Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

200 files changed, 18866 insertions, 0 deletions

diff --git a/toolkit/components/search/tests/SearchTestUtils.sys.mjs b/toolkit/components/search/tests/SearchTestUtils.sys.mjs
new file mode 100644
index 0000000000..a2dc9b9e01
--- /dev/null
+++ b/toolkit/components/search/tests/SearchTestUtils.sys.mjs
@@ -0,0 +1,505 @@
+import { MockRegistrar } from "resource://testing-common/MockRegistrar.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  AddonManager: "resource://gre/modules/AddonManager.sys.mjs",
+  AddonTestUtils: "resource://testing-common/AddonTestUtils.sys.mjs",
+  ExtensionTestUtils:
+    "resource://testing-common/ExtensionXPCShellUtils.sys.mjs",
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+  SearchUtils: "resource://gre/modules/SearchUtils.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+var gTestScope;
+
+export var SearchTestUtils = {
+  init(testScope) {
+    gTestScope = testScope;
+    this._isMochitest = !Services.env.exists("XPCSHELL_TEST_PROFILE_DIR");
+    if (this._isMochitest) {
+      this._isMochitest = true;
+      lazy.AddonTestUtils.initMochitest(testScope);
+    } else {
+      this._isMochitest = false;
+      // This handles xpcshell-tests.
+      gTestScope.ExtensionTestUtils = lazy.ExtensionTestUtils;
+      this.initXPCShellAddonManager(testScope);
+    }
+  },
+
+  /**
+   * Adds an OpenSearch based engine to the search service. It will remove
+   * the engine at the end of the test.
+   *
+   * @param {object} options
+   *   The options for the new search engine.
+   * @param {string} options.url
+   *   The URL of the engine to add.
+   * @param {boolean} [options.setAsDefault]
+   *   Whether or not to set the engine as default automatically. If this is
+   *   true, the engine will be set as default, and the previous default engine
+   *   will be restored when the test exits.
+   * @param {boolean} [options.setAsDefaultPrivate]
+   *   Whether or not to set the engine as default automatically for private mode.
+   *   If this is true, the engine will be set as default, and the previous default
+   *   engine will be restored when the test exits.
+   * @returns {Promise} Returns a promise that is resolved with the new engine
+   *                    or rejected if it fails.
+   */
+  async promiseNewSearchEngine({
+    url,
+    setAsDefault = false,
+    setAsDefaultPrivate = false,
+  }) {
+    // OpenSearch engines can only be added via http protocols.
+    url = url.replace("chrome://mochitests/content", "https://example.com");
+    let engine = await Services.search.addOpenSearchEngine(url, "");
+    let previousEngine = Services.search.defaultEngine;
+    let previousPrivateEngine = Services.search.defaultPrivateEngine;
+    if (setAsDefault) {
+      await Services.search.setDefault(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      );
+    }
+    if (setAsDefaultPrivate) {
+      await Services.search.setDefaultPrivate(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      );
+    }
+    gTestScope.registerCleanupFunction(async () => {
+      if (setAsDefault) {
+        await Services.search.setDefault(
+          previousEngine,
+          Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+        );
+      }
+      if (setAsDefaultPrivate) {
+        await Services.search.setDefaultPrivate(
+          previousPrivateEngine,
+          Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+        );
+      }
+      try {
+        await Services.search.removeEngine(engine);
+      } catch (ex) {
+        // Don't throw if the test has already removed it.
+      }
+    });
+    return engine;
+  },
+
+  /**
+   * Returns a promise that is resolved when an observer notification from the
+   * search service fires with the specified data.
+   *
+   * @param {*} expectedData
+   *        The value the observer notification sends that causes us to resolve
+   *        the promise.
+   * @param {string} topic
+   *        The notification topic to observe. Defaults to 'browser-search-service'.
+   * @returns {Promise}
+   *        Returns a promise that is resolved with the subject of the
+   *        topic once the topic with the data has been observed.
+   */
+  promiseSearchNotification(expectedData, topic = "browser-search-service") {
+    return new Promise(resolve => {
+      Services.obs.addObserver(function observer(aSubject, aTopic, aData) {
+        if (aData != expectedData) {
+          return;
+        }
+
+        Services.obs.removeObserver(observer, topic);
+        // Let the stack unwind.
+        Services.tm.dispatchToMainThread(() => resolve(aSubject));
+      }, topic);
+    });
+  },
+
+  /**
+   * Load engines from test data located in particular folders.
+   *
+   * @param {string} [folder]
+   *   The folder name to use.
+   * @param {string} [subFolder]
+   *   The subfolder to use, if any.
+   * @param {Array} [config]
+   *   An array which contains the configuration to set.
+   * @returns {object}
+   *   An object that is a sinon stub for the configuration getter.
+   */
+  async useTestEngines(folder = "data", subFolder = null, config = null) {
+    let url = `resource://test/${folder}/`;
+    if (subFolder) {
+      url += `${subFolder}/`;
+    }
+    let resProt = Services.io
+      .getProtocolHandler("resource")
+      .QueryInterface(Ci.nsIResProtocolHandler);
+    resProt.setSubstitution("search-extensions", Services.io.newURI(url));
+
+    const settings = await lazy.RemoteSettings(lazy.SearchUtils.SETTINGS_KEY);
+    if (config) {
+      return lazy.sinon.stub(settings, "get").returns(config);
+    }
+
+    let response = await fetch(`resource://search-extensions/engines.json`);
+    let json = await response.json();
+    return lazy.sinon.stub(settings, "get").returns(json.data);
+  },
+
+  async useMochitestEngines(testDir) {
+    // Replace the path we load search engines from with
+    // the path to our test data.
+    let resProt = Services.io
+      .getProtocolHandler("resource")
+      .QueryInterface(Ci.nsIResProtocolHandler);
+    let originalSubstitution = resProt.getSubstitution("search-extensions");
+    resProt.setSubstitution(
+      "search-extensions",
+      Services.io.newURI("file://" + testDir.path)
+    );
+    gTestScope.registerCleanupFunction(() => {
+      resProt.setSubstitution("search-extensions", originalSubstitution);
+    });
+  },
+
+  /**
+   * Convert a list of engine configurations into engine objects.
+   *
+   * @param {Array} engineConfigurations
+   *   An array of engine configurations.
+   */
+  async searchConfigToEngines(engineConfigurations) {
+    let engines = [];
+    for (let config of engineConfigurations) {
+      let engine = await Services.search.wrappedJSObject._makeEngineFromConfig(
+        config
+      );
+      engines.push(engine);
+    }
+    return engines;
+  },
+
+  /**
+   * Provides various setup for xpcshell-tests installing WebExtensions. Should
+   * be called from the global scope of the test.
+   *
+   * @param {object} scope
+   *  The global scope of the test being run.
+   * @param {*} usePrivilegedSignatures
+   *  How to sign created addons.
+   */
+  initXPCShellAddonManager(scope, usePrivilegedSignatures = false) {
+    let scopes =
+      lazy.AddonManager.SCOPE_PROFILE | lazy.AddonManager.SCOPE_APPLICATION;
+    Services.prefs.setIntPref("extensions.enabledScopes", scopes);
+    // Only do this once.
+    try {
+      gTestScope.ExtensionTestUtils.init(scope);
+    } catch (ex) {
+      // This can happen if init is called twice.
+      if (ex.result != Cr.NS_ERROR_FILE_ALREADY_EXISTS) {
+        throw ex;
+      }
+    }
+    lazy.AddonTestUtils.usePrivilegedSignatures = usePrivilegedSignatures;
+    lazy.AddonTestUtils.overrideCertDB();
+  },
+
+  /**
+   * Add a search engine as a WebExtension.
+   *
+   * Note: for tests, the extension must generally be unloaded before
+   * `registerCleanupFunction`s are triggered. See bug 1694409.
+   *
+   * This function automatically registers an unload for the extension, this
+   * may be skipped with the skipUnload argument.
+   *
+   * @param {object} [manifest]
+   *   See {@link createEngineManifest}
+   * @param {object} [options]
+   *   Options for how the engine is installed and uninstalled.
+   * @param {boolean} [options.setAsDefault]
+   *   Whether or not to set the engine as default automatically. If this is
+   *   true, the engine will be set as default, and the previous default engine
+   *   will be restored when the test exits.
+   * @param {boolean} [options.setAsDefaultPrivate]
+   *   Whether or not to set the engine as default automatically for private mode.
+   *   If this is true, the engine will be set as default, and the previous default
+   *   engine will be restored when the test exits.
+   * @param {boolean} [options.skipUnload]
+   *   If true, this will skip the automatic unloading of the extension.
+   * @param {object} [files]
+   *   A key value object where the keys are the filenames and their contents are
+   *   the values. Used for simulating locales and other files in the WebExtension.
+   * @returns {object}
+   *   The loaded extension.
+   */
+  async installSearchExtension(
+    manifest = {},
+    {
+      setAsDefault = false,
+      setAsDefaultPrivate = false,
+      skipUnload = false,
+    } = {},
+    files = {}
+  ) {
+    await Services.search.init();
+
+    let extensionInfo = {
+      useAddonManager: "permanent",
+      files,
+      manifest: this.createEngineManifest(manifest),
+    };
+
+    let extension;
+
+    let previousEngine = Services.search.defaultEngine;
+    let previousPrivateEngine = Services.search.defaultPrivateEngine;
+
+    async function cleanup() {
+      if (setAsDefault) {
+        await Services.search.setDefault(
+          previousEngine,
+          Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+        );
+      }
+      if (setAsDefaultPrivate) {
+        await Services.search.setDefaultPrivate(
+          previousPrivateEngine,
+          Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+        );
+      }
+      await extension.unload();
+    }
+
+    // Cleanup must be registered before loading the extension to avoid
+    // failures for mochitests.
+    if (!skipUnload && this._isMochitest) {
+      gTestScope.registerCleanupFunction(cleanup);
+    }
+
+    extension = gTestScope.ExtensionTestUtils.loadExtension(extensionInfo);
+    await extension.startup();
+    await lazy.AddonTestUtils.waitForSearchProviderStartup(extension);
+    let engine = Services.search.getEngineByName(manifest.name);
+
+    if (setAsDefault) {
+      await Services.search.setDefault(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      );
+    }
+    if (setAsDefaultPrivate) {
+      await Services.search.setDefaultPrivate(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      );
+    }
+
+    // For xpcshell-tests we must register the unload after adding the extension.
+    // See bug 1694409 for why this is.
+    if (!skipUnload && !this._isMochitest) {
+      gTestScope.registerCleanupFunction(cleanup);
+    }
+
+    return extension;
+  },
+
+  /**
+   * Install a search engine as a system extension to simulate
+   * Normandy updates. For xpcshell-tests only.
+   *
+   * @param {object} [options]
+   *   See {@link createEngineManifest}
+   */
+  async installSystemSearchExtension(options = {}) {
+    options.id = (options.id ?? "example") + "@search.mozilla.org";
+    let xpi = await lazy.AddonTestUtils.createTempWebExtensionFile({
+      manifest: this.createEngineManifest(options),
+      background() {
+        // eslint-disable-next-line no-undef
+        browser.test.sendMessage("started");
+      },
+    });
+    let wrapper = gTestScope.ExtensionTestUtils.expectExtension(options.id);
+
+    const install = await lazy.AddonManager.getInstallForURL(
+      `file://${xpi.path}`,
+      {
+        useSystemLocation: true,
+      }
+    );
+
+    install.install();
+
+    await wrapper.awaitStartup();
+    await wrapper.awaitMessage("started");
+
+    return wrapper;
+  },
+
+  /**
+   * Create a search engine extension manifest.
+   *
+   * @param {object} [options]
+   *   The options for the manifest.
+   * @param {string} [options.id]
+   *   The id to use for the WebExtension.
+   * @param {string} [options.name]
+   *   The display name to use for the WebExtension.
+   * @param {string} [options.version]
+   *   The version to use for the WebExtension.
+   * @param {string} [options.favicon_url]
+   *   The favicon to use for the search engine in the WebExtension.
+   * @param {string} [options.keyword]
+   *   The keyword to use for the search engine.
+   * @param {string} [options.encoding]
+   *   The encoding to use for the search engine.
+   * @param {string} [options.search_url]
+   *   The search URL to use for the search engine.
+   * @param {string} [options.search_url_get_params]
+   *   The GET search URL parameters to use for the search engine
+   * @param {string} [options.search_url_post_params]
+   *   The POST search URL parameters to use for the search engine
+   * @param {string} [options.suggest_url]
+   *   The suggestion URL to use for the search engine.
+   * @param {string} [options.suggest_url_get_params]
+   *   The suggestion URL parameters to use for the search engine.
+   * @param {string} [options.search_form]
+   *   The search form to use for the search engine.
+   * @returns {object}
+   *   The generated manifest.
+   */
+  createEngineManifest(options = {}) {
+    options.name = options.name ?? "Example";
+    options.id = options.id ?? options.name.toLowerCase().replaceAll(" ", "");
+    if (!options.id.includes("@")) {
+      options.id += "@tests.mozilla.org";
+    }
+    options.version = options.version ?? "1.0";
+    let manifest = {
+      version: options.version,
+      browser_specific_settings: {
+        gecko: {
+          id: options.id,
+        },
+      },
+      chrome_settings_overrides: {
+        search_provider: {
+          name: options.name,
+          search_url: options.search_url ?? "https://example.com/",
+        },
+      },
+    };
+
+    if (options.default_locale) {
+      manifest.default_locale = options.default_locale;
+    }
+
+    if (options.search_url_post_params) {
+      manifest.chrome_settings_overrides.search_provider.search_url_post_params =
+        options.search_url_post_params;
+    } else {
+      manifest.chrome_settings_overrides.search_provider.search_url_get_params =
+        options.search_url_get_params ?? "?q={searchTerms}";
+    }
+
+    if (options.favicon_url) {
+      manifest.chrome_settings_overrides.search_provider.favicon_url =
+        options.favicon_url;
+    }
+    if (options.encoding) {
+      manifest.chrome_settings_overrides.search_provider.encoding =
+        options.encoding;
+    }
+    if (options.keyword) {
+      manifest.chrome_settings_overrides.search_provider.keyword =
+        options.keyword;
+    }
+    if (options.suggest_url) {
+      manifest.chrome_settings_overrides.search_provider.suggest_url =
+        options.suggest_url;
+    }
+    if (options.suggest_url) {
+      manifest.chrome_settings_overrides.search_provider.suggest_url_get_params =
+        options.suggest_url_get_params;
+    }
+    if (options.search_form) {
+      manifest.chrome_settings_overrides.search_provider.search_form =
+        options.search_form;
+    }
+    if (options.favicon_url) {
+      manifest.chrome_settings_overrides.search_provider.favicon_url =
+        options.favicon_url;
+    }
+    return manifest;
+  },
+
+  /**
+   * A mock idleService that allows us to simulate RemoteSettings
+   * configuration updates.
+   */
+  idleService: {
+    _observers: new Set(),
+
+    _reset() {
+      this._observers.clear();
+    },
+
+    _fireObservers(state) {
+      for (let observer of this._observers.values()) {
+        observer.observe(observer, state, null);
+      }
+    },
+
+    QueryInterface: ChromeUtils.generateQI(["nsIUserIdleService"]),
+    idleTime: 19999,
+
+    addIdleObserver(observer, time) {
+      this._observers.add(observer);
+    },
+
+    removeIdleObserver(observer, time) {
+      this._observers.delete(observer);
+    },
+  },
+
+  /**
+   * Register the mock idleSerice.
+   */
+  useMockIdleService() {
+    let fakeIdleService = MockRegistrar.register(
+      "@mozilla.org/widget/useridleservice;1",
+      SearchTestUtils.idleService
+    );
+    gTestScope.registerCleanupFunction(() => {
+      MockRegistrar.unregister(fakeIdleService);
+    });
+  },
+
+  /**
+   * Simulates an update to the RemoteSettings configuration.
+   *
+   * @param {object} [config]
+   *  The new configuration.
+   */
+  async updateRemoteSettingsConfig(config) {
+    if (!config) {
+      let settings = lazy.RemoteSettings(lazy.SearchUtils.SETTINGS_KEY);
+      config = await settings.get();
+    }
+    const reloadObserved =
+      SearchTestUtils.promiseSearchNotification("engines-reloaded");
+    await lazy.RemoteSettings(lazy.SearchUtils.SETTINGS_KEY).emit("sync", {
+      data: { current: config },
+    });
+
+    this.idleService._fireObservers("idle");
+    await reloadObserved;
+  },
+};
diff --git a/toolkit/components/search/tests/xpcshell/data/bigIcon.ico b/toolkit/components/search/tests/xpcshell/data/bigIcon.ico
new file mode 100644
index 0000000000..f22522411d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/bigIcon.ico
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-app/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-app/manifest.json
new file mode 100644
index 0000000000..14bc27bdd4
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-app/manifest.json
@@ -0,0 +1,24 @@
+{
+  "name": "TestEngineApp",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-app@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A test search engine installed in the application directory",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "TestEngineApp",
+      "search_url": "https://localhost/",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-chromeicon/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-chromeicon/manifest.json
new file mode 100644
index 0000000000..d2896b78f8
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-chromeicon/manifest.json
@@ -0,0 +1,23 @@
+{
+  "name": "engine-chromeicon",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-chromeicon@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine-chromeicon",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/en/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/en/messages.json
new file mode 100644
index 0000000000..07580b8ea5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/en/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-diff-name-en"
+  },
+  "searchUrl": {
+    "message": "https://en.wikipedia.com/search"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/gd/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/gd/messages.json
new file mode 100644
index 0000000000..de01d16bf0
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/_locales/gd/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-diff-name-gd"
+  },
+  "searchUrl": {
+    "message": "https://gd.wikipedia.com/search"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-diff-name/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/manifest.json
new file mode 100644
index 0000000000..3c80765f61
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-diff-name/manifest.json
@@ -0,0 +1,21 @@
+{
+  "name": "engine-diff-name",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-diff-name@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "icons": {
+    "16": "favicon.png"
+  },
+  "default_locale": "en",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "__MSG_extensionName__",
+      "search_url": "__MSG_searchUrl__"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-fr.xml b/toolkit/components/search/tests/xpcshell/data/engine-fr.xml
new file mode 100644
index 0000000000..4bb4426a12
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-fr.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>

+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">

+<ShortName>Test search engine (fr)</ShortName>

+<Description>A test search engine (based on Google search for a different locale)</Description>

+<InputEncoding>ISO-8859-1</InputEncoding>

+<Url type="text/html" method="GET" template="http://www.google.fr/search">

+  <Param name="q" value="{searchTerms}"/>

+  <Param name="ie" value="iso-8859-1"/>

+  <Param name="oe" value="iso-8859-1"/>

+</Url>

+<SearchForm>http://www.google.fr/</SearchForm>

+</SearchPlugin>

diff --git a/toolkit/components/search/tests/xpcshell/data/engine-fr/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-fr/manifest.json
new file mode 100644
index 0000000000..cc895d26d9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-fr/manifest.json
@@ -0,0 +1,32 @@
+{
+  "name": "Test search engine (fr)",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-fr@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A test search engine (based on Google search for a different locale)",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Test search engine (fr)",
+      "search_url": "https://www.google.fr/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "ie",
+          "value": "iso-8859-1"
+        },
+        {
+          "name": "oe",
+          "value": "iso-8859-1"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-override/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-override/manifest.json
new file mode 100644
index 0000000000..a894be0a41
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-override/manifest.json
@@ -0,0 +1,24 @@
+{
+  "name": "bug645970",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-override@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "override",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "bug645970",
+      "search_url": "https://searchtest.local",
+      "params": [
+        {
+          "name": "search",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-pref/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-pref/manifest.json
new file mode 100644
index 0000000000..a876520bc2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-pref/manifest.json
@@ -0,0 +1,28 @@
+{
+  "name": "engine-pref",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-pref@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine-pref",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "code",
+          "condition": "pref",
+          "pref": "code"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-purposes/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-purposes/manifest.json
new file mode 100644
index 0000000000..fc709063e1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-purposes/manifest.json
@@ -0,0 +1,62 @@
+{
+  "name": "Test Engine With Purposes",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-purposes@search.mozilla.org"
+    }
+  },
+  "description": "A test search engine with purposes",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Test Engine With Purposes",
+      "search_url": "https://www.example.com/search",
+      "params": [
+        {
+          "name": "form",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "MOZKEYWORD"
+        },
+        {
+          "name": "form",
+          "condition": "purpose",
+          "purpose": "contextmenu",
+          "value": "MOZCONTEXT"
+        },
+        {
+          "name": "form",
+          "condition": "purpose",
+          "purpose": "newtab",
+          "value": "MOZNEWTAB"
+        },
+        {
+          "name": "form",
+          "condition": "purpose",
+          "purpose": "searchbar",
+          "value": "MOZSEARCHBAR"
+        },
+        {
+          "name": "form",
+          "condition": "purpose",
+          "purpose": "homepage",
+          "value": "MOZHOMEPAGE"
+        },
+        {
+          "name": "pc",
+          "value": "FIREFOX"
+        },
+        {
+          "name": "channel",
+          "condition": "pref",
+          "pref": "testChannelEnabled"
+        },
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-rel-searchform-purpose/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-rel-searchform-purpose/manifest.json
new file mode 100644
index 0000000000..ed4a609e7c
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-rel-searchform-purpose/manifest.json
@@ -0,0 +1,41 @@
+{
+  "name": "engine-rel-searchform-purpose",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-rel-searchform-purpose@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine-rel-searchform-purpose",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "contextmenu",
+          "value": "rcs"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "fflb"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "searchbar",
+          "value": "sb"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-reordered/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-reordered/manifest.json
new file mode 100644
index 0000000000..cc3fc95430
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-reordered/manifest.json
@@ -0,0 +1,40 @@
+{
+  "name": "Test search engine (Reordered)",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-reordered@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A test search engine (based on Google search)",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Test search engine (Reordered)",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "contextmenu",
+          "value": "rcs"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "fflb"
+        }
+      ],
+      "suggest_url": "https://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/en/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/en/messages.json
new file mode 100644
index 0000000000..1cc3f68ee1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/en/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-resourceicon"
+  },
+  "searchUrl": {
+    "message": "https://www.google.com/search"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/gd/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/gd/messages.json
new file mode 100644
index 0000000000..3c02e6a2af
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/_locales/gd/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-resourceicon-gd"
+  },
+  "searchUrl": {
+    "message": "https://www.google.com/search"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/manifest.json
new file mode 100644
index 0000000000..dc62336145
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-resourceicon/manifest.json
@@ -0,0 +1,21 @@
+{
+  "name": "engine-resourceicon",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-resourceicon@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "icons": {
+    "16": "favicon.png"
+  },
+  "default_locale": "en",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "__MSG_extensionName__",
+      "search_url": "__MSG_searchUrl__"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/en/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/en/messages.json
new file mode 100644
index 0000000000..ee808e7a62
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/en/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-same-name"
+  },
+  "searchUrl": {
+    "message": "https://www.google.com/search?q={searchTerms}"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/gd/messages.json b/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/gd/messages.json
new file mode 100644
index 0000000000..476a9e56cc
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-same-name/_locales/gd/messages.json
@@ -0,0 +1,8 @@
+{
+  "extensionName": {
+    "message": "engine-same-name"
+  },
+  "searchUrl": {
+    "message": "https://www.example.com/search?q={searchTerms}"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-same-name/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-same-name/manifest.json
new file mode 100644
index 0000000000..dc8a4c5d45
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-same-name/manifest.json
@@ -0,0 +1,21 @@
+{
+  "name": "engine-same-name",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-same-name@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "icons": {
+    "16": "favicon.png"
+  },
+  "default_locale": "en",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "__MSG_extensionName__",
+      "search_url": "__MSG_searchUrl__"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine-system-purpose/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine-system-purpose/manifest.json
new file mode 100644
index 0000000000..d268af8eab
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine-system-purpose/manifest.json
@@ -0,0 +1,35 @@
+{
+  "name": "engine-system-purpose",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine-system-purpose@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine-system-purpose",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "searchbar",
+          "value": "sb"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "system",
+          "value": "sys"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine.xml b/toolkit/components/search/tests/xpcshell/data/engine.xml
new file mode 100644
index 0000000000..a665e46b0b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
+<ShortName>Test search engine</ShortName>
+<Description>A test search engine (based on Google search)</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA</Image>
+<Url type="application/x-suggestions+json" method="GET" template="https://suggestqueries.google.com/complete/search?output=firefox&amp;client=firefox&amp;hl={moz:locale}&amp;q={searchTerms}"/>
+<Url type="text/html" method="GET" template="https://www.google.com/search">
+  <Param name="q" value="{searchTerms}"/>
+  <!-- Dynamic parameters -->
+  <MozParam name="channel" condition="purpose" purpose="contextmenu" value="rcs"/>
+  <MozParam name="channel" condition="purpose" purpose="keyword" value="fflb"/>
+</Url>
+<SearchForm>http://www.google.com/</SearchForm>
+</SearchPlugin>
diff --git a/toolkit/components/search/tests/xpcshell/data/engine/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine/manifest.json
new file mode 100644
index 0000000000..30d221f388
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine/manifest.json
@@ -0,0 +1,40 @@
+{
+  "name": "Test search engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A test search engine (based on Google search)",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Test search engine",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "contextmenu",
+          "value": "rcs"
+        },
+        {
+          "name": "channel",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "fflb"
+        }
+      ],
+      "suggest_url": "https://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engine2.xml b/toolkit/components/search/tests/xpcshell/data/engine2.xml
new file mode 100644
index 0000000000..9957bfdf48
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine2.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/"> 
+  <ShortName>A second test engine</ShortName> 
+  <Description>A second test search engine (based on DuckDuckGo)</Description> 
+  <InputEncoding>UTF-8</InputEncoding> 
+  <LongName>A second test search engine (based on DuckDuckGo)</LongName> 
+  <Image width="16" height="16">data:image/vnd.microsoft.icon;base64,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</Image>
+  <Url type="text/html" method="get" template="https://duckduckgo.com/?q={searchTerms}"/>  
+</OpenSearchDescription> 
diff --git a/toolkit/components/search/tests/xpcshell/data/engine2/manifest.json b/toolkit/components/search/tests/xpcshell/data/engine2/manifest.json
new file mode 100644
index 0000000000..7dd4b15931
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engine2/manifest.json
@@ -0,0 +1,18 @@
+{
+  "name": "A second test engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine2@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A second test search engine (based on DuckDuckGo)",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "A second test engine",
+      "search_url": "https://duckduckgo.com/?q={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engineImages.xml b/toolkit/components/search/tests/xpcshell/data/engineImages.xml
new file mode 100644
index 0000000000..65b550b31b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engineImages.xml
@@ -0,0 +1,22 @@
+<!-- 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/. -->
+
+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
+    <ShortName>IconsTest</ShortName>
+    <Description>IconsTest. Search by Test.</Description>
+    <InputEncoding>UTF-8</InputEncoding>
+    <Image width="16" height="16">data:image/x-icon;base64,ico16</Image>
+    <Image width="32" height="32">data:image/x-icon;base64,ico32</Image>
+    <Image width="74" height="74">data:image/png;base64,ico74</Image>
+    <Url type="application/x-suggestions+json" template="http://api.bing.com/osjson.aspx">
+        <Param name="query" value="{searchTerms}"/>
+        <Param name="form" value="MOZW"/>
+    </Url>
+    <Url type="text/html" method="GET" template="http://www.bing.com/search">
+        <Param name="q" value="{searchTerms}"/>
+        <MozParam name="pc" condition="pref" pref="ms-pc"/>
+        <Param name="form" value="MOZW"/>
+    </Url>
+    <SearchForm>http://www.bing.com/search</SearchForm>
+</SearchPlugin>
diff --git a/toolkit/components/search/tests/xpcshell/data/engineImages/manifest.json b/toolkit/components/search/tests/xpcshell/data/engineImages/manifest.json
new file mode 100644
index 0000000000..b5366a6eb6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engineImages/manifest.json
@@ -0,0 +1,37 @@
+{
+  "name": "IconsTest",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engineImages@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "IconsTest. Search by Test.",
+  "icons": {
+    "16": "data:image/x-icon;base64,ico16"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "IconsTest",
+      "search_url": "https://www.bing.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "form",
+          "value": "MOZW"
+        },
+        {
+          "name": "pc",
+          "condition": "pref",
+          "pref": "ms-pc"
+        }
+      ],
+      "suggest_url": "https://api.bing.com/osjson.aspxquery={searchTerms}&form=MOZW"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engineMaker.sjs b/toolkit/components/search/tests/xpcshell/data/engineMaker.sjs
new file mode 100644
index 0000000000..4b32003dcf
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engineMaker.sjs
@@ -0,0 +1,77 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Dynamically create an OpenSearch search engine offering search suggestions
+ * via searchSuggestions.sjs.
