Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 2511 insertions, 0 deletions

diff --git a/remote/marionette/test/xpcshell/.eslintrc.js b/remote/marionette/test/xpcshell/.eslintrc.js
new file mode 100644
index 0000000000..2ef179ab5e
--- /dev/null
+++ b/remote/marionette/test/xpcshell/.eslintrc.js
@@ -0,0 +1,7 @@
+"use strict";
+
+module.exports = {
+  rules: {
+    camelcase: "off",
+  },
+};
diff --git a/remote/marionette/test/xpcshell/README b/remote/marionette/test/xpcshell/README
new file mode 100644
index 0000000000..ce516d17ca
--- /dev/null
+++ b/remote/marionette/test/xpcshell/README
@@ -0,0 +1,16 @@
+To run the tests in this directory, from the top source directory,
+either invoke the test despatcher in mach:
+
+	% ./mach test remote/marionette/test/xpcshell
+
+Or call out the harness specifically:
+
+	% ./mach xpcshell-test remote/marionette/test/xpcshell
+
+The latter gives you the --sequential option which can be useful
+when debugging to prevent tests from running in parallel.
+
+When adding new tests you must make sure they are listed in
+xpcshell.ini, otherwise they will not run on try.
+
+See also ../../doc/Testing.md for more advice on our other types of tests.
diff --git a/remote/marionette/test/xpcshell/head.js b/remote/marionette/test/xpcshell/head.js
new file mode 100644
index 0000000000..2e7cf578d3
--- /dev/null
+++ b/remote/marionette/test/xpcshell/head.js
@@ -0,0 +1,3 @@
+const SVG_NS = "http://www.w3.org/2000/svg";
+const XHTML_NS = "http://www.w3.org/1999/xhtml";
+const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
diff --git a/remote/marionette/test/xpcshell/test_actors.js b/remote/marionette/test/xpcshell/test_actors.js
new file mode 100644
index 0000000000..9b24d1d10f
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_actors.js
@@ -0,0 +1,55 @@
+/* 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";
+
+const {
+  getMarionetteCommandsActorProxy,
+  registerCommandsActor,
+  unregisterCommandsActor,
+} = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/actors/MarionetteCommandsParent.sys.mjs"
+);
+const { enableEventsActor, disableEventsActor } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/actors/MarionetteEventsParent.sys.mjs"
+);
+
+registerCleanupFunction(function () {
+  unregisterCommandsActor();
+  disableEventsActor();
+});
+
+add_task(function test_commandsActor_register() {
+  registerCommandsActor();
+  unregisterCommandsActor();
+
+  registerCommandsActor();
+  registerCommandsActor();
+  unregisterCommandsActor();
+});
+
+add_task(async function test_commandsActor_getActorProxy_noBrowsingContext() {
+  registerCommandsActor();
+
+  try {
+    await getMarionetteCommandsActorProxy(() => null).sendQuery("foo", "bar");
+    ok(false, "Expected NoBrowsingContext error not raised");
+  } catch (e) {
+    ok(
+      e.message.includes("No BrowsingContext found"),
+      "Expected default error message found"
+    );
+  }
+
+  unregisterCommandsActor();
+});
+
+add_task(function test_eventsActor_enable_disable() {
+  enableEventsActor();
+  disableEventsActor();
+
+  enableEventsActor();
+  enableEventsActor();
+  disableEventsActor();
+});
diff --git a/remote/marionette/test/xpcshell/test_browser.js b/remote/marionette/test/xpcshell/test_browser.js
new file mode 100644
index 0000000000..fdd83ba7e3
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_browser.js
@@ -0,0 +1,21 @@
+const { Context } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/browser.sys.mjs"
+);
+
+add_task(function test_Context() {
+  ok(Context.hasOwnProperty("Chrome"));
+  ok(Context.hasOwnProperty("Content"));
+  equal(typeof Context.Chrome, "string");
+  equal(typeof Context.Content, "string");
+  equal(Context.Chrome, "chrome");
+  equal(Context.Content, "content");
+});
+
+add_task(function test_Context_fromString() {
+  equal(Context.fromString("chrome"), Context.Chrome);
+  equal(Context.fromString("content"), Context.Content);
+
+  for (let typ of ["", "foo", true, 42, [], {}, null, undefined]) {
+    Assert.throws(() => Context.fromString(typ), /TypeError/);
+  }
+});
diff --git a/remote/marionette/test/xpcshell/test_cookie.js b/remote/marionette/test/xpcshell/test_cookie.js
new file mode 100644
index 0000000000..b5ce5e9008
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_cookie.js
@@ -0,0 +1,362 @@
+/* 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/. */
+
+const { cookie } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/cookie.sys.mjs"
+);
+
+/* eslint-disable mozilla/use-chromeutils-generateqi */
+
+cookie.manager = {
+  cookies: [],
+
+  add(
+    domain,
+    path,
+    name,
+    value,
+    secure,
+    httpOnly,
+    session,
+    expiry,
+    originAttributes,
+    sameSite
+  ) {
+    if (name === "fail") {
+      throw new Error("An error occurred while adding cookie");
+    }
+    let newCookie = {
+      host: domain,
+      path,
+      name,
+      value,
+      isSecure: secure,
+      isHttpOnly: httpOnly,
+      isSession: session,
+      expiry,
+      originAttributes,
+      sameSite,
+    };
+    cookie.manager.cookies.push(newCookie);
+  },
+
+  remove(host, name, path) {
+    for (let i = 0; i < this.cookies.length; ++i) {
+      let candidate = this.cookies[i];
+      if (
+        candidate.host === host &&
+        candidate.name === name &&
+        candidate.path === path
+      ) {
+        return this.cookies.splice(i, 1);
+      }
+    }
+    return false;
+  },
+
+  getCookiesFromHost(host) {
+    let hostCookies = this.cookies.filter(
+      c => c.host === host || c.host === "." + host
+    );
+
+    return hostCookies;
+  },
+};
+
+add_task(function test_fromJSON() {
+  // object
+  for (let invalidType of ["foo", 42, true, [], null, undefined]) {
+    Assert.throws(() => cookie.fromJSON(invalidType), /Expected cookie object/);
+  }
+
+  // name and value
+  for (let invalidType of [42, true, [], {}, null, undefined]) {
+    Assert.throws(
+      () => cookie.fromJSON({ name: invalidType }),
+      /Cookie name must be string/
+    );
+    Assert.throws(
+      () => cookie.fromJSON({ name: "foo", value: invalidType }),
+      /Cookie value must be string/
+    );
+  }
+
+  // domain
+  for (let invalidType of [42, true, [], {}, null]) {
+    let domainTest = {
+      name: "foo",
+      value: "bar",
+      domain: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(domainTest),
+      /Cookie domain must be string/
+    );
+  }
+  let domainTest = {
+    name: "foo",
+    value: "bar",
+    domain: "domain",
+  };
+  let parsedCookie = cookie.fromJSON(domainTest);
+  equal(parsedCookie.domain, "domain");
+
+  // path
+  for (let invalidType of [42, true, [], {}, null]) {
+    let pathTest = {
+      name: "foo",
+      value: "bar",
+      path: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(pathTest),
+      /Cookie path must be string/
+    );
+  }
+
+  // secure
+  for (let invalidType of ["foo", 42, [], {}, null]) {
+    let secureTest = {
+      name: "foo",
+      value: "bar",
+      secure: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(secureTest),
+      /Cookie secure flag must be boolean/
+    );
+  }
+
+  // httpOnly
+  for (let invalidType of ["foo", 42, [], {}, null]) {
+    let httpOnlyTest = {
+      name: "foo",
+      value: "bar",
+      httpOnly: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(httpOnlyTest),
+      /Cookie httpOnly flag must be boolean/
+    );
+  }
+
+  // expiry
+  for (let invalidType of [
+    -1,
+    Number.MAX_SAFE_INTEGER + 1,
+    "foo",
+    true,
+    [],
+    {},
+    null,
+  ]) {
+    let expiryTest = {
+      name: "foo",
+      value: "bar",
+      expiry: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(expiryTest),
+      /Cookie expiry must be a positive integer/
+    );
+  }
+
+  // sameSite
+  for (let invalidType of ["foo", 42, [], {}, null]) {
+    const sameSiteTest = {
+      name: "foo",
+      value: "bar",
+      sameSite: invalidType,
+    };
+    Assert.throws(
+      () => cookie.fromJSON(sameSiteTest),
+      /Cookie SameSite flag must be one of None, Lax, or Strict/
+    );
+  }
+
+  // bare requirements
+  let bare = cookie.fromJSON({ name: "name", value: "value" });
+  equal("name", bare.name);
+  equal("value", bare.value);
+  for (let missing of [
+    "path",
+    "secure",
+    "httpOnly",
+    "session",
+    "expiry",
+    "sameSite",
+  ]) {
+    ok(!bare.hasOwnProperty(missing));
+  }
+
+  // everything
+  let full = cookie.fromJSON({
+    name: "name",
+    value: "value",
+    domain: ".domain",
+    path: "path",
+    secure: true,
+    httpOnly: true,
+    expiry: 42,
+    sameSite: "Lax",
