Adding upstream version 124.0.1.upstream/124.0.1

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

22 files changed, 2265 insertions, 0 deletions

diff --git a/browser/base/content/test/tabPrompts/auth-route.sjs b/browser/base/content/test/tabPrompts/auth-route.sjs
new file mode 100644
index 0000000000..4f113a8add
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/auth-route.sjs
@@ -0,0 +1,28 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+function handleRequest(request, response) {
+  let body;
+  // guest:guest
+  let expectedHeader = "Basic Z3Vlc3Q6Z3Vlc3Q=";
+  // correct login credentials provided
+  if (
+    request.hasHeader("Authorization") &&
+    request.getHeader("Authorization") == expectedHeader
+  ) {
+    response.setStatusLine(request.httpVersion, 200, "OK, authorized");
+    response.setHeader("Content-Type", "text", false);
+
+    body = "success";
+  } else {
+    // incorrect credentials
+    response.setStatusLine(request.httpVersion, 401, "Unauthorized");
+    response.setHeader("WWW-Authenticate", 'Basic realm="secret"', false);
+    response.setHeader("Content-Type", "text", false);
+
+    body = "failed";
+  }
+  response.bodyOutputStream.write(body, body.length);
+}
diff --git a/browser/base/content/test/tabPrompts/browser.toml b/browser/base/content/test/tabPrompts/browser.toml
new file mode 100644
index 0000000000..037f1f0d2b
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser.toml
@@ -0,0 +1,50 @@
+[DEFAULT]
+
+["browser_abort_when_in_modal_state.js"]
+
+["browser_auth_spoofing_protection.js"]
+support-files = [
+  "redirect-crossDomain.html",
+  "redirect-sameDomain.html",
+  "auth-route.sjs",
+]
+
+["browser_auth_spoofing_url_copy.js"]
+support-files = [
+  "redirect-crossDomain.html",
+  "auth-route.sjs",
+]
+
+["browser_auth_spoofing_url_drag_and_drop.js"]
+support-files = [
+  "redirect-crossDomain.html",
+  "redirect-sameDomain.html",
+  "auth-route.sjs",
+]
+
+["browser_beforeunload_urlbar.js"]
+support-files = ["file_beforeunload_stop.html"]
+
+["browser_closeTabSpecificPanels.js"]
+skip-if = ["verify && debug && (os == 'linux')"]
+
+["browser_confirmFolderUpload.js"]
+
+["browser_contentOrigins.js"]
+support-files = ["file_beforeunload_stop.html"]
+
+["browser_multiplePrompts.js"]
+
+["browser_openPromptInBackgroundTab.js"]
+https_first_disabled = true
+support-files = ["openPromptOffTimeout.html"]
+
+["browser_promptFocus.js"]
+
+["browser_prompt_close_event.js"]
+
+["browser_prompt_closed_window.js"]
+
+["browser_switchTabPermissionPrompt.js"]
+
+["browser_windowPrompt.js"]
diff --git a/browser/base/content/test/tabPrompts/browser_abort_when_in_modal_state.js b/browser/base/content/test/tabPrompts/browser_abort_when_in_modal_state.js
new file mode 100644
index 0000000000..cb3a1f72d6
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_abort_when_in_modal_state.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PromiseTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PromiseTestUtils.sys.mjs"
+);
+
+/**
+ * Check that if we're using a window-modal prompt,
+ * the next synchronous window-internal modal prompt aborts rather than
+ * leaving us in a deadlock about how to enter modal state.
+ */
+add_task(async function test_check_multiple_prompts() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+  let container = document.getElementById("window-modal-dialog");
+  let dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+  let firstDialogClosedPromise = new Promise(resolve => {
+    // Avoid blocking the test on the (sync) alert by sticking it in a timeout:
+    setTimeout(() => {
+      Services.prompt.alertBC(
+        window.browsingContext,
+        Ci.nsIPrompt.MODAL_TYPE_WINDOW,
+        "Some title",
+        "some message"
+      );
+      resolve();
+    }, 0);
+  });
+  let dialogWin = await dialogPromise;
+
+  // Check circumstances of opening.
+  ok(
+    !dialogWin.docShell.chromeEventHandler,
+    "Should not have embedded the dialog."
+  );
+
+  PromiseTestUtils.expectUncaughtRejection(/could not be shown/);
+  let rv = Services.prompt.confirm(
+    window,
+    "I should not appear",
+    "because another prompt was open"
+  );
+  is(rv, false, "Prompt should have been canceled.");
+
+  info("Accepting dialog");
+  dialogWin.document.querySelector("dialog").acceptDialog();
+
+  await firstDialogClosedPromise;
+
+  await BrowserTestUtils.waitForMutationCondition(
+    container,
+    { childList: true, attributes: true },
+    () => !container.hasChildNodes() && !container.open
+  );
+});
diff --git a/browser/base/content/test/tabPrompts/browser_auth_spoofing_protection.js b/browser/base/content/test/tabPrompts/browser_auth_spoofing_protection.js
new file mode 100644
index 0000000000..86d7c992c5
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_auth_spoofing_protection.js
@@ -0,0 +1,236 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  UrlbarTestUtils: "resource://testing-common/UrlbarTestUtils.sys.mjs",
+});
+
+let TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.com"
+);
+
+let TEST_PATH_AUTH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.org"
+);
+
+const CROSS_DOMAIN_URL = TEST_PATH + "redirect-crossDomain.html";
+
+const SAME_DOMAIN_URL = TEST_PATH + "redirect-sameDomain.html";
+
+const AUTH_URL = TEST_PATH_AUTH + "auth-route.sjs";
+
+/**
+ * Opens a new tab with a url that ether redirects us cross or same domain
+ *
+ * @param {Boolean} doConfirmPrompt - true if we want to test the case when the user accepts the prompt,
+ *         false if we want to test the case when the user cancels the prompt.
+ * @param {Boolean} crossDomain - if true we will open a url that redirects us to a cross domain url,
+ *        if false, we will open a url that redirects us to a same domain url
+ * @param {Boolean} prefEnabled true will enable "privacy.authPromptSpoofingProtection",
+ *        false will disable the pref
+ */
+async function trigger401AndHandle(doConfirmPrompt, crossDomain, prefEnabled) {
+  await SpecialPowers.pushPrefEnv({
+    set: [["privacy.authPromptSpoofingProtection", prefEnabled]],
+  });
+  let url = crossDomain ? CROSS_DOMAIN_URL : SAME_DOMAIN_URL;
+  let dialogShown = waitForDialog(doConfirmPrompt, crossDomain, prefEnabled);
+  await BrowserTestUtils.withNewTab(url, async function () {
+    await dialogShown;
+  });
+  await new Promise(resolve => {
+    Services.clearData.deleteData(
+      Ci.nsIClearDataService.CLEAR_AUTH_CACHE,
+      resolve
+    );
+  });
+}
+
+async function waitForDialog(doConfirmPrompt, crossDomain, prefEnabled) {
+  await TestUtils.topicObserved("common-dialog-loaded");
+  let dialog = gBrowser.getTabDialogBox(gBrowser.selectedBrowser)
+    ._tabDialogManager._topDialog;
+  let dialogDocument = dialog._frame.contentDocument;
+  if (crossDomain) {
+    if (prefEnabled) {
+      Assert.equal(
+        dialog._overlay.getAttribute("hideContent"),
+        "true",
+        "Dialog overlay hides the current sites content"
+      );
+      Assert.equal(
+        window.gURLBar.value,
+        UrlbarTestUtils.trimURL(AUTH_URL),
+        "Correct location is provided by the prompt"
+      );
+      Assert.equal(
+        window.gBrowser.selectedTab.label,
+        "example.org",
+        "Tab title is manipulated"
+      );
+      // switch to another tab and make sure we dont mess up this new tabs url bar and tab title
+      let tab = await BrowserTestUtils.openNewForegroundTab(
+        gBrowser,
+        "https://example.org:443"
+      );
+      Assert.equal(
+        window.gURLBar.value,
+        UrlbarTestUtils.trimURL("https://example.org"),
+        "No location is provided by the prompt, correct location is displayed"
+      );
+      Assert.equal(
+        window.gBrowser.selectedTab.label,
+        "mochitest index /",
+        "Tab title is not manipulated"
+      );
+      // switch back to our tab with the prompt and make sure the url bar state and tab title is still there
+      BrowserTestUtils.removeTab(tab);
+      Assert.equal(
+        window.gURLBar.value,
+        UrlbarTestUtils.trimURL(AUTH_URL),
+        "Correct location is provided by the prompt"
+      );
+      Assert.equal(
+        window.gBrowser.selectedTab.label,
+        "example.org",
+        "Tab title is manipulated"
+      );
+      // make sure a value that the user types in has a higher priority than our prompts location
+      gBrowser.selectedBrowser.userTypedValue = "user value";
+      gURLBar.setURI();
+      Assert.equal(
+        window.gURLBar.value,
+        "user value",
+        "User typed value is shown"
+      );
+      // if the user clears the url bar we again fall back to the location of the prompt if we trigger setURI by a tab switch
+      gBrowser.selectedBrowser.userTypedValue = "";
+      gURLBar.setURI(null, true);
+      Assert.equal(
+        window.gURLBar.value,
+        UrlbarTestUtils.trimURL(AUTH_URL),
+        "Correct location is provided by the prompt"
+      );
+      // Cross domain and pref is not enabled
+    } else {
+      Assert.equal(
+        dialog._overlay.getAttribute("hideContent"),
+        "",
+        "Dialog overlay does not hide the current sites content"
+      );
+      Assert.equal(
+        window.gURLBar.value,
+        UrlbarTestUtils.trimURL(CROSS_DOMAIN_URL),
+        "No location is provided by the prompt, correct location is displayed"
+      );
+      Assert.equal(
+        window.gBrowser.selectedTab.label,