+ *
+ * The engine is constructed by passing a JSON object with engine details as the query string.
+ */
+
+function handleRequest(request, response) {
+  let engineData = JSON.parse(unescape(request.queryString).replace("+", " "));
+
+  if (!engineData.baseURL) {
+    response.setStatusLine(request.httpVersion, 500, "baseURL required");
+    return;
+  }
+
+  engineData.name = engineData.name || "Generated test engine";
+  engineData.description =
+    engineData.description || "Generated test engine description";
+  engineData.method = engineData.method || "GET";
+
+  response.setStatusLine(request.httpVersion, 200, "OK");
+  createOpenSearchEngine(response, engineData);
+}
+
+/**
+ * Create an OpenSearch engine for the given base URL.
+ *
+ * @param {Response} response
+ *   The response object to write the engine to.
+ * @param {object} engineData
+ *   Information about the search engine to write to the response.
+ */
+function createOpenSearchEngine(response, engineData) {
+  let params = "";
+  let queryString = "";
+  if (engineData.method == "POST") {
+    params = "<Param name='q' value='{searchTerms}'/>";
+  } else {
+    queryString = "?q={searchTerms}";
+  }
+  let type = "type='application/x-suggestions+json'";
+  if (engineData.alternativeJSONType) {
+    type = "type='application/json' rel='suggestions'";
+  }
+  let image = "";
+  if (engineData.image) {
+    image = `<Image width="16" height="16">${engineData.baseURL}${engineData.image}</Image>`;
+  }
+  let updateFile = "";
+  if (engineData.updateFile) {
+    updateFile = `<Url type="application/opensearchdescription+xml"
+      rel="self"
+      template="${engineData.baseURL}${engineData.updateFile}" />
+    `;
+  }
+
+  let result = `<?xml version='1.0' encoding='utf-8'?>
+<OpenSearchDescription xmlns='http://a9.com/-/spec/opensearch/1.1/'>
+  <ShortName>${engineData.name}</ShortName>
+  <Description>${engineData.description}</Description>
+  <InputEncoding>UTF-8</InputEncoding>
+  <LongName>${engineData.name}</LongName>
+  ${image}
+  <Url ${type} method='${engineData.method}'
+       template='${engineData.baseURL}searchSuggestions.sjs${queryString}'>
+    ${params}
+  </Url>
+  <Url type='text/html' method='${engineData.method}'
+       template='${engineData.baseURL}${queryString}'/>
+  ${updateFile}
+</OpenSearchDescription>
+`;
+  response.write(result);
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engines-no-order-hint.json b/toolkit/components/search/tests/xpcshell/data/engines-no-order-hint.json
new file mode 100644
index 0000000000..85c89fb388
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engines-no-order-hint.json
@@ -0,0 +1,83 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "engine@search.mozilla.org"
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-rel-searchform-purpose@search.mozilla.org"
+      },
+      "orderHint": 1000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-chromeicon@search.mozilla.org"
+      },
+      "orderHint": 1000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        },
+        {
+          "included": { "regions": ["ru"] },
+          "default": "no"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-resourceicon@search.mozilla.org"
+      },
+      "appliesTo": [
+        {
+          "included": { "locales": { "matches": ["en-US", "fr"] } },
+          "excluded": {
+            "regions": ["ru"]
+          },
+          "default": "no"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-reordered@search.mozilla.org"
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-pref@search.mozilla.org"
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de"] } },
+          "default": "no"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/engines.json b/toolkit/components/search/tests/xpcshell/data/engines.json
new file mode 100644
index 0000000000..01bcfd1d05
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/engines.json
@@ -0,0 +1,98 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "engine@search.mozilla.org"
+      },
+      "orderHint": 10000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["gd"] } },
+          "default": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-pref@search.mozilla.org"
+      },
+      "orderHint": 7000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de"] } },
+          "default": "no",
+          "defaultPrivate": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-rel-searchform-purpose@search.mozilla.org"
+      },
+      "orderHint": 6000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        },
+        {
+          "included": { "locales": { "matches": ["gd"] } },
+          "orderHint": 9000
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-chromeicon@search.mozilla.org"
+      },
+      "orderHint": 8000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        },
+        {
+          "included": { "regions": ["ru"] },
+          "default": "no"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-resourceicon@search.mozilla.org"
+      },
+      "orderHint": 9000,
+      "appliesTo": [
+        {
+          "included": { "locales": { "matches": ["en-US", "fr"] } },
+          "excluded": { "regions": ["ru"] },
+          "default": "no"
+        },
+        {
+          "included": { "locales": { "matches": ["gd"] } },
+          "default": "yes",
+          "webExtension": {
+            "locales": ["gd"]
+          }
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine-reordered@search.mozilla.org"
+      },
+      "orderHint": 5000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "excluded": { "locales": { "matches": ["de", "fr"] } },
+          "default": "no"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/af/messages.json b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/af/messages.json
new file mode 100644
index 0000000000..29ddd24df5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/af/messages.json
@@ -0,0 +1,17 @@
+{
+  "extensionName": {
+    "message": "Multilocale"
+  },
+  "extensionDescription": {
+    "message": "Wikipedia, die vrye ensiklopedie"
+  },
+  "url_lang": {
+    "message": "af"
+  },
+  "searchUrl": {
+    "message": "https://af.wikipedia.org/wiki/Spesiaal:Soek"
+  },
+  "suggestUrl": {
+    "message": "https://af.wikipedia.org/w/api.php"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/an/messages.json b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/an/messages.json
new file mode 100644
index 0000000000..d21d910463
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/_locales/an/messages.json
@@ -0,0 +1,17 @@
+{
+  "extensionName": {
+    "message": "Multilocale"
+  },
+  "extensionDescription": {
+    "message": "A enciclopedia Libre"
+  },
+  "url_lang": {
+    "message": "an"
+  },
+  "searchUrl": {
+    "message": "https://an.wikipedia.org/wiki/Especial:Mirar"
+  },
+  "suggestUrl": {
+    "message": "https://an.wikipedia.org/w/api.php"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/favicon.ico b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/favicon.ico
new file mode 100644
index 0000000000..4314071e24
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/favicon.ico
diff --git a/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/manifest.json b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/manifest.json
new file mode 100644
index 0000000000..0fd835ca40
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/geolookup-extensions/multilocale/manifest.json
@@ -0,0 +1,23 @@
+{
+  "name": "__MSG_extensionName__",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "multilocale@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "__MSG_extensionDescription__",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "default_locale": "af",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "__MSG_extensionName__",
+      "search_url": "__MSG_searchUrl__",
+      "suggest_url": "__MSG_searchUrl__"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/iconsRedirect.sjs b/toolkit/components/search/tests/xpcshell/data/iconsRedirect.sjs
new file mode 100644
index 0000000000..e08fb0b65a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/iconsRedirect.sjs
@@ -0,0 +1,18 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Redirect a request for an icon to a different place, using a different
+ * content-type.
+ */
+
+function handleRequest(request, response) {
+  response.setStatusLine("1.1", 302, "Moved");
+  if (request.queryString == "type=invalid") {
+    response.setHeader("Content-Type", "image/png", false);
+    response.setHeader("Location", "engine.xml", false);
+  } else {
+    response.setHeader("Content-Type", "text/html", false);
+    response.setHeader("Location", "remoteIcon.ico", false);
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/remoteIcon.ico b/toolkit/components/search/tests/xpcshell/data/remoteIcon.ico
new file mode 100644
index 0000000000..442ab4dc80
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/remoteIcon.ico
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy-correct-default-engine-hashes.json b/toolkit/components/search/tests/xpcshell/data/search-legacy-correct-default-engine-hashes.json
new file mode 100644
index 0000000000..e6091b7230
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy-correct-default-engine-hashes.json
@@ -0,0 +1,112 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {
+    "current": "engine2",
+    "private": "engine2"
+  },
+  "engines": [
+    {
+      "_name": "engine1",
+      "_shortName": "engine1",
+      "_loadPath": "[other]addEngineWithDetails:engine1@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico"
+      },
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_urls": [
+        {
+          "template": "https://1.example.com/search",
+          "rels": [],
+          "resultDomain": "1.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine1@search.mozilla.org"
+    },
+    {
+      "_name": "engine2",
+      "_shortName": "engine2",
+      "_loadPath": "[other]addEngineWithDetails:engine2@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico"
+      },
+      "_metaData": {
+        "alias": null,
+        "hidden": false
+      },
+      "_urls": [
+        {
+          "template": "https://2.example.com/search",
+          "rels": [],
+          "resultDomain": "2.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine2@search.mozilla.org"
+    },
+    {
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "resultDomain": "suggestqueries.google.com",
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "keyword"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "extensionID": "test-addon-id@mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy-no-ids.json b/toolkit/components/search/tests/xpcshell/data/search-legacy-no-ids.json
new file mode 100644
index 0000000000..733c323876
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy-no-ids.json
@@ -0,0 +1,87 @@
+{
+  "version": 6,
+  "engines": [
+    { "_name": "Google", "_isAppProvided": true, "_metaData": { "order": 1 } },
+    {
+      "_name": "Wikipedia (en)",
+      "_isAppProvided": true,
+      "_metaData": { "order": 7 }
+    },
+    { "_name": "Bing", "_isAppProvided": true, "_metaData": { "order": 3 } },
+    {
+      "_name": "Amazon.co.uk",
+      "_isAppProvided": true,
+      "_metaData": { "order": 2 }
+    },
+    {
+      "_name": "DuckDuckGo",
+      "_isAppProvided": true,
+      "_metaData": { "order": 4 }
+    },
+    { "_name": "eBay", "_isAppProvided": true, "_metaData": { "order": 5 } },
+    {
+      "_name": "Policy",
+      "_loadPath": "[other]addEngineWithDetails:set-via-policy",
+      "_metaData": { "alias": "PolicyAlias", "order": 6 }
+    },
+    {
+      "_name": "Bugzilla@Mozilla",
+      "_loadPath": "[https]bugzilla.mozilla.org/bugzillamozilla.xml",
+      "description": "Bugzilla@Mozilla Quick Search",
+      "_metaData": {
+        "loadPathHash": "Bxz6jVe3IIBxLLaafUus536LMyLKoGZm7xsBv/yiTw8=",
+        "order": 8,
+        "alias": "bugzillaAlias"
+      },
+      "_urls": [
+        {
+          "params": [],
+          "rels": [],
+          "template": "https://bugzilla.mozilla.org/buglist.cgi?quicksearch={searchTerms}"
+        }
+      ],
+      "_orderHint": null,
+      "_telemetryId": null,
+      "_updateInterval": null,
+      "_updateURL": null,
+      "_iconUpdateURL": null,
+      "_extensionID": null,
+      "_locale": null,
+      "_definedAliases": []
+    },
+    {
+      "_name": "User",
+      "_loadPath": "[other]addEngineWithDetails:set-via-user",
+      "_metaData": {
+        "order": 9,
+        "alias": "UserAlias"
+      },
+      "_urls": [
+        {
+          "params": [],
+          "rels": [],
+          "template": "https://example.com/test?q={searchTerms}"
+        }
+      ],
+      "_telemetryId": null,
+      "_updateInterval": null,
+      "_updateURL": null,
+      "_iconUpdateURL": null,
+      "_extensionID": null,
+      "_locale": null,
+      "_hasPreferredIcon": null
+    },
+    { "_name": "Amazon.com", "_isAppProvided": true, "_metaData": {} }
+  ],
+  "metaData": {
+    "useSavedOrder": true,
+    "locale": "en-US",
+    "region": "GB",
+    "channel": "default",
+    "experiment": "",
+    "distroID": "",
+    "appDefaultEngine": "Google",
+    "current": "Bing",
+    "hash": "5Of6s1D+BDjPRti1wqtFyBTH1PnOf9n6cRwWlEXZhd0="
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy-old-loadPaths.json b/toolkit/components/search/tests/xpcshell/data/search-legacy-old-loadPaths.json
new file mode 100644
index 0000000000..f716fb3e4a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy-old-loadPaths.json
@@ -0,0 +1,135 @@
+{
+  "version": 7,
+  "engines": [
+    {
+      "id": "google@search.mozilla.orgdefault",
+      "_name": "Google",
+      "_isAppProvided": true,
+      "_metaData": { "order": 1 }
+    },
+    {
+      "id": "amazon@search.mozilla.orgen-GB",
+      "_name": "Amazon.co.uk",
+      "_isAppProvided": true,
+      "_metaData": { "order": 2 }
+    },
+    {
+      "id": "bing@search.mozilla.orgdefault",
+      "_name": "Bing",
+      "_isAppProvided": true,
+      "_metaData": { "order": 3 }
+    },
+    {
+      "id": "ddg@search.mozilla.orgdefault",
+      "_name": "DuckDuckGo",
+      "_isAppProvided": true,
+      "_metaData": { "order": 4 }
+    },
+    {
+      "id": "ebay@search.mozilla.orguk",
+      "_name": "eBay",
+      "_isAppProvided": true,
+      "_metaData": { "order": 5 }
+    },
+    {
+      "id": "wikipedia@search.mozilla.orgdefault",
+      "_name": "Wikipedia (en)",
+      "_isAppProvided": true,
+      "_metaData": { "order": 6 }
+    },
+    {
+      "id": "policy-Policy",
+      "_name": "Policy",
+      "_loadPath": "[other]addEngineWithDetails:set-via-policy",
+      "_metaData": { "alias": "PolicyAlias", "order": 6 }
+    },
+    {
+      "id": "bbc163e7-7b1a-47aa-a32c-c59062de2753",
+      "_name": "Bugzilla@Mozilla",
+      "_loadPath": "[https]bugzilla.mozilla.org/bugzillamozilla.xml",
+      "description": "Bugzilla@Mozilla Quick Search",
+      "_metaData": {
+        "loadPathHash": "Bxz6jVe3IIBxLLaafUus536LMyLKoGZm7xsBv/yiTw8=",
+        "order": 8,
+        "alias": "bugzillaAlias"
+      },
+      "_urls": [
+        {
+          "params": [],
+          "rels": [],
+          "template": "https://bugzilla.mozilla.org/buglist.cgi?quicksearch={searchTerms}"
+        }
+      ],
+      "_orderHint": null,
+      "_telemetryId": null,
+      "_updateInterval": null,
+      "_updateURL": null,
+      "_iconUpdateURL": null,
+      "_extensionID": null,
+      "_locale": null,
+      "_definedAliases": []
+    },
+    {
+      "id": "bbc163e7-7b1a-47aa-a32c-c59062de2754",
+      "_name": "User",
+      "_loadPath": "[other]addEngineWithDetails:set-via-user",
+      "_metaData": {
+        "order": 9,
+        "alias": "UserAlias"
+      },
+      "_urls": [
+        {
+          "params": [],
+          "rels": [],
+          "template": "https://example.com/test?q={searchTerms}"
+        }
+      ],
+      "_telemetryId": null,
+      "_updateInterval": null,
+      "_updateURL": null,
+      "_iconUpdateURL": null,
+      "_extensionID": null,
+      "_locale": null,
+      "_hasPreferredIcon": null
+    },
+    {
+      "id": "example@tests.mozilla.orgdefault",
+      "_name": "Example",
+      "_loadPath": "[other]addEngineWithDetails:example@tests.mozilla.org",
+      "description": null,
+      "_iconURL": "",
+      "_metaData": {},
+      "_urls": [
+        {
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ],
+          "rels": [],
+          "template": "https://example.com/"
+        }
+      ],
+      "_telemetryId": null,
+      "_updateInterval": null,
+      "_updateURL": null,
+      "_iconUpdateURL": null,
+      "_extensionID": "example@tests.mozilla.org",
+      "_locale": "default",
+      "_definedAliases": [],
+      "_hasPreferredIcon": null
+    }
+  ],
+  "metaData": {
+    "useSavedOrder": true,
+    "locale": "en-US",
+    "region": "GB",
+    "channel": "default",
+    "experiment": "",
+    "distroID": "",
+    "appDefaultEngine": "Google",
+    "current": "Bing",
+    "hash": "5Of6s1D+BDjPRti1wqtFyBTH1PnOf9n6cRwWlEXZhd0="
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-default-engine-hashes.json b/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-default-engine-hashes.json
new file mode 100644
index 0000000000..ca7081f565
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-default-engine-hashes.json
@@ -0,0 +1,114 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {
+    "current": "engine2",
+    "private": "engine2",
+    "hash": "wrong-hash-o/HzjHlVpb97AFGH3pY1GZ6CoTQkQslUKRd38/qasto=",
+    "privateHash": "wrong-hash-o/HzjHlVpb97AFGH3pY1GZ6CoTQkQslUKRd38/qasto="
+  },
+  "engines": [
+    {
+      "_name": "engine1",
+      "_shortName": "engine1",
+      "_loadPath": "[other]addEngineWithDetails:engine1@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico"
+      },
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_urls": [
+        {
+          "template": "https://1.example.com/search",
+          "rels": [],
+          "resultDomain": "1.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine1@search.mozilla.org"
+    },
+    {
+      "_name": "engine2",
+      "_shortName": "engine2",
+      "_loadPath": "[other]addEngineWithDetails:engine2@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico"
+      },
+      "_metaData": {
+        "alias": null,
+        "hidden": false
+      },
+      "_urls": [
+        {
+          "template": "https://2.example.com/search",
+          "rels": [],
+          "resultDomain": "2.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine2@search.mozilla.org"
+    },
+    {
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "resultDomain": "suggestqueries.google.com",
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "keyword"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "extensionID": "test-addon-id@mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-third-party-engine-hashes.json b/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-third-party-engine-hashes.json
new file mode 100644
index 0000000000..25329e083f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy-wrong-third-party-engine-hashes.json
@@ -0,0 +1,114 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {
+    "current": "Test search engine",
+    "private": "Test search engine",
+    "hash": "wrong-hash-o/HzjHlVpb97AFGH3pY1GZ6CoTQkQslUKRd38/qasto=",
+    "privateHash": "wrong-hash-o/HzjHlVpb97AFGH3pY1GZ6CoTQkQslUKRd38/qasto="
+  },
+  "engines": [
+    {
+      "_name": "engine1",
+      "_shortName": "engine1",
+      "_loadPath": "[other]addEngineWithDetails:engine1@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico"
+      },
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_urls": [
+        {
+          "template": "https://1.example.com/search",
+          "rels": [],
+          "resultDomain": "1.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine1@search.mozilla.org"
+    },
+    {
+      "_name": "engine2",
+      "_shortName": "engine2",
+      "_loadPath": "[other]addEngineWithDetails:engine2@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico"
+      },
+      "_metaData": {
+        "alias": null,
+        "hidden": false
+      },
+      "_urls": [
+        {
+          "template": "https://2.example.com/search",
+          "rels": [],
+          "resultDomain": "2.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine2@search.mozilla.org"
+    },
+    {
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "resultDomain": "suggestqueries.google.com",
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "keyword"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "extensionID": "test-addon-id@mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-legacy.json b/toolkit/components/search/tests/xpcshell/data/search-legacy.json
new file mode 100644
index 0000000000..c8416f3813
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-legacy.json
@@ -0,0 +1,109 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "engine1",
+      "_shortName": "engine1",
+      "_loadPath": "[other]addEngineWithDetails:engine1@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://9c38b851-bede-2244-a086-9be8128dd64d/favicon.ico"
+      },
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_urls": [
+        {
+          "template": "https://1.example.com/search",
+          "rels": [],
+          "resultDomain": "1.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine1@search.mozilla.org"
+    },
+    {
+      "_name": "engine2",
+      "_shortName": "engine2",
+      "_loadPath": "[other]addEngineWithDetails:engine2@search.mozilla.org",
+      "description": "A small test engine",
+      "__searchForm": null,
+      "_iconURL": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico",
+      "_iconMapObj": {
+        "{}": "moz-extension://0ea1d9b5-a14c-0e42-afaf-f25e8261c135/favicon.ico"
+      },
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_urls": [
+        {
+          "template": "https://2.example.com/search",
+          "rels": [],
+          "resultDomain": "2.example.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "_isBuiltin": true,
+      "queryCharset": "UTF-8",
+      "extensionID": "engine2@search.mozilla.org"
+    },
+    {
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "resultDomain": "suggestqueries.google.com",
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "keyword"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "extensionID": "test-addon-id@mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-migration.json b/toolkit/components/search/tests/xpcshell/data/search-migration.json
new file mode 100644
index 0000000000..520149a370
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-migration.json
@@ -0,0 +1,68 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "engine1",
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "engine2",
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "simple",
+      "_loadPath": "jar:[profile]/extensions/simple@tests.mozilla.org.xpi!/simple.xml",
+      "_shortName": "simple",
+      "description": "A migration test engine",
+      "__searchForm": "http://www.example.com/",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://www.example.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8"
+    },
+    {
+      "_name": "simple search",
+      "_loadPath": "[other]addEngineWithDetails:simple@tests.mozilla.org",
+      "_shortName": "simple search",
+      "description": "A migration test engine",
+      "__searchForm": "http://www.example.com/",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://www.example.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "_extensionID": "simple@tests.mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-obsolete-app.json b/toolkit/components/search/tests/xpcshell/data/search-obsolete-app.json
new file mode 100644
index 0000000000..151359ff73
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-obsolete-app.json
@@ -0,0 +1,41 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "engine1",
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "engine2",
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "App",
+      "_shortName": "app",
+      "_loadPath": "jar:[app]/omni.ja!distribution.xml",
+      "description": "App Search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "_readOnly": false
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-obsolete-distribution.json b/toolkit/components/search/tests/xpcshell/data/search-obsolete-distribution.json
new file mode 100644
index 0000000000..efc609a5af
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-obsolete-distribution.json
@@ -0,0 +1,41 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "engine1",
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "engine2",
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "Distribution",
+      "_shortName": "distribution",
+      "_loadPath": "[distribution]/searchplugins/common/distribution.xml",
+      "description": "Distribution Search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "_readOnly": false
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search-obsolete-langpack.json b/toolkit/components/search/tests/xpcshell/data/search-obsolete-langpack.json
new file mode 100644
index 0000000000..8c45b4d61f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search-obsolete-langpack.json
@@ -0,0 +1,91 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "engine1",
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "engine2",
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_isAppProvided": true
+    },
+    {
+      "_name": "Langpack",
+      "_shortName": "langpack-ru",
+      "_loadPath": "jar:[app]/extensions/langpack-ru@firefox.mozilla.org.xpi!browser/langpack.xml",
+      "description": "Langpack search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8"
+    },
+    {
+      "_name": "Langpack1",
+      "_shortName": "langpack1-ru",
+      "_loadPath": "[app]/extensions/langpack-ru@firefox.mozilla.org.xpi!browser/langpack1.xml",
+      "description": "Langpack1 search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example1.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example1.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8"
+    },
+    {
+      "_name": "Langpack2",
+      "_shortName": "langpack2-ru",
+      "_loadPath": "jar:[profile]/extensions/langpack-ru@firefox.mozilla.org.xpi!browser/langpack2.xml",
+      "description": "Langpack2 search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example2.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example2.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8"
+    },
+    {
+      "_name": "Langpack3",
+      "_shortName": "langpack3-ru",
+      "_loadPath": "jar:[other]/langpack-ru@firefox.mozilla.org.xpi!browser/langpack3.xml",
+      "description": "Langpack3 search",
+      "__searchForm": null,
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "https://example3.com/search",
+          "rels": ["searchform"],
+          "resultDomain": "example3.com",
+          "params": []
+        }
+      ],
+      "queryCharset": "UTF-8"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search.json b/toolkit/components/search/tests/xpcshell/data/search.json
new file mode 100644
index 0000000000..79d1368687
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search.json
@@ -0,0 +1,72 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "id": "engine1@search.mozilla.orgdefault",
+      "_name": "engine1",
+      "_metaData": {
+        "alias": "testAlias"
+      },
+      "_isAppProvided": true
+    },
+    {
+      "id": "engine2@search.mozilla.orgdefault",
+      "_name": "engine2",
+      "_metaData": {
+        "alias": null,
+        "hidden": true
+      },
+      "_isAppProvided": true
+    },
+    {
+      "id": "test-addon-id@mozilla.orgdefault",
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "resultDomain": "suggestqueries.google.com",
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "rels": [],
+          "resultDomain": "google.com",
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "searchbar"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            },
+            {
+              "name": "myparam",
+              "mozparam": true,
+              "condition": "pref",
+              "pref": "test"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8",
+      "_extensionID": "test-addon-id@mozilla.org"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/searchSuggestions.sjs b/toolkit/components/search/tests/xpcshell/data/searchSuggestions.sjs
new file mode 100644
index 0000000000..85f51795b6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/searchSuggestions.sjs
@@ -0,0 +1,181 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let { setTimeout } = ChromeUtils.importESModule(
+  "resource://gre/modules/Timer.sys.mjs"
+);
+let { NetUtil } = ChromeUtils.import("resource://gre/modules/NetUtil.jsm");
+
+Cu.importGlobalProperties(["TextEncoder"]);
+
+/**
+ * Provide search suggestions in the OpenSearch JSON format.