+  });
+  equal("name", full.name);
+  equal("value", full.value);
+  equal(".domain", full.domain);
+  equal("path", full.path);
+  equal(true, full.secure);
+  equal(true, full.httpOnly);
+  equal(42, full.expiry);
+  equal("Lax", full.sameSite);
+});
+
+add_task(function test_add() {
+  cookie.manager.cookies = [];
+
+  for (let invalidType of [42, true, [], {}, null, undefined]) {
+    Assert.throws(
+      () => cookie.add({ name: invalidType }),
+      /Cookie name must be string/
+    );
+    Assert.throws(
+      () => cookie.add({ name: "name", value: invalidType }),
+      /Cookie value must be string/
+    );
+    Assert.throws(
+      () => cookie.add({ name: "name", value: "value", domain: invalidType }),
+      /Cookie domain must be string/
+    );
+  }
+
+  cookie.add({
+    name: "name",
+    value: "value",
+    domain: "domain",
+  });
+  equal(1, cookie.manager.cookies.length);
+  equal("name", cookie.manager.cookies[0].name);
+  equal("value", cookie.manager.cookies[0].value);
+  equal(".domain", cookie.manager.cookies[0].host);
+  equal("/", cookie.manager.cookies[0].path);
+  ok(cookie.manager.cookies[0].expiry > new Date(Date.now()).getTime() / 1000);
+
+  cookie.add({
+    name: "name2",
+    value: "value2",
+    domain: "domain2",
+  });
+  equal(2, cookie.manager.cookies.length);
+
+  Assert.throws(() => {
+    let biscuit = { name: "name3", value: "value3", domain: "domain3" };
+    cookie.add(biscuit, { restrictToHost: "other domain" });
+  }, /Cookies may only be set for the current domain/);
+
+  cookie.add({
+    name: "name4",
+    value: "value4",
+    domain: "my.domain:1234",
+  });
+  equal(".my.domain", cookie.manager.cookies[2].host);
+
+  cookie.add({
+    name: "name5",
+    value: "value5",
+    domain: "domain5",
+    path: "/foo/bar",
+  });
+  equal("/foo/bar", cookie.manager.cookies[3].path);
+
+  cookie.add({
+    name: "name6",
+    value: "value",
+    domain: ".domain",
+  });
+  equal(".domain", cookie.manager.cookies[4].host);
+
+  const sameSiteMap = new Map([
+    ["None", Ci.nsICookie.SAMESITE_NONE],
+    ["Lax", Ci.nsICookie.SAMESITE_LAX],
+    ["Strict", Ci.nsICookie.SAMESITE_STRICT],
+  ]);
+
+  Array.from(sameSiteMap.keys()).forEach((entry, index) => {
+    cookie.add({
+      name: "name" + index,
+      value: "value",
+      domain: ".domain",
+      sameSite: entry,
+    });
+    equal(sameSiteMap.get(entry), cookie.manager.cookies[5 + index].sameSite);
+  });
+
+  Assert.throws(() => {
+    cookie.add({ name: "fail", value: "value6", domain: "domain6" });
+  }, /UnableToSetCookieError/);
+});
+
+add_task(function test_remove() {
+  cookie.manager.cookies = [];
+
+  let crumble = {
+    name: "test_remove",
+    value: "value",
+    domain: "domain",
+    path: "/custom/path",
+  };
+
+  equal(0, cookie.manager.cookies.length);
+  cookie.add(crumble);
+  equal(1, cookie.manager.cookies.length);
+
+  cookie.remove(crumble);
+  equal(0, cookie.manager.cookies.length);
+  equal(undefined, cookie.manager.cookies[0]);
+});
+
+add_task(function test_iter() {
+  cookie.manager.cookies = [];
+  let tomorrow = new Date();
+  tomorrow.setHours(tomorrow.getHours() + 24);
+
+  cookie.add({
+    expiry: tomorrow,
+    name: "0",
+    value: "",
+    domain: "foo.example.com",
+  });
+  cookie.add({
+    expiry: tomorrow,
+    name: "1",
+    value: "",
+    domain: "bar.example.com",
+  });
+
+  let fooCookies = [...cookie.iter("foo.example.com")];
+  equal(1, fooCookies.length);
+  equal(".foo.example.com", fooCookies[0].domain);
+  equal(true, fooCookies[0].hasOwnProperty("expiry"));
+
+  cookie.add({
+    name: "aSessionCookie",
+    value: "",
+    domain: "session.com",
+  });
+
+  let sessionCookies = [...cookie.iter("session.com")];
+  equal(1, sessionCookies.length);
+  equal("aSessionCookie", sessionCookies[0].name);
+  equal(false, sessionCookies[0].hasOwnProperty("expiry"));
+
+  cookie.add({
+    name: "2",
+    value: "",
+    domain: "samesite.example.com",
+    sameSite: "Lax",
+  });
+
+  let sameSiteCookies = [...cookie.iter("samesite.example.com")];
+  equal(1, sameSiteCookies.length);
+  equal("Lax", sameSiteCookies[0].sameSite);
+});
diff --git a/remote/marionette/test/xpcshell/test_element.js b/remote/marionette/test/xpcshell/test_element.js
new file mode 100644
index 0000000000..7b2379b1ab
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_element.js
@@ -0,0 +1,789 @@
+/* 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/. */
+
+const { element, ShadowRoot, WebElement, WebFrame, WebReference, WebWindow } =
+  ChromeUtils.importESModule(
+    "chrome://remote/content/marionette/element.sys.mjs"
+  );
+const { NodeCache } = ChromeUtils.importESModule(
+  "chrome://remote/content/shared/webdriver/NodeCache.sys.mjs"
+);
+
+const MemoryReporter = Cc["@mozilla.org/memory-reporter-manager;1"].getService(
+  Ci.nsIMemoryReporterManager
+);
+
+class MockElement {
+  constructor(tagName, attrs = {}) {
+    this.tagName = tagName;
+    this.localName = tagName;
+
+    this.isConnected = false;
+    this.ownerGlobal = {
+      document: {
+        isActive() {
+          return true;
+        },
+      },
+    };
+
+    for (let attr in attrs) {
+      this[attr] = attrs[attr];
+    }
+  }
+
+  get nodeType() {
+    return 1;
+  }
+
+  get ELEMENT_NODE() {
+    return 1;
+  }
+
+  // this is a severely limited CSS selector
+  // that only supports lists of tag names
+  matches(selector) {
+    let tags = selector.split(",");
+    return tags.includes(this.localName);
+  }
+}
+
+class MockXULElement extends MockElement {
+  constructor(tagName, attrs = {}) {
+    super(tagName, attrs);
+    this.namespaceURI = XUL_NS;
+
+    if (typeof this.ownerDocument == "undefined") {
+      this.ownerDocument = {};
+    }
+    if (typeof this.ownerDocument.documentElement == "undefined") {
+      this.ownerDocument.documentElement = { namespaceURI: XUL_NS };
+    }
+  }
+}
+
+const xulEl = new MockXULElement("text");
+
+const domElInPrivilegedDocument = new MockElement("input", {
+  nodePrincipal: { isSystemPrincipal: true },
+});
+const xulElInPrivilegedDocument = new MockXULElement("text", {
+  nodePrincipal: { isSystemPrincipal: true },
+});
+
+function setupTest() {
+  const browser = Services.appShell.createWindowlessBrowser(false);
+
+  browser.document.body.innerHTML = `
+    <div id="foo" style="margin: 50px">
+      <iframe></iframe>
+      <video></video>
+      <svg xmlns="http://www.w3.org/2000/svg"></svg>
+      <textarea></textarea>
+    </div>
+  `;
+
+  const divEl = browser.document.querySelector("div");
+  const svgEl = browser.document.querySelector("svg");
+  const textareaEl = browser.document.querySelector("textarea");
+  const videoEl = browser.document.querySelector("video");
+
+  const iframeEl = browser.document.querySelector("iframe");
+  const childEl = iframeEl.contentDocument.createElement("div");
+  iframeEl.contentDocument.body.appendChild(childEl);
+
+  const shadowRoot = videoEl.openOrClosedShadowRoot;
+
+  return {
+    browser,
+    nodeCache: new NodeCache(),
+    childEl,
+    divEl,
+    iframeEl,
+    shadowRoot,
+    svgEl,
+    textareaEl,
+    videoEl,
+  };
+}
+
+add_task(function test_findClosest() {
+  const { divEl, videoEl } = setupTest();
+
+  equal(element.findClosest(divEl, "foo"), null);
+  equal(element.findClosest(videoEl, "div"), divEl);
+});
+
+add_task(function test_isSelected() {
+  const { browser, divEl } = setupTest();
+
+  const checkbox = browser.document.createElement("input");
+  checkbox.setAttribute("type", "checkbox");
+
+  ok(!element.isSelected(checkbox));
+  checkbox.checked = true;
+  ok(element.isSelected(checkbox));
+
+  // selected is not a property of <input type=checkbox>
+  checkbox.selected = true;
+  checkbox.checked = false;
+  ok(!element.isSelected(checkbox));
+
+  const option = browser.document.createElement("option");
+
+  ok(!element.isSelected(option));
+  option.selected = true;
+  ok(element.isSelected(option));
+
+  // checked is not a property of <option>
+  option.checked = true;
+  option.selected = false;
+  ok(!element.isSelected(option));
+
+  // anything else should not be selected
+  for (const type of [undefined, null, "foo", true, [], {}, divEl]) {
+    ok(!element.isSelected(type));
+  }
+});
+
+add_task(function test_isElement() {
+  const { divEl, iframeEl, shadowRoot, svgEl } = setupTest();
+
+  ok(element.isElement(divEl));
+  ok(element.isElement(svgEl));
+  ok(element.isElement(xulEl));
+  ok(element.isElement(domElInPrivilegedDocument));
+  ok(element.isElement(xulElInPrivilegedDocument));
+
+  ok(!element.isElement(shadowRoot));
