox);
+
+  // Override the hasInstance handler in the window, so that we can detect when
+  // we end up triggering hasInstance in the window's compartment.
+  window.eval(`
+    document[Symbol.hasInstance] = function() {
+      throw "hasInstance_in_window";
+    };
+  `);
+
+  sandbox.domobj = window.document.body;
+  Assert.ok(sandbox.eval(`domobj.wrappedJSObject`),
+            "DOM object is a XrayWrapper");
+  Assert.ok(sandbox.eval(`DOMObjectWithHasInstance.wrappedJSObject`),
+            "DOM object with Symbol.hasInstance is a XrayWrapper");
+
+  for (let Obj of ["ObjectWithHasInstance", "DOMObjectWithHasInstance"]) {
+    // Tests Xray vision *inside* the sandbox. The Symbol.hasInstance member
+    // is a property / expando object in the sandbox's compartment, so the
+    // "instanceof" operator should always trigger the hasInstance function.
+    Assert.ok(sandbox.eval(`[] instanceof ${Obj}`),
+              `Should call ${Obj}[Symbol.hasInstance] when left operand has no Xrays`);
+    Assert.ok(sandbox.eval(`domobj instanceof ${Obj}`),
+              `Should call ${Obj}[Symbol.hasInstance] when left operand has Xrays`);
+    Assert.ok(sandbox.eval(`domobj.wrappedJSObject instanceof ${Obj}`),
+              `Should call ${Obj}[Symbol.hasInstance] when left operand has waived Xrays`);
+
+    // Tests Xray vision *outside* the sandbox. The Symbol.hasInstance member
+    // should be hidden by Xrays.
+    let sandboxObjWithHasInstance = sandbox[Obj];
+    Assert.ok(Cu.isXrayWrapper(sandboxObjWithHasInstance),
+              `sandbox.${Obj} is a XrayWrapper`);
+    Assert.throws(
+      () => sandbox.Object() instanceof sandboxObjWithHasInstance,
+      /sandboxObjWithHasInstance is not a function/,
+      `sandbox.${Obj}[Symbol.hasInstance] should be hidden by Xrays`);
+
+    Assert.throws(
+      () => Cu.waiveXrays(sandbox.Object()) instanceof sandboxObjWithHasInstance,
+      /sandboxObjWithHasInstance is not a function/,
+      `sandbox.${Obj}[Symbol.hasInstance] should be hidden by Xrays, despite the waived Xrays at the left`);
+
+    // (Cases where the left operand has no Xrays are checked below.)
+  }
+
+  // hasInstance is expected to be called, but still trigger an error because
+  // properties of the object from the current context should not be readable
+  // by the hasInstance function in the sandbox with a different principal.
+  Assert.throws(
+    () => [] instanceof Cu.waiveXrays(sandbox.ObjectWithHasInstance),
+    /Permission denied to access property "throwsIfVCannotBeAccessed"/,
+    `Should call (waived) sandbox.ObjectWithHasInstance[Symbol.hasInstance] when the right operand has waived Xrays`);
+
+  // The Xray waiver on the right operand should be sufficient to call
+  // hasInstance even if the left operand still has Xrays.
+  Assert.ok(sandbox.Object() instanceof Cu.waiveXrays(sandbox.ObjectWithHasInstance),
+            `Should call (waived) sandbox.ObjectWithHasInstance[Symbol.hasInstance] when the right operand has waived Xrays`);
+  Assert.ok(Cu.waiveXrays(sandbox.Object()) instanceof Cu.waiveXrays(sandbox.ObjectWithHasInstance),
+            `Should call (waived) sandbox.ObjectWithHasInstance[Symbol.hasInstance] when both operands have waived Xrays`);
+
+  // When Xrays of the DOM object are waived, we end up in the owner document's
+  // compartment (instead of the sandbox).