+ */
+
+function handleRequest(request, response) {
+  // Get the query parameters from the query string.
+  let query = parseQueryString(request.queryString);
+
+  function convertToUtf8(str) {
+    return String.fromCharCode(...new TextEncoder().encode(str));
+  }
+
+  function writeSuggestions(q, completions = []) {
+    let jsonString = JSON.stringify([q, completions]);
+
+    // This script must be evaluated as UTF-8 for this to write out the bytes of
+    // the string in UTF-8.  If it's evaluated as Latin-1, the written bytes
+    // will be the result of UTF-8-encoding the result-string *twice*, which
+    // will break the "I ❤️" case further down.
+    let stringOfUtf8Bytes = convertToUtf8(jsonString);
+
+    response.write(stringOfUtf8Bytes);
+  }
+
+  /**
+   * Sends `data` as suggestions directly. This is useful when testing rich
+   * suggestions, which do not conform to the object shape sent by
+   * writeSuggestions.
+   *
+   * @param {Array} data The data to send as suggestions.
+   */
+  function writeSuggestionsDirectly(data) {
+    let jsonString = JSON.stringify(data);
+    let stringOfUtf8Bytes = convertToUtf8(jsonString);
+    response.setHeader("Content-Type", "application/json", false);
+    response.write(stringOfUtf8Bytes);
+  }
+
+  response.setStatusLine(request.httpVersion, 200, "OK");
+
+  let q = request.method == "GET" ? query.q : undefined;
+  if (q == "cookie") {
+    response.setHeader("Set-Cookie", "cookie=1");
+    writeSuggestions(q);
+  } else if (q == "no remote" || q == "no results") {
+    writeSuggestions(q);
+  } else if (q == "Query Mismatch") {
+    writeSuggestions("This is an incorrect query string", ["some result"]);
+  } else if (q == "Query Case Mismatch") {
+    writeSuggestions(q.toUpperCase(), [q]);
+  } else if (q == "") {
+    writeSuggestions("", ["The server should never be sent an empty query"]);
+  } else if (q && q.startsWith("mo")) {
+    writeSuggestions(q, ["Mozilla", "modern", "mom"]);
+  } else if (q && q.startsWith("I ❤️")) {
+    writeSuggestions(q, ["I ❤️ Mozilla"]);
+  } else if (q && q.startsWith("stü")) {
+    writeSuggestions("st\\u00FC", ["stühle", "stüssy"]);
+  } else if (q && q.startsWith("tailjunk ")) {
+    writeSuggestionsDirectly([
+      q,
+      [q + " normal", q + " tail 1", q + " tail 2"],
+      [],
+      {
+        "google:irrelevantparameter": [],
+        "google:badformat": {
+          "google:suggestdetail": [
+            {},
+            { mp: "… ", t: "tail 1" },
+            { mp: "… ", t: "tail 2" },
+          ],
+        },
+      },
+    ]);
+  } else if (q && q.startsWith("tailjunk few ")) {
+    writeSuggestionsDirectly([
+      q,
+      [q + " normal", q + " tail 1", q + " tail 2"],
+      [],
+      {
+        "google:irrelevantparameter": [],
+        "google:badformat": {
+          "google:suggestdetail": [{ mp: "… ", t: "tail 1" }],
+        },
+      },
+    ]);
+  } else if (q && q.startsWith("tailalt ")) {
+    writeSuggestionsDirectly([
+      q,
+      [q + " normal", q + " tail 1", q + " tail 2"],
+      {
+        "google:suggestdetail": [
+          {},
+          { mp: "… ", t: "tail 1" },
+          { mp: "… ", t: "tail 2" },
+        ],
+      },
+    ]);
+  } else if (q && q.startsWith("tail ")) {
+    writeSuggestionsDirectly([
+      q,
+      [q + " normal", q + " tail 1", q + " tail 2"],
+      [],
+      {
+        "google:irrelevantparameter": [],
+        "google:suggestdetail": [
+          {},
+          { mp: "… ", t: "tail 1" },
+          { mp: "… ", t: "tail 2" },
+        ],
+      },
+    ]);
+  } else if (q && q.startsWith("richempty ")) {
+    writeSuggestionsDirectly([
+      q,
+      [q + " normal", q + " tail 1", q + " tail 2"],
+      [],
+      {
+        "google:irrelevantparameter": [],
+        "google:suggestdetail": [],
+      },
+    ]);
+  } else if (q && q.startsWith("letter ")) {
+    let letters = [];
+    for (
+      let charCode = "A".charCodeAt();
+      charCode <= "Z".charCodeAt();
+      charCode++
+    ) {
+      letters.push("letter " + String.fromCharCode(charCode));
+    }
+    writeSuggestions(q, letters);
+  } else if (q && q.startsWith("HTTP ")) {
+    response.setStatusLine(request.httpVersion, q.replace("HTTP ", ""), q);
+    writeSuggestions(q, [q]);
+  } else if (q && q.startsWith("delay")) {
+    // Delay the response by delayMs milliseconds. 200ms is the default, less
+    // than the timeout but hopefully enough to abort before completion.
+    let match = /^delay([0-9]+)/.exec(q);
+    let delayMs = match ? parseInt(match[1]) : 200;
+    response.processAsync();
+    writeSuggestions(q, [q]);
+    setTimeout(() => response.finish(), delayMs);
+  } else if (q && q.startsWith("slow ")) {
+    // Delay the response by 10 seconds so the client timeout is reached.
+    response.processAsync();
+    writeSuggestions(q, [q]);
+    setTimeout(() => response.finish(), 10000);
+  } else if (request.method == "POST") {
+    // This includes headers, not just the body
+    let requestText = NetUtil.readInputStreamToString(
+      request.bodyInputStream,
+      request.bodyInputStream.available()
+    );
+    // Only use the last line which contains the encoded params
+    let requestLines = requestText.split("\n");
+    let postParams = parseQueryString(requestLines[requestLines.length - 1]);
+    writeSuggestions(postParams.q, ["Mozilla", "modern", "mom"]);
+  } else {
+    response.setStatusLine(request.httpVersion, 404, "Not Found");
+  }
+}
+
+function parseQueryString(queryString) {
+  let query = {};
+  queryString.split("&").forEach(function (val) {
+    let [name, value] = val.split("=");
+    query[name] = decodeURIComponent(value).replace(/[+]/g, " ");
+  });
+  return query;
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/search_ignorelist.json b/toolkit/components/search/tests/xpcshell/data/search_ignorelist.json
new file mode 100644
index 0000000000..35240893ec
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/search_ignorelist.json
@@ -0,0 +1,51 @@
+{
+  "version": 1,
+  "buildID": "20121106",
+  "locale": "en-US",
+  "metaData": {},
+  "engines": [
+    {
+      "_name": "Test search engine",
+      "_shortName": "test-search-engine",
+      "description": "A test search engine (based on Google search)",
+      "extensionID": "test-addon-id@mozilla.org",
+      "__searchForm": "http://www.google.com/",
+      "_iconURL": "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAAAIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9FsfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2FPtft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2FggM%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJvvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYSBHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWcTxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4jwA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsggA7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFEMwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCTIYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesAAN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOcAAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      "_metaData": {},
+      "_urls": [
+        {
+          "template": "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox&hl={moz:locale}&q={searchTerms}",
+          "rels": [],
+          "type": "application/x-suggestions+json",
+          "params": []
+        },
+        {
+          "template": "http://www.google.com/search",
+          "resultDomain": "google.com",
+          "rels": [],
+          "params": [
+            {
+              "name": "q",
+              "value": "{searchTerms}"
+            },
+            {
+              "name": "ignore",
+              "value": "true"
+            },
+            {
+              "name": "channel",
+              "value": "fflb",
+              "purpose": "keyword"
+            },
+            {
+              "name": "channel",
+              "value": "rcs",
+              "purpose": "contextmenu"
+            }
+          ]
+        }
+      ],
+      "queryCharset": "UTF-8"
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data/svgIcon.svg b/toolkit/components/search/tests/xpcshell/data/svgIcon.svg
new file mode 100644
index 0000000000..e2550f8d5d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data/svgIcon.svg
@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     width="16" height="16" viewBox="0 0 16 16">
+  <rect x="4" y="4" width="8px" height="8px" style="fill: blue" />
+</svg>
diff --git a/toolkit/components/search/tests/xpcshell/data1/engine1/manifest.json b/toolkit/components/search/tests/xpcshell/data1/engine1/manifest.json
new file mode 100644
index 0000000000..5fa44ea692
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data1/engine1/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "engine1",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine1@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine1",
+      "search_url": "https://1.example.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data1/engine2/manifest.json b/toolkit/components/search/tests/xpcshell/data1/engine2/manifest.json
new file mode 100644
index 0000000000..7ab094198b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data1/engine2/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "engine2",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "engine2@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine2",
+      "search_url": "https://2.example.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data1/engines.json b/toolkit/components/search/tests/xpcshell/data1/engines.json
new file mode 100644
index 0000000000..05556ef87c
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data1/engines.json
@@ -0,0 +1,60 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "engine1@search.mozilla.org"
+      },
+      "orderHint": 10000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes-if-no-other",
+          "defaultPrivate": "yes-if-no-other"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "engine2@search.mozilla.org"
+      },
+      "orderHint": 7000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "no"
+        },
+        {
+          "included": { "everywhere": true },
+          "default": "yes",
+          "experiment": "exp1"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "exp2@search.mozilla.org"
+      },
+      "orderHint": 5000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "defaultPrivate": "yes",
+          "experiment": "exp2"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "exp3@search.mozilla.org"
+      },
+      "orderHint": 20000,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes",
+          "experiment": "exp3"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/data1/exp2/manifest.json b/toolkit/components/search/tests/xpcshell/data1/exp2/manifest.json
new file mode 100644
index 0000000000..0cd0e080b9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data1/exp2/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "exp2",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "exp2@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "exp2",
+      "search_url": "https://2.example.com/searchexp",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/data1/exp3/manifest.json b/toolkit/components/search/tests/xpcshell/data1/exp3/manifest.json
new file mode 100644
index 0000000000..4e023e0fef
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/data1/exp3/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "exp3",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "exp3@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "exp3",
+      "search_url": "https://3.example.com/searchexp",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/head_search.js b/toolkit/components/search/tests/xpcshell/head_search.js
new file mode 100644
index 0000000000..749fd2f4ad
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/head_search.js
@@ -0,0 +1,512 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  FileUtils: "resource://gre/modules/FileUtils.sys.mjs",
+  PromiseUtils: "resource://gre/modules/PromiseUtils.sys.mjs",
+  Region: "resource://gre/modules/Region.sys.mjs",
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+  RemoteSettingsClient:
+    "resource://services-settings/RemoteSettingsClient.sys.mjs",
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+  SearchService: "resource://gre/modules/SearchService.sys.mjs",
+  SearchSettings: "resource://gre/modules/SearchSettings.sys.mjs",
+  SearchTestUtils: "resource://testing-common/SearchTestUtils.sys.mjs",
+  SearchUtils: "resource://gre/modules/SearchUtils.sys.mjs",
+  TestUtils: "resource://testing-common/TestUtils.sys.mjs",
+  clearTimeout: "resource://gre/modules/Timer.sys.mjs",
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+var { HttpServer } = ChromeUtils.import("resource://testing-common/httpd.js");
+var { AddonTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/AddonTestUtils.sys.mjs"
+);
+const { ExtensionTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/ExtensionXPCShellUtils.sys.mjs"
+);
+
+SearchTestUtils.init(this);
+
+const SETTINGS_FILENAME = "search.json.mozlz4";
+
+// nsSearchService.js uses Services.appinfo.name to build a salt for a hash.
+// eslint-disable-next-line mozilla/use-services
+var XULRuntime = Cc["@mozilla.org/xre/runtime;1"].getService(Ci.nsIXULRuntime);
+
+// Expand the amount of information available in error logs
+Services.prefs.setBoolPref("browser.search.log", true);
+Services.prefs.setBoolPref("browser.region.log", true);
+
+AddonTestUtils.init(this, false);
+AddonTestUtils.createAppInfo(
+  "xpcshell@tests.mozilla.org",
+  "XPCShell",
+  "42",
+  "42"
+);
+
+// Allow telemetry probes which may otherwise be disabled for some applications (e.g. Thunderbird)
+Services.prefs.setBoolPref(
+  "toolkit.telemetry.testing.overrideProductsCheck",
+  true
+);
+
+// For tests, allow the settings to write sooner than it would do normally so that
+// the tests that need to wait for it can run a bit faster.
+SearchSettings.SETTNGS_INVALIDATION_DELAY = 250;
+
+async function promiseSettingsData() {
+  let path = PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME);
+  return IOUtils.readJSON(path, { decompress: true });
+}
+
+function promiseSaveSettingsData(data) {
+  return IOUtils.writeJSON(
+    PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME),
+    data,
+    { compress: true }
+  );
+}
+
+async function promiseEngineMetadata() {
+  let settings = await promiseSettingsData();
+  let data = {};
+  for (let engine of settings.engines) {
+    data[engine._name] = engine._metaData;
+  }
+  return data;
+}
+
+async function promiseGlobalMetadata() {
+  return (await promiseSettingsData()).metaData;
+}
+
+async function promiseSaveGlobalMetadata(globalData) {
+  let data = await promiseSettingsData();
+  data.metaData = globalData;
+  await promiseSaveSettingsData(data);
+}
+
+function promiseDefaultNotification(type = "normal") {
+  return SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE[
+      type == "private" ? "DEFAULT_PRIVATE" : "DEFAULT"
+    ],
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+}
+
+/**
+ * Clean the profile of any settings file left from a previous run.
+ *
+ * @returns {boolean}
+ *   Indicates if the settings file existed.
+ */
+function removeSettingsFile() {
+  let file = do_get_profile().clone();
+  file.append(SETTINGS_FILENAME);
+  if (file.exists()) {
+    file.remove(false);
+    return true;
+  }
+  return false;
+}
+
+/**
+ * isUSTimezone taken from nsSearchService.js
+ *
+ * @returns {boolean}
+ */
+function isUSTimezone() {
+  // Timezone assumptions! We assume that if the system clock's timezone is
+  // between Newfoundland and Hawaii, that the user is in North America.
+
+  // This includes all of South America as well, but we have relatively few
+  // en-US users there, so that's OK.
+
+  // 150 minutes = 2.5 hours (UTC-2.5), which is
+  // Newfoundland Daylight Time (http://www.timeanddate.com/time/zones/ndt)
+
+  // 600 minutes = 10 hours (UTC-10), which is
+  // Hawaii-Aleutian Standard Time (http://www.timeanddate.com/time/zones/hast)
+
+  let UTCOffset = new Date().getTimezoneOffset();
+  return UTCOffset >= 150 && UTCOffset <= 600;
+}
+
+const kTestEngineName = "Test search engine";
+
+/**
+ * Waits for the settings file to be saved.
+ *
+ * @returns {Promise} Resolved when the settings file is saved.
+ */
+function promiseAfterSettings() {
+  return SearchTestUtils.promiseSearchNotification(
+    "write-settings-to-disk-complete"
+  );
+}
+
+/**
+ * Sets the home region, and waits for the search service to reload the engines.
+ *
+ * @param {string} region
+ *   The region to set.
+ */
+async function promiseSetHomeRegion(region) {
+  let promise = SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Region._setHomeRegion(region);
+  await promise;
+}
+
+/**
+ * Sets the requested/available locales and waits for the search service to
+ * reload the engines.
+ *
+ * @param {string} locale
+ *   The locale to set.
+ */
+async function promiseSetLocale(locale) {
+  if (!Services.locale.availableLocales.includes(locale)) {
+    throw new Error(
+      `"${locale}" needs to be included in Services.locales.availableLocales at the start of the test.`
+    );
+  }
+
+  let promise = SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Services.locale.requestedLocales = [locale];
+  await promise;
+}
+
+/**
+ * Read a JSON file and return the JS object
+ *
+ * @param {nsIFile} file
+ *   The file to read.
+ * @returns {object}
+ *   Returns the JSON object if the file was successfully read,
+ *   false otherwise.
+ */
+async function readJSONFile(file) {
+  return JSON.parse(await IOUtils.readUTF8(file.path));
+}
+
+/**
+ * Recursively compare two objects and check that every property of expectedObj has the same value
+ * on actualObj.
+ *
+ * @param {object} expectedObj
+ *   The source object that we expect to match
+ * @param {object} actualObj
+ *   The object to check against the source
+ * @param {Function} skipProp
+ *   A function that is called with the property name and its value, to see if
+ *   testing that property should be skipped or not.
+ */
+function isSubObjectOf(expectedObj, actualObj, skipProp) {
+  for (let prop in expectedObj) {
+    if (skipProp && skipProp(prop, expectedObj[prop])) {
+      continue;
+    }
+    if (expectedObj[prop] instanceof Object) {
+      Assert.equal(
+        actualObj[prop]?.length,
+        expectedObj[prop].length,
+        `Should have the correct length for property ${prop}`
+      );
+      isSubObjectOf(expectedObj[prop], actualObj[prop], skipProp);
+    } else {
+      Assert.equal(
+        actualObj[prop],
+        expectedObj[prop],
+        `Should have the correct value for property ${prop}`
+      );
+    }
+  }
+}
+
+/**
+ * After useHttpServer() is called, this string contains the URL of the "data"
+ * directory, including the final slash.
+ */
+var gDataUrl;
+
+/**
+ * Initializes the HTTP server and ensures that it is terminated when tests end.
+ *
+ * @param {string} dir
+ *   The test sub-directory to use for the engines.
+ * @returns {HttpServer}
+ *   The HttpServer object in case further customization is needed.
+ */
+function useHttpServer(dir = "data") {
+  let httpServer = new HttpServer();
+  httpServer.start(-1);
+  httpServer.registerDirectory("/", do_get_cwd());
+  gDataUrl = `http://localhost:${httpServer.identity.primaryPort}/${dir}/`;
+  registerCleanupFunction(async function cleanup_httpServer() {
+    await new Promise(resolve => {
+      httpServer.stop(resolve);
+    });
+  });
+  return httpServer;
+}
+
+// This "enum" from nsSearchService.js
+const TELEMETRY_RESULT_ENUM = {
+  SUCCESS: 0,
+  SUCCESS_WITHOUT_DATA: 1,
+  TIMEOUT: 2,
+  ERROR: 3,
+};
+
+/**
+ * Checks the value of the SEARCH_SERVICE_COUNTRY_FETCH_RESULT probe.
+ *
+ * @param {string|null} aExpectedValue
+ *   If a value from TELEMETRY_RESULT_ENUM, we expect to see this value
+ *   recorded exactly once in the probe.  If |null|, we expect to see
+ *   nothing recorded in the probe at all.
+ */
+function checkCountryResultTelemetry(aExpectedValue) {
+  let histogram = Services.telemetry.getHistogramById(
+    "SEARCH_SERVICE_COUNTRY_FETCH_RESULT"
+  );
+  let snapshot = histogram.snapshot();
+  if (aExpectedValue != null) {
+    equal(snapshot.values[aExpectedValue], 1);
+  } else {
+    deepEqual(snapshot.values, {});
+  }
+}
+
+/**
+ * Provides a basic set of remote settings for use in tests.
+ */
+async function setupRemoteSettings() {
+  const settings = await RemoteSettings("hijack-blocklists");
+  sinon.stub(settings, "get").returns([
+    {
+      id: "load-paths",
+      matches: ["[addon]searchignore@mozilla.com"],
+      _status: "synced",
+    },
+    {
+      id: "submission-urls",
+      matches: ["ignore=true"],
+      _status: "synced",
+    },
+  ]);
+}
+
+/**
+ * Helper function that sets up a server and respnds to region
+ * fetch requests.
+ *
+ * @param {string} region
+ *   The region that the server will respond with.
+ * @param {Promise|null} waitToRespond
+ *   A promise that the server will await on to delay responding
+ *   to the request.