+  ok(!element.isElement(divEl.ownerGlobal));
+  ok(!element.isElement(iframeEl.contentWindow));
+
+  for (const type of [true, 42, {}, [], undefined, null]) {
+    ok(!element.isElement(type));
+  }
+});
+
+add_task(function test_isDOMElement() {
+  const { divEl, iframeEl, shadowRoot, svgEl } = setupTest();
+
+  ok(element.isDOMElement(divEl));
+  ok(element.isDOMElement(svgEl));
+  ok(element.isDOMElement(domElInPrivilegedDocument));
+
+  ok(!element.isDOMElement(shadowRoot));
+  ok(!element.isDOMElement(divEl.ownerGlobal));
+  ok(!element.isDOMElement(iframeEl.contentWindow));
+  ok(!element.isDOMElement(xulEl));
+  ok(!element.isDOMElement(xulElInPrivilegedDocument));
+
+  for (const type of [true, 42, "foo", {}, [], undefined, null]) {
+    ok(!element.isDOMElement(type));
+  }
+});
+
+add_task(function test_isXULElement() {
+  const { divEl, iframeEl, shadowRoot, svgEl } = setupTest();
+
+  ok(element.isXULElement(xulEl));
+  ok(element.isXULElement(xulElInPrivilegedDocument));
+
+  ok(!element.isXULElement(divEl));
+  ok(!element.isXULElement(domElInPrivilegedDocument));
+  ok(!element.isXULElement(svgEl));
+  ok(!element.isXULElement(shadowRoot));
+  ok(!element.isXULElement(divEl.ownerGlobal));
+  ok(!element.isXULElement(iframeEl.contentWindow));
+
+  for (const type of [true, 42, "foo", {}, [], undefined, null]) {
+    ok(!element.isXULElement(type));
+  }
+});
+
+add_task(function test_isDOMWindow() {
+  const { divEl, iframeEl, shadowRoot, svgEl } = setupTest();
+
+  ok(element.isDOMWindow(divEl.ownerGlobal));
+  ok(element.isDOMWindow(iframeEl.contentWindow));
+
+  ok(!element.isDOMWindow(divEl));
+  ok(!element.isDOMWindow(svgEl));
+  ok(!element.isDOMWindow(shadowRoot));
+  ok(!element.isDOMWindow(domElInPrivilegedDocument));
+  ok(!element.isDOMWindow(xulEl));
+  ok(!element.isDOMWindow(xulElInPrivilegedDocument));
+
+  for (const type of [true, 42, {}, [], undefined, null]) {
+    ok(!element.isDOMWindow(type));
+  }
+});
+
+add_task(function test_isShadowRoot() {
+  const { browser, divEl, iframeEl, shadowRoot, svgEl } = setupTest();
+
+  ok(element.isShadowRoot(shadowRoot));
+
+  ok(!element.isShadowRoot(divEl));
+  ok(!element.isShadowRoot(svgEl));
+  ok(!element.isShadowRoot(divEl.ownerGlobal));
+  ok(!element.isShadowRoot(iframeEl.contentWindow));
+  ok(!element.isShadowRoot(xulEl));
+  ok(!element.isShadowRoot(domElInPrivilegedDocument));
+  ok(!element.isShadowRoot(xulElInPrivilegedDocument));
+
+  for (const type of [true, 42, "foo", {}, [], undefined, null]) {
+    ok(!element.isShadowRoot(type));
+  }
+
+  const documentFragment = browser.document.createDocumentFragment();
+  ok(!element.isShadowRoot(documentFragment));
+});
+
+add_task(function test_isReadOnly() {
+  const { browser, divEl, textareaEl } = setupTest();
+
+  const input = browser.document.createElement("input");
+  input.readOnly = true;
+  ok(element.isReadOnly(input));
+
+  textareaEl.readOnly = true;
+  ok(element.isReadOnly(textareaEl));
+
+  ok(!element.isReadOnly(divEl));
+  divEl.readOnly = true;
+  ok(!element.isReadOnly(divEl));
+
+  ok(!element.isReadOnly(null));
+});
+
+add_task(function test_isDisabled() {
+  const { browser, divEl, svgEl } = setupTest();
+
+  const select = browser.document.createElement("select");
+  const option = browser.document.createElement("option");
+  select.appendChild(option);
+  select.disabled = true;
+  ok(element.isDisabled(option));
+
+  const optgroup = browser.document.createElement("optgroup");
+  option.parentNode = optgroup;
+  ok(element.isDisabled(option));
+
+  optgroup.parentNode = select;
+  ok(element.isDisabled(option));
+
+  select.disabled = false;
+  ok(!element.isDisabled(option));
+
+  for (const type of ["button", "input", "select", "textarea"]) {
+    const elem = browser.document.createElement(type);
+    ok(!element.isDisabled(elem));
+    elem.disabled = true;
+    ok(element.isDisabled(elem));
+  }
+
+  ok(!element.isDisabled(divEl));
+
+  svgEl.disabled = true;
+  ok(!element.isDisabled(svgEl));
+
+  ok(!element.isDisabled(new MockXULElement("browser", { disabled: true })));
+});
+
+add_task(function test_isEditingHost() {
+  const { browser, divEl, svgEl } = setupTest();
+
+  ok(!element.isEditingHost(null));
+
+  ok(!element.isEditingHost(divEl));
+  divEl.contentEditable = true;
+  ok(element.isEditingHost(divEl));
+
+  ok(!element.isEditingHost(svgEl));
+  browser.document.designMode = "on";
+  ok(element.isEditingHost(svgEl));
+});
+
+add_task(function test_isEditable() {
+  const { browser, divEl, svgEl, textareaEl } = setupTest();
+
+  ok(!element.isEditable(null));
+
+  for (let type of [
+    "checkbox",
+    "radio",
+    "hidden",
+    "submit",
+    "button",
+    "image",
+  ]) {
+    const input = browser.document.createElement("input");
+    input.setAttribute("type", type);
+
+    ok(!element.isEditable(input));
+  }
+
+  const input = browser.document.createElement("input");
+  ok(element.isEditable(input));
+  input.setAttribute("type", "text");
+  ok(element.isEditable(input));
+
+  ok(element.isEditable(textareaEl));
+
+  const textareaDisabled = browser.document.createElement("textarea");
+  textareaDisabled.disabled = true;
+  ok(!element.isEditable(textareaDisabled));
+
+  const textareaReadOnly = browser.document.createElement("textarea");
+  textareaReadOnly.readOnly = true;
+  ok(!element.isEditable(textareaReadOnly));
+
+  ok(!element.isEditable(divEl));
+  divEl.contentEditable = true;
+  ok(element.isEditable(divEl));
+
+  ok(!element.isEditable(svgEl));
+  browser.document.designMode = "on";
+  ok(element.isEditable(svgEl));
+});
+
+add_task(function test_isMutableFormControlElement() {
+  const { browser, divEl, textareaEl } = setupTest();
+
+  ok(!element.isMutableFormControl(null));
+
+  ok(element.isMutableFormControl(textareaEl));
+
+  const textareaDisabled = browser.document.createElement("textarea");
+  textareaDisabled.disabled = true;
+  ok(!element.isMutableFormControl(textareaDisabled));
+
+  const textareaReadOnly = browser.document.createElement("textarea");
+  textareaReadOnly.readOnly = true;
+  ok(!element.isMutableFormControl(textareaReadOnly));
+
+  const mutableStates = new Set([
+    "color",
+    "date",
+    "datetime-local",
+    "email",
+    "file",
+    "month",
+    "number",
+    "password",
+    "range",
+    "search",
+    "tel",
+    "text",
+    "url",
+    "week",
+  ]);
+  for (const type of mutableStates) {
+    const input = browser.document.createElement("input");
+    input.setAttribute("type", type);
+    ok(element.isMutableFormControl(input));
+  }
+
+  const inputHidden = browser.document.createElement("input");
+  inputHidden.setAttribute("type", "hidden");
+  ok(!element.isMutableFormControl(inputHidden));
+
+  ok(!element.isMutableFormControl(divEl));
+  divEl.contentEditable = true;
+  ok(!element.isMutableFormControl(divEl));
+  browser.document.designMode = "on";
+  ok(!element.isMutableFormControl(divEl));
+});
+
+add_task(function test_coordinates() {
+  const { divEl } = setupTest();
+
+  let coords = element.coordinates(divEl);
+  ok(coords.hasOwnProperty("x"));
+  ok(coords.hasOwnProperty("y"));
+  equal(typeof coords.x, "number");
+  equal(typeof coords.y, "number");
+
+  deepEqual(element.coordinates(divEl), { x: 0, y: 0 });
+  deepEqual(element.coordinates(divEl, 10, 10), { x: 10, y: 10 });
+  deepEqual(element.coordinates(divEl, -5, -5), { x: -5, y: -5 });
+
+  Assert.throws(() => element.coordinates(null), /node is null/);
+
+  Assert.throws(
+    () => element.coordinates(divEl, "string", undefined),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, undefined, "string"),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, "string", "string"),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, {}, undefined),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, undefined, {}),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, {}, {}),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, [], undefined),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, undefined, []),
+    /Offset must be a number/
+  );
+  Assert.throws(
+    () => element.coordinates(divEl, [], []),
+    /Offset must be a number/
+  );
+});
+
+add_task(function test_isNodeReferenceKnown() {
+  const { browser, nodeCache, childEl, iframeEl, videoEl } = setupTest();
+
+  // Unknown node reference
+  ok(!element.isNodeReferenceKnown(browser.browsingContext, "foo", nodeCache));
+
+  // Known node reference
+  const videoElRef = nodeCache.getOrCreateNodeReference(videoEl);
+  ok(
+    element.isNodeReferenceKnown(browser.browsingContext, videoElRef, nodeCache)