+  Assert.throws(
+    () => [] instanceof Cu.waiveXrays(sandbox.DOMObjectWithHasInstance),
+    /hasInstance_in_window/,
+    "Should call (waived) sandbox.DOMObjectWithHasInstance[Symbol.hasInstance] when the right operand has waived Xrays");
+
+  Assert.throws(
+    () => Cu.waiveXrays(sandbox.Object()) instanceof Cu.waiveXrays(sandbox.DOMObjectWithHasInstance),
+    /hasInstance_in_window/,
+    "Should call (waived) sandbox.DOMObjectWithHasInstance[Symbol.hasInstance] when both operands have waived Xrays");
+
+  webnav.close();
+});
diff --git a/js/xpconnect/tests/unit/test_xray_named_element_access.js b/js/xpconnect/tests/unit/test_xray_named_element_access.js
new file mode 100644
index 0000000000..c35bf352a9
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_named_element_access.js
@@ -0,0 +1,23 @@
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=1273251
+"use strict"
+
+ChromeUtils.importESModule("resource://gre/modules/Preferences.sys.mjs");
+
+add_task(async function() {
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+
+  docShell.createAboutBlankContentViewer(null, null);
+
+  let window = webnav.document.defaultView;
+  let unwrapped = Cu.waiveXrays(window);
+
+  window.document.body.innerHTML = '<div id="foo"></div>';
+
+  equal(window.foo, undefined, "Should not have named X-ray property access");
+  equal(typeof unwrapped.foo, "object", "Should always have non-X-ray named property access");
+
+  webnav.close();
+});
+
diff --git a/js/xpconnect/tests/unit/test_xray_regexp.js b/js/xpconnect/tests/unit/test_xray_regexp.js
new file mode 100644
index 0000000000..72eb9563d0
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xray_regexp.js
@@ -0,0 +1,7 @@
+function run_test() {
+    var sandbox = Cu.Sandbox('http://www.example.com');
+    var regexp = Cu.evalInSandbox("/test/i", sandbox);
+    equal(RegExp.prototype.toString.call(regexp), "/test/i");
+    var prototype = Cu.evalInSandbox("RegExp.prototype", sandbox);
+    equal(typeof prototype.lastIndex, "undefined");
+}
diff --git a/js/xpconnect/tests/unit/test_xrayed_arguments.js b/js/xpconnect/tests/unit/test_xrayed_arguments.js
new file mode 100644
index 0000000000..fae0a0c865
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xrayed_arguments.js
@@ -0,0 +1,16 @@
+function run_test() {
+  var sbContent = Cu.Sandbox(null);
+  let xrayedArgs = sbContent.eval("(function(a, b) { return arguments; })('hi', 42)");
+
+  function checkArgs(a) {
+    Assert.equal(a.length, 2);
+    Assert.equal(a[0], 'hi');
+    Assert.equal(a[1], 42);
+  }
+
+  // Check Xrays to the args.
+  checkArgs(xrayedArgs);
+
+  // Make sure the spread operator works.
+  checkArgs([...xrayedArgs]);
+}
diff --git a/js/xpconnect/tests/unit/test_xrayed_iterator.js b/js/xpconnect/tests/unit/test_xrayed_iterator.js
new file mode 100644
index 0000000000..26d40420a3
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_xrayed_iterator.js
@@ -0,0 +1,40 @@
+Services.prefs.setBoolPref("security.allow_eval_with_system_principal", true);
+registerCleanupFunction(() => {
+  Services.prefs.clearUserPref("security.allow_eval_with_system_principal");
+});
+
+function run_test() {
+
+  var toEval = [
+    "var customIterator = {",
+    "  _array: [6, 7, 8, 9]",
+    "};",
+    "customIterator[Symbol.iterator] = function* () {",
+    "    for (var i = 0; i < this._array.length; ++i)",
+    "      yield this._array[i];",
+    "};"
+  ].join('\n');
+
+  function checkIterator(iterator) {
+    var control = [6, 7, 8, 9];
+    var i = 0;
+    for (var item of iterator) {
+      Assert.equal(item, control[i]);
+      ++i;
+    }
+  }
+
+  // First, try in our own scope.
+  eval(toEval);
+  checkIterator(customIterator);
+
+  // Next, try a vanilla CCW.
+  var sbChrome = Cu.Sandbox(this);
+  Cu.evalInSandbox(toEval, sbChrome, '1.7');
+  checkIterator(sbChrome.customIterator);
+
+  // Finally, try an Xray waiver.