+ */
+function useCustomGeoServer(region, waitToRespond = Promise.resolve()) {
+  let srv = useHttpServer();
+  srv.registerPathHandler("/fetch_region", async (req, res) => {
+    res.processAsync();
+    await waitToRespond;
+    res.setStatusLine("1.1", 200, "OK");
+    res.write(JSON.stringify({ country_code: region }));
+    res.finish();
+  });
+
+  Services.prefs.setCharPref(
+    "browser.region.network.url",
+    `http://localhost:${srv.identity.primaryPort}/fetch_region`
+  );
+}
+
+/**
+ * @typedef {object} TelemetryDetails
+ * @property {string} engineId
+ *   The telemetry ID for the search engine.
+ * @property {string} [displayName]
+ *   The search engine's display name.
+ * @property {string} [loadPath]
+ *   The load path for the search engine.
+ * @property {string} [submissionUrl]
+ *   The submission URL for the search engine.
+ * @property {string} [verified]
+ *   Whether the search engine is verified.
+ */
+
+/**
+ * Asserts that default search engine telemetry has been correctly reported
+ * to Glean.
+ *
+ * @param {object} expected
+ *   An object containing telemetry details for normal and private engines.
+ * @param {TelemetryDetails} expected.normal
+ *   An object with the expected details for the normal search engine.
+ * @param {TelemetryDetails} [expected.private]
+ *   An object with the expected details for the private search engine.
+ */
+async function assertGleanDefaultEngine(expected) {
+  await TestUtils.waitForCondition(
+    () =>
+      Glean.searchEngineDefault.engineId.testGetValue() ==
+      (expected.normal.engineId ?? ""),
+    "Should have set the correct telemetry id for the normal engine"
+  );
+
+  await TestUtils.waitForCondition(
+    () =>
+      Glean.searchEnginePrivate.engineId.testGetValue() ==
+      (expected.private?.engineId ?? ""),
+    "Should have set the correct telemetry id for the private engine"
+  );
+
+  for (let property of [
+    "displayName",
+    "loadPath",
+    "submissionUrl",
+    "verified",
+  ]) {
+    if (property in expected.normal) {
+      Assert.equal(
+        Glean.searchEngineDefault[property].testGetValue(),
+        expected.normal[property] ?? "",
+        `Should have set ${property} correctly`
+      );
+    }
+    if (expected.private && property in expected.private) {
+      Assert.equal(
+        Glean.searchEnginePrivate[property].testGetValue(),
+        expected.private[property] ?? "",
+        `Should have set ${property} correctly`
+      );
+    }
+  }
+}
+
+/**
+ * A simple observer to ensure we get only the expected notifications.
+ */
+class SearchObserver {
+  constructor(expectedNotifications, returnEngineForNotification = false) {
+    this.observer = this.observer.bind(this);
+    this.deferred = PromiseUtils.defer();
+    this.expectedNotifications = expectedNotifications;
+    this.returnEngineForNotification = returnEngineForNotification;
+
+    Services.obs.addObserver(this.observer, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+    this.timeout = setTimeout(this.handleTimeout.bind(this), 1000);
+  }
+
+  get promise() {
+    return this.deferred.promise;
+  }
+
+  handleTimeout() {
+    this.deferred.reject(
+      new Error(
+        "Waiting for Notifications timed out, only received: " +
+          this.expectedNotifications.join(",")
+      )
+    );
+  }
+
+  observer(subject, topic, data) {
+    Assert.greater(
+      this.expectedNotifications.length,
+      0,
+      "Should be expecting a notification"
+    );
+    Assert.equal(
+      data,
+      this.expectedNotifications[0],
+      "Should have received the next expected notification"
+    );
+
+    if (
+      this.returnEngineForNotification &&
+      data == this.returnEngineForNotification
+    ) {
+      this.engineToReturn = subject.QueryInterface(Ci.nsISearchEngine);
+    }
+
+    this.expectedNotifications.shift();
+
+    if (!this.expectedNotifications.length) {
+      clearTimeout(this.timeout);
+      delete this.timeout;
+      this.deferred.resolve(this.engineToReturn);
+      Services.obs.removeObserver(
+        this.observer,
+        SearchUtils.TOPIC_ENGINE_MODIFIED
+      );
+    }
+  }
+}
+
+/**
+ * Some tests might trigger initialisation which will trigger the search settings
+ * update. We need to make sure we wait for that to finish before we exit, otherwise
+ * it may cause shutdown issues.
+ */
+let updatePromise = SearchTestUtils.promiseSearchNotification(
+  "settings-update-complete"
+);
+
+registerCleanupFunction(async () => {
+  if (Services.search.isInitialized) {
+    await updatePromise;
+  }
+});
+
+let consoleAllowList = [
+  // Harness issues.
+  'property "localProfileDir" is non-configurable and can\'t be deleted',
+  'property "profileDir" is non-configurable and can\'t be deleted',
+  // These can be emitted by `resource://services-settings/Utils.jsm` when
+  // remote settings is fetched (e.g. via IgnoreLists).
+  "NetworkError: Network request failed",
+  // Also remote settings, see bug 1812040.
+  "Unexpected content-type",
+];
+
+let endConsoleListening = TestUtils.listenForConsoleMessages();
+
+registerCleanupFunction(async () => {
+  let msgs = await endConsoleListening();
+  for (let msg of msgs) {
+    msg = msg.wrappedJSObject;
+    if (msg.level != "error") {
+      continue;
+    }
+
+    if (!msg.arguments?.length) {
+      Assert.ok(
+        false,
+        "Unexpected console message received during test: " + msg
+      );
+    } else {
+      let firstArg = msg.arguments[0];
+      // Use the appropriate message depending on the object supplied to
+      // the first argument.
+      let message = firstArg.messageContents ?? firstArg.message ?? firstArg;
+      if (!consoleAllowList.some(e => message.includes(e))) {
+        Assert.ok(
+          false,
+          "Unexpected console message received during test: " + message
+        );
+      }
+    }
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/method-extensions/engines.json b/toolkit/components/search/tests/xpcshell/method-extensions/engines.json
new file mode 100644
index 0000000000..4c0a009f37
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/method-extensions/engines.json
@@ -0,0 +1,45 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "get@search.mozilla.org"
+      },
+      "params": {
+        "searchUrlGetParams": [
+          { "name": "config", "value": "1" },
+          { "name": "search", "value": "{searchTerms}" }
+        ],
+        "suggestUrlGetParams": [
+          { "name": "config", "value": "1" },
+          { "name": "suggest", "value": "{searchTerms}" }
+        ]
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "post@search.mozilla.org"
+      },
+      "params": {
+        "searchUrlPostParams": [
+          { "name": "config", "value": "1" },
+          { "name": "search", "value": "{searchTerms}" }
+        ],
+        "suggestUrlPostParams": [
+          { "name": "config", "value": "1" },
+          { "name": "suggest", "value": "{searchTerms}" }
+        ]
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true }
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/method-extensions/get/manifest.json b/toolkit/components/search/tests/xpcshell/method-extensions/get/manifest.json
new file mode 100644
index 0000000000..a85cdaaa0f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/method-extensions/get/manifest.json
@@ -0,0 +1,21 @@
+{
+  "name": "Get Engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "description": "Get engine to test get params",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "get@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Get Engine",
+      "search_url": "https://example.com",
+      "search_url_get_params": "webExtension=1&search={searchTerms}",
+      "suggest_url": "https://example.com",
+      "suggest_url_get_params": "webExtension=1&suggest={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/method-extensions/post/manifest.json b/toolkit/components/search/tests/xpcshell/method-extensions/post/manifest.json
new file mode 100644
index 0000000000..dce9bfb512
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/method-extensions/post/manifest.json
@@ -0,0 +1,21 @@
+{
+  "name": "Post Engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "description": "Get engine to test ost params",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "post@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Post Engine",
+      "search_url": "https://example.com",
+      "search_url_post_params": "webExtension=1&search={searchTerms}",
+      "suggest_url": "https://example.com",
+      "suggest_url_post_params": "webExtension=1&suggest={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/chromeicon.xml b/toolkit/components/search/tests/xpcshell/opensearch/chromeicon.xml
new file mode 100644
index 0000000000..856732c6d6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/chromeicon.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
+<ShortName>engine-chromeicon</ShortName>
+<Image width="16" height="16">chrome://branding/content/icon16.png</Image>
+<Image width="32" height="32">chrome://branding/content/icon32.png</Image>
+<Url type="text/html" method="GET" template="http://www.google.com/search">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+</SearchPlugin>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated1.xml b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated1.xml
new file mode 100644
index 0000000000..3131c25f37
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated1.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ii1</ShortName>
+<Description>Insecure and insecurely updated 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://example.com/ii1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="http://example.com/ii1.xml" />
+<SearchForm>http://example.com/ii1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated2.xml b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated2.xml
new file mode 100644
index 0000000000..a3c850d4d9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-insecurely-updated2.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ii2</ShortName>
+<Description>Insecure and insecurely updated 2</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://example.com/ii2">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="http://example.com/ii2.xml" />
+<SearchForm>http://example.com/ii2</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-no-update-url1.xml b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-no-update-url1.xml
new file mode 100644
index 0000000000..75a5da8e7f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-no-update-url1.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>inu1</ShortName>
+<Description>Insecure and no update URL 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://example.com/inu1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>http://example.com/inu1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-securely-updated1.xml b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-securely-updated1.xml
new file mode 100644
index 0000000000..9427747722
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/insecure-and-securely-updated1.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>is1</ShortName>
+<Description>Insecure and securely updated 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://example.com/is1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="https://example.com/is1.xml" />
+<SearchForm>http://example.com/is1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/invalid.xml b/toolkit/components/search/tests/xpcshell/opensearch/invalid.xml
new file mode 100644
index 0000000000..e8efce6726
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/invalid.xml
@@ -0,0 +1 @@
+# An invalid xml engine file.
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/mozilla-ns.xml b/toolkit/components/search/tests/xpcshell/opensearch/mozilla-ns.xml
new file mode 100644
index 0000000000..f185f94868
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/mozilla-ns.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
+<ShortName>mozilla-ns</ShortName>
+<Description>An engine using mozilla namespace</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/search">
+  <Param name="q" value="{searchTerms}"/>
+  <MozParam name="channel" condition="purpose" purpose="searchbar" value="test"/>
+</Url>
+<SearchForm>https://example.com/</SearchForm>
+</SearchPlugin>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/post.xml b/toolkit/components/search/tests/xpcshell/opensearch/post.xml
new file mode 100644
index 0000000000..621e49c872
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/post.xml
@@ -0,0 +1,8 @@
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
+  <ShortName>Post</ShortName>
+  <Url type="text/html" method="POST" template="https://example.com/post">
+    <Param name="searchterms" value="{searchTerms}"/>
+  </Url>
+  <Url type="text/html" method="POST" template="http://engine-rel-searchform-post.xml/POST" rel="searchform"/>
+  <SearchForm>http://engine-rel-searchform-post.xml/?search</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/resourceicon.xml b/toolkit/components/search/tests/xpcshell/opensearch/resourceicon.xml
new file mode 100644
index 0000000000..32861c34ea
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/resourceicon.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
+<ShortName>engine-resourceicon</ShortName>
+<Image width="16" height="16">resource://search-extensions/icon16.png</Image>
+<Image width="32" height="32">resource://search-extensions/icon32.png</Image>
+<Url type="text/html" method="GET" template="http://www.google.com/search">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+</SearchPlugin>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated1.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated1.xml
new file mode 100644
index 0000000000..d8a62d0e18
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated1.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>si1</ShortName>
+<Description>Secure and insecurely updated 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/si1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="http://example.com/si1.xml" />
+<SearchForm>https://example.com/si1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated2.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated2.xml
new file mode 100644
index 0000000000..f707e5eb3d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-insecurely-updated2.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>si2</ShortName>
+<Description>Secure and insecurely updated 2</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/si2">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="http://example.com/si2.xml" />
+<SearchForm>https://example.com/si2</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-no-update-url1.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-no-update-url1.xml
new file mode 100644
index 0000000000..6dcbbb126c
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-no-update-url1.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>snu1</ShortName>
+<Description>Secure and no update URL 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/snu1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>https://example.com/snu1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated-insecure-form.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated-insecure-form.xml
new file mode 100644
index 0000000000..15a0b6a517
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated-insecure-form.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ssif</ShortName>
+<Description>Secure and securely updated insecure form</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/ssif">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="https://example.com/ssif.xml" />
+<SearchForm>http://example.com/ssif</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated1.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated1.xml
new file mode 100644
index 0000000000..593c8bec8c
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated1.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ss1</ShortName>
+<Description>Secure and securely updated 1</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/ss1">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="https://example.com/ss1.xml" />
+<SearchForm>https://example.com/ss1</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated2.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated2.xml
new file mode 100644
index 0000000000..30a20b754a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated2.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ss2</ShortName>
+<Description>Secure and securely updated 2</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/ss2">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="https://example.com/ss2.xml" />
+<SearchForm>https://example.com/ss2</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated3.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated3.xml
new file mode 100644
index 0000000000..8b86a82199
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-and-securely-updated3.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>ss3</ShortName>
+<Description>Secure and securely updated 3</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/ss3">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/opensearchdescription+xml"
+     rel="self"
+     template="https://example.com/ss3.xml" />
+<SearchForm>https://example.com/ss3</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-localhost.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-localhost.xml
new file mode 100644
index 0000000000..89d96f2c43
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-localhost.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>sl</ShortName>
+<Description>Secure localhost</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://localhost:8080">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>http://localhost:8080/sl</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv2.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv2.xml
new file mode 100644
index 0000000000..8da3995a71
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv2.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>sov2</ShortName>
+<Description>Secure onion v2</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://s3zkf3ortukqklec.onion">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>http://s3zkf3ortukqklec.onion/sov2</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv3.xml b/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv3.xml
new file mode 100644
index 0000000000..c8256ca28a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/secure-onionv3.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>sov3</ShortName>
+<Description>Secure onion v3</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="http://ydemw5wg5cseltau22u4fjfrmfshopaldpoznsirb3rgo2gv6uh4s2y5.onion">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>http://ydemw5wg5cseltau22u4fjfrmfshopaldpoznsirb3rgo2gv6uh4s2y5.onion/sov3</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/simple.xml b/toolkit/components/search/tests/xpcshell/opensearch/simple.xml
new file mode 100644
index 0000000000..ee38e51bca
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/simple.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.0/">
+<ShortName>simple</ShortName>
+<Description>A small test engine</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/search">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<SearchForm>https://example.com/</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/suggestion-alternate.xml b/toolkit/components/search/tests/xpcshell/opensearch/suggestion-alternate.xml
new file mode 100644
index 0000000000..7a961520b9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/suggestion-alternate.xml
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearchdescription/1.1/">
+<ShortName>suggestion-alternate</ShortName>
+<Description>A small engine with suggestions</Description>
+<InputEncoding>UTF-8</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/search">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/json" rel="suggestions" method="GET"
+     template="https://example.com/suggest">
+  <Param name="suggestion" value="{searchTerms}"/>
+</Url>
+
+<SearchForm>https://example.com/</SearchForm>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/opensearch/suggestion.xml b/toolkit/components/search/tests/xpcshell/opensearch/suggestion.xml
new file mode 100644
index 0000000000..8d2f701a36
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/opensearch/suggestion.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearchdescription/1.0/">
+<ShortName>suggestion</ShortName>
+<Description>A small engine with suggestions</Description>
+<InputEncoding>windows-1252</InputEncoding>
+<Image width="16" height="16">data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC</Image>
+<Url type="text/html" method="GET" template="https://example.com/search">
+  <Param name="q" value="{searchTerms}"/>
+</Url>
+<Url type="application/x-suggestions+json" method="GET"
+     template="https://example.com/suggest">
+  <Param name="suggestion" value="{searchTerms}"/>
+</Url>
+<Url type="text/html" method="GET" template="http://engine-rel-searchform.xml/?search" rel="searchform"/>
+</OpenSearchDescription>
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/head_searchconfig.js b/toolkit/components/search/tests/xpcshell/searchconfigs/head_searchconfig.js
new file mode 100644
index 0000000000..87ade57a51
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/head_searchconfig.js
@@ -0,0 +1,614 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+
+ChromeUtils.defineESModuleGetters(this, {
+  AddonManager: "resource://gre/modules/AddonManager.sys.mjs",
+  AddonTestUtils: "resource://testing-common/AddonTestUtils.sys.mjs",
+  Region: "resource://gre/modules/Region.sys.mjs",
+  RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
+  SearchEngine: "resource://gre/modules/SearchEngine.sys.mjs",
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+  SearchTestUtils: "resource://testing-common/SearchTestUtils.sys.mjs",
+  SearchUtils: "resource://gre/modules/SearchUtils.sys.mjs",
+  sinon: "resource://testing-common/Sinon.sys.mjs",
+});
+
+XPCOMUtils.defineLazyModuleGetters(this, {
+  ObjectUtils: "resource://gre/modules/ObjectUtils.jsm",
+});
+
+XPCOMUtils.defineLazyGlobalGetters(this, ["fetch"]);
+
+const GLOBAL_SCOPE = this;
+const TEST_DEBUG = Services.env.get("TEST_DEBUG");
+
+const URLTYPE_SUGGEST_JSON = "application/x-suggestions+json";
+const URLTYPE_SEARCH_HTML = "text/html";
+const SUBMISSION_PURPOSES = [
+  "searchbar",
+  "keyword",
+  "contextmenu",
+  "homepage",
+  "newtab",
+];
+
+let engineSelector;
+
+/**
+ * This function is used to override the remote settings configuration
+ * if the SEARCH_CONFIG environment variable is set. This allows testing
+ * against a remote server.
+ */
+async function maybeSetupConfig() {
+  const SEARCH_CONFIG = Services.env.get("SEARCH_CONFIG");
+  if (SEARCH_CONFIG) {
+    if (!(SEARCH_CONFIG in SearchUtils.ENGINES_URLS)) {
+      throw new Error(`Invalid value for SEARCH_CONFIG`);
+    }
+    const url = SearchUtils.ENGINES_URLS[SEARCH_CONFIG];
+    const response = await fetch(url);
+    const config = await response.json();
+    const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+    sinon.stub(settings, "get").returns(config.data);
+  }
+}
+
+/**
+ * This class implements the test harness for search configuration tests.
+ * These tests are designed to ensure that the correct search engines are
+ * loaded for the various region/locale configurations.
+ *
+ * The configuration for each test is represented by an object having the
+ * following properties:
+ *
+ * - identifier (string)
+ *   The identifier for the search engine under test.
+ * - default (object)
+ *   An inclusion/exclusion configuration (see below) to detail when this engine
+ *   should be listed as default.
+ *
+ * The inclusion/exclusion configuration is represented as an object having the
+ * following properties:
+ *
+ * - included (array)
+ *   An optional array of region/locale pairs.
+ * - excluded (array)
+ *   An optional array of region/locale pairs.
+ *
+ * If the object is empty, the engine is assumed not to be part of any locale/region
+ * pair.
+ * If the object has `excluded` but not `included`, then the engine is assumed to
+ * be part of every locale/region pair except for where it matches the exclusions.
+ *
+ * The region/locale pairs are represented as an object having the following
+ * properties:
+ *
+ * - region (array)
+ *   An array of two-letter region codes.
+ * - locale (object)
+ *   A locale object which may consist of:
+ *   - matches (array)
+ *     An array of locale strings which should exactly match the locale.
+ *   - startsWith (array)
+ *     An array of locale strings which the locale should start with.
+ */
+class SearchConfigTest {
+  /**
+   * @param {object} config
+   *   The initial configuration for this test, see above.
+   */
+  constructor(config = {}) {
+    this._config = config;
+  }
+
+  /**
+   * Sets up the test.
+   *
+   * @param {string} [version]
+   *   The version to simulate for running the tests.
+   */
+  async setup(version = "42.0") {
+    AddonTestUtils.init(GLOBAL_SCOPE);
+    AddonTestUtils.createAppInfo(
+      "xpcshell@tests.mozilla.org",
+      "XPCShell",
+      version,
+      version
+    );
+
+    await maybeSetupConfig();
+
+    // Disable region checks.
+    Services.prefs.setBoolPref("browser.search.geoSpecificDefaults", false);
+
+    // Enable separatePrivateDefault testing. We test with this on, as we have
+    // separate tests for ensuring the normal = private when this is off.
+    Services.prefs.setBoolPref(
+      SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+      true
+    );
+    Services.prefs.setBoolPref(
+      SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+      true
+    );
+
+    await AddonTestUtils.promiseStartupManager();
+    await Services.search.init();
+
+    // We must use the engine selector that the search service has created (if
+    // it has), as remote settings can only easily deal with us loading the
+    // configuration once - after that, it tries to access the network.
+    engineSelector =
+      Services.search.wrappedJSObject._engineSelector ||
+      new SearchEngineSelector();
+
+    // Note: we don't use the helper function here, so that we have at least
+    // one message output per process.
+    Assert.ok(
+      Services.search.isInitialized,
+      "Should have correctly initialized the search service"
+    );
+  }
+
+  /**
+   * Runs the test.
+   */
+  async run() {
+    const locales = await this._getLocales();
+    const regions = this._regions;
+
+    // We loop on region and then locale, so that we always cause a re-init
+    // when updating the requested/available locales.
+    for (let region of regions) {
+      for (let locale of locales) {
+        const engines = await this._getEngines(region, locale);
+        this._assertEngineRules([engines[0]], region, locale, "default");
+        const isPresent = this._assertAvailableEngines(region, locale, engines);
+        if (isPresent) {
+          this._assertEngineDetails(region, locale, engines);
+        }
+      }
+    }
+  }
+
+  async _getEngines(region, locale) {
+    let engines = [];
+    let configs = await engineSelector.fetchEngineConfiguration({
+      locale,
+      region: region || "default",
+      channel: SearchUtils.MODIFIED_APP_CHANNEL,
+    });
+    for (let config of configs.engines) {
+      let engine = await Services.search.wrappedJSObject._makeEngineFromConfig(
+        config
+      );
+      engines.push(engine);
+    }
+    return engines;
+  }
+
+  /**
+   * @returns {Set} the list of regions for the tests to run with.
+   */
+  get _regions() {
+    // TODO: The legacy configuration worked with null as an unknown region,
+    // for the search engine selector, we expect "default" but apply the
+    // fallback in _getEngines. Once we remove the legacy configuration, we can
+    // simplify this.
+    if (TEST_DEBUG) {
+      return new Set(["by", "cn", "kz", "us", "ru", "tr", null]);
+    }
+    return [...Services.intl.getAvailableLocaleDisplayNames("region"), null];
+  }
+
+  /**
+   * @returns {Array} the list of locales for the tests to run with.
+   */
+  async _getLocales() {
+    if (TEST_DEBUG) {
+      return ["be", "en-US", "kk", "tr", "ru", "zh-CN", "ach", "unknown"];
+    }
+    const data = await IOUtils.readUTF8(do_get_file("all-locales").path);
+    // "en-US" is not in all-locales as it is the default locale
+    // add it manually to ensure it is tested.
+    let locales = [...data.split("\n").filter(e => e != ""), "en-US"];
+    // BCP47 requires all variants are 5-8 characters long. Our
+    // build sytem uses the short `mac` variant, this is invalid, and inside
+    // the app we turn it into `ja-JP-macos`
+    locales = locales.map(l => (l == "ja-JP-mac" ? "ja-JP-macos" : l));
+    // The locale sometimes can be unknown or a strange name, e.g. if the updater
+    // is disabled, it may be "und", add one here so we know what happens if we
+    // hit it.
+    locales.push("unknown");
+    return locales;
+  }
+
+  /**
+   * Determines if a locale matches with a locales section in the configuration.
+   *
+   * @param {object} locales
+   *   The config locales config, containing the locals to match against.
+   * @param {Array} [locales.matches]
+   *   Array of locale names to match exactly.
+   * @param {Array} [locales.startsWith]
+   *   Array of locale names to match the start.
+   * @param {string} locale
+   *   The two-letter locale code.
+   * @returns {boolean}
+   *   True if the locale matches.
+   */
+  _localeIncludes(locales, locale) {
+    if ("matches" in locales && locales.matches.includes(locale)) {
+      return true;
+    }
+    if ("startsWith" in locales) {
+      return !!locales.startsWith.find(element => locale.startsWith(element));
+    }
+
+    return false;
+  }
+
+  /**
+   * Determines if a locale/region pair match a section of the configuration.
+   *
+   * @param {object} section
+   *   The configuration section to match against.
+   * @param {string} region
+   *   The two-letter region code.
+   * @param {string} locale
+   *   The two-letter locale code.
+   * @returns {boolean}
+   *   True if the locale/region pair matches the section.
+   */
+  _localeRegionInSection(section, region, locale) {
+    for (const { regions, locales } of section) {
+      // If we only specify a regions or locales section then
+      // it is always considered included in the other section.