+  );
+
+  // Different top-level browsing context
+  const browser2 = Services.appShell.createWindowlessBrowser(false);
+  ok(
+    !element.isNodeReferenceKnown(
+      browser2.browsingContext,
+      videoElRef,
+      nodeCache
+    )
+  );
+
+  // Different child browsing context
+  const childElRef = nodeCache.getOrCreateNodeReference(childEl);
+  const childBrowsingContext = iframeEl.contentWindow.browsingContext;
+  ok(element.isNodeReferenceKnown(childBrowsingContext, childElRef, nodeCache));
+
+  const iframeEl2 = browser2.document.createElement("iframe");
+  browser2.document.body.appendChild(iframeEl2);
+  const childBrowsingContext2 = iframeEl2.contentWindow.browsingContext;
+  ok(
+    !element.isNodeReferenceKnown(childBrowsingContext2, childElRef, nodeCache)
+  );
+});
+
+add_task(function test_getKnownElement() {
+  const { browser, nodeCache, shadowRoot, videoEl } = setupTest();
+
+  // Unknown element reference
+  Assert.throws(() => {
+    element.getKnownElement(browser.browsingContext, "foo", nodeCache);
+  }, /NoSuchElementError/);
+
+  // With a ShadowRoot reference
+  const shadowRootRef = nodeCache.getOrCreateNodeReference(shadowRoot);
+  Assert.throws(() => {
+    element.getKnownElement(browser.browsingContext, shadowRootRef, nodeCache);
+  }, /NoSuchElementError/);
+
+  // Deleted element (eg. garbage collected)
+  let detachedEl = browser.document.createElement("div");
+  const detachedElRef = nodeCache.getOrCreateNodeReference(detachedEl);
+
+  // ... not connected to the DOM
+  Assert.throws(() => {
+    element.getKnownElement(browser.browsingContext, detachedElRef, nodeCache);
+  }, /StaleElementReferenceError/);
+
+  // ... element garbage collected
+  detachedEl = null;
+  MemoryReporter.minimizeMemoryUsage(() => {
+    Assert.throws(() => {
+      element.getKnownElement(
+        browser.browsingContext,
+        detachedElRef,
+        nodeCache
+      );
+    }, /StaleElementReferenceError/);
+  });
+
+  // Known element reference
+  const videoElRef = nodeCache.getOrCreateNodeReference(videoEl);
+  equal(
+    element.getKnownElement(browser.browsingContext, videoElRef, nodeCache),
+    videoEl
+  );
+});
+
+add_task(function test_getKnownShadowRoot() {
+  const { browser, nodeCache, shadowRoot, videoEl } = setupTest();
+
+  const videoElRef = nodeCache.getOrCreateNodeReference(videoEl);
+
+  // Unknown ShadowRoot reference
+  Assert.throws(() => {
+    element.getKnownShadowRoot(browser.browsingContext, "foo", nodeCache);
+  }, /NoSuchShadowRootError/);
+
+  // With a HTMLElement reference
+  Assert.throws(() => {
+    element.getKnownShadowRoot(browser.browsingContext, videoElRef, nodeCache);
+  }, /NoSuchShadowRootError/);
+
+  // Known ShadowRoot reference
+  const shadowRootRef = nodeCache.getOrCreateNodeReference(shadowRoot);
+  equal(
+    element.getKnownShadowRoot(
+      browser.browsingContext,
+      shadowRootRef,
+      nodeCache
+    ),
+    shadowRoot
+  );
+
+  // Detached ShadowRoot host
+  let el = browser.document.createElement("div");
+  let detachedShadowRoot = el.attachShadow({ mode: "open" });
+  detachedShadowRoot.innerHTML = "<input></input>";
+
+  const detachedShadowRootRef =
+    nodeCache.getOrCreateNodeReference(detachedShadowRoot);
+
+  // ... not connected to the DOM
+  Assert.throws(() => {
+    element.getKnownShadowRoot(
+      browser.browsingContext,
+      detachedShadowRootRef,
+      nodeCache
+    );
+  }, /DetachedShadowRootError/);
+
+  // ... host and shadow root garbage collected
+  el = null;
+  detachedShadowRoot = null;
+  MemoryReporter.minimizeMemoryUsage(() => {
+    Assert.throws(() => {
+      element.getKnownShadowRoot(
+        browser.browsingContext,
+        detachedShadowRootRef,
+        nodeCache
+      );
+    }, /DetachedShadowRootError/);
+  });
+});
+
+add_task(function test_isDetached() {
+  const { childEl, iframeEl } = setupTest();
+
+  let detachedShadowRoot = childEl.attachShadow({ mode: "open" });
+  detachedShadowRoot.innerHTML = "<input></input>";
+
+  // Connected to the DOM
+  ok(!element.isDetached(detachedShadowRoot));
+
+  // Node document (ownerDocument) is not the active document
+  iframeEl.remove();
+  ok(element.isDetached(detachedShadowRoot));
+
+  // host element is stale (eg. not connected)
+  detachedShadowRoot.host.remove();
+  equal(childEl.isConnected, false);
+  ok(element.isDetached(detachedShadowRoot));
+});
+
+add_task(function test_isStale() {
+  const { childEl, iframeEl } = setupTest();
+
+  // Connected to the DOM
+  ok(!element.isStale(childEl));
+
+  // Not part of the active document
+  iframeEl.remove();
+  ok(element.isStale(childEl));
+
+  // Not connected to the DOM
+  childEl.remove();
+  ok(element.isStale(childEl));
+});
+
+add_task(function test_WebReference_ctor() {
+  const el = new WebReference("foo");
+  equal(el.uuid, "foo");
+
+  for (let t of [42, true, [], {}, null, undefined]) {
+    Assert.throws(() => new WebReference(t), /to be a string/);
+  }
+});
+
+add_task(function test_WebElemenet_is() {
+  const a = new WebReference("a");
+  const b = new WebReference("b");
+
+  ok(a.is(a));
+  ok(b.is(b));
+  ok(!a.is(b));
+  ok(!b.is(a));
+
+  ok(!a.is({}));
+});
+
+add_task(function test_WebReference_from() {
+  const { divEl, iframeEl } = setupTest();
+
+  ok(WebReference.from(divEl) instanceof WebElement);
+  ok(WebReference.from(xulEl) instanceof WebElement);
+  ok(WebReference.from(divEl.ownerGlobal) instanceof WebWindow);
+  ok(WebReference.from(iframeEl.contentWindow) instanceof WebFrame);
+  ok(WebReference.from(domElInPrivilegedDocument) instanceof WebElement);
+  ok(WebReference.from(xulElInPrivilegedDocument) instanceof WebElement);
+
+  Assert.throws(() => WebReference.from({}), /InvalidArgumentError/);
+});
+
+add_task(function test_WebReference_fromJSON_WebElement() {
+  const { Identifier } = WebElement;
+
+  const ref = { [Identifier]: "foo" };
+  const webEl = WebReference.fromJSON(ref);
+  ok(webEl instanceof WebElement);
+  equal(webEl.uuid, "foo");
+
+  let identifierPrecedence = {
+    [Identifier]: "identifier-uuid",
+  };
+  const precedenceEl = WebReference.fromJSON(identifierPrecedence);
+  ok(precedenceEl instanceof WebElement);
+  equal(precedenceEl.uuid, "identifier-uuid");
+});
+
+add_task(function test_WebReference_fromJSON_WebWindow() {
+  const ref = { [WebWindow.Identifier]: "foo" };
+  const win = WebReference.fromJSON(ref);
+
+  ok(win instanceof WebWindow);
+  equal(win.uuid, "foo");
+});
+
+add_task(function test_WebReference_fromJSON_WebFrame() {
+  const ref = { [WebFrame.Identifier]: "foo" };
+  const frame = WebReference.fromJSON(ref);
+  ok(frame instanceof WebFrame);
+  equal(frame.uuid, "foo");
+});
+
+add_task(function test_WebReference_fromJSON_malformed() {
+  Assert.throws(() => WebReference.fromJSON({}), /InvalidArgumentError/);
+  Assert.throws(() => WebReference.fromJSON(null), /InvalidArgumentError/);
+});
+
+add_task(function test_WebReference_isReference() {
+  for (let t of [42, true, "foo", [], {}]) {
+    ok(!WebReference.isReference(t));
+  }
+
+  ok(WebReference.isReference({ [WebElement.Identifier]: "foo" }));
+  ok(WebReference.isReference({ [WebWindow.Identifier]: "foo" }));
+  ok(WebReference.isReference({ [WebFrame.Identifier]: "foo" }));
+});
+
+add_task(function test_WebElement_toJSON() {
+  const { Identifier } = WebElement;
+
+  const el = new WebElement("foo");
+  const json = el.toJSON();
+
+  ok(Identifier in json);
+  equal(json[Identifier], "foo");
+});
+
+add_task(function test_WebElement_fromJSON() {
+  const { Identifier } = WebElement;
+
+  const el = WebElement.fromJSON({ [Identifier]: "foo" });
+  ok(el instanceof WebElement);
+  equal(el.uuid, "foo");
+
+  Assert.throws(() => WebElement.fromJSON({}), /InvalidArgumentError/);
+});
+
+add_task(function test_WebElement_fromUUID() {
+  const domWebEl = WebElement.fromUUID("bar");
+
+  ok(domWebEl instanceof WebElement);
+  equal(domWebEl.uuid, "bar");
+
+  Assert.throws(() => WebElement.fromUUID(), /InvalidArgumentError/);
+});
+
+add_task(function test_ShadowRoot_toJSON() {
+  const { Identifier } = ShadowRoot;
+
+  const shadowRoot = new ShadowRoot("foo");
+  const json = shadowRoot.toJSON();
+
+  ok(Identifier in json);
+  equal(json[Identifier], "foo");
+});
+
+add_task(function test_ShadowRoot_fromJSON() {
+  const { Identifier } = ShadowRoot;
+
+  const shadowRoot = ShadowRoot.fromJSON({ [Identifier]: "foo" });
+  ok(shadowRoot instanceof ShadowRoot);
+  equal(shadowRoot.uuid, "foo");
+
+  Assert.throws(() => ShadowRoot.fromJSON({}), /InvalidArgumentError/);
+});
+
+add_task(function test_ShadowRoot_fromUUID() {