+  var sbContent = Cu.Sandbox('http://www.example.com');
+  Cu.evalInSandbox(toEval, sbContent, '1.7');
+  checkIterator(Cu.waiveXrays(sbContent.customIterator));
+}
diff --git a/js/xpconnect/tests/unit/uninitialized_lexical.jsm b/js/xpconnect/tests/unit/uninitialized_lexical.jsm
new file mode 100644
index 0000000000..e0d661bcd4
--- /dev/null
+++ b/js/xpconnect/tests/unit/uninitialized_lexical.jsm
@@ -0,0 +1,2 @@
+var EXPORTED_SYMBOLS = ["foo"];
+const foo = ChromeUtils.import("resource://test/uninitialized_lexical.jsm");
diff --git a/js/xpconnect/tests/unit/xpcshell.ini b/js/xpconnect/tests/unit/xpcshell.ini
new file mode 100644
index 0000000000..23c1270028
--- /dev/null
+++ b/js/xpconnect/tests/unit/xpcshell.ini
@@ -0,0 +1,223 @@
+[DEFAULT]
+head = head.js
+support-files =
+  CatRegistrationComponents.manifest
+  CatBackgroundTaskRegistrationComponents.manifest
+  bogus_element_type.jsm
+  bogus_exports_type.jsm
+  bug451678_subscript.js
+  TestBlob.jsm
+  TestFile.jsm
+  environment_script.js
+  environment_loadscript.jsm
+  environment_checkscript.jsm
+  file_simple_script.js
+  importer.jsm
+  recursive_importA.jsm
+  recursive_importB.jsm
+  ReturnCodeChild.jsm
+  ReturnCodeChild.sys.mjs
+  syntax_error.jsm
+  uninitialized_lexical.jsm
+  es6module.js
+  es6import.js
+  es6module_throws.js
+  es6module_missing_import.js
+  es6module_parse_error.js
+  es6module_parse_error_in_import.js
+  es6module_cycle_a.js
+  es6module_cycle_b.js
+  es6module_cycle_c.js
+  es6module_top_level_await.js
+  es6module_devtoolsLoader.js
+  es6module_devtoolsLoader.sys.mjs
+  es6module_devtoolsLoader_only.js
+  esmified-1.sys.mjs
+  esmified-2.sys.mjs
+  esmified-3.sys.mjs
+  esmified-4.sys.mjs
+  esmified-5.sys.mjs
+  esmified-6.sys.mjs
+  esmified-not-exported.sys.mjs
+  not-esmified-not-exported.jsm
+  esm_lazy-1.sys.mjs
+  esm_lazy-2.sys.mjs
+  jsm_loaded-1.jsm
+  jsm_loaded-2.jsm
+  jsm_loaded-3.jsm
+  es6module_loaded-1.sys.mjs
+  es6module_loaded-2.sys.mjs
+  es6module_loaded-3.sys.mjs
+  api_script.js
+  import_stack.jsm
+  import_stack.sys.mjs
+  import_stack_static_1.sys.mjs
+  import_stack_static_2.sys.mjs
+  import_stack_static_3.sys.mjs
+  import_stack_static_4.sys.mjs
+  es6module_import_error.js
+  es6module_import_error2.js
+  es6module_dynamic_import.js
+  es6module_dynamic_import2.js
+  es6module_absolute.js
+  es6module_absolute2.js
+  envChain.jsm
+  envChain_subscript.jsm
+  error_export.sys.mjs
+  error_import.sys.mjs
+  error_other.sys.mjs
+
+[test_allowWaivers.js]
+[test_bogus_files.js]
+[test_bug267645.js]
+[test_bug408412.js]
+[test_bug451678.js]
+[test_bug604362.js]
+[test_bug677864.js]
+[test_bug711404.js]
+[test_bug742444.js]
+[test_bug778409.js]
+[test_bug780370.js]
+[test_bug809652.js]
+[test_bug809674.js]
+[test_bug813901.js]
+[test_bug845201.js]
+[test_bug845862.js]
+[test_bug849730.js]
+[test_bug851895.js]
+[test_bug853709.js]
+[test_bug856067.js]
+[test_bug868675.js]
+[test_bug867486.js]
+[test_bug872772.js]
+[test_bug885800.js]
+[test_bug930091.js]
+[test_bug976151.js]
+[test_bug1001094.js]
+[test_bug1021312.js]
+[test_bug1033253.js]
+[test_bug1033920.js]
+[test_bug1033927.js]
+[test_bug1034262.js]
+[test_bug1081990.js]
+[test_bug1110546.js]
+[test_bug1131707.js]
+[test_bug1150771.js]
+[test_bug1151385.js]
+[test_bug1170311.js]
+[test_bug1244222.js]
+[test_bug1617527.js]
+[test_bug_442086.js]