+      const inRegions = !regions || regions.includes(region);
+      const inLocales = !locales || this._localeIncludes(locales, locale);
+      if (inRegions && inLocales) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Helper function to find an engine from within a list.
+   *
+   * @param {Array} engines
+   *   The list of engines to check.
+   * @param {string} identifier
+   *   The identifier to look for in the list.
+   * @param {boolean} exactMatch
+   *   Whether to use an exactMatch for the identifier.
+   * @returns {Engine}
+   *   Returns the engine if found, null otherwise.
+   */
+  _findEngine(engines, identifier, exactMatch) {
+    return engines.find(engine =>
+      exactMatch
+        ? engine.identifier == identifier
+        : engine.identifier.startsWith(identifier)
+    );
+  }
+
+  /**
+   * Asserts whether the engines rules defined in the configuration are met.
+   *
+   * @param {Array} engines
+   *   The list of engines to check.
+   * @param {string} region
+   *   The two-letter region code.
+   * @param {string} locale
+   *   The two-letter locale code.
+   * @param {string} section
+   *   The section of the configuration to check.
+   * @returns {boolean}
+   *   Returns true if the engine is expected to be present, false otherwise.
+   */
+  _assertEngineRules(engines, region, locale, section) {
+    const infoString = `region: "${region}" locale: "${locale}"`;
+    const config = this._config[section];
+    const hasIncluded = "included" in config;
+    const hasExcluded = "excluded" in config;
+    const identifierIncluded = !!this._findEngine(
+      engines,
+      this._config.identifier,
+      this._config.identifierExactMatch ?? false
+    );
+
+    // If there's not included/excluded, then this shouldn't be the default anywhere.
+    if (section == "default" && !hasIncluded && !hasExcluded) {
+      this.assertOk(
+        !identifierIncluded,
+        `Should not be ${section} for any locale/region,
+         currently set for ${infoString}`
+      );
+      return false;
+    }
+
+    // If there's no included section, we assume the engine is default everywhere
+    // and we should apply the exclusions instead.
+    let included =
+      hasIncluded &&
+      this._localeRegionInSection(config.included, region, locale);
+
+    let excluded =
+      hasExcluded &&
+      this._localeRegionInSection(config.excluded, region, locale);
+    if (
+      (included && (!hasExcluded || !excluded)) ||
+      (!hasIncluded && hasExcluded && !excluded)
+    ) {
+      this.assertOk(
+        identifierIncluded,
+        `Should be ${section} for ${infoString}`
+      );
+      return true;
+    }
+    this.assertOk(
+      !identifierIncluded,
+      `Should not be ${section} for ${infoString}`
+    );
+    return false;
+  }
+
+  /**
+   * Asserts whether the engine is correctly set as default or not.
+   *
+   * @param {string} region
+   *   The two-letter region code.
+   * @param {string} locale
+   *   The two-letter locale code.
+   */
+  _assertDefaultEngines(region, locale) {
+    this._assertEngineRules(
+      [Services.search.appDefaultEngine],
+      region,
+      locale,
+      "default"
+    );
+    // At the moment, this uses the same section as the normal default, as
+    // we don't set this differently for any region/locale.
+    this._assertEngineRules(
+      [Services.search.appPrivateDefaultEngine],
+      region,
+      locale,
+      "default"
+    );
+  }
+
+  /**
+   * Asserts whether the engine is correctly available or not.
+   *
+   * @param {string} region
+   *   The two-letter region code.
+   * @param {string} locale
+   *   The two-letter locale code.
+   * @param {Array} engines
+   *   The current visible engines.
+   * @returns {boolean}
+   *   Returns true if the engine is expected to be present, false otherwise.
+   */
+  _assertAvailableEngines(region, locale, engines) {
+    return this._assertEngineRules(engines, region, locale, "available");
+  }
+
+  /**
+   * Asserts the engine follows various rules.
+   *
+   * @param {string} region
+   *   The two-letter region code.
+   * @param {string} locale
+   *   The two-letter locale code.
+   * @param {Array} engines
+   *   The current visible engines.
+   */
+  _assertEngineDetails(region, locale, engines) {
+    const details = this._config.details.filter(value => {
+      const included = this._localeRegionInSection(
+        value.included,
+        region,
+        locale
+      );
+      const excluded =
+        value.excluded &&
+        this._localeRegionInSection(value.excluded, region, locale);
+      return included && !excluded;
+    });
+    this.assertEqual(
+      details.length,
+      1,
+      `Should have just one details section for region: ${region} locale: ${locale}`
+    );
+
+    const engine = this._findEngine(
+      engines,
+      this._config.identifier,
+      this._config.identifierExactMatch ?? false
+    );
+    this.assertOk(engine, "Should have an engine present");
+
+    if (this._config.aliases) {
+      this.assertDeepEqual(
+        engine.aliases,
+        this._config.aliases,
+        "Should have the correct aliases for the engine"
+      );
+    }
+
+    const location = `in region:${region}, locale:${locale}`;
+
+    for (const rule of details) {
+      this._assertCorrectDomains(location, engine, rule);
+      if (rule.codes) {
+        this._assertCorrectCodes(location, engine, rule);
+      }
+      if (rule.searchUrlCode || rule.suggestUrlCode) {
+        this._assertCorrectUrlCode(location, engine, rule);
+      }
+      if (rule.aliases) {
+        this.assertDeepEqual(
+          engine.aliases,
+          rule.aliases,
+          "Should have the correct aliases for the engine"
+        );
+      }
+      if (rule.telemetryId) {
+        this.assertEqual(
+          engine.telemetryId,
+          rule.telemetryId,
+          `Should have the correct telemetryId ${location}.`
+        );
+      }
+    }
+  }
+
+  /**
+   * Asserts whether the engine is using the correct domains or not.
+   *
+   * @param {string} location
+   *   Debug string with locale + region information.
+   * @param {object} engine
+   *   The engine being tested.
+   * @param {object} rules
+   *   Rules to test.
+   */
+  _assertCorrectDomains(location, engine, rules) {
+    this.assertOk(
+      rules.domain,
+      `Should have an expectedDomain for the engine ${location}`
+    );
+
+    const searchForm = new URL(engine.searchForm);
+    this.assertOk(
+      searchForm.host.endsWith(rules.domain),
+      `Should have the correct search form domain ${location}.
+       Got "${searchForm.host}", expected to end with "${rules.domain}".`
+    );
+
+    let submission = engine.getSubmission("test", URLTYPE_SEARCH_HTML);
+
+    this.assertOk(
+      submission.uri.host.endsWith(rules.domain),
+      `Should have the correct domain for type: ${URLTYPE_SEARCH_HTML} ${location}.
+       Got "${submission.uri.host}", expected to end with "${rules.domain}".`
+    );
+
+    submission = engine.getSubmission("test", URLTYPE_SUGGEST_JSON);
+    if (this._config.noSuggestionsURL || rules.noSuggestionsURL) {
+      this.assertOk(!submission, "Should not have a submission url");
+    } else if (this._config.suggestionUrlBase) {
+      this.assertEqual(
+        submission.uri.prePath + submission.uri.filePath,
+        this._config.suggestionUrlBase,
+        `Should have the correct domain for type: ${URLTYPE_SUGGEST_JSON} ${location}.`
+      );
+      this.assertOk(
+        submission.uri.query.includes(rules.suggestUrlCode),
+        `Should have the code in the uri`
+      );
+    }
+  }
+
+  /**
+   * Asserts whether the engine is using the correct codes or not.
+   *
+   * @param {string} location
+   *   Debug string with locale + region information.
+   * @param {object} engine
+   *   The engine being tested.
+   * @param {object} rules
+   *   Rules to test.
+   */
+  _assertCorrectCodes(location, engine, rules) {
+    for (const purpose of SUBMISSION_PURPOSES) {
+      // Don't need to repeat the code if we use it for all purposes.
+      const code =
+        typeof rules.codes === "string" ? rules.codes : rules.codes[purpose];
+      const submission = engine.getSubmission("test", "text/html", purpose);
+      const submissionQueryParams = submission.uri.query.split("&");
+      this.assertOk(
+        submissionQueryParams.includes(code),
+        `Expected "${code}" in url "${submission.uri.spec}" from purpose "${purpose}" ${location}`
+      );
+
+      const paramName = code.split("=")[0];
+      this.assertOk(
+        submissionQueryParams.filter(param => param.startsWith(paramName))
+          .length == 1,
+        `Expected only one "${paramName}" parameter in "${submission.uri.spec}" from purpose "${purpose}" ${location}`
+      );
+    }
+  }
+
+  /**
+   * Asserts whether the engine is using the correct URL codes or not.
+   *
+   * @param {string} location
+   *   Debug string with locale + region information.
+   * @param {object} engine
+   *   The engine being tested.
+   * @param {object} rule
+   *   Rules to test.
+   */
+  _assertCorrectUrlCode(location, engine, rule) {
+    if (rule.searchUrlCode) {
+      const submission = engine.getSubmission("test", URLTYPE_SEARCH_HTML);
+      this.assertOk(
+        submission.uri.query.split("&").includes(rule.searchUrlCode),
+        `Expected "${rule.searchUrlCode}" in search url "${submission.uri.spec}"`
+      );
+      let uri = engine.searchForm;
+      this.assertOk(
+        !uri.includes(rule.searchUrlCode),
+        `"${rule.searchUrlCode}" should not be in the search form URL.`
+      );
+    }
+    if (rule.searchUrlCodeNotInQuery) {
+      const submission = engine.getSubmission("test", URLTYPE_SEARCH_HTML);
+      this.assertOk(
+        submission.uri.includes(rule.searchUrlCodeNotInQuery),
+        `Expected "${rule.searchUrlCodeNotInQuery}" in search url "${submission.uri.spec}"`
+      );
+    }
+    if (rule.suggestUrlCode) {
+      const submission = engine.getSubmission("test", URLTYPE_SUGGEST_JSON);
+      this.assertOk(
+        submission.uri.query.split("&").includes(rule.suggestUrlCode),
+        `Expected "${rule.suggestUrlCode}" in suggestion url "${submission.uri.spec}"`
+      );
+    }
+  }
+
+  /**
+   * Helper functions which avoid outputting test results when there are no
+   * failures. These help the tests to run faster, and avoid clogging up the
+   * python test runner process.
+   */
+
+  assertOk(value, message) {
+    if (!value || TEST_DEBUG) {
+      Assert.ok(value, message);
+    }
+  }
+
+  assertEqual(actual, expected, message) {
+    if (actual != expected || TEST_DEBUG) {
+      Assert.equal(actual, expected, message);
+    }
+  }
+
+  assertDeepEqual(actual, expected, message) {
+    if (!ObjectUtils.deepEqual(actual, expected)) {
+      Assert.deepEqual(actual, expected, message);
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_amazon.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_amazon.js
new file mode 100644
index 0000000000..30d4d478f0
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_amazon.js
@@ -0,0 +1,361 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const mainShippedRegions = [
+  "at",
+  "au",
+  "be",
+  "ca",
+  "ch",
+  "cn",
+  "de",
+  "es",
+  "fr",
+  "mc",
+  "gb",
+  "ie",
+  "it",
+  "jp",
+  "nl",
+  "pt",
+  "se",
+  "sm",
+  "us",
+  "va",
+];
+
+const amazondotcomLocales = [
+  "ach",
+  "af",
+  "ar",
+  "az",
+  "bg",
+  "cak",
+  "cy",
+  "da",
+  "el",
+  "en-US",
+  "en-GB",
+  "eo",
+  "es-AR",
+  "eu",
+  "fa",
+  "ga-IE",
+  "gd",
+  "gl",
+  "gn",
+  "hr",
+  "hy-AM",
+  "ia",
+  "is",
+  "ka",
+  "km",
+  "lt",
+  "mk",
+  "ms",
+  "my",
+  "nb-NO",
+  "nn-NO",
+  "pt-PT",
+  "ro",
+  "si",
+  "sq",
+  "sr",
+  "th",
+  "tl",
+  "trs",
+  "uz",
+];
+
+const test = new SearchConfigTest({
+  identifier: "amazon",
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        // The main regions we ship Amazon to. Below this are special cases.
+        regions: mainShippedRegions,
+      },
+      {
+        // Amazon.com ships to all of these locales, excluding the ones where
+        // we ship other items, but it does not matter that they are duplicated
+        // in the available list.
+        locales: {
+          matches: amazondotcomLocales,
+        },
+      },
+      {
+        // Amazon.in
+        regions: ["in"],
+        locales: {
+          matches: ["bn", "gu-IN", "kn", "mr", "pa-IN", "ta", "te", "ur"],
+        },
+      },
+    ],
+    excluded: [
+      {
+        // Extra special case for cn as that only ships to the one locale.
+        regions: ["in"],
+        locales: {
+          matches: amazondotcomLocales,
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      domain: "amazon.com.au",
+      telemetryId: "amazon-au",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["au"],
+        },
+      ],
+      suggestionUrlBase: "https://completion.amazon.com.au/search/complete",
+      suggestUrlCode: "mkt=111172",
+    },
+    {
+      domain: "amazon.ca",
+      telemetryId: "amazon-ca",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["ca"],
+        },
+      ],
+      searchUrlCode: "tag=mozillacanada-20",
+      suggestionUrlBase: "https://completion.amazon.ca/search/complete",
+      suggestUrlCode: "mkt=7",
+    },
+    {
+      domain: "amazon.cn",
+      telemetryId: "amazondotcn",
+      included: [
+        {
+          regions: ["cn"],
+        },
+      ],
+      searchUrlCode: "ix=sunray",
+      noSuggestionsURL: true,
+    },
+    {
+      domain: "amazon.co.jp",
+      telemetryId: "amazon-jp",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["jp"],
+        },
+      ],
+      searchUrlCode: "tag=mozillajapan-fx-22",
+      suggestionUrlBase: "https://completion.amazon.co.jp/search/complete",
+      suggestUrlCode: "mkt=6",
+    },
+    {
+      domain: "amazon.co.uk",
+      telemetryId: "amazon-en-GB",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["gb", "ie"],
+        },
+      ],
+      searchUrlCode: "tag=firefox-uk-21",
+      suggestionUrlBase: "https://completion.amazon.co.uk/search/complete",
+      suggestUrlCode: "mkt=3",
+    },
+    {
+      domain: "amazon.com",
+      telemetryId: "amazondotcom-us",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["us"],
+        },
+      ],
+      searchUrlCode: "tag=moz-us-20",
+    },
+    {
+      domain: "amazon.com",
+      telemetryId: "amazondotcom",
+      aliases: ["@amazon"],
+      included: [
+        {
+          locales: {
+            matches: amazondotcomLocales,
+          },
+        },
+      ],
+      excluded: [{ regions: mainShippedRegions }],
+      searchUrlCode: "tag=mozilla-20",
+    },
+    {
+      domain: "amazon.de",
+      telemetryId: "amazon-de",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["at", "ch", "de"],
+        },
+      ],
+      searchUrlCode: "tag=firefox-de-21",
+      suggestionUrlBase: "https://completion.amazon.de/search/complete",
+      suggestUrlCode: "mkt=4",
+    },
+    {
+      domain: "amazon.es",
+      telemetryId: "amazon-es",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["es", "pt"],
+        },
+      ],
+      searchUrlCode: "tag=mozillaspain-21",
+      suggestionUrlBase: "https://completion.amazon.es/search/complete",
+      suggestUrlCode: "mkt=44551",
+    },
+    {
+      domain: "amazon.fr",
+      telemetryId: "amazon-france",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["fr", "mc"],
+        },
+        {
+          regions: ["be"],
+          locales: {
+            matches: ["fr"],
+          },
+        },
+      ],
+      searchUrlCode: "tag=firefox-fr-21",
+      suggestionUrlBase: "https://completion.amazon.fr/search/complete",
+      suggestUrlCode: "mkt=5",
+    },
+    {
+      domain: "amazon.in",
+      telemetryId: "amazon-in",
+      aliases: ["@amazon"],
+      included: [
+        {
+          locales: {
+            matches: ["bn", "gu-IN", "kn", "mr", "pa-IN", "ta", "te", "ur"],
+          },
+          regions: ["in"],
+        },
+      ],
+      suggestionUrlBase: "https://completion.amazon.in/search/complete",
+      suggestUrlCode: "mkt=44571",
+    },
+    {
+      domain: "amazon.it",
+      telemetryId: "amazon-it",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["it", "sm", "va"],
+        },
+      ],
+      searchUrlCode: "tag=firefoxit-21",
+      suggestionUrlBase: "https://completion.amazon.it/search/complete",
+      suggestUrlCode: "mkt=35691",
+    },
+    {
+      domain: "amazon.nl",
+      telemetryId: "amazon-nl",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["nl"],
+        },
+      ],
+      searchUrlCode: "tag=mozillanether-21",
+      suggestionUrlBase: "https://completion.amazon.nl/search/complete",
+      suggestUrlCode: "mkt=328451",
+    },
+    {
+      domain: "amazon.nl",
+      telemetryId: "amazon-nl",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["be"],
+        },
+      ],
+      excluded: [
+        {
+          locales: {
+            matches: ["fr"],
+          },
+        },
+      ],
+      searchUrlCode: "tag=mozillanether-21",
+      suggestionUrlBase: "https://completion.amazon.nl/search/complete",
+      suggestUrlCode: "mkt=328451",
+    },
+    {
+      domain: "amazon.se",
+      telemetryId: "amazon-se",
+      aliases: ["@amazon"],
+      included: [
+        {
+          regions: ["se"],
+        },
+      ],
+      searchUrlCode: "tag=mozillasweede-21",
+      suggestionUrlBase: "https://completion.amazon.se/search/complete",
+      suggestUrlCode: "mkt=704403121",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  // We only need to do setup on one of the tests.
+  await test.setup("89.0");
+});
+
+add_task(async function test_searchConfig_amazon() {
+  await test.run();
+});
+
+add_task(async function test_searchConfig_amazon_pre89() {
+  AddonTestUtils.createAppInfo(
+    "xpcshell@tests.mozilla.org",
+    "XPCShell",
+    "88.0",
+    "88.0"
+  );
+  // For pre-89, Amazon has a slightly different config.
+  let details = test._config.details.find(
+    d => d.telemetryId == "amazondotcom-us"
+  );
+  details.telemetryId = "amazondotcom";
+  details.searchUrlCode = "tag=mozilla-20";
+
+  // nl not present due to urls that don't work.
+  let availableIn = test._config.available.included;
+  availableIn[0].regions = availableIn[0].regions.filter(
+    r => r != "be" && r != "nl"
+  );
+  availableIn.push({
+    regions: ["be"],
+    locales: {
+      matches: ["fr"],
+    },
+  });
+  // Due to the way the exclusions work, no Amazon present in nl/be in the
+  // dot com locales for pre-89.
+  test._config.available.excluded[0].regions.push("be", "nl");
+  test._config.details = test._config.details.filter(
+    d => d.telemetryId != "amazon-nl"
+  );
+
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_baidu.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_baidu.js
new file mode 100644
index 0000000000..01094b260a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_baidu.js
@@ -0,0 +1,43 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "baidu",
+  aliases: ["@\u767E\u5EA6", "@baidu"],
+  default: {
+    included: [
+      {
+        regions: ["cn"],
+        locales: {
+          matches: ["zh-CN"],
+        },
+      },
+    ],
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["zh-CN"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "baidu.com",
+      telemetryId: "baidu",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_baidu() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_bing.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_bing.js
new file mode 100644
index 0000000000..5e91c9f49b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_bing.js
@@ -0,0 +1,133 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "bing",
+  aliases: ["@bing"],
+  default: {
+    // Not included anywhere.
+  },
+  available: {
+    included: [
+      {
+        // regions: [
+        // These arent currently enforced.