+  const shadowRoot = ShadowRoot.fromUUID("baz");
+
+  ok(shadowRoot instanceof ShadowRoot);
+  equal(shadowRoot.uuid, "baz");
+
+  Assert.throws(() => ShadowRoot.fromUUID(), /InvalidArgumentError/);
+});
+
+add_task(function test_WebWindow_toJSON() {
+  const win = new WebWindow("foo");
+  const json = win.toJSON();
+
+  ok(WebWindow.Identifier in json);
+  equal(json[WebWindow.Identifier], "foo");
+});
+
+add_task(function test_WebWindow_fromJSON() {
+  const ref = { [WebWindow.Identifier]: "foo" };
+  const win = WebWindow.fromJSON(ref);
+
+  ok(win instanceof WebWindow);
+  equal(win.uuid, "foo");
+});
+
+add_task(function test_WebFrame_toJSON() {
+  const frame = new WebFrame("foo");
+  const json = frame.toJSON();
+
+  ok(WebFrame.Identifier in json);
+  equal(json[WebFrame.Identifier], "foo");
+});
+
+add_task(function test_WebFrame_fromJSON() {
+  const ref = { [WebFrame.Identifier]: "foo" };
+  const win = WebFrame.fromJSON(ref);
+
+  ok(win instanceof WebFrame);
+  equal(win.uuid, "foo");
+});
diff --git a/remote/marionette/test/xpcshell/test_json.js b/remote/marionette/test/xpcshell/test_json.js
new file mode 100644
index 0000000000..479e1fe473
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_json.js
@@ -0,0 +1,275 @@
+const { json } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/json.sys.mjs"
+);
+const { NodeCache } = ChromeUtils.importESModule(
+  "chrome://remote/content/shared/webdriver/NodeCache.sys.mjs"
+);
+const { ShadowRoot, WebElement, WebReference } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/element.sys.mjs"
+);
+
+function setupTest() {
+  const browser = Services.appShell.createWindowlessBrowser(false);
+  const nodeCache = new NodeCache();
+
+  const htmlEl = browser.document.createElement("video");
+  browser.document.body.appendChild(htmlEl);
+
+  const svgEl = browser.document.createElementNS(
+    "http://www.w3.org/2000/svg",
+    "rect"
+  );
+  browser.document.body.appendChild(svgEl);
+
+  const shadowRoot = htmlEl.openOrClosedShadowRoot;
+
+  const iframeEl = browser.document.createElement("iframe");
+  browser.document.body.appendChild(iframeEl);
+  const childEl = iframeEl.contentDocument.createElement("div");
+
+  return { browser, nodeCache, childEl, iframeEl, htmlEl, shadowRoot, svgEl };
+}
+
+add_task(function test_clone_generalTypes() {
+  const { nodeCache } = setupTest();
+
+  // null
+  equal(json.clone(undefined, nodeCache), null);
+  equal(json.clone(null, nodeCache), null);
+
+  // primitives
+  equal(json.clone(true, nodeCache), true);
+  equal(json.clone(42, nodeCache), 42);
+  equal(json.clone("foo", nodeCache), "foo");
+
+  // toJSON
+  equal(
+    json.clone({
+      toJSON() {
+        return "foo";
+      },
+    }),
+    "foo"
+  );
+});
+
+add_task(function test_clone_ShadowRoot() {
+  const { nodeCache, shadowRoot } = setupTest();
+
+  const shadowRootRef = nodeCache.getOrCreateNodeReference(shadowRoot);
+  deepEqual(
+    json.clone(shadowRoot, nodeCache),
+    WebReference.from(shadowRoot, shadowRootRef).toJSON()
+  );
+});
+
+add_task(function test_clone_WebElement() {
+  const { htmlEl, nodeCache, svgEl } = setupTest();
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+  deepEqual(
+    json.clone(htmlEl, nodeCache),
+    WebReference.from(htmlEl, htmlElRef).toJSON()
+  );
+
+  // Check an element with a different namespace
+  const svgElRef = nodeCache.getOrCreateNodeReference(svgEl);
+  deepEqual(
+    json.clone(svgEl, nodeCache),
+    WebReference.from(svgEl, svgElRef).toJSON()
+  );
+});
+
+add_task(function test_clone_Sequences() {
+  const { htmlEl, nodeCache } = setupTest();
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+
+  const input = [
+    null,
+    true,
+    [],
+    htmlEl,
+    {
+      toJSON() {
+        return "foo";
+      },
+    },
+    { bar: "baz" },
+  ];
+
+  const actual = json.clone(input, nodeCache);
+
+  equal(actual[0], null);
+  equal(actual[1], true);
+  deepEqual(actual[2], []);
+  deepEqual(actual[3], { [WebElement.Identifier]: htmlElRef });
+  equal(actual[4], "foo");
+  deepEqual(actual[5], { bar: "baz" });
+});
+
+add_task(function test_clone_objects() {
+  const { htmlEl, nodeCache } = setupTest();
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+
+  const input = {
+    null: null,
+    boolean: true,
+    array: [42],
+    element: htmlEl,
+    toJSON: {
+      toJSON() {
+        return "foo";
+      },
+    },
+    object: { bar: "baz" },
+  };
+
+  const actual = json.clone(input, nodeCache);
+
+  equal(actual.null, null);
+  equal(actual.boolean, true);
+  deepEqual(actual.array, [42]);
+  deepEqual(actual.element, { [WebElement.Identifier]: htmlElRef });
+  equal(actual.toJSON, "foo");
+  deepEqual(actual.object, { bar: "baz" });
+});
+
+add_task(function test_clone_сyclicReference() {
+  const { nodeCache } = setupTest();
+
+  // object
+  Assert.throws(() => {
+    const obj = {};
+    obj.reference = obj;
+    json.clone(obj, nodeCache);
+  }, /JavaScriptError/);
+
+  // array
+  Assert.throws(() => {
+    const array = [];
+    array.push(array);
+    json.clone(array, nodeCache);
+  }, /JavaScriptError/);
+
+  // array in object
+  Assert.throws(() => {
+    const array = [];
+    array.push(array);
+    json.clone({ array }, nodeCache);
+  }, /JavaScriptError/);
+
+  // object in array
+  Assert.throws(() => {
+    const obj = {};
+    obj.reference = obj;
+    json.clone([obj], nodeCache);
+  }, /JavaScriptError/);
+});
+
+add_task(function test_deserialize_generalTypes() {
+  const { browser, nodeCache } = setupTest();
+  const win = browser.document.ownerGlobal;
+
+  // null
+  equal(json.deserialize(undefined, nodeCache, win), undefined);
+  equal(json.deserialize(null, nodeCache, win), null);
+
+  // primitives
+  equal(json.deserialize(true, nodeCache, win), true);
+  equal(json.deserialize(42, nodeCache, win), 42);
+  equal(json.deserialize("foo", nodeCache, win), "foo");
+});
+
+add_task(function test_deserialize_ShadowRoot() {
+  const { browser, nodeCache, shadowRoot } = setupTest();
+  const win = browser.document.ownerGlobal;
+
+  // Fails to resolve for unknown elements
+  const unknownShadowRootId = { [ShadowRoot.Identifier]: "foo" };
+  Assert.throws(() => {
+    json.deserialize(unknownShadowRootId, nodeCache, win);
+  }, /NoSuchShadowRootError/);
+
+  const shadowRootRef = nodeCache.getOrCreateNodeReference(shadowRoot);
+  const shadowRootEl = { [ShadowRoot.Identifier]: shadowRootRef };
+
+  // Fails to resolve for missing window reference
+  Assert.throws(() => json.deserialize(shadowRootEl, nodeCache), /TypeError/);
+
+  // Previously seen element is associated with original web element reference
+  const root = json.deserialize(shadowRootEl, nodeCache, win);
+  deepEqual(root, shadowRoot);
+  deepEqual(root, nodeCache.getNode(browser.browsingContext, shadowRootRef));
+});
+
+add_task(function test_deserialize_WebElement() {
+  const { browser, htmlEl, nodeCache } = setupTest();
+  const win = browser.document.ownerGlobal;
+
+  // Fails to resolve for unknown elements
+  const unknownWebElId = { [WebElement.Identifier]: "foo" };
+  Assert.throws(() => {
+    json.deserialize(unknownWebElId, nodeCache, win);
+  }, /NoSuchElementError/);
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+  const htmlWebEl = { [WebElement.Identifier]: htmlElRef };
+
+  // Fails to resolve for missing window reference
+  Assert.throws(() => json.deserialize(htmlWebEl, nodeCache), /TypeError/);
+
+  // Previously seen element is associated with original web element reference
+  const el = json.deserialize(htmlWebEl, nodeCache, win);
+  deepEqual(el, htmlEl);
+  deepEqual(el, nodeCache.getNode(browser.browsingContext, htmlElRef));
+});
+
+add_task(function test_deserialize_Sequences() {
+  const { browser, htmlEl, nodeCache } = setupTest();
+  const win = browser.document.ownerGlobal;
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+
+  const input = [
+    null,
+    true,
+    [42],
+    { [WebElement.Identifier]: htmlElRef },
+    { bar: "baz" },
+  ];
+
+  const actual = json.deserialize(input, nodeCache, win);
+
+  equal(actual[0], null);
+  equal(actual[1], true);
+  deepEqual(actual[2], [42]);
+  deepEqual(actual[3], htmlEl);
+  deepEqual(actual[4], { bar: "baz" });
+});
+
+add_task(function test_deserialize_objects() {
+  const { browser, htmlEl, nodeCache } = setupTest();
+  const win = browser.document.ownerGlobal;
+
+  const htmlElRef = nodeCache.getOrCreateNodeReference(htmlEl);
+
+  const input = {
+    null: null,
+    boolean: true,
+    array: [42],
+    element: { [WebElement.Identifier]: htmlElRef },
+    object: { bar: "baz" },