+        "example.com",
+        "Tab title is not manipulated"
+      );
+    }
+    // same domain
+  } else {
+    Assert.equal(
+      dialog._overlay.getAttribute("hideContent"),
+      "",
+      "Dialog overlay does not hide the current sites content"
+    );
+    Assert.equal(
+      window.gURLBar.value,
+      UrlbarTestUtils.trimURL(SAME_DOMAIN_URL),
+      "No location is provided by the prompt, correct location is displayed"
+    );
+    Assert.equal(
+      window.gBrowser.selectedTab.label,
+      "example.com",
+      "Tab title is not manipulated"
+    );
+  }
+
+  let onDialogClosed = BrowserTestUtils.waitForEvent(
+    window,
+    "DOMModalDialogClosed"
+  );
+  if (doConfirmPrompt) {
+    dialogDocument.getElementById("loginTextbox").value = "guest";
+    dialogDocument.getElementById("password1Textbox").value = "guest";
+    dialogDocument.getElementById("commonDialog").acceptDialog();
+  } else {
+    dialogDocument.getElementById("commonDialog").cancelDialog();
+  }
+
+  // wait for the dialog to be closed to check that the URLBar state is reset
+  await onDialogClosed;
+  // Due to bug 1812014, the url bar will be clear if we have set its value to "" while the prompt was open
+  // so we trigger a tab switch again to have the uri displayed to be able to check its value
+  gURLBar.setURI(null, true);
+  Assert.equal(
+    window.gURLBar.value,
+    UrlbarTestUtils.trimURL(crossDomain ? CROSS_DOMAIN_URL : SAME_DOMAIN_URL),
+    "No location is provided by the prompt"
+  );
+  Assert.equal(
+    window.gBrowser.selectedTab.label,
+    "example.com",
+    "Tab title is not manipulated"
+  );
+}
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [["privacy.authPromptSpoofingProtection", true]],
+  });
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms apply if the 401 is from a different base domain than the current sites,
+ * canceling the prompt
+ */
+add_task(async function testCrossDomainCancelPrefEnabled() {
+  await trigger401AndHandle(false, true, true);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms apply if the 401 is from a different base domain than the current sites,
+ * accepting the prompt
+ */
+add_task(async function testCrossDomainAcceptPrefEnabled() {
+  await trigger401AndHandle(true, true, true);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms do not apply if "privacy.authPromptSpoofingProtection" is not set to true
+ * canceling the prompt
+ */
+add_task(async function testCrossDomainCancelPrefDisabled() {
+  await trigger401AndHandle(false, true, false);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms do not apply if "privacy.authPromptSpoofingProtection" is not set to true,
+ * accepting the prompt
+ */
+add_task(async function testCrossDomainAcceptPrefDisabled() {
+  await trigger401AndHandle(true, true, false);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms are not triggered by a 401 within the same base domain as the current sites,
+ * canceling the prompt
+ */
+add_task(async function testSameDomainCancelPrefEnabled() {
+  await trigger401AndHandle(false, false, true);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms are not triggered by a 401 within the same base domain as the current sites,
+ * accepting the prompt
+ */
+add_task(async function testSameDomainAcceptPrefEnabled() {
+  await trigger401AndHandle(true, false, true);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_copy.js b/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_copy.js
new file mode 100644
index 0000000000..f955999e8b
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_copy.js
@@ -0,0 +1,137 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { UrlbarTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/UrlbarTestUtils.sys.mjs"
+);
+
+let TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.com"
+);
+
+let TEST_PATH_AUTH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.org"
+);
+
+const CROSS_DOMAIN_URL = TEST_PATH + "redirect-crossDomain.html";
+
+const AUTH_URL = TEST_PATH_AUTH + "auth-route.sjs";
+
+/**
+ * Opens a new tab with a url that redirects us cross domain
+ * tests that auth anti-spoofing mechanisms cover url copy while prompt is open
+ *
+ */
+async function trigger401AndHandle() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["privacy.authPromptSpoofingProtection", true]],
+  });
+  let dialogShown = waitForDialogAndCopyURL();
+  await BrowserTestUtils.withNewTab(CROSS_DOMAIN_URL, async function () {
+    await dialogShown;
+  });
+  await new Promise(resolve => {
+    Services.clearData.deleteData(
+      Ci.nsIClearDataService.CLEAR_AUTH_CACHE,
+      resolve
+    );
+  });
+}
+
+async function waitForDialogAndCopyURL() {
+  await TestUtils.topicObserved("common-dialog-loaded");
+  let dialog = gBrowser.getTabDialogBox(gBrowser.selectedBrowser)
+    ._tabDialogManager._topDialog;
+  let dialogDocument = dialog._frame.contentDocument;
+
+  //select the whole URL
+  gURLBar.focus();
+  await SimpleTest.promiseClipboardChange(AUTH_URL, () => {
+    Assert.equal(
+      gURLBar.value,
+      UrlbarTestUtils.trimURL(AUTH_URL),
+      "url bar copy value set"
+    );
+    gURLBar.select();
+    goDoCommand("cmd_copy");
+  });
+
+  // select only part of the URL
+  gURLBar.focus();
+  let endOfSelectionRange =
+    UrlbarTestUtils.trimURL(AUTH_URL).indexOf("/auth-route.sjs");
+
+  let isProtocolTrimmed = AUTH_URL.startsWith(
+    UrlbarTestUtils.getTrimmedProtocolWithSlashes()
+  );
+  await SimpleTest.promiseClipboardChange(
+    AUTH_URL.substring(
+      0,
+      endOfSelectionRange +
+        (isProtocolTrimmed
+          ? UrlbarTestUtils.getTrimmedProtocolWithSlashes().length
+          : 0)
+    ),
+    () => {
+      Assert.equal(
+        gURLBar.value,
+        UrlbarTestUtils.trimURL(AUTH_URL),
+        "url bar copy value set"
+      );
+      gURLBar.selectionStart = 0;
+      gURLBar.selectionEnd = endOfSelectionRange;
+      goDoCommand("cmd_copy");
+    }
+  );
+  let onDialogClosed = BrowserTestUtils.waitForEvent(
+    window,
+    "DOMModalDialogClosed"
+  );
+  dialogDocument.getElementById("commonDialog").cancelDialog();
+
+  await onDialogClosed;
+  Assert.equal(
+    window.gURLBar.value,
+    UrlbarTestUtils.trimURL(CROSS_DOMAIN_URL),
+    "No location is provided by the prompt"
+  );
+
+  //select the whole URL after URL is reset to normal
+  gURLBar.focus();
+  await SimpleTest.promiseClipboardChange(CROSS_DOMAIN_URL, () => {
+    Assert.equal(
+      gURLBar.value,
+      UrlbarTestUtils.trimURL(CROSS_DOMAIN_URL),
+      "url bar copy value set"
+    );
+    gURLBar.select();
+    goDoCommand("cmd_copy");
+  });
+}
+
+/**
+ * Tests that the 401 auth spoofing mechanisms covers the url bar copy action properly,
+ * canceling the prompt
+ */
+add_task(async function testUrlCopy() {
+  SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.urlbar.trimHttps", false],
+      ["browser.urlbar.trimURLs", true],
+    ],
+  });
+  await trigger401AndHandle();
+  SpecialPowers.popPrefEnv();
+
+  SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.urlbar.trimHttps", true],
+      ["browser.urlbar.trimURLs", true],
+    ],
+  });
+  await trigger401AndHandle();
+});
diff --git a/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_drag_and_drop.js b/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_drag_and_drop.js
new file mode 100644
index 0000000000..829fa91f75
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_auth_spoofing_url_drag_and_drop.js
@@ -0,0 +1,100 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+let TEST_PATH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.com"
+);
+
+let TEST_PATH_AUTH = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.org"
+);
+
+const CROSS_DOMAIN_URL = TEST_PATH + "redirect-crossDomain.html";
+
+const SAME_DOMAIN_URL = TEST_PATH + "redirect-sameDomain.html";
+
+const AUTH_URL = TEST_PATH_AUTH + "auth-route.sjs";
+
+/**
+ * Opens a new tab with a url that ether redirects us cross or same domain
+ *
+ * @param {Boolean} crossDomain - if true we will open a url that redirects us to a cross domain url,
+ *        if false, we will open a url that redirects us to a same domain url
+ */
+async function trigger401AndHandle(crossDomain) {
+  let dialogShown = waitForDialogAndDragNDropURL(crossDomain);
+  await BrowserTestUtils.withNewTab(
+    crossDomain ? CROSS_DOMAIN_URL : SAME_DOMAIN_URL,
+    async function () {
+      await dialogShown;
+    }
+  );
+  await new Promise(resolve => {
+    Services.clearData.deleteData(
+      Ci.nsIClearDataService.CLEAR_AUTH_CACHE,
+      resolve
+    );
+  });
+}
+
+async function waitForDialogAndDragNDropURL(crossDomain) {
+  await TestUtils.topicObserved("common-dialog-loaded");
+  let dialog = gBrowser.getTabDialogBox(gBrowser.selectedBrowser)
+    ._tabDialogManager._topDialog;
+  let dialogDocument = dialog._frame.contentDocument;
+
+  let urlbar = document.getElementById("urlbar-input");
+  let dataTran = new DataTransfer();
+  let urlEvent = new DragEvent("dragstart", { dataTransfer: dataTran });
+  let urlBarContainer = document.getElementById("urlbar-input-container");
+  // We intentionally turn off a11y_checks for the following click, because
+  // it is send to prepare the URL Bar for the mouse-specific action - for a
+  // drag event, while there are other ways are accessible for users of
+  // assistive technology and keyboards, therefore this test can be excluded
+  // from the accessibility tests.
+  AccessibilityUtils.setEnv({ mustHaveAccessibleRule: false });
+  urlBarContainer.click();
+  AccessibilityUtils.resetEnv();
+  // trigger a drag event in the gUrlBar
+  urlbar.dispatchEvent(urlEvent);
+  // this should set some propperties on our event, like the url we are dragging
+  if (crossDomain) {
+    is(
+      urlEvent.dataTransfer.getData("text/plain"),
+      AUTH_URL,
+      "correct cross Domain URL is dragged over"
+    );
+  } else {
+    is(
+      urlEvent.dataTransfer.getData("text/plain"),
+      SAME_DOMAIN_URL,
+      "correct same domain URL is dragged over"
+    );
+  }
+
+  let onDialogClosed = BrowserTestUtils.waitForEvent(
+    window,
+    "DOMModalDialogClosed"
+  );
+  dialogDocument.getElementById("commonDialog").cancelDialog();
+
+  await onDialogClosed;
+}
+
+/**
+ * Tests that the 401 auth spoofing mechanisms covers the url bar drag and drop action propperly,
+ */
+add_task(async function testUrlDragAndDrop() {
+  await trigger401AndHandle(true);
+});
+
+/**
+ * Tests that the 401 auth spoofing mechanisms do not apply to the url bar drag and drop action if the 401 is not from a different base domain,
+ */
+add_task(async function testUrlDragAndDrop() {
+  await trigger401AndHandle(false);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_beforeunload_urlbar.js b/browser/base/content/test/tabPrompts/browser_beforeunload_urlbar.js
new file mode 100644
index 0000000000..52044b5874
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_beforeunload_urlbar.js
@@ -0,0 +1,75 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+  "http://example.com"
+);
+
+const CONTENT_PROMPT_SUBDIALOG = Services.prefs.getBoolPref(
+  "prompts.contentPromptSubDialog",
+  false
+);
+
+add_task(async function test_beforeunload_stay_clears_urlbar() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.require_user_interaction_for_beforeunload", false]],
+  });
+
+  const TEST_URL = TEST_ROOT + "file_beforeunload_stop.html";
+  await BrowserTestUtils.withNewTab(TEST_URL, async function (browser) {
+    gURLBar.focus();
+    // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+    const inputValue = "http://example.org/?q=typed";
+    gURLBar.value = inputValue.slice(0, -1);
+    EventUtils.sendString(inputValue.slice(-1));
+
+    if (CONTENT_PROMPT_SUBDIALOG) {
+      let promptOpenedPromise =
+        BrowserTestUtils.promiseAlertDialogOpen("cancel");
+      EventUtils.synthesizeKey("VK_RETURN");
+      await promptOpenedPromise;
+      await TestUtils.waitForTick();
+    } else {
+      let promptOpenedPromise = TestUtils.topicObserved(
+        "tabmodal-dialog-loaded"
+      );
+      EventUtils.synthesizeKey("VK_RETURN");
+      await promptOpenedPromise;
+      let promptElement = browser.parentNode.querySelector("tabmodalprompt");
+
+      // Click the cancel button
+      promptElement.querySelector(".tabmodalprompt-button1").click();
+      await TestUtils.waitForCondition(
+        () => promptElement.parentNode == null,
+        "tabprompt should be removed"
+      );
+    }
+
+    // Can't just compare directly with TEST_URL because the URL may be trimmed.
+    // Just need it to not be the example.org thing we typed in.
+    ok(
+      gURLBar.value.endsWith("_stop.html"),
+      "Url bar should be reset to point to the stop html file"
+    );
+    ok(
+      gURLBar.value.includes("example.com"),
+      "Url bar should be reset to example.com"
+    );
+    // Check the lock/identity icons are back:
+    is(
+      gURLBar.textbox.getAttribute("pageproxystate"),
+      "valid",
+      "Should be in valid pageproxy state."
+    );
+
+    // Now we need to get rid of the handler to avoid the prompt coming up when trying to close the
+    // tab when we exit `withNewTab`. :-)
+    await SpecialPowers.spawn(browser, [], function () {
+      content.window.onbeforeunload = null;
+    });
+  });
+});
diff --git a/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js b/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js
new file mode 100644
index 0000000000..8d789ad512
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_closeTabSpecificPanels.js
@@ -0,0 +1,53 @@
+"use strict";
+
+/*
+ * This test creates multiple panels, one that has been tagged as specific to its tab's content
+ * and one that isn't. When a tab loses focus, panel specific to that tab should close.
+ * The non-specific panel should remain open.
+ *
+ */
+
+add_task(async function () {
+  let tab1 = BrowserTestUtils.addTab(gBrowser, "http://mochi.test:8888/#0");
+  let tab2 = BrowserTestUtils.addTab(gBrowser, "http://mochi.test:8888/#1");
+  let specificPanel = document.createXULElement("panel");
+  specificPanel.setAttribute("tabspecific", "true");
+  specificPanel.setAttribute("noautohide", "true");
+  let generalPanel = document.createXULElement("panel");
+  generalPanel.setAttribute("noautohide", "true");
+  let anchor = document.getElementById(CustomizableUI.AREA_NAVBAR);
+
+  anchor.appendChild(specificPanel);
+  anchor.appendChild(generalPanel);
+  is(specificPanel.state, "closed", "specificPanel starts as closed");
+  is(generalPanel.state, "closed", "generalPanel starts as closed");
+
+  let specificPanelPromise = BrowserTestUtils.waitForEvent(
+    specificPanel,
+    "popupshown"
+  );
+  specificPanel.openPopupAtScreen(210, 210);
+  await specificPanelPromise;
+  is(specificPanel.state, "open", "specificPanel has been opened");
+
+  let generalPanelPromise = BrowserTestUtils.waitForEvent(
+    generalPanel,
+    "popupshown"
+  );
+  generalPanel.openPopupAtScreen(510, 510);
+  await generalPanelPromise;
+  is(generalPanel.state, "open", "generalPanel has been opened");
+
+  gBrowser.tabContainer.advanceSelectedTab(-1, true);
+  is(
+    specificPanel.state,
+    "closed",
+    "specificPanel panel is closed after its tab loses focus"
+  );
+  is(generalPanel.state, "open", "generalPanel is still open after tab switch");
+
+  specificPanel.remove();
+  generalPanel.remove();
+  gBrowser.removeTab(tab1);
+  gBrowser.removeTab(tab2);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_confirmFolderUpload.js b/browser/base/content/test/tabPrompts/browser_confirmFolderUpload.js
new file mode 100644
index 0000000000..62b0ed4f2b
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_confirmFolderUpload.js
@@ -0,0 +1,141 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PromptTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PromptTestUtils.sys.mjs"
+);
+
+/**
+ * Create a temporary test directory that will be cleaned up on test shutdown.
+ * @returns {String} - absolute directory path.
+ */
+function getTestDirectory() {
+  let tmpDir = Services.dirsvc.get("TmpD", Ci.nsIFile);
+  tmpDir.append("testdir");
+  if (!tmpDir.exists()) {
+    tmpDir.create(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+    registerCleanupFunction(() => {
+      tmpDir.remove(true);
+    });
+  }
+
+  let file1 = tmpDir.clone();
+  file1.append("foo.txt");
+  if (!file1.exists()) {
+    file1.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+  }
+
+  let file2 = tmpDir.clone();
+  file2.append("bar.txt");
+  if (!file2.exists()) {
+    file2.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o600);
+  }
+
+  return tmpDir.path;
+}
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      // Allow using our MockFilePicker in the content process.
+      ["dom.filesystem.pathcheck.disabled", true],
+      ["dom.webkitBlink.dirPicker.enabled", true],
+    ],
+  });
+});
+
+/**
+ * Create a file input, select a folder and wait for the upload confirmation
+ * prompt to open.
+ * @param {boolean} confirmUpload - Whether to accept (true) or cancel the
+ * prompt (false).
+ * @returns {Promise} - Resolves once the prompt has been closed.
+ */
+async function testUploadPrompt(confirmUpload) {
+  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+  await BrowserTestUtils.withNewTab("http://example.com", async browser => {
+    // Create file input element
+    await ContentTask.spawn(browser, null, () => {
+      let input = content.document.createElement("input");
+      input.id = "filepicker";
+      input.setAttribute("type", "file");
+      input.setAttribute("webkitdirectory", "");
+      content.document.body.appendChild(input);
+    });
+
+    // If we're confirming the dialog, register a  "change" listener on the
+    // file input.
+    let changePromise;
+    if (confirmUpload) {
+      changePromise = ContentTask.spawn(browser, null, async () => {
+        let input = content.document.getElementById("filepicker");
+        return ContentTaskUtils.waitForEvent(input, "change").then(
+          e => e.target.files.length
+        );
+      });
+    }
+
+    // Register prompt promise
+    let promptPromise = PromptTestUtils.waitForPrompt(browser, {
+      modalType: Services.prompt.MODAL_TYPE_TAB,
+      promptType: "confirmEx",
+    });
+
+    // Open filepicker
+    let path = getTestDirectory();
+    await ContentTask.spawn(browser, { path }, args => {
+      let MockFilePicker = content.SpecialPowers.MockFilePicker;
+      MockFilePicker.init(
+        content,
+        "A Mock File Picker",
+        content.SpecialPowers.Ci.nsIFilePicker.modeGetFolder
+      );
+      MockFilePicker.useDirectory(args.path);
+
+      let input = content.document.getElementById("filepicker");
+      input.click();
+    });
+
+    // Wait for confirmation prompt
+    let prompt = await promptPromise;
+    ok(prompt, "Shown upload confirmation prompt");
+    is(prompt.ui.button0.label, "Upload", "Accept button label");
+    ok(prompt.ui.button1.hasAttribute("default"), "Cancel is default button");
+
+    // Close confirmation prompt
+    await PromptTestUtils.handlePrompt(prompt, {
+      buttonNumClick: confirmUpload ? 0 : 1,
+    });
+
+    // If we accepted, wait for the input elements "change" event
+    if (changePromise) {
+      let fileCount = await changePromise;
+      is(fileCount, 2, "Should have selected 2 files");
+    } else {
+      let fileCount = await ContentTask.spawn(browser, null, () => {
+        return content.document.getElementById("filepicker").files.length;
+      });
+
+      is(fileCount, 0, "Should not have selected any files");
+    }
+
+    // Cleanup
+    await ContentTask.spawn(browser, null, () => {
+      content.SpecialPowers.MockFilePicker.cleanup();
+    });
+  });
+}
+
+// Tests the confirmation prompt that shows after the user picked a folder.
+
+// Confirm the prompt
+add_task(async function test_confirm() {
+  await testUploadPrompt(true);
+});
+
+// Cancel the prompt
+add_task(async function test_cancel() {
+  await testUploadPrompt(false);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_contentOrigins.js b/browser/base/content/test/tabPrompts/browser_contentOrigins.js
new file mode 100644
index 0000000000..10c8809490
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_contentOrigins.js
@@ -0,0 +1,219 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PromptTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PromptTestUtils.sys.mjs"
+);
+
+let { HttpServer } = ChromeUtils.importESModule(
+  "resource://testing-common/httpd.sys.mjs"
+);
+
+const TEST_ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content",
+  "https://example.com"
+);
+
+async function checkAlert(
+  pageToLoad,
+  expectedTitle,
+  expectedIcon = "chrome://global/skin/icons/defaultFavicon.svg"
+) {
+  function openFn(browser) {
+    return SpecialPowers.spawn(browser, [], () => {
+      if (content.document.nodePrincipal.isSystemPrincipal) {
+        // Can't eval in privileged contexts due to CSP, just call directly:
+        content.alert("Test");
+      } else {
+        // Eval everywhere else so it gets the principal of the loaded page.
+        content.eval("alert('Test')");
+      }
+    });
+  }
+  return checkDialog(pageToLoad, openFn, expectedTitle, expectedIcon);
+}
+
+async function checkBeforeunload(
+  pageToLoad,
+  expectedTitle,
+  expectedIcon = "chrome://global/skin/icons/defaultFavicon.svg"
+) {
+  async function openFn(browser) {
+    let tab = gBrowser.getTabForBrowser(browser);
+    await BrowserTestUtils.synthesizeMouseAtCenter(
+      "body",
+      {},
+      browser.browsingContext
+    );
+    return gBrowser.removeTab(tab); // trigger beforeunload.
+  }
+  return checkDialog(pageToLoad, openFn, expectedTitle, expectedIcon);
+}
+
+async function checkDialog(
+  pageToLoad,
+  openFn,
+  expectedTitle,
+  expectedIcon,
+  modalType = Ci.nsIPrompt.MODAL_TYPE_CONTENT
+) {
+  return BrowserTestUtils.withNewTab(pageToLoad, async browser => {
+    let promptPromise = PromptTestUtils.waitForPrompt(browser, {
+      modalType,
+    });
+    let spawnPromise = openFn(browser);
+    let dialog = await promptPromise;
+
+    let doc = dialog.ui.prompt.document;
+    let titleEl = doc.getElementById("titleText");
+    if (expectedTitle.value) {
+      is(titleEl.textContent, expectedTitle.value, "Title should match.");
+    } else {
+      is(
+        titleEl.dataset.l10nId,
+        expectedTitle.l10nId,
+        "Title l10n id should match."
+      );
+    }
+    ok(
+      !titleEl.parentNode.hasAttribute("overflown"),
+      "Title should fit without overflowing."
+    );
+
+    ok(BrowserTestUtils.isVisible(titleEl), "New title should be shown.");
+    ok(
+      BrowserTestUtils.isHidden(doc.getElementById("infoTitle")),
+      "Old title should be hidden."
+    );
+    let iconCS = doc.ownerGlobal.getComputedStyle(
+      doc.querySelector(".titleIcon")
+    );
+    is(
+      iconCS.backgroundImage,
+      `url("${expectedIcon}")`,
+      "Icon is as expected."
+    );
+
+    // This is not particularly neat, but we want to also test overflow
+    // Our test systems don't have hosts that long, so just fake it:
+    if (browser.currentURI.asciiHost == "example.com") {
+      let longerDomain = "extravagantly.long.".repeat(10) + "example.com";
+      doc.documentElement.setAttribute(
+        "headertitle",
+        JSON.stringify({ raw: longerDomain, shouldUseMaskFade: true })
+      );
+      info("Wait for the prompt title to update.");
+      await BrowserTestUtils.waitForMutationCondition(
+        titleEl,
+        { characterData: true, attributes: true },
+        () =>
+          titleEl.textContent == longerDomain &&
+          titleEl.parentNode.hasAttribute("overflown")
+      );
+      is(titleEl.textContent, longerDomain, "The longer domain is reflected.");
+      ok(
+        titleEl.parentNode.hasAttribute("overflown"),
+        "The domain should overflow."
+      );
+    }
+
+    // Close the prompt again.
+    await PromptTestUtils.handlePrompt(dialog);
+    // The alert in the content process was sync, we need to make sure it gets
+    // cleaned up, but couldn't await it above because that'd hang the test!
+    await spawnPromise;
+  });
+}
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["prompts.contentPromptSubDialog", true],
+      ["prompts.modalType.httpAuth", Ci.nsIPrompt.MODAL_TYPE_TAB],
+      ["prompts.tabChromePromptSubDialog", true],
+    ],
+  });
+});
+
+add_task(async function test_check_prompt_origin_display() {
+  await checkAlert("https://example.com/", { value: "example.com" });
+  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+  await checkAlert("http://example.com/", { value: "example.com" });
+  await checkAlert("data:text/html,<body>", {
+    l10nId: "common-dialog-title-null",
+  });
+
+  let homeDir = Services.dirsvc.get("Home", Ci.nsIFile);
+  let fileURI = Services.io.newFileURI(homeDir).spec;
+  await checkAlert(fileURI, { value: "file://" });
+
+  await checkAlert(
+    "about:config",
+    { l10nId: "common-dialog-title-system" },
+    "chrome://branding/content/icon32.png"
+  );
+
+  await checkBeforeunload(TEST_ROOT + "file_beforeunload_stop.html", {
+    value: "example.com",
+  });
+});
+
+add_task(async function test_check_auth() {
+  let server = new HttpServer();
+  registerCleanupFunction(() => {
+    return new Promise(resolve => {
+      server.stop(() => {
+        server = null;
+        resolve();
+      });
+    });
+  });
+
+  function forbiddenHandler(meta, res) {
+    res.setStatusLine(meta.httpVersion, 401, "Unauthorized");
+    res.setHeader("WWW-Authenticate", 'Basic realm="Realm"');
+  }
+  function pageHandler(meta, res) {
+    res.setStatusLine(meta.httpVersion, 200, "OK");
+    res.setHeader("Content-Type", "text/html");
+    let body = "<html><body></body></html>";
+    res.bodyOutputStream.write(body, body.length);
+  }
+  server.registerPathHandler("/forbidden", forbiddenHandler);
+  server.registerPathHandler("/page", pageHandler);
+  server.start(-1);
+
+  const HOST = `localhost:${server.identity.primaryPort}`;
+  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+  const AUTH_URI = `http://${HOST}/forbidden`;
+
+  // Try a simple load:
+  await checkDialog(
+    "https://example.com/",
+    browser => BrowserTestUtils.startLoadingURIString(browser, AUTH_URI),
+    HOST,
+    "chrome://global/skin/icons/defaultFavicon.svg",
+    Ci.nsIPrompt.MODAL_TYPE_TAB
+  );
+
+  let subframeLoad = function (browser) {
+    return SpecialPowers.spawn(browser, [AUTH_URI], uri => {
+      let f = content.document.createElement("iframe");
+      f.src = uri;
+      content.document.body.appendChild(f);
+    });
+  };
+
+  // Try x-origin subframe:
+  await checkDialog(
+    // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+    "http://example.org/1",
+    subframeLoad,
+    HOST,
+    /* Because this is x-origin, we expect a different icon: */
+    "chrome://global/skin/icons/security-broken.svg",
+    Ci.nsIPrompt.MODAL_TYPE_TAB
+  );
+});
diff --git a/browser/base/content/test/tabPrompts/browser_multiplePrompts.js b/browser/base/content/test/tabPrompts/browser_multiplePrompts.js
new file mode 100644
index 0000000000..597b7dfd6f
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_multiplePrompts.js
@@ -0,0 +1,171 @@
+"use strict";
+
+const CONTENT_PROMPT_SUBDIALOG = Services.prefs.getBoolPref(
+  "prompts.contentPromptSubDialog",
+  false
+);
+
+/**
+ * Goes through a stacked series of dialogs opened with
+ * CONTENT_PROMPT_SUBDIALOG set to true, and ensures that
+ * the oldest one is front-most and has the right type. It
+ * then closes the oldest to newest dialog.
+ *
+ * @param {Element} tab The <tab> that has had content dialogs opened
+ * for it.
+ * @param {Number} promptCount How many dialogs we expected to have been
+ * opened.
+ *
+ * @return {Promise}
+ * @resolves {undefined} Once the dialogs have all been closed.
+ */
+async function closeDialogs(tab, dialogCount) {
+  let dialogElementsCount = dialogCount;
+  let dialogs =
+    tab.linkedBrowser.tabDialogBox.getContentDialogManager().dialogs;
+
+  is(
+    dialogs.length,
+    dialogElementsCount,
+    "There should be " + dialogElementsCount + " dialog(s)."
+  );
+
+  let i = dialogElementsCount - 1;
+  for (let dialog of dialogs) {
+    dialog.focus(true);
+    await dialog._dialogReady;
+
+    let dialogWindow = dialog.frameContentWindow;
+    let expectedType = ["alert", "prompt", "confirm"][i % 3];
+
+    is(
+      dialogWindow.Dialog.args.text,
+      expectedType + " countdown #" + i,
+      "The #" + i + " alert should be labelled as such."
+    );
+    i--;
+
+    dialogWindow.Dialog.ui.button0.click();
+
+    // The click is handled async; wait for an event loop turn for that to
+    // happen.
+    await new Promise(function (resolve) {
+      Services.tm.dispatchToMainThread(resolve);
+    });
+  }
+
+  dialogs = tab.linkedBrowser.tabDialogBox.getContentDialogManager().dialogs;
+  is(dialogs.length, 0, "Dialogs should all be dismissed.");
+}
+
+/**
+ * Goes through a stacked series of tabprompt modals opened with
+ * CONTENT_PROMPT_SUBDIALOG set to false, and ensures that
+ * the oldest one is front-most and has the right type. It also
+ * ensures that the other tabprompt modals are hidden. It
+ * then closes the oldest to newest dialog.
+ *
+ * @param {Element} tab The <tab> that has had tabprompt modals opened
+ * for it.
+ * @param {Number} promptCount How many modals we expected to have been
+ * opened.
+ *
+ * @return {Promise}
+ * @resolves {undefined} Once the modals have all been closed.
+ */
+async function closeTabModals(tab, promptCount) {
+  let promptElementsCount = promptCount;
+  while (promptElementsCount--) {
+    let promptElements =
+      tab.linkedBrowser.parentNode.querySelectorAll("tabmodalprompt");
+    is(
+      promptElements.length,
+      promptElementsCount + 1,
+      "There should be " + (promptElementsCount + 1) + " prompt(s)."
+    );
+    // The oldest should be the first.
+    let i = 0;
+
+    for (let promptElement of promptElements) {
+      let prompt = tab.linkedBrowser.tabModalPromptBox.getPrompt(promptElement);
+      let expectedType = ["alert", "prompt", "confirm"][i % 3];
+      is(
+        prompt.Dialog.args.text,
+        expectedType + " countdown #" + i,
+        "The #" + i + " alert should be labelled as such."
+      );
+      if (i !== promptElementsCount) {
+        is(prompt.element.hidden, true, "This prompt should be hidden.");
+        i++;
+        continue;
+      }
+
+      is(prompt.element.hidden, false, "The last prompt should not be hidden.");
+      prompt.onButtonClick(0);
+
+      // The click is handled async; wait for an event loop turn for that to
+      // happen.
+      await new Promise(function (resolve) {
+        Services.tm.dispatchToMainThread(resolve);
+      });
+    }
+  }
+
+  let promptElements =
+    tab.linkedBrowser.parentNode.querySelectorAll("tabmodalprompt");
+  is(promptElements.length, 0, "Prompts should all be dismissed.");
+}
+
+/*
+ * This test triggers multiple alerts on one single tab, because it"s possible
+ * for web content to do so. The behavior is described in bug 1266353.
+ *
+ * We assert the presentation of the multiple alerts, ensuring we show only
+ * the oldest one.
+ */
+add_task(async function () {
+  const PROMPTCOUNT = 9;
+
+  let unopenedPromptCount = PROMPTCOUNT;
+
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+    "http://example.com",
+    true
+  );
+  info("Tab loaded");
+
+  let promptsOpenedPromise = BrowserTestUtils.waitForEvent(
+    tab.linkedBrowser,
+    "DOMWillOpenModalDialog",
+    false,
+    () => {
+      unopenedPromptCount--;
+      return unopenedPromptCount == 0;
+    }
+  );
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [PROMPTCOUNT], maxPrompts => {
+    var i = maxPrompts;
+    let fns = ["alert", "prompt", "confirm"];
+    function openDialog() {
+      i--;
+      if (i) {
+        SpecialPowers.Services.tm.dispatchToMainThread(openDialog);
+      }
+      content[fns[i % 3]](fns[i % 3] + " countdown #" + i);
+    }
+    SpecialPowers.Services.tm.dispatchToMainThread(openDialog);
+  });
+
+  await promptsOpenedPromise;
+
+  if (CONTENT_PROMPT_SUBDIALOG) {
+    await closeDialogs(tab, PROMPTCOUNT);
+  } else {
+    await closeTabModals(tab, PROMPTCOUNT);
+  }
+
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_openPromptInBackgroundTab.js b/browser/base/content/test/tabPrompts/browser_openPromptInBackgroundTab.js
new file mode 100644
index 0000000000..6b116b71f9
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_openPromptInBackgroundTab.js
@@ -0,0 +1,262 @@
+"use strict";
+
+const { PermissionTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PermissionTestUtils.sys.mjs"
+);
+
+const ROOT = getRootDirectory(gTestPath).replace(
+  "chrome://mochitests/content/",
+  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+  "http://example.com/"
+);
+let pageWithAlert = ROOT + "openPromptOffTimeout.html";
+
+registerCleanupFunction(function () {
+  Services.perms.removeAll();
+});
+
+/*
+ * This test opens a tab that alerts when it is hidden. We then switch away
+ * from the tab, and check that by default the tab is not automatically
+ * re-selected. We also check that a checkbox appears in the alert that allows
+ * the user to enable this automatically re-selecting. We then check that
+ * checking the checkbox does actually enable that behaviour.
+ */
+add_task(async function test_old_modal_ui() {
+  // We're intentionally testing the old modal mechanism, so disable the new one.
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.contentPromptSubDialog", false]],
+  });
+
+  let firstTab = gBrowser.selectedTab;
+  // load page that opens prompt when page is hidden
+  let openedTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    pageWithAlert,
+    true
+  );
+  let openedTabGotAttentionPromise = BrowserTestUtils.waitForAttribute(
+    "attention",
+    openedTab
+  );
+  // switch away from that tab again - this triggers the alert.
+  await BrowserTestUtils.switchTab(gBrowser, firstTab);
+  // ... but that's async on e10s...
+  await openedTabGotAttentionPromise;
+  // check for attention attribute
+  is(
+    openedTab.hasAttribute("attention"),
+    true,
+    "Tab with alert should have 'attention' attribute."
+  );
+  ok(!openedTab.selected, "Tab with alert should not be selected");
+
+  // switch tab back, and check the checkbox is displayed:
+  await BrowserTestUtils.switchTab(gBrowser, openedTab);
+  // check the prompt is there, and the extra row is present
+  let promptElements =
+    openedTab.linkedBrowser.parentNode.querySelectorAll("tabmodalprompt");
+  is(promptElements.length, 1, "There should be 1 prompt");
+  let ourPromptElement = promptElements[0];
+  let checkbox = ourPromptElement.querySelector(
+    "checkbox[label*='example.com']"
+  );
+  ok(checkbox, "The checkbox should be there");
+  ok(!checkbox.checked, "Checkbox shouldn't be checked");
+  // tick box and accept dialog
+  checkbox.checked = true;
+  let ourPrompt =
+    openedTab.linkedBrowser.tabModalPromptBox.getPrompt(ourPromptElement);
+  ourPrompt.onButtonClick(0);
+  // Wait for that click to actually be handled completely.
+  await new Promise(function (resolve) {
+    Services.tm.dispatchToMainThread(resolve);
+  });
+  // check permission is set
+  is(
+    Services.perms.ALLOW_ACTION,
+    PermissionTestUtils.testPermission(pageWithAlert, "focus-tab-by-prompt"),
+    "Tab switching should now be allowed"
+  );
+
+  // Check if the control center shows the correct permission.
+  let shown = BrowserTestUtils.waitForEvent(
+    window,
+    "popupshown",
+    true,
+    event => event.target == gPermissionPanel._permissionPopup
+  );
+  gPermissionPanel._identityPermissionBox.click();
+  await shown;
+  let labelText = SitePermissions.getPermissionLabel("focus-tab-by-prompt");
+  let permissionsList = document.getElementById(
+    "permission-popup-permission-list"
+  );
+  let label = permissionsList.querySelector(
+    ".permission-popup-permission-label"
+  );
+  is(label.textContent, labelText);
+  gPermissionPanel._permissionPopup.hidePopup();
+
+  // Check if the identity icon signals granted permission.
+  ok(
+    gPermissionPanel._identityPermissionBox.hasAttribute("hasPermissions"),
+    "identity-box signals granted permissions"
+  );
+
+  let openedTabSelectedPromise = BrowserTestUtils.waitForAttribute(
+    "selected",
+    openedTab,
+    "true"
+  );
+  // switch to other tab again
+  await BrowserTestUtils.switchTab(gBrowser, firstTab);
+
+  // This is sync in non-e10s, but in e10s we need to wait for this, so yield anyway.
+  // Note that the switchTab promise doesn't actually guarantee anything about *which*
+  // tab ends up as selected when its event fires, so using that here wouldn't work.
+  await openedTabSelectedPromise;
+  // should be switched back
+  ok(openedTab.selected, "Ta-dah, the other tab should now be selected again!");
+
+  // In e10s, with the conformant promise scheduling, we have to wait for next tick
+  // to ensure that the prompt is open before removing the opened tab, because the
+  // promise callback of 'openedTabSelectedPromise' could be done at the middle of
+  // RemotePrompt.openTabPrompt() while 'DOMModalDialogClosed' event is fired.
+  await TestUtils.waitForTick();
+
+  BrowserTestUtils.removeTab(openedTab);
+});
+
+add_task(async function test_new_modal_ui() {
+  // We're intentionally testing the new modal mechanism, so make sure it's enabled.
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.contentPromptSubDialog", true]],
+  });
+
+  // Make sure we clear the focus tab permission set in the previous test
+  PermissionTestUtils.remove(pageWithAlert, "focus-tab-by-prompt");
+
+  let firstTab = gBrowser.selectedTab;
+  // load page that opens prompt when page is hidden
+  let openedTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    pageWithAlert,
+    true
+  );
+  let openedTabGotAttentionPromise = BrowserTestUtils.waitForAttribute(
+    "attention",
+    openedTab
+  );
+  // switch away from that tab again - this triggers the alert.
+  await BrowserTestUtils.switchTab(gBrowser, firstTab);
+  // ... but that's async on e10s...
+  await openedTabGotAttentionPromise;
+  // check for attention attribute
+  is(
+    openedTab.hasAttribute("attention"),
+    true,
+    "Tab with alert should have 'attention' attribute."
+  );
+  ok(!openedTab.selected, "Tab with alert should not be selected");
+
+  // switch tab back, and check the checkbox is displayed:
+  await BrowserTestUtils.switchTab(gBrowser, openedTab);
+  // check the prompt is there
+  let promptElements = openedTab.linkedBrowser.parentNode.querySelectorAll(
+    ".content-prompt-dialog"
+  );
+
+  let dialogBox = gBrowser.getTabDialogBox(openedTab.linkedBrowser);
+  let contentPromptManager = dialogBox.getContentDialogManager();
+  is(promptElements.length, 1, "There should be 1 prompt");
+  is(
+    contentPromptManager._dialogs.length,
+    1,
+    "Content prompt manager should have 1 dialog box."
+  );
+
+  // make sure the checkbox appears and that the permission for allowing tab switching
+  // is set when the checkbox is tickted and the dialog is accepted
+  let dialog = contentPromptManager._dialogs[0];
+
+  await dialog._dialogReady;
+
+  let dialogDoc = dialog._frame.contentWindow.document;
+  let checkbox = dialogDoc.querySelector("checkbox[label*='example.com']");
+  let button = dialogDoc.querySelector("#commonDialog").getButton("accept");
+
+  ok(checkbox, "The checkbox should be there");
+  ok(!checkbox.checked, "Checkbox shouldn't be checked");
+
+  // tick box and accept dialog
+  checkbox.checked = true;
+  button.click();
+  // Wait for that click to actually be handled completely.
+  await new Promise(function (resolve) {
+    Services.tm.dispatchToMainThread(resolve);
+  });
+
+  ok(!contentPromptManager._dialogs.length, "Dialog should be closed");
+
+  // check permission is set
+  is(
+    Services.perms.ALLOW_ACTION,
+    PermissionTestUtils.testPermission(pageWithAlert, "focus-tab-by-prompt"),
+    "Tab switching should now be allowed"
+  );
+
+  // Check if the control center shows the correct permission.
+  let shown = BrowserTestUtils.waitForEvent(
+    window,
+    "popupshown",
+    true,
+    event => event.target == gPermissionPanel._permissionPopup
+  );
+  gPermissionPanel._identityPermissionBox.click();
+  await shown;
+  let labelText = SitePermissions.getPermissionLabel("focus-tab-by-prompt");
+  let permissionsList = document.getElementById(
+    "permission-popup-permission-list"
+  );
+  let label = permissionsList.querySelector(
+    ".permission-popup-permission-label"
+  );
+  is(label.textContent, labelText);
+  gPermissionPanel.hidePopup();
+
+  // Check if the identity icon signals granted permission.
+  ok(
+    gPermissionPanel._identityPermissionBox.hasAttribute("hasPermissions"),
+    "identity-permission-box signals granted permissions"
+  );
+
+  let openedTabSelectedPromise = BrowserTestUtils.waitForAttribute(
+    "selected",
+    openedTab,
+    "true"
+  );
+
+  // switch to other tab again
+  await BrowserTestUtils.switchTab(gBrowser, firstTab);
+
+  // This is sync in non-e10s, but in e10s we need to wait for this, so yield anyway.
+  // Note that the switchTab promise doesn't actually guarantee anything about *which*
+  // tab ends up as selected when its event fires, so using that here wouldn't work.
+  await openedTabSelectedPromise;
+
+  Assert.strictEqual(contentPromptManager._dialogs.length, 1, "Dialog opened.");
+  dialog = contentPromptManager._dialogs[0];
+  await dialog._dialogReady;
+
+  // should be switched back
+  ok(openedTab.selected, "Ta-dah, the other tab should now be selected again!");
+
+  // In e10s, with the conformant promise scheduling, we have to wait for next tick
+  // to ensure that the prompt is open before removing the opened tab, because the
+  // promise callback of 'openedTabSelectedPromise' could be done at the middle of
+  // RemotePrompt.openTabPrompt() while 'DOMModalDialogClosed' event is fired.
+  // await TestUtils.waitForTick();
+
+  await BrowserTestUtils.removeTab(openedTab);
+});
diff --git a/browser/base/content/test/tabPrompts/browser_promptFocus.js b/browser/base/content/test/tabPrompts/browser_promptFocus.js
new file mode 100644
index 0000000000..89ca064c10
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_promptFocus.js
@@ -0,0 +1,170 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PromptTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PromptTestUtils.sys.mjs"
+);
+
+// MacOS has different default focus behavior for prompts.
+const isMacOS = Services.appinfo.OS === "Darwin";
+
+/**
+ * Tests that prompts are focused when switching tabs.
+ */
+add_task(async function test_tabdialogbox_tab_switch_focus() {
+  // Open 3 tabs
+  let tabPromises = [];
+  for (let i = 0; i < 3; i += 1) {
+    tabPromises.push(
+      BrowserTestUtils.openNewForegroundTab(
+        gBrowser,
+        // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+        "http://example.com",
+        true
+      )
+    );
+  }
+  // Wait for tabs to be ready
+  let tabs = await Promise.all(tabPromises);
+  let [tabA, tabB, tabC] = tabs;
+
+  // Spawn two prompts, which have different default focus as determined by
+  // CommonDialog#setDefaultFocus.
+  let openPromise = PromptTestUtils.waitForPrompt(tabA.linkedBrowser, {
+    modalType: Services.prompt.MODAL_TYPE_TAB,
+    promptType: "confirm",
+  });
+  Services.prompt.asyncConfirm(
+    tabA.linkedBrowser.browsingContext,
+    Services.prompt.MODAL_TYPE_TAB,
+    null,
+    "prompt A"
+  );
+  let promptA = await openPromise;
+
+  openPromise = PromptTestUtils.waitForPrompt(tabB.linkedBrowser, {
+    modalType: Services.prompt.MODAL_TYPE_TAB,
+    promptType: "promptPassword",
+  });
+  Services.prompt.asyncPromptPassword(
+    tabB.linkedBrowser.browsingContext,
+    Services.prompt.MODAL_TYPE_TAB,
+    null,
+    "prompt B",
+    "",
+    null,
+    false
+  );
+  let promptB = await openPromise;
+
+  // Switch tabs and check if the correct element was focused.
+
+  // Switch back to the third tab which doesn't have a prompt.
+  await BrowserTestUtils.switchTab(gBrowser, tabC);
+  is(
+    Services.focus.focusedElement,
+    tabC.linkedBrowser,
+    "Tab without prompt should have focus on browser."
+  );
+
+  // Switch to first tab which has prompt
+  await BrowserTestUtils.switchTab(gBrowser, tabA);
+
+  if (isMacOS) {
+    is(
+      Services.focus.focusedElement,
+      promptA.ui.infoBody,
+      "Tab with prompt should have focus on body."
+    );
+  } else {
+    is(
+      Services.focus.focusedElement,
+      promptA.ui.button0,
+      "Tab with prompt should have focus on default button."
+    );
+  }
+
+  await PromptTestUtils.handlePrompt(promptA);
+
+  // Switch to second tab which has prompt
+  await BrowserTestUtils.switchTab(gBrowser, tabB);
+  is(
+    Services.focus.focusedElement,
+    promptB.ui.password1Textbox,
+    "Tab with password prompt should have focus on password field."
+  );
+  await PromptTestUtils.handlePrompt(promptB);
+
+  // Cleanup
+  tabs.forEach(tab => {
+    BrowserTestUtils.removeTab(tab);
+  });
+});
+
+/**
+ * Tests that an alert prompt has focus on the default element.
+ * @param {CommonDialog} prompt - Prompt to test focus for.
+ * @param {number} index - Index of the prompt to log.
+ */
+function testAlertPromptFocus(prompt, index) {
+  if (isMacOS) {
+    is(
+      Services.focus.focusedElement,
+      prompt.ui.infoBody,
+      `Prompt #${index} should have focus on body.`
+    );
+  } else {
+    is(
+      Services.focus.focusedElement,
+      prompt.ui.button0,
+      `Prompt #${index} should have focus on default button.`
+    );
+  }
+}
+
+/**
+ * Test that we set the correct focus when queuing multiple prompts.
+ */
+add_task(async function test_tabdialogbox_prompt_queue_focus() {
+  await BrowserTestUtils.withNewTab(gBrowser, async browser => {
+    const PROMPT_COUNT = 10;
+
+    let firstPromptPromise = PromptTestUtils.waitForPrompt(browser, {
+      modalType: Services.prompt.MODAL_TYPE_TAB,
+      promptType: "alert",
+    });
+
+    for (let i = 0; i < PROMPT_COUNT; i += 1) {
+      Services.prompt.asyncAlert(
+        browser.browsingContext,
+        Services.prompt.MODAL_TYPE_TAB,
+        null,
+        "prompt " + i
+      );
+    }
+
+    // Close prompts one by one and check focus.
+    let nextPromptPromise = firstPromptPromise;
+    for (let i = 0; i < PROMPT_COUNT; i += 1) {
+      let p = await nextPromptPromise;
+      testAlertPromptFocus(p, i);
+
+      if (i < PROMPT_COUNT - 1) {
+        nextPromptPromise = PromptTestUtils.waitForPrompt(browser, {
+          modalType: Services.prompt.MODAL_TYPE_TAB,
+          promptType: "alert",
+        });
+      }
+      await PromptTestUtils.handlePrompt(p);
+    }
+
+    // All prompts are closed, focus should be back on the browser.
+    is(
+      Services.focus.focusedElement,
+      browser,
+      "Tab without prompts should have focus on browser."
+    );
+  });
+});
diff --git a/browser/base/content/test/tabPrompts/browser_prompt_close_event.js b/browser/base/content/test/tabPrompts/browser_prompt_close_event.js
new file mode 100644
index 0000000000..9705062cef
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_prompt_close_event.js
@@ -0,0 +1,164 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Execute the provided script content by generating a dynamic script tag and
+ * inserting it in the page for the current selected browser.
+ *
+ * @param {string} script
+ *     The script to execute.
+ * @returns {Promise}
+ *     A promise that resolves when the script node was added and removed from
+ *     the content page.
+ */
+function createScriptNode(script) {
+  return SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [script],
+    function (_script) {
+      const scriptTag = content.document.createElement("script");
+      scriptTag.append(content.document.createTextNode(_script));
+      content.document.body.append(scriptTag);
+    }
+  );
+}
+
+add_task(
+  async function test_close_prompt_event_detail_accepted_with_default_value() {
+    const closed = BrowserTestUtils.waitForEvent(
+      window,
+      "DOMModalDialogClosed"
+    );
+
+    const promptPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+    const defaultValue = "Default value";
+    await createScriptNode(
+      `setTimeout(() => window.prompt('Enter your name:', '${defaultValue}'))`
+    );
+    const promptWin = await promptPromise;
+
+    info("accepting prompt with default value.");
+    promptWin.document.querySelector("dialog").acceptDialog();
+
+    const closedEvent = await closed;
+
+    is(
+      closedEvent.detail.areLeaving,
+      true,
+      "Received correct `areLeaving` value in the event detail"
+    );
+    is(
+      closedEvent.detail.value,
+      defaultValue,
+      "Received correct `value` value in the event detail"
+    );
+  }
+);
+
+add_task(
+  async function test_close_prompt_event_detail_accepted_with_amended_default_value() {
+    const closed = BrowserTestUtils.waitForEvent(
+      window,
+      "DOMModalDialogClosed"
+    );
+
+    const promptPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+    const defaultValue = "Default value";
+    await createScriptNode(
+      `setTimeout(() => window.prompt('Enter your name:', '${defaultValue}'))`
+    );
+    const promptWin = await promptPromise;
+
+    const amendedValue = "Test";
+    promptWin.document.getElementById("loginTextbox").value = amendedValue;
+
+    info("accepting prompt with amended value.");
+    promptWin.document.querySelector("dialog").acceptDialog();
+
+    const closedEvent = await closed;
+
+    is(
+      closedEvent.detail.areLeaving,
+      true,
+      "Received correct `areLeaving` value in the event detail"
+    );
+    is(
+      closedEvent.detail.value,
+      amendedValue,
+      "Received correct `value` value in the event detail"
+    );
+  }
+);
+
+add_task(
+  async function test_close_prompt_event_detail_dismissed_with_default_value() {
+    const closed = BrowserTestUtils.waitForEvent(
+      window,
+      "DOMModalDialogClosed"
+    );
+
+    const promptPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+    const defaultValue = "Default value";
+    await createScriptNode(
+      `setTimeout(() => window.prompt('Enter your name:', '${defaultValue}'))`
+    );
+    const promptWin = await promptPromise;
+
+    info("Dismissing prompt with default value.");
+    promptWin.document.querySelector("dialog").cancelDialog();
+
+    const closedEvent = await closed;
+
+    is(
+      closedEvent.detail.areLeaving,
+      false,
+      "Received correct `areLeaving` value in the event detail"
+    );
+    is(
+      closedEvent.detail.value,
+      null,
+      "Received correct `value` value in the event detail"
+    );
+  }
+);
+
+add_task(
+  async function test_close_prompt_event_detail_dismissed_with_amended_default_value() {
+    const closed = BrowserTestUtils.waitForEvent(
+      window,
+      "DOMModalDialogClosed"
+    );
+
+    const promptPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+    const defaultValue = "Default value";
+    await createScriptNode(
+      `setTimeout(() => window.prompt('Enter your name:', '${defaultValue}'))`
+    );
+    const promptWin = await promptPromise;
+
+    const amendedValue = "Test";
+    promptWin.document.getElementById("loginTextbox").value = amendedValue;
+
+    info("Dismissing prompt with amended value.");
+    promptWin.document.querySelector("dialog").cancelDialog();
+
+    const closedEvent = await closed;
+
+    is(
+      closedEvent.detail.areLeaving,
+      false,
+      "Received correct `areLeaving` value in the event detail"
+    );
+    is(
+      closedEvent.detail.value,
+      null,
+      "Received correct `value` value in the event detail"
+    );
+  }
+);
diff --git a/browser/base/content/test/tabPrompts/browser_prompt_closed_window.js b/browser/base/content/test/tabPrompts/browser_prompt_closed_window.js
new file mode 100644
index 0000000000..4db3286691
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_prompt_closed_window.js
@@ -0,0 +1,40 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Check that if we loop prompts from a closed tab, they don't
+ * start showing up as window prompts.
+ */
+add_task(async function test_closed_tab_doesnt_show_prompt() {
+  let newWin = await BrowserTestUtils.openNewBrowserWindow();
+
+  // Get a promise for the initial, in-tab prompt:
+  let promptPromise = BrowserTestUtils.promiseAlertDialogOpen();
+  await ContentTask.spawn(newWin.gBrowser.selectedBrowser, [], function () {
+    // Don't want to block, so use setTimeout with 0 timeout:
+    content.setTimeout(
+      () =>
+        content.eval(
+          'let i = 0; while (!prompt("Prompts a lot!") && i++ < 10);'
+        ),
+      0
+    );
+  });
+  // wait for the first prompt to have appeared:
+  await promptPromise;
+
+  // Now close the containing tab, and check for windowed prompts appearing.
+  let opened = false;
+  let obs = () => {
+    opened = true;
+  };
+  Services.obs.addObserver(obs, "domwindowopened");
+  registerCleanupFunction(() =>
+    Services.obs.removeObserver(obs, "domwindowopened")
+  );
+  await BrowserTestUtils.closeWindow(newWin);
+
+  ok(!opened, "Should not have opened a prompt when closing the main window.");
+});
diff --git a/browser/base/content/test/tabPrompts/browser_switchTabPermissionPrompt.js b/browser/base/content/test/tabPrompts/browser_switchTabPermissionPrompt.js
new file mode 100644
index 0000000000..4c77a51275
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_switchTabPermissionPrompt.js
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function test_check_file_prompt() {
+  let initialTab = gBrowser.selectedTab;
+  await BrowserTestUtils.withNewTab("about:blank", async browser => {
+    await BrowserTestUtils.switchTab(gBrowser, initialTab);
+
+    let testHelper = async function (uri, expectedValue) {
+      BrowserTestUtils.startLoadingURIString(browser, uri);
+      await BrowserTestUtils.browserLoaded(browser, false, uri);
+      let dialogFinishedShowing = TestUtils.topicObserved(
+        "common-dialog-loaded"
+      );
+      await SpecialPowers.spawn(browser, [], () => {
+        content.setTimeout(() => {
+          content.alert("Hello");
+        }, 0);
+      });
+
+      let [dialogWin] = await dialogFinishedShowing;
+      let checkbox = dialogWin.document.getElementById("checkbox");
+      info("Got: " + checkbox.label);
+      ok(
+        checkbox.label.includes(expectedValue),
+        `Checkbox label should mention domain (${expectedValue}).`
+      );
+
+      dialogWin.document.querySelector("dialog").acceptDialog();
+    };
+
+    await testHelper("https://example.com/1", "example.com");
+    await testHelper("about:robots", "about:");
+    let file = Services.io.newFileURI(
+      Services.dirsvc.get("Desk", Ci.nsIFile)
+    ).spec;
+    await testHelper(file, "file://");
+  });
+});
diff --git a/browser/base/content/test/tabPrompts/browser_windowPrompt.js b/browser/base/content/test/tabPrompts/browser_windowPrompt.js
new file mode 100644
index 0000000000..535142f485
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_windowPrompt.js
@@ -0,0 +1,259 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Check that the in-window modal dialogs work correctly.
+ */
+add_task(async function test_check_window_modal_prompt_service() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+  let dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+  // Avoid blocking the test on the (sync) alert by sticking it in a timeout:
+  setTimeout(
+    () => Services.prompt.alert(window, "Some title", "some message"),
+    0
+  );
+  let dialogWin = await dialogPromise;
+
+  // Check dialog content:
+  is(
+    dialogWin.document.getElementById("infoTitle").textContent,
+    "Some title",
+    "Title should be correct."
+  );
+  ok(
+    !dialogWin.document.getElementById("infoTitle").hidden,
+    "Title should be shown."
+  );
+  is(
+    dialogWin.document.getElementById("infoBody").textContent,
+    "some message",
+    "Body text should be correct."
+  );
+
+  // Check circumstances of opening.
+  ok(
+    dialogWin?.docShell?.chromeEventHandler,
+    "Should have embedded the dialog."
+  );
+  for (let menu of document.querySelectorAll("menubar > menu")) {
+    ok(menu.disabled, `Menu ${menu.id} should be disabled.`);
+  }
+
+  let container = dialogWin.docShell.chromeEventHandler.closest("dialog");
+  let closedPromise = BrowserTestUtils.waitForMutationCondition(
+    container,
+    { childList: true, attributes: true },
+    () => !container.hasChildNodes() && !container.open
+  );
+
+  EventUtils.sendKey("ESCAPE");
+  await closedPromise;
+
+  await BrowserTestUtils.waitForMutationCondition(
+    document.querySelector("menubar > menu"),
+    { attributes: true },
+    () => !document.querySelector("menubar > menu").disabled
+  );
+
+  // Check we cleaned up:
+  for (let menu of document.querySelectorAll("menubar > menu")) {
+    ok(!menu.disabled, `Menu ${menu.id} should not be disabled anymore.`);
+  }
+});
+
+/**
+ * Check that the dialog's own closing methods being invoked don't break things.
+ */
+add_task(async function test_check_window_modal_prompt_service() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+  let dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+  // Avoid blocking the test on the (sync) alert by sticking it in a timeout:
+  setTimeout(
+    () => Services.prompt.alert(window, "Some title", "some message"),
+    0
+  );
+  let dialogWin = await dialogPromise;
+
+  // Check circumstances of opening.
+  ok(
+    dialogWin?.docShell?.chromeEventHandler,
+    "Should have embedded the dialog."
+  );
+
+  let container = dialogWin.docShell.chromeEventHandler.closest("dialog");
+  let closedPromise = BrowserTestUtils.waitForMutationCondition(
+    container,
+    { childList: true, attributes: true },
+    () => !container.hasChildNodes() && !container.open
+  );
+
+  // This can also be invoked by the user if the escape key is handled
+  // outside of our embedded dialog.
+  container.close();
+  await closedPromise;
+
+  // Check we cleaned up:
+  for (let menu of document.querySelectorAll("menubar > menu")) {
+    ok(!menu.disabled, `Menu ${menu.id} should not be disabled anymore.`);
+  }
+});
+
+add_task(async function test_check_multiple_prompts() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+  let container = document.getElementById("window-modal-dialog");
+  let dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+  let firstDialogClosedPromise = new Promise(resolve => {
+    // Avoid blocking the test on the (sync) alert by sticking it in a timeout:
+    setTimeout(() => {
+      Services.prompt.alert(window, "Some title", "some message");
+      resolve();
+    }, 0);
+  });
+  let dialogWin = await dialogPromise;
+
+  // Check circumstances of opening.
+  ok(
+    dialogWin?.docShell?.chromeEventHandler,
+    "Should have embedded the dialog."
+  );
+  is(container.childElementCount, 1, "Should only have 1 dialog in the DOM.");
+
+  let secondDialogClosedPromise = new Promise(resolve => {
+    // Avoid blocking the test on the (sync) alert by sticking it in a timeout:
+    setTimeout(() => {
+      Services.prompt.alert(window, "Another title", "another message");
+      resolve();
+    }, 0);
+  });
+
+  dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+
+  info("Accepting dialog");
+  dialogWin.document.querySelector("dialog").acceptDialog();
+
+  let oldWin = dialogWin;
+
+  info("Second dialog should automatically come up.");
+  dialogWin = await dialogPromise;
+
+  isnot(oldWin, dialogWin, "Opened a new dialog.");
+  ok(container.open, "Dialog should be open.");
+
+  info("Now close the second dialog.");
+  dialogWin.document.querySelector("dialog").acceptDialog();
+
+  await firstDialogClosedPromise;
+  await secondDialogClosedPromise;
+
+  await BrowserTestUtils.waitForMutationCondition(
+    container,
+    { childList: true, attributes: true },
+    () => !container.hasChildNodes() && !container.open
+  );
+  // Check we cleaned up:
+  for (let menu of document.querySelectorAll("menubar > menu")) {
+    ok(!menu.disabled, `Menu ${menu.id} should not be disabled anymore.`);
+  }
+});
+
+/**
+ * Check that the in-window modal dialogs un-minimizes windows when necessary.
+ */
+add_task(async function test_check_minimize_response() {
+  // Window minimization doesn't necessarily work on Linux...
+  if (AppConstants.platform == "linux") {
+    return;
+  }
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+
+  let promiseSizeModeChange = BrowserTestUtils.waitForEvent(
+    window,
+    "sizemodechange"
+  );
+  window.minimize();
+  await promiseSizeModeChange;
+  is(window.windowState, window.STATE_MINIMIZED, "Should be minimized.");
+
+  promiseSizeModeChange = BrowserTestUtils.waitForEvent(
+    window,
+    "sizemodechange"
+  );
+  let dialogPromise = BrowserTestUtils.promiseAlertDialogOpen();
+  // Use an async alert to avoid blocking.
+  Services.prompt.asyncAlert(
+    window.browsingContext,
+    Ci.nsIPrompt.MODAL_TYPE_INTERNAL_WINDOW,
+    "Some title",
+    "some message"
+  );
+  let dialogWin = await dialogPromise;
+  await promiseSizeModeChange;
+
+  isnot(
+    window.windowState,
+    window.STATE_MINIMIZED,
+    "Should no longer be minimized."
+  );
+
+  // Check dialog content:
+  is(
+    dialogWin.document.getElementById("infoTitle").textContent,
+    "Some title",
+    "Title should be correct."
+  );
+
+  let container = dialogWin.docShell.chromeEventHandler.closest("dialog");
+  let closedPromise = BrowserTestUtils.waitForMutationCondition(
+    container,
+    { childList: true, attributes: true },
+    () => !container.hasChildNodes() && !container.open
+  );
+
+  EventUtils.sendKey("ESCAPE");
+  await closedPromise;
+
+  await BrowserTestUtils.waitForMutationCondition(
+    document.querySelector("menubar > menu"),
+    { attributes: true },
+    () => !document.querySelector("menubar > menu").disabled
+  );
+});
+
+/**
+ * Tests that we get a closed callback even when closing the prompt before the
+ * underlying SubDialog has fully opened.
+ */
+add_task(async function test_closed_callback() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["prompts.windowPromptSubDialog", true]],
+  });
+
+  let promptClosedPromise = Services.prompt.asyncAlert(
+    window.browsingContext,
+    Services.prompt.MODAL_TYPE_INTERNAL_WINDOW,
+    "Hello",
+    "Hello, World!"
+  );
+
+  let dialog = gDialogBox._dialog;
+  ok(dialog, "gDialogBox should have a dialog");
+
+  // Directly close the dialog without waiting for it to initialize.
+  dialog.close();
+
+  info("Waiting for prompt close");
+  await promptClosedPromise;
+
+  ok(!gDialogBox._dialog, "gDialogBox should no longer have a dialog");
+});
diff --git a/browser/base/content/test/tabPrompts/file_beforeunload_stop.html b/browser/base/content/test/tabPrompts/file_beforeunload_stop.html
new file mode 100644
index 0000000000..7273e60c65
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/file_beforeunload_stop.html
@@ -0,0 +1,8 @@
+<body>
+  <p>I will ask not to be closed.</p>
+  <script>
+    window.onbeforeunload = function() {
+      return "true";
+    };
+  </script>
+</body>
diff --git a/browser/base/content/test/tabPrompts/openPromptOffTimeout.html b/browser/base/content/test/tabPrompts/openPromptOffTimeout.html
new file mode 100644
index 0000000000..5dfd8cbeff
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/openPromptOffTimeout.html
@@ -0,0 +1,10 @@
+<body>
+This page opens an alert box when the page is hidden.
+<script>
+document.addEventListener("visibilitychange", () => {
+  if (document.hidden) {
+    alert("You hid my page!");
+  }
+});
+</script>
+</body>
diff --git a/browser/base/content/test/tabPrompts/redirect-crossDomain-tabTitle-update.html b/browser/base/content/test/tabPrompts/redirect-crossDomain-tabTitle-update.html
new file mode 100644
index 0000000000..773b3e47d9
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/redirect-crossDomain-tabTitle-update.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <title>example.com</title>
+  </head>
+  <body>
+    I am a friendly test page!
+    <script>
+      document.title="tab title update 1";
+      window.location.href="https://example.org:443/browser/browser/base/content/test/tabPrompts/auth-route.sjs";
+      document.title ="tab title update 2";
+    </script>
+  </body>
+</html>
diff --git a/browser/base/content/test/tabPrompts/redirect-crossDomain.html b/browser/base/content/test/tabPrompts/redirect-crossDomain.html
new file mode 100644
index 0000000000..ebae2c060a
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/redirect-crossDomain.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <title>example.com</title>
+  </head>
+  <body>
+    I am a friendly test page!
+    <script>
+      window.location.href="https://example.org:443/browser/browser/base/content/test/tabPrompts/auth-route.sjs";
+    </script>
+  </body>
+</html>
diff --git a/browser/base/content/test/tabPrompts/redirect-sameDomain.html b/browser/base/content/test/tabPrompts/redirect-sameDomain.html
new file mode 100644
index 0000000000..2e50689d1e
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/redirect-sameDomain.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <title>example.com</title>
+  </head>
+  <body>
+    I am a friendly test page!
+    <script>
+      window.location.href="https://test1.example.com:443/browser/browser/base/content/test/tabPrompts/auth-route.sjs";
+    </script>
+  </body>
+</html>