+        // "au", "at", "be", "br", "ca", "fi", "fr", "de",
+        // "in", "ie", "it", "jp", "my", "mx", "nl", "nz",
+        // "no", "sg", "es", "se", "ch", "gb", "us",
+        // ],
+        locales: {
+          matches: [
+            "ach",
+            "af",
+            "an",
+            "ar",
+            "ast",
+            "az",
+            "bs",
+            "ca",
+            "ca-valencia",
+            "cak",
+            "cs",
+            "cy",
+            "da",
+            "de",
+            "dsb",
+            "el",
+            "eo",
+            "es-CL",
+            "es-ES",
+            "es-MX",
+            "eu",
+            "fa",
+            "ff",
+            "fi",
+            "fr",
+            "fur",
+            "fy-NL",
+            "gd",
+            "gl",
+            "gn",
+            "gu-IN",
+            "he",
+            "hi-IN",
+            "hr",
+            "hsb",
+            "hy-AM",
+            "ia",
+            "id",
+            "is",
+            "it",
+            "ja-JP-macos",
+            "ja",
+            "ka",
+            "kab",
+            "km",
+            "kn",
+            "lij",
+            "lo",
+            "lt",
+            "meh",
+            "mk",
+            "ms",
+            "my",
+            "nb-NO",
+            "ne-NP",
+            "nl",
+            "nn-NO",
+            "oc",
+            "pa-IN",
+            "pt-BR",
+            "rm",
+            "ro",
+            "sc",
+            "sco",
+            "son",
+            "sq",
+            "sr",
+            "sv-SE",
+            "te",
+            "th",
+            "tl",
+            "tr",
+            "trs",
+            "uk",
+            "ur",
+            "uz",
+            "wo",
+            "xh",
+            "zh-CN",
+          ],
+          startsWith: ["bn", "en"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "bing.com",
+      telemetryId:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr" ? "bing-esr" : "bing",
+      codes: {
+        searchbar: "form=MOZSBR",
+        keyword: "form=MOZLBR",
+        contextmenu: "form=MOZCON",
+        homepage: "form=MOZSPG",
+        newtab: "form=MOZTSB",
+      },
+      searchUrlCode:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr" ? "pc=MOZR" : "pc=MOZI",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_bing() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_distributions.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_distributions.js
new file mode 100644
index 0000000000..0b44a5509e
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_distributions.js
@@ -0,0 +1,346 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+  SearchService: "resource://gre/modules/SearchService.sys.mjs",
+});
+
+const tests = [];
+
+for (let canonicalId of ["canonical", "canonical-001"]) {
+  tests.push({
+    locale: "en-US",
+    region: "US",
+    distribution: canonicalId,
+    test: engines =>
+      hasParams(engines, "Google", "searchbar", "client=ubuntu") &&
+      hasParams(engines, "Google", "searchbar", "channel=fs") &&
+      hasTelemetryId(engines, "Google", "google-canonical"),
+  });
+
+  tests.push({
+    locale: "en-US",
+    region: "GB",
+    distribution: canonicalId,
+    test: engines =>
+      hasParams(engines, "Google", "searchbar", "client=ubuntu") &&
+      hasParams(engines, "Google", "searchbar", "channel=fs") &&
+      hasTelemetryId(engines, "Google", "google-canonical"),
+  });
+}
+
+tests.push({
+  locale: "en-US",
+  region: "US",
+  distribution: "canonical-002",
+  test: engines =>
+    hasParams(engines, "Google", "searchbar", "client=ubuntu-sn") &&
+    hasParams(engines, "Google", "searchbar", "channel=fs") &&
+    hasTelemetryId(engines, "Google", "google-ubuntu-sn"),
+});
+
+tests.push({
+  locale: "en-US",
+  region: "GB",
+  distribution: "canonical-002",
+  test: engines =>
+    hasParams(engines, "Google", "searchbar", "client=ubuntu-sn") &&
+    hasParams(engines, "Google", "searchbar", "channel=fs") &&
+    hasTelemetryId(engines, "Google", "google-ubuntu-sn"),
+});
+
+tests.push({
+  locale: "zh-CN",
+  region: "CN",
+  distribution: "MozillaOnline",
+  test: engines =>
+    hasParams(engines, "亚马逊", "searchbar", "ie=UTF8") &&
+    hasParams(engines, "亚马逊", "suggestions", "tag=mozilla") &&
+    hasParams(engines, "亚马逊", "homepage", "camp=536") &&
+    hasParams(engines, "亚马逊", "homepage", "creative=3200") &&
+    hasParams(engines, "亚马逊", "homepage", "index=aps") &&
+    hasParams(engines, "亚马逊", "homepage", "linkCode=ur2") &&
+    hasEnginesFirst(engines, ["百度", "Bing", "Google", "亚马逊", "维基百科"]),
+});
+
+tests.push({
+  locale: "fr",
+  distribution: "qwant-001",
+  test: engines =>
+    hasParams(engines, "Qwant", "searchbar", "client=firefoxqwant") &&
+    hasDefault(engines, "Qwant") &&
+    hasEnginesFirst(engines, ["Qwant", "Qwant Junior"]),
+});
+
+tests.push({
+  locale: "fr",
+  distribution: "qwant-001",
+  test: engines =>
+    hasParams(engines, "Qwant Junior", "searchbar", "client=firefoxqwant"),
+});
+
+tests.push({
+  locale: "fr",
+  distribution: "qwant-002",
+  test: engines =>
+    hasParams(engines, "Qwant", "searchbar", "client=firefoxqwant") &&
+    hasDefault(engines, "Qwant") &&
+    hasEnginesFirst(engines, ["Qwant", "Qwant Junior"]),
+});
+
+tests.push({
+  locale: "fr",
+  distribution: "qwant-002",
+  test: engines =>
+    hasParams(engines, "Qwant Junior", "searchbar", "client=firefoxqwant"),
+});
+
+for (const locale of ["en-US", "de"]) {
+  tests.push({
+    locale,
+    distribution: "1und1",
+    test: engines =>
+      hasParams(engines, "1&1 Suche", "searchbar", "enc=UTF-8") &&
+      hasDefault(engines, "1&1 Suche") &&
+      hasEnginesFirst(engines, ["1&1 Suche"]),
+  });
+
+  tests.push({
+    locale,
+    distribution: "gmx",
+    test: engines =>
+      hasParams(engines, "GMX Suche", "searchbar", "enc=UTF-8") &&
+      hasDefault(engines, "GMX Suche") &&
+      hasEnginesFirst(engines, ["GMX Suche"]),
+  });
+
+  tests.push({
+    locale,
+    distribution: "gmx",
+    test: engines =>
+      hasParams(engines, "GMX Shopping", "searchbar", "origin=br_osd"),
+  });
+
+  tests.push({
+    locale,
+    distribution: "mail.com",
+    test: engines =>
+      hasParams(engines, "mail.com search", "searchbar", "enc=UTF-8") &&
+      hasDefault(engines, "mail.com search") &&
+      hasEnginesFirst(engines, ["mail.com search"]),
+  });
+
+  tests.push({
+    locale,
+    distribution: "webde",
+    test: engines =>
+      hasParams(engines, "WEB.DE Suche", "searchbar", "enc=UTF-8") &&
+      hasDefault(engines, "WEB.DE Suche") &&
+      hasEnginesFirst(engines, ["WEB.DE Suche"]),
+  });
+}
+
+tests.push({
+  locale: "ru",
+  region: "RU",
+  distribution: "gmx",
+  test: engines => hasDefault(engines, "GMX Suche"),
+});
+
+tests.push({
+  locale: "en-GB",
+  distribution: "gmxcouk",
+  test: engines =>
+    hasURLs(
+      engines,
+      "GMX Search",
+      "https://go.gmx.co.uk/br/moz_search_web/?enc=UTF-8&q=test",
+      "https://suggestplugin.gmx.co.uk/s?q=test&brand=gmxcouk&origin=moz_splugin_ff&enc=UTF-8"
+    ) &&
+    hasDefault(engines, "GMX Search") &&
+    hasEnginesFirst(engines, ["GMX Search"]),
+});
+
+tests.push({
+  locale: "ru",
+  region: "RU",
+  distribution: "gmxcouk",
+  test: engines => hasDefault(engines, "GMX Search"),
+});
+
+tests.push({
+  locale: "es",
+  distribution: "gmxes",
+  test: engines =>
+    hasURLs(
+      engines,
+      "GMX - Búsqueda web",
+      "https://go.gmx.es/br/moz_search_web/?enc=UTF-8&q=test",
+      "https://suggestplugin.gmx.es/s?q=test&brand=gmxes&origin=moz_splugin_ff&enc=UTF-8"
+    ) &&
+    hasDefault(engines, "GMX Search") &&
+    hasEnginesFirst(engines, ["GMX Search"]),
+});
+
+tests.push({
+  locale: "ru",
+  region: "RU",
+  distribution: "gmxes",
+  test: engines => hasDefault(engines, "GMX - Búsqueda web"),
+});
+
+tests.push({
+  locale: "fr",
+  distribution: "gmxfr",
+  test: engines =>
+    hasURLs(
+      engines,
+      "GMX - Recherche web",
+      "https://go.gmx.fr/br/moz_search_web/?enc=UTF-8&q=test",
+      "https://suggestplugin.gmx.fr/s?q=test&brand=gmxfr&origin=moz_splugin_ff&enc=UTF-8"
+    ) &&
+    hasDefault(engines, "GMX Search") &&
+    hasEnginesFirst(engines, ["GMX Search"]),
+});
+
+tests.push({
+  locale: "ru",
+  region: "RU",
+  distribution: "gmxfr",
+  test: engines => hasDefault(engines, "GMX - Recherche web"),
+});
+
+tests.push({
+  locale: "en-US",
+  region: "US",
+  distribution: "mint-001",
+  test: engines =>
+    hasParams(engines, "DuckDuckGo", "searchbar", "t=lm") &&
+    hasParams(engines, "Google", "searchbar", "client=firefox-b-1-lm") &&
+    hasDefault(engines, "Google") &&
+    hasEnginesFirst(engines, ["Google"]) &&
+    hasTelemetryId(engines, "Google", "google-b-1-lm"),
+});
+
+tests.push({
+  locale: "en-GB",
+  region: "GB",
+  distribution: "mint-001",
+  test: engines =>
+    hasParams(engines, "DuckDuckGo", "searchbar", "t=lm") &&
+    hasParams(engines, "Google", "searchbar", "client=firefox-b-lm") &&
+    hasDefault(engines, "Google") &&
+    hasEnginesFirst(engines, ["Google"]) &&
+    hasTelemetryId(engines, "Google", "google-b-lm"),
+});
+
+function hasURLs(engines, engineName, url, suggestURL) {
+  let engine = engines.find(e => e._name === engineName);
+  Assert.ok(engine, `Should be able to find ${engineName}`);
+
+  let submission = engine.getSubmission("test", "text/html");
+  Assert.equal(
+    submission.uri.spec,
+    url,
+    `Should have the correct submission url for ${engineName}`
+  );
+
+  submission = engine.getSubmission("test", "application/x-suggestions+json");
+  Assert.equal(
+    submission.uri.spec,
+    suggestURL,
+    `Should have the correct suggestion url for ${engineName}`
+  );
+}
+
+function hasParams(engines, engineName, purpose, param) {
+  let engine = engines.find(e => e._name === engineName);
+  Assert.ok(engine, `Should be able to find ${engineName}`);
+
+  let submission = engine.getSubmission("test", "text/html", purpose);
+  let queries = submission.uri.query.split("&");
+
+  let paramNames = new Set();
+  for (let query of queries) {
+    let queryParam = query.split("=")[0];
+    Assert.ok(
+      !paramNames.has(queryParam),
+      `Should not have a duplicate ${queryParam} param`
+    );
+    paramNames.add(queryParam);
+  }
+
+  let result = queries.includes(param);
+  Assert.ok(result, `expect ${submission.uri.query} to include ${param}`);
+  return true;
+}
+
+function hasTelemetryId(engines, engineName, telemetryId) {
+  let engine = engines.find(e => e._name === engineName);
+  Assert.ok(engine, `Should be able to find ${engineName}`);
+
+  Assert.equal(
+    engine.telemetryId,
+    telemetryId,
+    "Should have the correct telemetryId"
+  );
+  return true;
+}
+
+function hasDefault(engines, expectedDefaultName) {
+  Assert.equal(
+    engines[0].name,
+    expectedDefaultName,
+    "Should have the expected engine set as default"
+  );
+  return true;
+}
+
+function hasEnginesFirst(engines, expectedEngines) {
+  for (let [i, expectedEngine] of expectedEngines.entries()) {
+    Assert.equal(
+      engines[i].name,
+      expectedEngine,
+      `Should have the expected engine in position ${i}`
+    );
+  }
+}
+
+engineSelector = new SearchEngineSelector();
+
+AddonTestUtils.init(GLOBAL_SCOPE);
+AddonTestUtils.createAppInfo(
+  "xpcshell@tests.mozilla.org",
+  "XPCShell",
+  "42",
+  "42"
+);
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  await maybeSetupConfig();
+});
+
+add_task(async function test_expected_distribution_engines() {
+  let searchService = new SearchService();
+  for (const { distribution, locale = "en-US", region = "US", test } of tests) {
+    let config = await engineSelector.fetchEngineConfiguration({
+      locale,
+      region,
+      distroID: distribution,
+    });
+    let engines = await SearchTestUtils.searchConfigToEngines(config.engines);
+    searchService._engines = engines;
+    searchService._searchDefault = {
+      id: config.engines[0].webExtension.id,
+      locale:
+        config.engines[0]?.webExtension?.locale ?? SearchUtils.DEFAULT_TAG,
+    };
+    engines = searchService._sortEnginesByDefaults(engines);
+    test(engines);
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_duckduckgo.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_duckduckgo.js
new file mode 100644
index 0000000000..379ef9d217
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_duckduckgo.js
@@ -0,0 +1,35 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "ddg",
+  aliases: ["@duckduckgo", "@ddg"],
+  default: {
+    // Not included anywhere.
+  },
+  available: {
+    excluded: [
+      // Should be available everywhere.
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "duckduckgo.com",
+      telemetryId:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr" ? "ddg-esr" : "ddg",
+      searchUrlCode:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr" ? "t=ftsa" : "t=ffab",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_duckduckgo() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_ebay.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_ebay.js
new file mode 100644
index 0000000000..df89072425
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_ebay.js
@@ -0,0 +1,290 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const DOMAIN_LOCALES = {
+  "ebay-ca": ["en-CA"],
+  "ebay-ch": ["rm"],
+  "ebay-de": ["de", "dsb", "hsb"],
+  "ebay-es": ["an", "ast", "ca", "ca-valencia", "es-ES", "eu", "gl"],
+  "ebay-ie": ["ga-IE", "ie"],
+  "ebay-it": ["fur", "it", "lij", "sc"],
+  "ebay-nl": ["fy-NL", "nl"],
+  "ebay-uk": ["cy", "en-GB", "gd"],
+};
+
+const test = new SearchConfigTest({
+  identifier: "ebay",
+  aliases: ["@ebay"],
+  default: {
+    // Not included anywhere.
+  },
+  available: {
+    included: [
+      {
+        // We don't currently enforce by region, but do locale instead.
+        // regions: [
+        //   "us", "gb", "ca", "ie", "fr", "it", "de", "at", "es", "nl", "ch", "au"
+        // ],
+        locales: {
+          matches: [
+            "an",
+            "ast",
+            "br",
+            "ca",
+            "ca-valencia",
+            "cy",
+            "de",
+            "dsb",
+            "en-CA",
+            "en-GB",
+            "es-ES",
+            "eu",
+            "fur",
+            "fr",
+            "fy-NL",
+            "ga-IE",
+            "gd",
+            "gl",
+            "hsb",
+            "it",
+            "lij",
+            "nl",
+            "rm",
+            "sc",
+            "wo",
+          ],
+        },
+      },
+      {
+        regions: ["au", "be", "ca", "ch", "gb", "ie", "nl", "us"],
+        locales: {
+          matches: ["en-US"],
+        },
+      },
+      {
+        regions: ["gb"],
+        locales: {
+          matches: ["sco"],
+        },
+      },
+    ],
+  },
+  suggestionUrlBase: "https://autosug.ebay.com/autosug",
+  details: [
+    {
+      // Note: These should be based on region, but we don't currently enforce that.
+      // Note: the order here is important. A region/locale match higher up in the
+      // list will override a region/locale match lower down.
+      domain: "www.befr.ebay.be",
+      telemetryId: "ebay-be",
+      included: [
+        {
+          regions: ["be"],
+          locales: {
+            matches: ["br", "unknown", "en-US", "fr", "fy-NL", "nl", "wo"],
+          },
+        },
+      ],
+      searchUrlCode: "mkrid=1553-53471-19255-0",
+      suggestUrlCode: "sId=23",
+    },
+    {
+      domain: "www.ebay.at",
+      telemetryId: "ebay-at",
+      included: [
+        {
+          regions: ["at"],
+          locales: { matches: ["de", "dsb", "hsb"] },
+        },
+      ],
+      searchUrlCode: "mkrid=5221-53469-19255-0",
+      suggestUrlCode: "sId=16",
+    },
+    {
+      domain: "www.ebay.ca",
+      telemetryId: "ebay-ca",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-ca"] },
+        },
+        {
+          regions: ["ca"],
+        },
+      ],
+      excluded: [
+        {
+          locales: {
+            matches: [
+              ...DOMAIN_LOCALES["ebay-ch"],
+              ...DOMAIN_LOCALES["ebay-de"],
+              ...DOMAIN_LOCALES["ebay-es"],
+              ...DOMAIN_LOCALES["ebay-ie"],
+              ...DOMAIN_LOCALES["ebay-it"],
+              ...DOMAIN_LOCALES["ebay-nl"],
+              ...DOMAIN_LOCALES["ebay-uk"],
+            ],
+          },
+        },
+      ],
+      searchUrlCode: "mkrid=706-53473-19255-0",
+      suggestUrlCode: "sId=2",
+    },
+    {
+      domain: "www.ebay.ch",
+      telemetryId: "ebay-ch",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-ch"] },
+        },
+        {
+          regions: ["ch"],
+        },
+      ],
+      excluded: [
+        {
+          locales: {
+            matches: [
+              ...DOMAIN_LOCALES["ebay-ca"],
+              ...DOMAIN_LOCALES["ebay-es"],
+              ...DOMAIN_LOCALES["ebay-ie"],
+              ...DOMAIN_LOCALES["ebay-it"],
+              ...DOMAIN_LOCALES["ebay-nl"],
+              ...DOMAIN_LOCALES["ebay-uk"],
+            ],
+          },
+        },
+      ],
+      searchUrlCode: "mkrid=5222-53480-19255-0",
+      suggestUrlCode: "sId=193",
+    },
+    {
+      domain: "www.ebay.com",
+      telemetryId: "ebay",
+      included: [
+        {
+          locales: { matches: ["unknown", "en-US"] },
+        },
+      ],
+      excluded: [{ regions: ["au", "be", "ca", "ch", "gb", "ie", "nl"] }],
+      searchUrlCode: "mkrid=711-53200-19255-0",
+      suggestUrlCode: "sId=0",
+    },
+    {
+      domain: "www.ebay.com.au",
+      telemetryId: "ebay-au",
+      included: [
+        {
+          regions: ["au"],
+          locales: { matches: ["cy", "unknown", "en-GB", "en-US", "gd"] },
+        },
+      ],
+      searchUrlCode: "mkrid=705-53470-19255-0",
+      suggestUrlCode: "sId=15",
+    },
+    {
+      domain: "www.ebay.ie",
+      telemetryId: "ebay-ie",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-ie"] },
+        },
+        {
+          regions: ["ie"],
+          locales: { matches: ["cy", "unknown", "en-GB", "en-US", "gd"] },
+        },
+      ],
+      searchUrlCode: "mkrid=5282-53468-19255-0",
+      suggestUrlCode: "sId=205",
+    },
+    {
+      domain: "www.ebay.co.uk",
+      telemetryId: "ebay-uk",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-uk"] },
+        },
+        {
+          locales: { matches: ["unknown", "en-US", "sco"] },
+          regions: ["gb"],
+        },
+      ],
+      excluded: [{ regions: ["au", "ie"] }],
+      searchUrlCode: "mkrid=710-53481-19255-0",
+      suggestUrlCode: "sId=3",
+    },
+    {
+      domain: "www.ebay.de",
+      telemetryId: "ebay-de",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-de"] },
+        },
+      ],
+      excluded: [{ regions: ["at", "ch"] }],
+      searchUrlCode: "mkrid=707-53477-19255-0",
+      suggestUrlCode: "sId=77",
+    },
+    {
+      domain: "www.ebay.es",
+      telemetryId: "ebay-es",
+      included: [
+        {
+          locales: {
+            matches: DOMAIN_LOCALES["ebay-es"],
+          },
+        },
+      ],
+      searchUrlCode: "mkrid=1185-53479-19255-0",
+      suggestUrlCode: "sId=186",
+    },
+    {
+      domain: "www.ebay.fr",
+      telemetryId: "ebay-fr",
+      included: [
+        {
+          locales: { matches: ["br", "fr", "wo"] },
+        },
+      ],
+      excluded: [{ regions: ["be", "ca", "ch"] }],
+      searchUrlCode: "mkrid=709-53476-19255-0",
+      suggestUrlCode: "sId=71",
+    },
+    {
+      domain: "www.ebay.it",
+      telemetryId: "ebay-it",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-it"] },
+        },
+      ],
+      searchUrlCode: "mkrid=724-53478-19255-0",
+      suggestUrlCode: "sId=101",
+    },
+    {
+      domain: "www.ebay.nl",
+      telemetryId: "ebay-nl",
+      included: [
+        {
+          locales: { matches: DOMAIN_LOCALES["ebay-nl"] },
+        },
+        {
+          locales: { matches: ["unknown", "en-US"] },
+          regions: ["nl"],
+        },
+      ],
+      excluded: [{ regions: ["be"] }],
+      searchUrlCode: "mkrid=1346-53482-19255-0",
+      suggestUrlCode: "sId=146",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_ebay() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_ecosia.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_ecosia.js
new file mode 100644
index 0000000000..61d2fd9abc
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_ecosia.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "ecosia",
+  aliases: [],
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["de"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "www.ecosia.org",
+      telemetryId: "ecosia",
+      searchUrlCode: "tt=mzl",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_ecosia() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_google.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_google.js
new file mode 100644
index 0000000000..dc2098b066
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_google.js
@@ -0,0 +1,173 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
+});
+
+const test = new SearchConfigTest({
+  identifier: "google",
+  aliases: ["@google"],
+  default: {
+    // Included everywhere apart from the exclusions below. These are basically
+    // just excluding what Yandex and Baidu include.
+    excluded: [
+      {
+        regions: ["cn"],
+        locales: {
+          matches: ["zh-CN"],
+        },
+      },
+    ],
+  },
+  available: {
+    excluded: [
+      // Should be available everywhere.
+    ],
+  },
+  details: [
+    {
+      included: [{ regions: ["us"] }],
+      domain: "google.com",
+      telemetryId:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr"
+          ? "google-b-1-e"
+          : "google-b-1-d",
+      codes:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr"
+          ? "client=firefox-b-1-e"
+          : "client=firefox-b-1-d",
+    },
+    {
+      excluded: [{ regions: ["us", "by", "kz", "ru", "tr"] }],
+      included: [{}],
+      domain: "google.com",
+      telemetryId:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr" ? "google-b-e" : "google-b-d",
+      codes:
+        SearchUtils.MODIFIED_APP_CHANNEL == "esr"
+          ? "client=firefox-b-e"
+          : "client=firefox-b-d",
+    },
+    {
+      included: [{ regions: ["by", "kz", "ru", "tr"] }],
+      domain: "google.com",
+      telemetryId: "google-com-nocodes",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  sinon.spy(NimbusFeatures.search, "onUpdate");
+  sinon.stub(NimbusFeatures.search, "ready").resolves();
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_google() {
+  await test.run();
+});
+
+add_task(async function test_searchConfig_google_with_mozparam() {
+  // Test a couple of configurations with a MozParam set up.
+  const TEST_DATA = [
+    {
+      locale: "en-US",
+      region: "US",
+      pref: "google_channel_us",
+      expected: "us_param",
+    },
+    {
+      locale: "en-US",
+      region: "GB",
+      pref: "google_channel_row",
+      expected: "row_param",
+    },
+  ];
+
+  const defaultBranch = Services.prefs.getDefaultBranch(
+    SearchUtils.BROWSER_SEARCH_PREF
+  );
+  for (const testData of TEST_DATA) {
+    defaultBranch.setCharPref("param." + testData.pref, testData.expected);
+  }
+
+  for (const testData of TEST_DATA) {
+    info(`Checking region ${testData.region}, locale ${testData.locale}`);
+    const engines = await test._getEngines(testData.region, testData.locale);
+
+    Assert.ok(
+      engines[0].identifier.startsWith("google"),
+      "Should have the correct engine"
+    );
+    console.log(engines[0]);
+
+    const submission = engines[0].getSubmission("test", URLTYPE_SEARCH_HTML);
+    Assert.ok(
+      submission.uri.query.split("&").includes("channel=" + testData.expected),
+      "Should be including the correct MozParam parameter for the engine"
+    );
+  }
+
+  // Reset the pref values for next tests
+  for (const testData of TEST_DATA) {
+    defaultBranch.setCharPref("param." + testData.pref, "");
+  }
+});
+
+add_task(async function test_searchConfig_google_with_nimbus() {
+  let sandbox = sinon.createSandbox();
+  // Test a couple of configurations with a MozParam set up.
+  const TEST_DATA = [
+    {
+      locale: "en-US",
+      region: "US",
+      expected: "nimbus_us_param",
+    },
+    {
+      locale: "en-US",
+      region: "GB",
+      expected: "nimbus_row_param",
+    },
+  ];
+
+  Assert.ok(
+    NimbusFeatures.search.onUpdate.called,
+    "Should register an update listener for Nimbus experiments"
+  );
+  // Stub getVariable to populate the cache with our expected data
+  sandbox.stub(NimbusFeatures.search, "getVariable").returns([
+    { key: "google_channel_us", value: "nimbus_us_param" },
+    { key: "google_channel_row", value: "nimbus_row_param" },
+  ]);
+  // Set the pref cache with Nimbus values
+  NimbusFeatures.search.onUpdate.firstCall.args[0]();
+
+  for (const testData of TEST_DATA) {
+    info(`Checking region ${testData.region}, locale ${testData.locale}`);
+    const engines = await test._getEngines(testData.region, testData.locale);
+
+    Assert.ok(
+      engines[0].identifier.startsWith("google"),
+      "Should have the correct engine"
+    );
+    console.log(engines[0]);
+
+    const submission = engines[0].getSubmission("test", URLTYPE_SEARCH_HTML);
+    Assert.ok(
+      NimbusFeatures.search.ready.called,
+      "Should wait for Nimbus to get ready"
+    );
+    Assert.ok(
+      NimbusFeatures.search.getVariable,
+      "Should call NimbusFeatures.search.getVariable to populate the cache"
+    );
+    Assert.ok(
+      submission.uri.query.split("&").includes("channel=" + testData.expected),
+      "Should be including the correct MozParam parameter for the engine"
+    );
+  }
+
+  sandbox.restore();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_mailru.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_mailru.js
new file mode 100644
index 0000000000..4d413f0b5b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_mailru.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "mailru",
+  aliases: [],
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["ru"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "go.mail.ru",
+      telemetryId: "mailru",
+      codes: "gp=900200",
+      searchUrlCode: "frc=900200",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_mailru() {
+  await test.run();
+}).skip();
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_qwant.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_qwant.js
new file mode 100644
index 0000000000..8db31fcc24
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_qwant.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "qwant",
+  aliases: ["@qwant"],
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["fr"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "www.qwant.com",
+      telemetryId: "qwant",
+      searchUrlCode: "client=brz-moz",
+      suggestUrlCode: "client=opensearch",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_qwant() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_rakuten.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_rakuten.js
new file mode 100644
index 0000000000..0577490dc2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_rakuten.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "rakuten",
+  aliases: [],
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["ja", "ja-JP-macos"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "rakuten.co.jp",
+      telemetryId: "rakuten",
+      searchUrlCodeNotInQuery: "013ca98b.cd7c5f0c",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_rakuten() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_selector_db_out_of_date.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_selector_db_out_of_date.js
new file mode 100644
index 0000000000..742cfaec8a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_selector_db_out_of_date.js
@@ -0,0 +1,58 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  RemoteSettingsWorker:
+    "resource://services-settings/RemoteSettingsWorker.sys.mjs",
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+do_get_profile();
+
+add_task(async function test_selector_db_out_of_date() {
+  let searchConfig = RemoteSettings(SearchUtils.SETTINGS_KEY);
+
+  // Do an initial get to pre-seed the database.
+  await searchConfig.get();
+
+  // Now clear the database and re-fill it.
+  let db = searchConfig.db;
+  await db.clear();
+  let databaseEntries = await db.list();
+  Assert.equal(databaseEntries.length, 0, "Should have cleared the database.");
+
+  // Add a dummy record with an out-of-date last modified.
+  await RemoteSettingsWorker._execute("_test_only_import", [
+    "main",
+    SearchUtils.SETTINGS_KEY,
+    [
+      {
+        id: "b70edfdd-1c3f-4b7b-ab55-38cb048636c0",
+        default: "yes",
+        webExtension: { id: "outofdate@search.mozilla.org" },
+        appliesTo: [{ included: { everywhere: true } }],
+        last_modified: 1606227264000,
+      },
+    ],
+    1606227264000,
+  ]);
+
+  // Now load the configuration and check we get what we expect.
+  let engineSelector = new SearchEngineSelector();
+  let result = await engineSelector.fetchEngineConfiguration({
+    // Use the fallback default locale/regions to get a simple list.
+    locale: "default",
+    region: "default",
+  });
+  Assert.deepEqual(
+    result.engines.map(e => e.webExtension.id),
+    [
+      "google@search.mozilla.org",
+      "wikipedia@search.mozilla.org",
+      "ddg@search.mozilla.org",
+    ],
+    "Should have returned the correct data."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_yahoojp.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_yahoojp.js
new file mode 100644
index 0000000000..25091fc37e
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_yahoojp.js
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "yahoo-jp",
+  identifierExactMatch: true,
+  aliases: [],
+  default: {
+    // Not default anywhere.
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["ja", "ja-JP-macos"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{}],
+      domain: "search.yahoo.co.jp",
+      telemetryId: "yahoo-jp",
+      searchUrlCode: "fr=mozff",
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_yahoojp() {
+  await test.run();
+});
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/test_yandex.js b/toolkit/components/search/tests/xpcshell/searchconfigs/test_yandex.js
new file mode 100644
index 0000000000..c315165e5f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/test_yandex.js
@@ -0,0 +1,117 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const test = new SearchConfigTest({
+  identifier: "yandex",
+  aliases: ["@\u044F\u043D\u0434\u0435\u043A\u0441", "@yandex"],
+  default: {
+    included: [
+      {
+        regions: ["ru", "tr", "by", "kz"],
+        locales: {
+          matches: ["ru", "tr", "be", "kk"],
+          startsWith: ["en"],
+        },
+      },
+    ],
+  },
+  available: {
+    included: [
+      {
+        locales: {
+          matches: ["az", "ru", "be", "kk", "tr"],
+        },
+      },
+      {
+        regions: ["ru", "tr", "by", "kz"],
+        locales: {
+          startsWith: ["en"],
+        },
+      },
+    ],
+  },
+  details: [
+    {
+      included: [{ locales: { matches: ["az"] } }],
+      domain: "yandex.az",
+      telemetryId: "yandex-az",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+    {
+      included: [{ locales: { startsWith: ["en"] } }],
+      domain: "yandex.com",
+      telemetryId: "yandex-en",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+    {
+      included: [{ locales: { matches: ["ru"] } }],
+      domain: "yandex.ru",
+      telemetryId: "yandex-ru",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+    {
+      included: [{ locales: { matches: ["be"] } }],
+      domain: "yandex.by",
+      telemetryId: "yandex-by",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+    {
+      included: [{ locales: { matches: ["kk"] } }],
+      domain: "yandex.kz",
+      telemetryId: "yandex-kk",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+    {
+      included: [{ locales: { matches: ["tr"] } }],
+      domain: "yandex.com.tr",
+      telemetryId: "yandex-tr",
+      codes: {
+        searchbar: "clid=2186618",
+        keyword: "clid=2186621",
+        contextmenu: "clid=2186623",
+        homepage: "clid=2186617",
+        newtab: "clid=2186620",
+      },
+    },
+  ],
+});
+
+add_task(async function setup() {
+  await test.setup();
+});
+
+add_task(async function test_searchConfig_yandex() {
+  await test.run();
+}).skip();
diff --git a/toolkit/components/search/tests/xpcshell/searchconfigs/xpcshell.ini b/toolkit/components/search/tests/xpcshell/searchconfigs/xpcshell.ini
new file mode 100644
index 0000000000..17cbd5350d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/searchconfigs/xpcshell.ini
@@ -0,0 +1,34 @@
+[DEFAULT]
+firefox-appdir = browser
+head = head_searchconfig.js
+dupe-manifest =
+support-files =
+  ../../../../../../browser/locales/all-locales
+tags=searchconfig remote-settings
+# These are extensive tests, we don't need to run them on asan/tsan.
+# They are also skipped for mobile and Thunderbird as these are specifically
+# testing the Firefox config at the moment.
+skip-if =
+  toolkit == 'android'
+  appname == "thunderbird"
+  asan
+  tsan
+  debug
+  (os == "win" && ccov)
+# These tests do take a little longer on Linux ccov, so allow that here.
+requesttimeoutfactor = 2
+
+[test_amazon.js]
+[test_baidu.js]
+[test_bing.js]
+[test_distributions.js]
+[test_duckduckgo.js]
+[test_ebay.js]
+[test_ecosia.js]
+[test_google.js]
+[test_mailru.js]
+[test_qwant.js]
+[test_rakuten.js]
+[test_selector_db_out_of_date.js]
+[test_yahoojp.js]
+[test_yandex.js]
diff --git a/toolkit/components/search/tests/xpcshell/simple-engines/basic/manifest.json b/toolkit/components/search/tests/xpcshell/simple-engines/basic/manifest.json
new file mode 100644
index 0000000000..b62eb9bb2b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/simple-engines/basic/manifest.json
@@ -0,0 +1,29 @@
+{
+  "name": "basic",
+  "manifest_version": 2,
+  "version": "1.0",
+  "description": "basic",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "basic@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "basic",
+      "search_url": "https://ar.wikipedia.org/wiki/%D8%AE%D8%A7%D8%B5:%D8%A8%D8%AD%D8%AB",
+      "params": [
+        {
+          "name": "search",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "sourceId",
+          "value": "Mozilla-search"
+        }
+      ],
+      "suggest_url": "https://ar.wikipedia.org/w/api.php?action=opensearch&search={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/simple-engines/engines.json b/toolkit/components/search/tests/xpcshell/simple-engines/engines.json
new file mode 100644
index 0000000000..f4ce227e9f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/simple-engines/engines.json
@@ -0,0 +1,27 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "basic@search.mozilla.org"
+      },
+      "telemetryId": "telemetry",
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "simple@search.mozilla.org"
+      },
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes"
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/simple-engines/hidden/manifest.json b/toolkit/components/search/tests/xpcshell/simple-engines/hidden/manifest.json
new file mode 100644
index 0000000000..203590f44d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/simple-engines/hidden/manifest.json
@@ -0,0 +1,29 @@
+{
+  "name": "hidden",
+  "manifest_version": 2,
+  "version": "1.0",
+  "description": "Hidden engine to test bug 1194265",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "hidden@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "hidden",
+      "search_url": "https://ar.wikipedia.org/wiki/%D8%AE%D8%A7%D8%B5:%D8%A8%D8%AD%D8%AB",
+      "params": [
+        {
+          "name": "search",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "sourceId",
+          "value": "Mozilla-search"
+        }
+      ],
+      "suggest_url": "https://ar.wikipedia.org/w/api.php?action=opensearch&search={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/simple-engines/simple/manifest.json b/toolkit/components/search/tests/xpcshell/simple-engines/simple/manifest.json
new file mode 100644
index 0000000000..67d2974753
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/simple-engines/simple/manifest.json
@@ -0,0 +1,29 @@
+{
+  "name": "Simple Engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "description": "Simple engine with a different name from the WebExtension id prefix",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "simple@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Simple Engine",
+      "search_url": "https://example.com",
+      "params": [
+        {
+          "name": "sourceId",
+          "value": "Mozilla-search"
+        },
+        {
+          "name": "search",
+          "value": "{searchTerms}"
+        }
+      ],
+      "suggest_url": "https://example.com?search={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/engines.json b/toolkit/components/search/tests/xpcshell/test-extensions/engines.json
new file mode 100644
index 0000000000..fcb5e03e82
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/engines.json
@@ -0,0 +1,58 @@
+{
+  "data": [
+    {
+      "webExtension": {
+        "id": "plainengine@search.mozilla.org"
+      },
+      "orderHint": 10000,
+      "sendAttributionRequest": true,
+      "appliesTo": [
+        {
+          "included": { "everywhere": true },
+          "default": "yes-if-no-other"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "special-engine@search.mozilla.org"
+      },
+      "orderHint": 7000,
+      "appliesTo": [
+        {
+          "included": { "regions": ["tr"] },
+          "default": "yes"
+        },
+        {
+          "included": { "everywhere": true },
+          "sendAttributionRequest": true
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "multilocale@search.mozilla.org",
+        "locales": ["an"]
+      },
+      "orderHint": 6000,
+      "appliesTo": [
+        {
+          "included": { "regions": ["an"] },
+          "default": "yes"
+        }
+      ]
+    },
+    {
+      "webExtension": {
+        "id": "multilocale@search.mozilla.org",
+        "locales": ["af", "an"]
+      },
+      "orderHint": 6500,
+      "appliesTo": [
+        {
+          "included": { "regions": ["af"] }
+        }
+      ]
+    }
+  ]
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/af/messages.json b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/af/messages.json
new file mode 100644
index 0000000000..95e49f9bc5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/af/messages.json
@@ -0,0 +1,20 @@
+{
+  "extensionName": {
+    "message": "Multilocale AF"
+  },
+  "extensionDescription": {
+    "message": "Wikipedia, die vrye ensiklopedie"
+  },
+  "url_lang": {
+    "message": "af"
+  },
+  "searchUrl": {
+    "message": "https://af.wikipedia.org/wiki/Spesiaal:Soek"
+  },
+  "suggestUrl": {
+    "message": "https://af.wikipedia.org/w/api.php"
+  },
+  "extensionIcon": {
+    "message": "favicon-af.ico"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/an/messages.json b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/an/messages.json
new file mode 100644
index 0000000000..6222338596
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/_locales/an/messages.json
@@ -0,0 +1,20 @@
+{
+  "extensionName": {
+    "message": "Multilocale AN"
+  },
+  "extensionDescription": {
+    "message": "A enciclopedia Libre"
+  },
+  "url_lang": {
+    "message": "an"
+  },
+  "searchUrl": {
+    "message": "https://an.wikipedia.org/wiki/Especial:Mirar"
+  },
+  "suggestUrl": {
+    "message": "https://an.wikipedia.org/w/api.php"
+  },
+  "extensionIcon": {
+    "message": "favicon-an.ico"
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-af.ico b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-af.ico
new file mode 100644
index 0000000000..4314071e24
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-af.ico
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-an.ico b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-an.ico
new file mode 100644
index 0000000000..dda80dfd88
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/favicon-an.ico
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/manifest.json b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/manifest.json
new file mode 100644
index 0000000000..a117ffb0db
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/multilocale/manifest.json
@@ -0,0 +1,23 @@
+{
+  "name": "__MSG_extensionName__",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "multilocale@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "__MSG_extensionDescription__",
+  "icons": {
+    "16": "__MSG_extensionIcon__"
+  },
+  "default_locale": "af",
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "__MSG_extensionName__",
+      "search_url": "__MSG_searchUrl__",
+      "suggest_url": "__MSG_searchUrl__"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/favicon.ico b/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/favicon.ico
new file mode 100644
index 0000000000..dda80dfd88
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/favicon.ico
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/manifest.json b/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/manifest.json
new file mode 100644
index 0000000000..cabb4c9f9a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/plainengine/manifest.json
@@ -0,0 +1,58 @@
+{
+  "name": "Plain",
+  "description": "Plain Engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "plainengine@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Plain",
+      "search_url": "https://duckduckgo.com/",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "t",
+          "condition": "purpose",
+          "purpose": "contextmenu",
+          "value": "ffcm"
+        },
+        {
+          "name": "t",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "ffab"
+        },
+        {
+          "name": "t",
+          "condition": "purpose",
+          "purpose": "searchbar",
+          "value": "ffsb"
+        },
+        {
+          "name": "t",
+          "condition": "purpose",
+          "purpose": "homepage",
+          "value": "ffhp"
+        },
+        {
+          "name": "t",
+          "condition": "purpose",
+          "purpose": "newtab",
+          "value": "ffnt"
+        }
+      ],
+      "suggest_url": "https://ac.duckduckgo.com/ac/q={searchTerms}&type=list"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/favicon.ico b/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/favicon.ico
new file mode 100644
index 0000000000..82339b3b1d
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/favicon.ico
diff --git a/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/manifest.json b/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/manifest.json
new file mode 100644
index 0000000000..1568c6ed55
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test-extensions/special-engine/manifest.json
@@ -0,0 +1,40 @@
+{
+  "name": "Special",
+  "description": "Special Engine",
+  "manifest_version": 2,
+  "version": "1.0",
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "special-engine@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "Special",
+      "search_url": "https://www.google.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        },
+        {
+          "name": "client",
+          "condition": "purpose",
+          "purpose": "keyword",
+          "value": "firefox-b-1-ab"
+        },
+        {
+          "name": "client",
+          "condition": "purpose",
+          "purpose": "searchbar",
+          "value": "firefox-b-1"
+        }
+      ],
+      "suggest_url": "https://www.google.com/complete/search?client=firefox&q={searchTerms}"
+    }
+  }
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_SearchStaticData.js b/toolkit/components/search/tests/xpcshell/test_SearchStaticData.js
new file mode 100644
index 0000000000..741953a1cf
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_SearchStaticData.js
@@ -0,0 +1,40 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests the SearchStaticData module.
+ */
+
+"use strict";
+
+const { SearchStaticData } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchStaticData.sys.mjs"
+);
+
+function run_test() {
+  Assert.ok(
+    SearchStaticData.getAlternateDomains("www.google.com").includes(
+      "www.google.fr"
+    )
+  );
+  Assert.ok(
+    SearchStaticData.getAlternateDomains("www.google.fr").includes(
+      "www.google.com"
+    )
+  );
+  Assert.ok(
+    SearchStaticData.getAlternateDomains("www.google.com").every(d =>
+      d.startsWith("www.google.")
+    )
+  );
+  Assert.ok(!SearchStaticData.getAlternateDomains("google.com").length);
+
+  // Test that methods from SearchStaticData module can be overwritten,
+  // needed for hotfixing.
+  let backup = SearchStaticData.getAlternateDomains;
+  SearchStaticData.getAlternateDomains = () => ["www.bing.fr"];
+  Assert.deepEqual(SearchStaticData.getAlternateDomains("www.bing.com"), [
+    "www.bing.fr",
+  ]);
+  SearchStaticData.getAlternateDomains = backup;
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_appDefaultEngine.js b/toolkit/components/search/tests/xpcshell/test_appDefaultEngine.js
new file mode 100644
index 0000000000..0b6fa30fdf
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_appDefaultEngine.js
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that appDefaultEngine property is set and switches correctly.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  Region._setHomeRegion("an", false);
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines("test-extensions");
+});
+
+add_task(async function test_appDefaultEngine() {
+  await Promise.all([Services.search.init(), promiseAfterSettings()]);
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "Multilocale AN",
+    "Should have returned the correct app default engine"
+  );
+});
+
+add_task(async function test_changeRegion() {
+  // Now change the region, and check we get the correct default according to
+  // the config file.
+
+  // Note: the test could be done with changing regions or locales. The important
+  // part is that the default engine is changing across the switch, and that
+  // the engine is not the first one in the new sorted engines list.
+  await promiseSetHomeRegion("tr");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    // Very important this default is not the first one in the list (which is
+    // the next fallback if the config one can't be found).
+    "Special",
+    "Should have returned the correct engine for the new locale"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_async.js b/toolkit/components/search/tests/xpcshell/test_async.js
new file mode 100644
index 0000000000..f00ba02755
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_async.js
@@ -0,0 +1,40 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines("simple-engines");
+  Services.fog.initializeFOG();
+});
+
+add_task(async function test_async() {
+  Assert.ok(!Services.search.isInitialized);
+
+  let aStatus = await Services.search.init();
+  Assert.ok(Components.isSuccessCode(aStatus));
+  Assert.ok(Services.search.isInitialized);
+
+  // test engines from dir are not loaded.
+  let engines = await Services.search.getEngines();
+  Assert.equal(engines.length, 2);
+
+  // test jar engine is loaded ok.
+  let engine = Services.search.getEngineByName("basic");
+  Assert.notEqual(engine, null);
+  Assert.ok(engine.isAppProvided, "Should be shown as an app-provided engine");
+
+  engine = Services.search.getEngineByName("Simple Engine");
+  Assert.notEqual(engine, null);
+  Assert.ok(engine.isAppProvided, "Should be shown as an app-provided engine");
+
+  // Check the hidden engine is not loaded.
+  engine = Services.search.getEngineByName("hidden");
+  Assert.equal(engine, null);
+
+  // Check if there is a value for startup_time
+  Assert.notEqual(
+    await Glean.searchService.startupTime.testGetValue(),
+    undefined,
+    "Should have a value stored in startup_time"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_config_attribution.js b/toolkit/components/search/tests/xpcshell/test_config_attribution.js
new file mode 100644
index 0000000000..9996cc83c4
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_config_attribution.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function setup() {
+  Region._setHomeRegion("an", false);
+  await SearchTestUtils.useTestEngines("test-extensions");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_send_attribution_request() {
+  let engine = await Services.search.getEngineByName("Plain");
+  Assert.ok(
+    engine.sendAttributionRequest,
+    "Should have noted to send the attribution request for Plain"
+  );
+
+  engine = await Services.search.getEngineByName("Special");
+  Assert.ok(
+    engine.sendAttributionRequest,
+    "Should have noted to send the attribution request for Special"
+  );
+
+  engine = await Services.search.getEngineByName("Multilocale AN");
+  Assert.ok(
+    !engine.sendAttributionRequest,
+    "Should not have noted to send the attribution request for Multilocale AN"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_config_engine_params.js b/toolkit/components/search/tests/xpcshell/test_config_engine_params.js
new file mode 100644
index 0000000000..795dc56324
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_config_engine_params.js
@@ -0,0 +1,68 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("method-extensions");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_get_extension() {
+  let engine = Services.search.getEngineByName("Get Engine");
+  Assert.notEqual(engine, null, "Should have found an engine");
+
+  let url = engine.wrappedJSObject._getURLOfType(SearchUtils.URL_TYPE.SEARCH);
+  Assert.equal(url.method, "GET", "Search URLs method is GET");
+
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://example.com/?config=1&search=foo",
+    "Search URLs should match"
+  );
+
+  let submissionSuggest = engine.getSubmission(
+    "bar",
+    SearchUtils.URL_TYPE.SUGGEST_JSON
+  );
+  Assert.equal(
+    submissionSuggest.uri.spec,
+    "https://example.com/?config=1&suggest=bar",
+    "Suggest URLs should match"
+  );
+});
+
+add_task(async function test_post_extension() {
+  let engine = Services.search.getEngineByName("Post Engine");
+  Assert.ok(!!engine, "Should have found an engine");
+
+  let url = engine.wrappedJSObject._getURLOfType(SearchUtils.URL_TYPE.SEARCH);
+  Assert.equal(url.method, "POST", "Search URLs method is POST");
+
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://example.com/",
+    "Search URLs should match"
+  );
+  Assert.equal(
+    submission.postData.data.data,
+    "config=1&search=foo",
+    "Search postData should match"
+  );
+
+  let submissionSuggest = engine.getSubmission(
+    "bar",
+    SearchUtils.URL_TYPE.SUGGEST_JSON
+  );
+  Assert.equal(
+    submissionSuggest.uri.spec,
+    "https://example.com/",
+    "Suggest URLs should match"
+  );
+  Assert.equal(
+    submissionSuggest.postData.data.data,
+    "config=1&suggest=bar",
+    "Suggest postData should match"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_defaultEngine.js b/toolkit/components/search/tests/xpcshell/test_defaultEngine.js
new file mode 100644
index 0000000000..24b7b2102a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_defaultEngine.js
@@ -0,0 +1,121 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that defaultEngine property can be set and yields the proper events and\
+ * behavior (search results)
+ */
+
+"use strict";
+
+let engine1;
+let engine2;
+
+add_setup(async () => {
+  do_get_profile();
+  Services.fog.initializeFOG();
+
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+
+  await Services.search.init();
+
+  engine1 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+  engine2 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine2.xml`,
+  });
+});
+
+function promiseDefaultNotification() {
+  return SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+}
+
+add_task(async function test_defaultEngine() {
+  let promise = promiseDefaultNotification();
+  Services.search.defaultEngine = engine1;
+  Assert.equal((await promise).wrappedJSObject, engine1);
+  Assert.equal(Services.search.defaultEngine.wrappedJSObject, engine1);
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-Test search engine",
+      displayName: "Test search engine",
+      loadPath: "[http]localhost/test-search-engine.xml",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "verified",
+    },
+  });
+
+  promise = promiseDefaultNotification();
+  Services.search.defaultEngine = engine2;
+  Assert.equal((await promise).wrappedJSObject, engine2);
+  Assert.equal(Services.search.defaultEngine.wrappedJSObject, engine2);
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-A second test engine",
+      displayName: "A second test engine",
+      loadPath: "[http]localhost/a-second-test-engine.xml",
+      submissionUrl: "https://duckduckgo.com/?q=",
+      verified: "verified",
+    },
+  });
+
+  promise = promiseDefaultNotification();
+  Services.search.defaultEngine = engine1;
+  Assert.equal((await promise).wrappedJSObject, engine1);
+  Assert.equal(Services.search.defaultEngine.wrappedJSObject, engine1);
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-Test search engine",
+      displayName: "Test search engine",
+      loadPath: "[http]localhost/test-search-engine.xml",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "verified",
+    },
+  });
+});
+
+add_task(async function test_telemetry_empty_submission_url() {
+  let engine = await Services.search.addOpenSearchEngine(
+    gDataUrl + "../opensearch/simple.xml",
+    null
+  );
+  Services.search.defaultPrivateEngine = engine;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-simple",
+      displayName: "simple",
+      loadPath: "[http]localhost/simple.xml",
+      submissionUrl: "blank:",
+      verified: "verified",
+    },
+    private: {
+      engineId: "",
+      displayName: "",
+      loadPath: "",
+      submissionUrl: "blank:",
+      verified: "",
+    },
+  });
+});
+
+add_task(async function test_switch_with_invalid_overriddenBy() {
+  engine1.wrappedJSObject.setAttr("overriddenBy", "random@id");
+
+  consoleAllowList.push(
+    "Test search engine had overriddenBy set, but no _overriddenData"
+  );
+
+  let promise = promiseDefaultNotification();
+  Services.search.defaultEngine = engine2;
+  Assert.equal((await promise).wrappedJSObject, engine2);
+  Assert.equal(Services.search.defaultEngine.wrappedJSObject, engine2);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_defaultEngine_experiments.js b/toolkit/components/search/tests/xpcshell/test_defaultEngine_experiments.js
new file mode 100644
index 0000000000..59cd0c0942
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_defaultEngine_experiments.js
@@ -0,0 +1,422 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that defaultEngine property can be set and yields the proper events and\
+ * behavior (search results)
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
+});
+
+let getVariableStub;
+
+let defaultGetVariable = name => {
+  if (name == "seperatePrivateDefaultUIEnabled") {
+    return true;
+  }
+  if (name == "seperatePrivateDefaultUrlbarResultEnabled") {
+    return false;
+  }
+  return undefined;
+};
+
+add_setup(async () => {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  sinon.spy(NimbusFeatures.searchConfiguration, "onUpdate");
+  sinon.stub(NimbusFeatures.searchConfiguration, "ready").resolves();
+  getVariableStub = sinon.stub(
+    NimbusFeatures.searchConfiguration,
+    "getVariable"
+  );
+  getVariableStub.callsFake(defaultGetVariable);
+
+  do_get_profile();
+  Services.fog.initializeFOG();
+
+  await SearchTestUtils.useTestEngines("data1");
+
+  await AddonTestUtils.promiseStartupManager();
+
+  let promiseSaved = promiseSaveSettingsData();
+  await Services.search.init();
+  await promiseSaved;
+});
+
+async function switchExperiment(newExperiment) {
+  let promiseReloaded =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  let promiseSaved = promiseSaveSettingsData();
+
+  // Stub getVariable to populate the cache with our expected data
+  getVariableStub.callsFake(name => {
+    if (name == "experiment") {
+      return newExperiment;
+    }
+    return defaultGetVariable(name);
+  });
+  for (let call of NimbusFeatures.searchConfiguration.onUpdate.getCalls()) {
+    call.args[0]();
+  }
+
+  await promiseReloaded;
+  await promiseSaved;
+}
+
+function getSettingsAttribute(setting) {
+  return Services.search.wrappedJSObject._settings.getVerifiedMetaDataAttribute(
+    setting
+  );
+}
+
+add_task(async function test_experiment_setting() {
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the application default engine as default"
+  );
+
+  // Start the experiment.
+  await switchExperiment("exp1");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have set the experiment engine as default"
+  );
+
+  // End the experiment.