+  };
+
+  const actual = json.deserialize(input, nodeCache, win);
+
+  equal(actual.null, null);
+  equal(actual.boolean, true);
+  deepEqual(actual.array, [42]);
+  deepEqual(actual.element, htmlEl);
+  deepEqual(actual.object, { bar: "baz" });
+
+  nodeCache.clear({ all: true });
+});
diff --git a/remote/marionette/test/xpcshell/test_message.js b/remote/marionette/test/xpcshell/test_message.js
new file mode 100644
index 0000000000..9926aea191
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_message.js
@@ -0,0 +1,245 @@
+/* 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/. */
+
+const { error } = ChromeUtils.importESModule(
+  "chrome://remote/content/shared/webdriver/Errors.sys.mjs"
+);
+const { Command, Message, Response } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/message.sys.mjs"
+);
+
+add_task(function test_Message_Origin() {
+  equal(0, Message.Origin.Client);
+  equal(1, Message.Origin.Server);
+});
+
+add_task(function test_Message_fromPacket() {
+  let cmd = new Command(4, "foo");
+  let resp = new Response(5, () => {});
+  resp.error = "foo";
+
+  ok(Message.fromPacket(cmd.toPacket()) instanceof Command);
+  ok(Message.fromPacket(resp.toPacket()) instanceof Response);
+  Assert.throws(
+    () => Message.fromPacket([3, 4, 5, 6]),
+    /Unrecognised message type in packet/
+  );
+});
+
+add_task(function test_Command() {
+  let cmd = new Command(42, "foo", { bar: "baz" });
+  equal(42, cmd.id);
+  equal("foo", cmd.name);
+  deepEqual({ bar: "baz" }, cmd.parameters);
+  equal(null, cmd.onerror);
+  equal(null, cmd.onresult);
+  equal(Message.Origin.Client, cmd.origin);
+  equal(false, cmd.sent);
+});
+
+add_task(function test_Command_onresponse() {
+  let onerrorOk = false;
+  let onresultOk = false;
+
+  let cmd = new Command(7, "foo");
+  cmd.onerror = () => (onerrorOk = true);
+  cmd.onresult = () => (onresultOk = true);
+
+  let errorResp = new Response(8, () => {});
+  errorResp.error = new error.WebDriverError("foo");
+
+  let bodyResp = new Response(9, () => {});
+  bodyResp.body = "bar";
+
+  cmd.onresponse(errorResp);
+  equal(true, onerrorOk);
+  equal(false, onresultOk);
+
+  cmd.onresponse(bodyResp);
+  equal(true, onresultOk);
+});
+
+add_task(function test_Command_ctor() {
+  let cmd = new Command(42, "bar", { bar: "baz" });
+  let msg = cmd.toPacket();
+
+  equal(Command.Type, msg[0]);
+  equal(cmd.id, msg[1]);
+  equal(cmd.name, msg[2]);
+  equal(cmd.parameters, msg[3]);
+});
+
+add_task(function test_Command_toString() {
+  let cmd = new Command(42, "foo", { bar: "baz" });
+  equal(JSON.stringify(cmd.toPacket()), cmd.toString());
+});
+
+add_task(function test_Command_fromPacket() {
+  let c1 = new Command(42, "foo", { bar: "baz" });
+
+  let msg = c1.toPacket();
+  let c2 = Command.fromPacket(msg);
+
+  equal(c1.id, c2.id);
+  equal(c1.name, c2.name);
+  equal(c1.parameters, c2.parameters);
+
+  Assert.throws(
+    () => Command.fromPacket([null, 2, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Command.fromPacket([1, 2, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Command.fromPacket([0, null, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Command.fromPacket([0, 2, null, {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Command.fromPacket([0, 2, "foo", false]),
+    /InvalidArgumentError/
+  );
+
+  let nullParams = Command.fromPacket([0, 2, "foo", null]);
+  equal(
+    "[object Object]",
+    Object.prototype.toString.call(nullParams.parameters)
+  );
+});
+
+add_task(function test_Command_Type() {
+  equal(0, Command.Type);
+});
+
+add_task(function test_Response_ctor() {
+  let handler = () => {
+    throw new Error("foo");
+  };
+
+  let resp = new Response(42, handler);
+  equal(42, resp.id);
+  equal(null, resp.error);
+  ok("origin" in resp);
+  equal(Message.Origin.Server, resp.origin);
+  equal(false, resp.sent);
+  equal(handler, resp.respHandler_);
+});
+
+add_task(function test_Response_sendConditionally() {
+  let fired = false;
+  let resp = new Response(42, () => (fired = true));
+  resp.sendConditionally(() => false);
+  equal(false, resp.sent);
+  equal(false, fired);
+  resp.sendConditionally(() => true);
+  equal(true, resp.sent);
+  equal(true, fired);
+});
+
+add_task(function test_Response_send() {
+  let fired = false;
+  let resp = new Response(42, () => (fired = true));
+  resp.send();
+  equal(true, resp.sent);
+  equal(true, fired);
+});
+
+add_task(function test_Response_sendError_sent() {
+  let resp = new Response(42, r => equal(false, r.sent));
+  resp.sendError(new error.WebDriverError());
+  ok(resp.sent);
+  Assert.throws(() => resp.send(), /already been sent/);
+});
+
+add_task(function test_Response_sendError_body() {
+  let resp = new Response(42, r => equal(null, r.body));
+  resp.sendError(new error.WebDriverError());
+});
+
+add_task(function test_Response_sendError_errorSerialisation() {
+  let err1 = new error.WebDriverError();
+  let resp1 = new Response(42);
+  resp1.sendError(err1);
+  equal(err1.status, resp1.error.error);
+  deepEqual(err1.toJSON(), resp1.error);
+
+  let err2 = new error.InvalidArgumentError();
+  let resp2 = new Response(43);
+  resp2.sendError(err2);
+  equal(err2.status, resp2.error.error);
+  deepEqual(err2.toJSON(), resp2.error);
+});
+
+add_task(function test_Response_sendError_wrapInternalError() {
+  let err = new ReferenceError("foo");
+
+  // errors that originate from JavaScript (i.e. Marionette implementation
+  // issues) should be converted to UnknownError for transport
+  let resp = new Response(42, r => {
+    equal("unknown error", r.error.error);
+    equal(false, resp.sent);
+  });
+
+  // they should also throw after being sent
+  Assert.throws(() => resp.sendError(err), /foo/);
+  equal(true, resp.sent);
+});
+
+add_task(function test_Response_toPacket() {
+  let resp = new Response(42, () => {});
+  let msg = resp.toPacket();
+
+  equal(Response.Type, msg[0]);
+  equal(resp.id, msg[1]);
+  equal(resp.error, msg[2]);
+  equal(resp.body, msg[3]);
+});
+
+add_task(function test_Response_toString() {
+  let resp = new Response(42, () => {});
+  resp.error = "foo";
+  resp.body = "bar";
+
+  equal(JSON.stringify(resp.toPacket()), resp.toString());
+});
+
+add_task(function test_Response_fromPacket() {
+  let r1 = new Response(42, () => {});
+  r1.error = "foo";
+  r1.body = "bar";
+
+  let msg = r1.toPacket();
+  let r2 = Response.fromPacket(msg);
+
+  equal(r1.id, r2.id);
+  equal(r1.error, r2.error);
+  equal(r1.body, r2.body);
+
+  Assert.throws(
+    () => Response.fromPacket([null, 2, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Response.fromPacket([0, 2, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Response.fromPacket([1, null, "foo", {}]),
+    /InvalidArgumentError/
+  );
+  Assert.throws(
+    () => Response.fromPacket([1, 2, null, {}]),
+    /InvalidArgumentError/
+  );
+  Response.fromPacket([1, 2, "foo", null]);
+});
+
+add_task(function test_Response_Type() {
+  equal(1, Response.Type);
+});
diff --git a/remote/marionette/test/xpcshell/test_modal.js b/remote/marionette/test/xpcshell/test_modal.js
new file mode 100644
index 0000000000..c36811f7ec
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_modal.js
@@ -0,0 +1,113 @@
+/* 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";
+
+const { modal } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/modal.sys.mjs"
+);
+
+const chromeWindow = {};
+
+const mockModalDialog = {
+  docShell: {
+    chromeEventHandler: null,
+  },
+  opener: {
+    ownerGlobal: chromeWindow,
+  },
+  Dialog: {
+    args: {
+      modalType: Services.prompt.MODAL_TYPE_WINDOW,
+    },
+  },
+};
+
+const mockCurBrowser = {
+  window: chromeWindow,
+};
+
+add_task(function test_addCallback() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+  let cb1 = () => true;
+  let cb2 = () => false;
+
+  equal(observer.callbacks.size, 0);
+  observer.add(cb1);
+  equal(observer.callbacks.size, 1);
+  observer.add(cb1);
+  equal(observer.callbacks.size, 1);
+  observer.add(cb2);
+  equal(observer.callbacks.size, 2);
+});
+
+add_task(function test_removeCallback() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+  let cb1 = () => true;
+  let cb2 = () => false;
+
+  equal(observer.callbacks.size, 0);
+  observer.add(cb1);
+  observer.add(cb2);
+
+  equal(observer.callbacks.size, 2);
+  observer.remove(cb1);
+  equal(observer.callbacks.size, 1);
+  observer.remove(cb1);
+  equal(observer.callbacks.size, 1);
+  observer.remove(cb2);
+  equal(observer.callbacks.size, 0);
+});
+
+add_task(function test_registerDialogClosedEventHandler() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+  let mockChromeWindow = {
+    addEventListener(event, cb) {
+      equal(
+        event,
+        "DOMModalDialogClosed",
+        "registered event for closing modal"
+      );
+      equal(cb, observer, "set itself as handler");
+    },
+  };
+
+  observer.observe(mockChromeWindow, "domwindowopened");
+});
+
+add_task(function test_handleCallbackOpenModalDialog() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+
+  observer.add((action, dialog) => {
+    equal(action, modal.ACTION_OPENED, "'opened' action has been passed");
+    equal(dialog, mockModalDialog, "dialog has been passed");
+  });
+  observer.observe(mockModalDialog, "common-dialog-loaded");
+});
+
+add_task(function test_handleCallbackCloseModalDialog() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+
+  observer.add((action, dialog) => {
+    equal(action, modal.ACTION_CLOSED, "'closed' action has been passed");
+    equal(dialog, mockModalDialog, "dialog has been passed");
+  });
+  observer.handleEvent({
+    type: "DOMModalDialogClosed",
+    target: mockModalDialog,
+  });
+});
+
+add_task(async function test_dialogClosed() {
+  let observer = new modal.DialogObserver(() => mockCurBrowser);
+
+  const dialogClosed = observer.dialogClosed();
+
+  observer.handleEvent({
+    type: "DOMModalDialogClosed",
+    target: mockModalDialog,
+  });
+
+  await dialogClosed;
+});
diff --git a/remote/marionette/test/xpcshell/test_navigate.js b/remote/marionette/test/xpcshell/test_navigate.js
new file mode 100644
index 0000000000..9b5e2a1bc7
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_navigate.js
@@ -0,0 +1,90 @@
+/* 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/. */
+
+const { navigate } = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/navigate.sys.mjs"
+);
+
+const mockTopContext = {
+  get children() {
+    return [mockNestedContext];
+  },
+  id: 7,
+  get top() {
+    return this;
+  },
+};
+
+const mockNestedContext = {
+  id: 8,
+  parent: mockTopContext,
+  top: mockTopContext,
+};
+
+add_task(function test_isLoadEventExpectedForCurrent() {
+  Assert.throws(
+    () => navigate.isLoadEventExpected(undefined),
+    /Expected at least one URL/
+  );
+
+  ok(navigate.isLoadEventExpected(new URL("http://a/")));
+});
+
+add_task(function test_isLoadEventExpectedForFuture() {
+  const data = [
+    { current: "http://a/", future: undefined, expected: true },
+    { current: "http://a/", future: "http://a/", expected: true },
+    { current: "http://a/", future: "http://a/#", expected: true },
+    { current: "http://a/#", future: "http://a/", expected: true },
+    { current: "http://a/#a", future: "http://a/#A", expected: true },
+    { current: "http://a/#a", future: "http://a/#a", expected: false },
+    { current: "http://a/", future: "javascript:whatever", expected: false },
+  ];
+
+  for (const entry of data) {
+    const current = new URL(entry.current);
+    const future = entry.future ? new URL(entry.future) : undefined;
+    equal(navigate.isLoadEventExpected(current, { future }), entry.expected);
+  }
+});
+
+add_task(function test_isLoadEventExpectedForTarget() {
+  for (const target of ["_parent", "_top"]) {
+    Assert.throws(
+      () => navigate.isLoadEventExpected(new URL("http://a"), { target }),
+      /Expected browsingContext when target is _parent or _top/
+    );
+  }
+
+  const data = [
+    { cur: "http://a/", target: "", expected: true },
+    { cur: "http://a/", target: "_blank", expected: false },
+    { cur: "http://a/", target: "_parent", bc: mockTopContext, expected: true },
+    {
+      cur: "http://a/",
+      target: "_parent",
+      bc: mockNestedContext,
+      expected: false,
+    },
+    { cur: "http://a/", target: "_self", expected: true },
+    { cur: "http://a/", target: "_top", bc: mockTopContext, expected: true },
+    {
+      cur: "http://a/",
+      target: "_top",
+      bc: mockNestedContext,
+      expected: false,
+    },
+  ];
+
+  for (const entry of data) {
+    const current = entry.cur ? new URL(entry.cur) : undefined;
+    equal(
+      navigate.isLoadEventExpected(current, {
+        target: entry.target,
+        browsingContext: entry.bc,
+      }),
+      entry.expected
+    );
+  }
+});
diff --git a/remote/marionette/test/xpcshell/test_prefs.js b/remote/marionette/test/xpcshell/test_prefs.js
new file mode 100644
index 0000000000..ac3432544b
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_prefs.js
@@ -0,0 +1,98 @@
+/* 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";
+
+const { Branch, EnvironmentPrefs, MarionettePrefs } =
+  ChromeUtils.importESModule(
+    "chrome://remote/content/marionette/prefs.sys.mjs"
+  );
+
+function reset() {
+  Services.prefs.setBoolPref("test.bool", false);
+  Services.prefs.setStringPref("test.string", "foo");
+  Services.prefs.setIntPref("test.int", 777);
+}
+
+// Give us something to work with:
+reset();
+
+add_task(function test_Branch_get_root() {
+  let root = new Branch(null);
+  equal(false, root.get("test.bool"));
+  equal("foo", root.get("test.string"));
+  equal(777, root.get("test.int"));
+  Assert.throws(() => root.get("doesnotexist"), /TypeError/);
+});
+
+add_task(function test_Branch_get_branch() {
+  let test = new Branch("test.");
+  equal(false, test.get("bool"));
+  equal("foo", test.get("string"));
+  equal(777, test.get("int"));
+  Assert.throws(() => test.get("doesnotexist"), /TypeError/);
+});
+
+add_task(function test_Branch_set_root() {
+  let root = new Branch(null);
+
+  try {
+    root.set("test.string", "bar");
+    root.set("test.in", 777);
+    root.set("test.bool", true);
+
+    equal("bar", Services.prefs.getStringPref("test.string"));
+    equal(777, Services.prefs.getIntPref("test.int"));
+    equal(true, Services.prefs.getBoolPref("test.bool"));
+  } finally {
+    reset();
+  }
+});
+
+add_task(function test_Branch_set_branch() {
+  let test = new Branch("test.");
+
+  try {
+    test.set("string", "bar");
+    test.set("int", 888);
+    test.set("bool", true);
+
+    equal("bar", Services.prefs.getStringPref("test.string"));
+    equal(888, Services.prefs.getIntPref("test.int"));
+    equal(true, Services.prefs.getBoolPref("test.bool"));
+  } finally {
+    reset();
+  }
+});
+
+add_task(function test_EnvironmentPrefs_from() {
+  let prefsTable = {
+    "test.bool": true,
+    "test.int": 888,
+    "test.string": "bar",
+  };
+  Services.env.set("FOO", JSON.stringify(prefsTable));
+
+  try {
+    for (let [key, value] of EnvironmentPrefs.from("FOO")) {
+      equal(prefsTable[key], value);
+    }
+  } finally {
+    Services.env.set("FOO", null);
+  }
+});
+
+add_task(function test_MarionettePrefs_getters() {
+  equal(false, MarionettePrefs.clickToStart);
+  equal(2828, MarionettePrefs.port);
+});
+
+add_task(function test_MarionettePrefs_setters() {
+  try {
+    MarionettePrefs.port = 777;
+    equal(777, MarionettePrefs.port);
+  } finally {
+    Services.prefs.clearUserPref("marionette.port");
+  }
+});
diff --git a/remote/marionette/test/xpcshell/test_sync.js b/remote/marionette/test/xpcshell/test_sync.js
new file mode 100644
index 0000000000..87ec44e960
--- /dev/null
+++ b/remote/marionette/test/xpcshell/test_sync.js
@@ -0,0 +1,419 @@
+/* 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/. */
+
+const {
+  DebounceCallback,
+  IdlePromise,
+  PollPromise,
+  Sleep,
+  TimedPromise,
+  waitForMessage,
+  waitForObserverTopic,
+} = ChromeUtils.importESModule(
+  "chrome://remote/content/marionette/sync.sys.mjs"
+);
+
+/**
+ * Mimic a message manager for sending messages.
+ */
+class MessageManager {
+  constructor() {
+    this.func = null;
+    this.message = null;
+  }
+
+  addMessageListener(message, func) {
+    this.func = func;
+    this.message = message;
+  }
+
+  removeMessageListener(message) {
+    this.func = null;
+    this.message = null;
+  }
+
+  send(message, data) {
+    if (this.func) {
+      this.func({
+        data,
+        message,
+        target: this,
+      });
+    }
+  }
+}
+
+/**
+ * Mimics nsITimer, but instead of using a system clock you can
+ * preprogram it to invoke the callback after a given number of ticks.
+ */
+class MockTimer {
+  constructor(ticksBeforeFiring) {
+    this.goal = ticksBeforeFiring;
+    this.ticks = 0;
+    this.cancelled = false;
+  }
+
+  initWithCallback(cb, timeout, type) {
+    this.ticks++;
+    if (this.ticks >= this.goal) {
+      cb();
+    }
+  }
+
+  cancel() {
+    this.cancelled = true;
+  }
+}
+
+add_task(function test_executeSoon_callback() {
+  // executeSoon() is already defined for xpcshell in head.js. As such import
+  // our implementation into a custom namespace.
+  let sync = ChromeUtils.importESModule(
+    "chrome://remote/content/marionette/sync.sys.mjs"
+  );
+
+  for (let func of ["foo", null, true, [], {}]) {
+    Assert.throws(() => sync.executeSoon(func), /TypeError/);
+  }
+
+  let a;
+  sync.executeSoon(() => {
+    a = 1;
+  });
+  executeSoon(() => equal(1, a));
+});
+
+add_task(function test_PollPromise_funcTypes() {
+  for (let type of ["foo", 42, null, undefined, true, [], {}]) {
+    Assert.throws(() => new PollPromise(type), /TypeError/);
+  }
+  new PollPromise(() => {});
+  new PollPromise(function () {});
+});
+
+add_task(function test_PollPromise_timeoutTypes() {
+  for (let timeout of ["foo", true, [], {}]) {
+    Assert.throws(() => new PollPromise(() => {}, { timeout }), /TypeError/);
+  }
+  for (let timeout of [1.2, -1]) {
+    Assert.throws(() => new PollPromise(() => {}, { timeout }), /RangeError/);
+  }
+  for (let timeout of [null, undefined, 42]) {
+    new PollPromise(resolve => resolve(1), { timeout });
+  }
+});
+
+add_task(function test_PollPromise_intervalTypes() {
+  for (let interval of ["foo", null, true, [], {}]) {
+    Assert.throws(() => new PollPromise(() => {}, { interval }), /TypeError/);
+  }
+  for (let interval of [1.2, -1]) {
+    Assert.throws(() => new PollPromise(() => {}, { interval }), /RangeError/);
+  }
+  new PollPromise(() => {}, { interval: 42 });
+});
+
+add_task(async function test_PollPromise_retvalTypes() {
+  for (let typ of [true, false, "foo", 42, [], {}]) {
+    strictEqual(typ, await new PollPromise(resolve => resolve(typ)));
+  }
+});
+
+add_task(async function test_PollPromise_rethrowError() {
+  let nevals = 0;
+  let err;
+  try {
+    await PollPromise(() => {
+      ++nevals;
+      throw new Error();
+    });
+  } catch (e) {
+    err = e;
+  }
+  equal(1, nevals);
+  ok(err instanceof Error);
+});
+
+add_task(async function test_PollPromise_noTimeout() {
+  let nevals = 0;
+  await new PollPromise((resolve, reject) => {
+    ++nevals;
+    nevals < 100 ? reject() : resolve();
+  });
+  equal(100, nevals);
+});
+
+add_task(async function test_PollPromise_zeroTimeout() {
+  // run at least once when timeout is 0
+  let nevals = 0;
+  let start = new Date().getTime();
+  await new PollPromise(
+    (resolve, reject) => {
+      ++nevals;
+      reject();
+    },
+    { timeout: 0 }
+  );
+  let end = new Date().getTime();
+  equal(1, nevals);
+  less(end - start, 500);
+});
+
+add_task(async function test_PollPromise_timeoutElapse() {
+  let nevals = 0;
+  let start = new Date().getTime();
+  await new PollPromise(
+    (resolve, reject) => {
+      ++nevals;
+      reject();
+    },
+    { timeout: 100 }
+  );
+  let end = new Date().getTime();
+  lessOrEqual(nevals, 11);
+  greaterOrEqual(end - start, 100);
+});
+
+add_task(async function test_PollPromise_interval() {
+  let nevals = 0;
+  await new PollPromise(
+    (resolve, reject) => {
+      ++nevals;
+      reject();
+    },
+    { timeout: 100, interval: 100 }
+  );
+  equal(2, nevals);
+});
+
+add_task(function test_TimedPromise_funcTypes() {
+  for (let type of ["foo", 42, null, undefined, true, [], {}]) {
+    Assert.throws(() => new TimedPromise(type), /TypeError/);
+  }
+  new TimedPromise(resolve => resolve());
+  new TimedPromise(function (resolve) {
+    resolve();
+  });
+});
+
+add_task(function test_TimedPromise_timeoutTypes() {
+  for (let timeout of ["foo", null, true, [], {}]) {
+    Assert.throws(
+      () => new TimedPromise(resolve => resolve(), { timeout }),
+      /TypeError/
+    );
+  }
+  for (let timeout of [1.2, -1]) {
+    Assert.throws(
+      () => new TimedPromise(resolve => resolve(), { timeout }),
+      /RangeError/
+    );
+  }
+  new TimedPromise(resolve => resolve(), { timeout: 42 });
+});
+
+add_task(async function test_TimedPromise_errorMessage() {
+  try {
+    await new TimedPromise(resolve => {}, { timeout: 0 });
+    ok(false, "Expected Timeout error not raised");
+  } catch (e) {
+    ok(
+      e.message.includes("TimedPromise timed out after"),
+      "Expected default error message found"
+    );
+  }
+
+  try {
+    await new TimedPromise(resolve => {}, {
+      errorMessage: "Not found",
+      timeout: 0,
+    });
+    ok(false, "Expected Timeout error not raised");
+  } catch (e) {
+    ok(
+      e.message.includes("Not found after"),
+      "Expected custom error message found"
+    );
+  }
+});
+
+add_task(async function test_Sleep() {
+  await Sleep(0);
+  for (let type of ["foo", true, null, undefined]) {
+    Assert.throws(() => new Sleep(type), /TypeError/);
+  }
+  Assert.throws(() => new Sleep(1.2), /RangeError/);
+  Assert.throws(() => new Sleep(-1), /RangeError/);
+});
+
+add_task(async function test_IdlePromise() {
+  let called = false;
+  let win = {
+    requestAnimationFrame(callback) {
+      called = true;
+      callback();
+    },
+  };
+  await IdlePromise(win);
+  ok(called);
+});
+
+add_task(async function test_IdlePromiseAbortWhenWindowClosed() {
+  let win = {
+    closed: true,
+    requestAnimationFrame() {},
+  };
+  await IdlePromise(win);
+});
+
+add_task(function test_DebounceCallback_constructor() {
+  for (let cb of [42, "foo", true, null, undefined, [], {}]) {
+    Assert.throws(() => new DebounceCallback(cb), /TypeError/);
+  }
+  for (let timeout of ["foo", true, [], {}, () => {}]) {
+    Assert.throws(
+      () => new DebounceCallback(() => {}, { timeout }),
+      /TypeError/
+    );
+  }
+  for (let timeout of [-1, 2.3, NaN]) {
+    Assert.throws(
+      () => new DebounceCallback(() => {}, { timeout }),
+      /RangeError/
+    );
+  }
+});
+
+add_task(async function test_DebounceCallback_repeatedCallback() {
+  let uniqueEvent = {};
+  let ncalls = 0;
+
+  let cb = ev => {
+    ncalls++;
+    equal(ev, uniqueEvent);
+  };
+  let debouncer = new DebounceCallback(cb);
+  debouncer.timer = new MockTimer(3);
+
+  // flood the debouncer with events,
+  // we only expect the last one to fire
+  debouncer.handleEvent(uniqueEvent);
+  debouncer.handleEvent(uniqueEvent);
+  debouncer.handleEvent(uniqueEvent);
+
+  equal(ncalls, 1);
+  ok(debouncer.timer.cancelled);
+});
+
+add_task(async function test_waitForMessage_messageManagerAndMessageTypes() {
+  let messageManager = new MessageManager();
+
+  for (let manager of ["foo", 42, null, undefined, true, [], {}]) {
+    Assert.throws(() => waitForMessage(manager, "message"), /TypeError/);
+  }
+
+  for (let message of [42, null, undefined, true, [], {}]) {
+    Assert.throws(() => waitForMessage(messageManager, message), /TypeError/);
+  }
+
+  let data = { foo: "bar" };
+  let sent = waitForMessage(messageManager, "message");
+  messageManager.send("message", data);
+  equal(data, await sent);
+});
+
+add_task(async function test_waitForMessage_checkFnTypes() {
+  let messageManager = new MessageManager();
+
+  for (let checkFn of ["foo", 42, true, [], {}]) {
+    Assert.throws(
+      () => waitForMessage(messageManager, "message", { checkFn }),
+      /TypeError/
+    );
+  }
+
+  let data1 = { fo: "bar" };
+  let data2 = { foo: "bar" };
+
+  for (let checkFn of [null, undefined, msg => "foo" in msg.data]) {
+    let expected_data = checkFn == null ? data1 : data2;
+
+    messageManager = new MessageManager();
+    let sent = waitForMessage(messageManager, "message", { checkFn });
+    messageManager.send("message", data1);
+    messageManager.send("message", data2);
+    equal(expected_data, await sent);
+  }
+});
+
+add_task(async function test_waitForObserverTopic_topicTypes() {
+  for (let topic of [42, null, undefined, true, [], {}]) {
+    Assert.throws(() => waitForObserverTopic(topic), /TypeError/);
+  }
+
+  let data = { foo: "bar" };
+  let sent = waitForObserverTopic("message");
+  Services.obs.notifyObservers(this, "message", data);
+  let result = await sent;
+  equal(this, result.subject);
+  equal(data, result.data);
+});
+
+add_task(async function test_waitForObserverTopic_checkFnTypes() {
+  for (let checkFn of ["foo", 42, true, [], {}]) {
+    Assert.throws(
+      () => waitForObserverTopic("message", { checkFn }),
+      /TypeError/
+    );
+  }
+
+  let data1 = { fo: "bar" };
+  let data2 = { foo: "bar" };
+
+  for (let checkFn of [null, undefined, (subject, data) => data == data2]) {
+    let expected_data = checkFn == null ? data1 : data2;
+
+    let sent = waitForObserverTopic("message");
+    Services.obs.notifyObservers(this, "message", data1);
+    Services.obs.notifyObservers(this, "message", data2);
+    let result = await sent;
+    equal(expected_data, result.data);
+  }
+});
+
+add_task(async function test_waitForObserverTopic_timeoutTypes() {
+  for (let timeout of ["foo", true, [], {}]) {
+    Assert.throws(
+      () => waitForObserverTopic("message", { timeout }),
+      /TypeError/
+    );
+  }
+  for (let timeout of [1.2, -1]) {
+    Assert.throws(
+      () => waitForObserverTopic("message", { timeout }),
+      /RangeError/
+    );
+  }
+  for (let timeout of [null, undefined, 42]) {
+    let data = { foo: "bar" };
+    let sent = waitForObserverTopic("message", { timeout });
+    Services.obs.notifyObservers(this, "message", data);
+    let result = await sent;
+    equal(this, result.subject);
+    equal(data, result.data);
+  }
+});
+
+add_task(async function test_waitForObserverTopic_timeoutElapse() {
+  try {
+    await waitForObserverTopic("message", { timeout: 0 });
+    ok(false, "Expected Timeout error not raised");
+  } catch (e) {
+    ok(
+      e.message.includes("waitForObserverTopic timed out after"),
+      "Expected error received"
+    );
+  }
+});
diff --git a/remote/marionette/test/xpcshell/xpcshell.ini b/remote/marionette/test/xpcshell/xpcshell.ini
new file mode 100644
index 0000000000..262d57ca39
--- /dev/null
+++ b/remote/marionette/test/xpcshell/xpcshell.ini
@@ -0,0 +1,18 @@
+# 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/.
+
+[DEFAULT]
+head = head.js
+skip-if = appname == "thunderbird"
+
+[test_actors.js]
+[test_browser.js]
+[test_cookie.js]
+[test_element.js]
+[test_json.js]
+[test_message.js]
+[test_modal.js]
+[test_navigate.js]
+[test_prefs.js]
+[test_sync.js]