+[test_callFunctionWithAsyncStack.js]
+[test_cenums.js]
+[test_compileScript.js]
+[test_deepFreezeClone.js]
+[test_defineModuleGetter.js]
+[test_eventSource.js]
+[test_file.js]
+skip-if = os == 'android' && processor == 'x86_64'
+[test_blob.js]
+[test_blob2.js]
+[test_file2.js]
+skip-if = os == 'android' && processor == 'x86_64'
+[test_getCallerLocation.js]
+[test_generateQI.js]
+[test_import.js]
+[test_import_fail.js]
+[test_isModuleLoaded.js]
+[test_js_weak_references.js]
+[test_onGarbageCollection-01.js]
+head = head_ongc.js
+[test_onGarbageCollection-02.js]
+head = head_ongc.js
+[test_onGarbageCollection-03.js]
+head = head_ongc.js
+[test_onGarbageCollection-04.js]
+head = head_ongc.js
+[test_onGarbageCollection-05.js]
+head = head_ongc.js
+[test_reflect_parse.js]
+[test_localeCompare.js]
+[test_recursive_import.js]
+[test_xpcomutils.js]
+[test_unload.js]
+[test_lazyproxy.js]
+[test_attributes.js]
+[test_params.js]
+[test_tearoffs.js]
+[test_want_components.js]
+[test_components.js]
+[test_allowedDomains.js]
+[test_allowedDomainsXHR.js]
+[test_nuke_sandbox.js]
+[test_nuke_sandbox_event_listeners.js]
+[test_nuke_webextension_wrappers.js]
+[test_subScriptLoader.js]
+[test_rewrap_dead_wrapper.js]
+[test_sandbox_metadata.js]
+[test_sandbox_DOMException.js]
+[test_exportFunction.js]
+[test_promise.js]
+[test_returncode.js]
+[test_textDecoder.js]
+[test_url.js]
+[test_URLSearchParams.js]
+[test_fileReader.js]
+[test_messageChannel.js]
+[test_crypto.js]
+[test_css.js]
+[test_rtcIdentityProvider.js]
+[test_sandbox_atob.js]
+[test_structuredClone.js]
+[test_isProxy.js]
+[test_js_memory_telemetry.js]
+[test_getObjectPrincipal.js]
+[test_sandbox_name.js]
+[test_storage.js]
+[test_watchdog_enable.js]
+head = head_watchdog.js
+[test_watchdog_disable.js]
+head = head_watchdog.js
+[test_watchdog_toggle.js]
+head = head_watchdog.js
+[test_watchdog_default.js]
+head = head_watchdog.js
+[test_watchdog_hibernate.js]
+head = head_watchdog.js
+[test_weak_keys.js]
+[test_xpcwn_instanceof.js]
+[test_xpcwn_tamperproof.js]
+[test_xrayed_arguments.js]
+[test_xrayed_iterator.js]
+[test_xray_instanceof.js]
+[test_xray_named_element_access.js]
+[test_private_field_xrays.js]
+[test_xray_SavedFrame.js]
+[test_xray_SavedFrame-02.js]
+[test_xray_regexp.js]
+[test_resolve_dead_promise.js]
+[test_function_names.js]
+[test_FrameScriptEnvironment.js]
+[test_SubscriptLoaderEnvironment.js]
+[test_SubscriptLoaderSandboxEnvironment.js]
+[test_SubscriptLoaderJSMEnvironment.js]
+[test_ComponentEnvironment.js]
+[test_wrapped_js_enumerator.js]
+[test_uawidget_scope.js]
+[test_uninitialized_lexical.js]
+[test_print_stderr.js]
+[test_import_devtools_loader.js]
+[test_import_es6_modules.js]
+[test_import_shim.js]
+[test_defineESModuleGetters.js]
+[test_loadedESModules.js]
+[test_import_from_sandbox.js]
+[test_import_stack.js]
+skip-if =
+    !nightly_build
+    !debug
+[test_envChain_frameScript.js]
+[test_envChain_JSM.js]
+[test_envChain_subscript.js]
+[test_envChain_subscript_in_JSM.js]
+[test_import_syntax_error.js]
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 19:33:14 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-07 19:33:14 +0000
commit	36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree	105e8c98ddea1c1e4784a60a5a6410fa416be2de /js/xpconnect/tests
parent	Initial commit. (diff)
download	firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip