Bug 1673962 - Test to cover the code path of canceling the Restart Required prompt when enabling a restart-required=true experimental feature. r=Gijs,preferences-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D95058

browser/components/preferences/tests/browser.ini

@@ -21,6 +21,7 @@ skip-if = !updater
 [browser_experimental_features_filter.js]
 [browser_experimental_features_hidden_when_not_public.js]
 [browser_experimental_features_resetall.js]
+[browser_experimental_features_restart_required_cancel.js]
 [browser_filetype_dialog.js]
 [browser_search_no_results_change_category.js]
 [browser_search_within_preferences_1.js]

browser/components/preferences/tests/browser_experimental_features_restart_required_cancel.js

@@ -0,0 +1,47 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function testInfiniteCancelLoop() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.preferences.experimental", true]],
+  });
+
+  const server = new DefinitionServer();
+  server.addDefinition({
+    id: "test-featureA",
+    isPublic: true,
+    preference: "test.feature.a",
+    restartRequired: true,
+  });
+  await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    `about:preferences?definitionsUrl=${encodeURIComponent(
+      server.definitionsUrl
+    )}#paneExperimental`
+  );
+  let doc = gBrowser.contentDocument;
+
+  // Trigger and cancel a feature that has restart-required=true to make
+  // sure that we don't enter an infinite loop of prompts.
+  let featureCheckbox = doc.getElementById("test-featureA");
+  ok(featureCheckbox, "Checkbox should exist");
+  let newWindowPromise = BrowserTestUtils.domWindowOpened();
+  featureCheckbox.click();
+
+  let restartWin = await newWindowPromise;
+  let dialog = await TestUtils.waitForCondition(() =>
+    restartWin.document.querySelector(`dialog`)
+  );
+  let cancelButton = dialog.shadowRoot.querySelector(`[dlgtype="cancel"]`);
+  ok(cancelButton, "Cancel button should exist in dialog");
+  let windowClosedPromise = BrowserTestUtils.domWindowClosed(restartWin);
+  cancelButton.click();
+  await windowClosedPromise;
+
+  // If a new prompt is opened then the test should fail since
+  // the prompt window will have leaked.
+
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});