+  await switchExperiment("");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have reset the default engine to the application default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should have kept the saved attribute as empty"
+  );
+});
+
+add_task(async function test_experiment_setting_to_same_as_user() {
+  Services.search.defaultEngine = Services.search.getEngineByName("engine2");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have the user selected engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault"
+  );
+
+  // Start the experiment, ensure user default is maintained.
+  await switchExperiment("exp1");
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault"
+  );
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine2",
+    "Should have set the experiment engine as default"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have set the experiment engine as default"
+  );
+
+  // End the experiment.
+  await switchExperiment("");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine1",
+    "Should have set the app default engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have kept the engine the same "
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault",
+    "Should have kept the saved attribute as the user's preference"
+  );
+});
+
+add_task(async function test_experiment_setting_user_changed_back_during() {
+  Services.search.defaultEngine = Services.search.getEngineByName("engine1");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the application default engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should have an empty settings attribute"
+  );
+
+  // Start the experiment.
+  await switchExperiment("exp1");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have set the experiment engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should still have an empty settings attribute"
+  );
+
+  // User resets to the original default engine.
+  Services.search.defaultEngine = Services.search.getEngineByName("engine1");
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the user selected engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine1@search.mozilla.orgdefault"
+  );
+
+  // Ending the experiment should keep the original default and reset the
+  // saved attribute.
+  await switchExperiment("");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine1",
+    "Should have set the app default engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have kept the engine the same"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should have reset the saved attribute to empty after the experiment ended"
+  );
+});
+
+add_task(async function test_experiment_setting_user_changed_back_private() {
+  Services.search.defaultPrivateEngine =
+    Services.search.getEngineByName("engine1");
+
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine1",
+    "Should have the user selected engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("privateDefaultEngineId"),
+    "",
+    "Should have an empty settings attribute"
+  );
+
+  // Start the experiment.
+  await switchExperiment("exp2");
+
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "exp2",
+    "Should have set the experiment engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should still have an empty settings attribute"
+  );
+
+  // User resets to the original default engine.
+  Services.search.defaultPrivateEngine =
+    Services.search.getEngineByName("engine1");
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine1",
+    "Should have the user selected engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("privateDefaultEngineId"),
+    "engine1@search.mozilla.orgdefault"
+  );
+
+  // Ending the experiment should keep the original default and reset the
+  // saved attribute.
+  await switchExperiment("");
+
+  Assert.equal(Services.search.appPrivateDefaultEngine.name, "engine1");
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have kept the engine the same "
+  );
+  Assert.equal(
+    getSettingsAttribute("privateDefaultEngineId"),
+    "",
+    "Should have reset the saved attribute to empty after the experiment ended"
+  );
+});
+
+add_task(async function test_experiment_setting_user_changed_to_other_during() {
+  Services.search.defaultEngine = Services.search.getEngineByName("engine1");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the application default engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should have an empty settings attribute"
+  );
+
+  // Start the experiment.
+  await switchExperiment("exp3");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "exp3",
+    "Should have set the experiment engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should still have an empty settings attribute"
+  );
+
+  // User changes to a different default engine
+  Services.search.defaultEngine = Services.search.getEngineByName("engine2");
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have the user selected engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault",
+    "Should have correctly set the user's default in settings"
+  );
+
+  // Ending the experiment should keep the original default and reset the
+  // saved attribute.
+  await switchExperiment("");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine1",
+    "Should have set the app default engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have kept the user's choice of engine"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault",
+    "Should have kept the user's choice in settings"
+  );
+});
+
+add_task(async function test_experiment_setting_user_hid_app_default_during() {
+  // Add all the test engines to be general search engines. This is important
+  // for the test, as the removed experiment engine needs to be a general search
+  // engine, and the first in the list (aided by the orderHint in
+  // data1/engines.json).
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS.add("engine1@search.mozilla.org");
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS.add("engine2@search.mozilla.org");
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS.add("exp2@search.mozilla.org");
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS.add("exp3@search.mozilla.org");
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+  Services.search.defaultEngine = Services.search.getEngineByName("engine1");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the application default engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should have an empty settings attribute"
+  );
+
+  // Start the experiment.
+  await switchExperiment("exp3");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "exp3",
+    "Should have set the experiment engine as default"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "",
+    "Should still have an empty settings attribute"
+  );
+
+  // User hides the original application engine
+  await Services.search.removeEngine(
+    Services.search.getEngineByName("engine1")
+  );
+  Assert.equal(
+    Services.search.getEngineByName("engine1").hidden,
+    true,
+    "Should have hid the selected engine"
+  );
+
+  // Ending the experiment should keep the original default and reset the
+  // saved attribute.
+  await switchExperiment("");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine1",
+    "Should have set the app default engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.hidden,
+    false,
+    "Should not have set default engine to an engine that is hidden"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have reset the user's engine to the next available engine"
+  );
+  Assert.equal(
+    getSettingsAttribute("defaultEngineId"),
+    "engine2@search.mozilla.orgdefault",
+    "Should have saved the choice in settings"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_defaultEngine_fallback.js b/toolkit/components/search/tests/xpcshell/test_defaultEngine_fallback.js
new file mode 100644
index 0000000000..3d8a36a2e0
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_defaultEngine_fallback.js
@@ -0,0 +1,406 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * This test is checking the fallbacks when an engine that is default is
+ * removed or hidden.
+ *
+ * The fallback procedure is:
+ *
+ * - Region/Locale default (if visible)
+ * - First visible engine
+ * - If no other visible engines, unhide the region/locale default and use it.
+ */
+
+let appDefault;
+let appPrivateDefault;
+
+add_task(async function setup() {
+  useHttpServer();
+  await SearchTestUtils.useTestEngines();
+
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS = new Set([
+    "engine-resourceicon@search.mozilla.org",
+    "engine-reordered@search.mozilla.org",
+  ]);
+
+  await AddonTestUtils.promiseStartupManager();
+
+  appDefault = await Services.search.getDefault();
+  appPrivateDefault = await Services.search.getDefaultPrivate();
+});
+
+function getDefault(privateMode) {
+  return privateMode
+    ? Services.search.getDefaultPrivate()
+    : Services.search.getDefault();
+}
+
+function setDefault(privateMode, engine) {
+  return privateMode
+    ? Services.search.setDefaultPrivate(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      )
+    : Services.search.setDefault(
+        engine,
+        Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+      );
+}
+
+async function checkFallbackDefaultRegion(checkPrivate) {
+  let defaultEngine = checkPrivate ? appPrivateDefault : appDefault;
+  let expectedDefaultNotification = checkPrivate
+    ? SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE
+    : SearchUtils.MODIFIED_TYPE.DEFAULT;
+  Services.search.restoreDefaultEngines();
+
+  let otherEngine = Services.search.getEngineByName("engine-chromeicon");
+  await setDefault(checkPrivate, otherEngine);
+
+  Assert.notEqual(
+    otherEngine,
+    defaultEngine,
+    "Sanity check engines are different"
+  );
+
+  const observer = new SearchObserver(
+    [
+      expectedDefaultNotification,
+      // For hiding (removing) the engine.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      SearchUtils.MODIFIED_TYPE.REMOVED,
+    ],
+    expectedDefaultNotification
+  );
+
+  await Services.search.removeEngine(otherEngine);
+
+  let notified = await observer.promise;
+
+  Assert.ok(otherEngine.hidden, "Should have hidden the removed engine");
+  Assert.equal(
+    (await getDefault(checkPrivate)).name,
+    defaultEngine.name,
+    "Should have reverted the defaultEngine to the region default"
+  );
+  Assert.equal(
+    notified.name,
+    defaultEngine.name,
+    "Should have notified the correct default engine"
+  );
+}
+
+add_task(async function test_default_fallback_to_region_default() {
+  await checkFallbackDefaultRegion(false);
+});
+
+add_task(async function test_default_private_fallback_to_region_default() {
+  await checkFallbackDefaultRegion(true);
+});
+
+async function checkFallbackFirstVisible(checkPrivate) {
+  let defaultEngine = checkPrivate ? appPrivateDefault : appDefault;
+  let expectedDefaultNotification = checkPrivate
+    ? SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE
+    : SearchUtils.MODIFIED_TYPE.DEFAULT;
+  Services.search.restoreDefaultEngines();
+
+  let otherEngine = Services.search.getEngineByName("engine-chromeicon");
+  await setDefault(checkPrivate, otherEngine);
+  await Services.search.removeEngine(defaultEngine);
+
+  Assert.notEqual(
+    otherEngine,
+    defaultEngine,
+    "Sanity check engines are different"
+  );
+
+  const observer = new SearchObserver(
+    checkPrivate
+      ? [
+          expectedDefaultNotification,
+          // For hiding (removing) the engine.
+          SearchUtils.MODIFIED_TYPE.CHANGED,
+          SearchUtils.MODIFIED_TYPE.REMOVED,
+        ]
+      : [
+          expectedDefaultNotification,
+          // For hiding (removing) the engine.
+          SearchUtils.MODIFIED_TYPE.CHANGED,
+          SearchUtils.MODIFIED_TYPE.REMOVED,
+        ],
+    expectedDefaultNotification
+  );
+
+  await Services.search.removeEngine(otherEngine);
+
+  let notified = await observer.promise;
+
+  Assert.equal(
+    (await getDefault(checkPrivate)).name,
+    "engine-resourceicon",
+    "Should have set the default engine to the first visible general engine"
+  );
+  Assert.equal(
+    notified.name,
+    "engine-resourceicon",
+    "Should have notified the correct default general engine"
+  );
+}
+
+add_task(async function test_default_fallback_to_first_gen_visible() {
+  await checkFallbackFirstVisible(false);
+});
+
+add_task(async function test_default_private_fallback_to_first_gen_visible() {
+  await checkFallbackFirstVisible(true);
+});
+
+// Removing all visible engines affects both the default and private default
+// engines.
+add_task(async function test_default_fallback_when_no_others_visible() {
+  // Remove all but one of the visible engines.
+  let visibleEngines = await Services.search.getVisibleEngines();
+  for (let i = 0; i < visibleEngines.length - 1; i++) {
+    await Services.search.removeEngine(visibleEngines[i]);
+  }
+  Assert.equal(
+    (await Services.search.getVisibleEngines()).length,
+    1,
+    "Should only have one visible engine"
+  );
+
+  const observer = new SearchObserver(
+    [
+      // Unhiding of the default engine.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      // Change of the default.
+      SearchUtils.MODIFIED_TYPE.DEFAULT,
+      // Unhiding of the default private.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE,
+      // Hiding the engine.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      SearchUtils.MODIFIED_TYPE.REMOVED,
+    ],
+    SearchUtils.MODIFIED_TYPE.DEFAULT
+  );
+
+  // Now remove the last engine, which should set the new default.
+  await Services.search.removeEngine(visibleEngines[visibleEngines.length - 1]);
+
+  let notified = await observer.promise;
+
+  Assert.equal(
+    (await getDefault(false)).name,
+    appDefault.name,
+    "Should fallback to the app default engine after removing all engines"
+  );
+  Assert.equal(
+    (await getDefault(true)).name,
+    appPrivateDefault.name,
+    "Should fallback to the app default private engine after removing all engines"
+  );
+  Assert.equal(
+    notified.name,
+    appDefault.name,
+    "Should have notified the correct default engine"
+  );
+  Assert.ok(
+    !appPrivateDefault.hidden,
+    "Should have unhidden the app default private engine"
+  );
+  Assert.equal(
+    (await Services.search.getVisibleEngines()).length,
+    2,
+    "Should now have two engines visible"
+  );
+});
+
+add_task(async function test_default_fallback_remove_default_no_visible() {
+  // Remove all but the default engine.
+  Services.search.defaultPrivateEngine = Services.search.defaultEngine;
+  let visibleEngines = await Services.search.getVisibleEngines();
+  for (let engine of visibleEngines) {
+    if (engine.name != appDefault.name) {
+      await Services.search.removeEngine(engine);
+    }
+  }
+  Assert.equal(
+    (await Services.search.getVisibleEngines()).length,
+    1,
+    "Should only have one visible engine"
+  );
+
+  const observer = new SearchObserver(
+    [
+      // Unhiding of the default engine.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      // Change of the default.
+      SearchUtils.MODIFIED_TYPE.DEFAULT,
+      SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE,
+      // Hiding the engine.
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      SearchUtils.MODIFIED_TYPE.REMOVED,
+    ],
+    SearchUtils.MODIFIED_TYPE.DEFAULT
+  );
+
+  // Now remove the last engine, which should set the new default.
+  await Services.search.removeEngine(appDefault);
+
+  let notified = await observer.promise;
+
+  Assert.equal(
+    (await getDefault(false)).name,
+    "engine-resourceicon",
+    "Should fallback the default engine to the first general search engine"
+  );
+  Assert.equal(
+    (await getDefault(true)).name,
+    "engine-resourceicon",
+    "Should fallback the default private engine to the first general search engine"
+  );
+  Assert.equal(
+    notified.name,
+    "engine-resourceicon",
+    "Should have notified the correct default engine"
+  );
+  Assert.ok(
+    !Services.search.getEngineByName("engine-resourceicon").hidden,
+    "Should have unhidden the new engine"
+  );
+  Assert.equal(
+    (await Services.search.getVisibleEngines()).length,
+    1,
+    "Should now have one engines visible"
+  );
+});
+
+add_task(
+  async function test_default_fallback_remove_default_no_visible_or_general() {
+    // Reset.
+    Services.search.restoreDefaultEngines();
+    Services.search.defaultEngine = Services.search.defaultPrivateEngine =
+      appPrivateDefault;
+
+    // Remove all but the default engine.
+    let visibleEngines = await Services.search.getVisibleEngines();
+    for (let engine of visibleEngines) {
+      if (engine.name != appPrivateDefault.name) {
+        await Services.search.removeEngine(engine);
+      }
+    }
+    Assert.deepEqual(
+      (await Services.search.getVisibleEngines()).map(e => e.name),
+      appPrivateDefault.name,
+      "Should only have one visible engine"
+    );
+
+    SearchUtils.GENERAL_SEARCH_ENGINE_IDS.clear();
+
+    const observer = new SearchObserver(
+      [
+        // Unhiding of the default engine.
+        SearchUtils.MODIFIED_TYPE.CHANGED,
+        // Change of the default.
+        SearchUtils.MODIFIED_TYPE.DEFAULT,
+        SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE,
+        // Hiding the engine.
+        SearchUtils.MODIFIED_TYPE.CHANGED,
+        SearchUtils.MODIFIED_TYPE.REMOVED,
+      ],
+      SearchUtils.MODIFIED_TYPE.DEFAULT
+    );
+
+    // Now remove the last engine, which should set the new default.
+    await Services.search.removeEngine(appPrivateDefault);
+
+    let notified = await observer.promise;
+
+    Assert.equal(
+      (await getDefault(false)).name,
+      "Test search engine",
+      "Should fallback to the first engine that isn't a general search engine"
+    );
+    Assert.equal(
+      (await getDefault(true)).name,
+      "Test search engine",
+      "Should fallback the private engine to the first engine that isn't a general search engine"
+    );
+    Assert.equal(
+      notified.name,
+      "Test search engine",
+      "Should have notified the correct default engine"
+    );
+    Assert.ok(
+      !Services.search.getEngineByName("Test search engine").hidden,
+      "Should have unhidden the new engine"
+    );
+    Assert.equal(
+      (await Services.search.getVisibleEngines()).length,
+      1,
+      "Should now have one engines visible"
+    );
+  }
+);
+
+// Test the other remove engine route - for removing non-application provided
+// engines.
+
+async function checkNonBuiltinFallback(checkPrivate) {
+  let defaultEngine = checkPrivate ? appPrivateDefault : appDefault;
+  let expectedDefaultNotification = checkPrivate
+    ? SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE
+    : SearchUtils.MODIFIED_TYPE.DEFAULT;
+  Services.search.restoreDefaultEngines();
+
+  let addedEngine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine2.xml`,
+  });
+
+  await setDefault(checkPrivate, addedEngine);
+
+  const observer = new SearchObserver(
+    [expectedDefaultNotification, SearchUtils.MODIFIED_TYPE.REMOVED],
+    expectedDefaultNotification
+  );
+
+  // Remove the current engine...
+  await Services.search.removeEngine(addedEngine);
+
+  // ... and verify we've reverted to the normal default engine.
+  Assert.equal(
+    (await getDefault(checkPrivate)).name,
+    defaultEngine.name,
+    "Should revert to the app default engine"
+  );
+
+  let notified = await observer.promise;
+  Assert.equal(
+    notified.name,
+    defaultEngine.name,
+    "Should have notified the correct default engine"
+  );
+}
+
+add_task(async function test_default_fallback_non_builtin() {
+  await checkNonBuiltinFallback(false);
+});
+
+add_task(async function test_default_fallback_non_builtin_private() {
+  await checkNonBuiltinFallback(true);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_defaultPrivateEngine.js b/toolkit/components/search/tests/xpcshell/test_defaultPrivateEngine.js
new file mode 100644
index 0000000000..74c0dc5188
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_defaultPrivateEngine.js
@@ -0,0 +1,582 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that defaultEngine property can be set and yields the proper events and\
+ * behavior (search results)
+ */
+
+"use strict";
+
+let engine1;
+let engine2;
+let appDefault;
+let appPrivateDefault;
+
+add_setup(async () => {
+  do_get_profile();
+  Services.fog.initializeFOG();
+
+  await SearchTestUtils.useTestEngines();
+
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  useHttpServer("opensearch");
+  await AddonTestUtils.promiseStartupManager();
+
+  await Services.search.init();
+
+  appDefault = Services.search.appDefaultEngine;
+  appPrivateDefault = Services.search.appPrivateDefaultEngine;
+  engine1 = Services.search.getEngineByName("engine-rel-searchform-purpose");
+  engine2 = Services.search.getEngineByName("engine-chromeicon");
+});
+
+add_task(async function test_defaultPrivateEngine() {
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    appPrivateDefault,
+    "Should have the app private default as the default private engine"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    appDefault,
+    "Should have the app default as the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+      displayName: "Test search engine",
+      loadPath: "[addon]engine@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+    private: {
+      engineId: "engine-pref",
+      displayName: "engine-pref",
+      loadPath: "[addon]engine-pref@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+  });
+
+  let promise = promiseDefaultNotification("private");
+  Services.search.defaultPrivateEngine = engine1;
+  Assert.equal(
+    await promise,
+    engine1,
+    "Should have notified setting the private engine to the new one"
+  );
+
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine1,
+    "Should have set the private engine to the new one"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    appDefault,
+    "Should not have changed the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+      displayName: "Test search engine",
+      loadPath: "[addon]engine@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+    private: {
+      engineId: "engine-rel-searchform-purpose",
+      displayName: "engine-rel-searchform-purpose",
+      loadPath: "[addon]engine-rel-searchform-purpose@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=&channel=sb",
+      verified: "default",
+    },
+  });
+
+  promise = promiseDefaultNotification("private");
+  await Services.search.setDefaultPrivate(
+    engine2,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(
+    await promise,
+    engine2,
+    "Should have notified setting the private engine to the new one using async api"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should have set the private engine to the new one using the async api"
+  );
+
+  // We use the names here as for some reason the getDefaultPrivate promise
+  // returns something which is an nsISearchEngine but doesn't compare
+  // exactly to what engine2 is.
+  Assert.equal(
+    (await Services.search.getDefaultPrivate()).name,
+    engine2.name,
+    "Should have got the correct private engine with the async api"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    appDefault,
+    "Should not have changed the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+      displayName: "Test search engine",
+      loadPath: "[addon]engine@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+      displayName: "engine-chromeicon",
+      loadPath: "[addon]engine-chromeicon@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+  });
+
+  promise = promiseDefaultNotification("private");
+  await Services.search.setDefaultPrivate(
+    engine1,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(
+    await promise,
+    engine1,
+    "Should have notified reverting the private engine to the selected one using async api"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine1,
+    "Should have reverted the private engine to the selected one using the async api"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+    },
+    private: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+  });
+
+  engine1.hidden = true;
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    appPrivateDefault,
+    "Should reset to the app default private engine when hiding the default"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    appDefault,
+    "Should not have changed the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+    },
+    private: {
+      engineId: "engine-pref",
+    },
+  });
+
+  engine1.hidden = false;
+  Services.search.defaultEngine = engine1;
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    appPrivateDefault,
+    "Setting the default engine should not affect the private default"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+    private: {
+      engineId: "engine-pref",
+    },
+  });
+
+  Services.search.defaultEngine = appDefault;
+});
+
+add_task(async function test_telemetry_private_empty_submission_url() {
+  let engine = await Services.search.addOpenSearchEngine(
+    gDataUrl + "simple.xml",
+    null
+  );
+  Services.search.defaultPrivateEngine = engine;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: appDefault.telemetryId,
+    },
+    private: {
+      engineId: "other-simple",
+      displayName: "simple",
+      loadPath: "[http]localhost/simple.xml",
+      submissionUrl: "blank:",
+      verified: "verified",
+    },
+  });
+
+  Services.search.defaultEngine = appDefault;
+});
+
+add_task(async function test_defaultPrivateEngine_turned_off() {
+  Services.search.defaultEngine = appDefault;
+  Services.search.defaultPrivateEngine = engine1;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+    },
+    private: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+  });
+
+  let promise = promiseDefaultNotification("private");
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+  Assert.equal(
+    await promise,
+    appDefault,
+    "Should have notified setting the first engine correctly."
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+
+  promise = promiseDefaultNotification("normal");
+  let privatePromise = promiseDefaultNotification("private");
+  Services.search.defaultEngine = engine1;
+  Assert.equal(
+    await promise,
+    engine1,
+    "Should have notified setting the first engine correctly."
+  );
+  Assert.equal(
+    await privatePromise,
+    engine1,
+    "Should have notified setting of the private engine as well."
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine1,
+    "Should be set to the first engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine1,
+    "Should keep the default engine in sync with the pref off"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+
+  promise = promiseDefaultNotification("private");
+  Services.search.defaultPrivateEngine = engine2;
+  Assert.equal(
+    await promise,
+    engine2,
+    "Should have notified setting the second engine correctly."
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should be set to the second engine correctly"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine1,
+    "Should not change the normal mode default engine"
+  );
+  Assert.equal(
+    Services.prefs.getBoolPref(
+      SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+      false
+    ),
+    true,
+    "Should have set the separate private default pref to true"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+    },
+  });
+
+  promise = promiseDefaultNotification("private");
+  Services.search.defaultPrivateEngine = engine1;
+  Assert.equal(
+    await promise,
+    engine1,
+    "Should have notified resetting to the first engine again"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine1,
+    "Should be reset to the first engine again"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine1,
+    "Should keep the default engine in sync with the pref off"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+    private: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+  });
+});
+
+add_task(async function test_defaultPrivateEngine_ui_turned_off() {
+  engine1.hidden = false;
+  engine2.hidden = false;
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  Services.search.defaultEngine = engine2;
+  Services.search.defaultPrivateEngine = engine1;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+  });
+
+  let promise = promiseDefaultNotification("private");
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    false
+  );
+  Assert.equal(
+    await promise,
+    engine2,
+    "Should have notified for resetting of the private pref."
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+
+  promise = promiseDefaultNotification("normal");
+  Services.search.defaultPrivateEngine = engine1;
+  Assert.equal(
+    await promise,
+    engine1,
+    "Should have notified setting the first engine correctly."
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine1,
+    "Should be set to the first engine correctly"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-rel-searchform-purpose",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+});
+
+add_task(async function test_defaultPrivateEngine_same_engine_toggle_pref() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  // Set the normal and private engines to be the same
+  Services.search.defaultEngine = engine2;
+  Services.search.defaultPrivateEngine = engine2;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+    },
+  });
+
+  // Disable pref
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should not change the default private engine"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine2,
+    "Should not change the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+
+  // Re-enable pref
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should not change the default private engine"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine2,
+    "Should not change the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+    },
+  });
+});
+
+add_task(async function test_defaultPrivateEngine_same_engine_toggle_ui_pref() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  // Set the normal and private engines to be the same
+  Services.search.defaultEngine = engine2;
+  Services.search.defaultPrivateEngine = engine2;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+    },
+  });
+
+  // Disable UI pref
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    false
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should not change the default private engine"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine2,
+    "Should not change the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "",
+    },
+  });
+
+  // Re-enable UI pref
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine,
+    engine2,
+    "Should not change the default private engine"
+  );
+  Assert.equal(
+    Services.search.defaultEngine,
+    engine2,
+    "Should not change the default engine"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine-chromeicon",
+    },
+    private: {
+      engineId: "engine-chromeicon",
+    },
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_alias.js b/toolkit/components/search/tests/xpcshell/test_engine_alias.js
new file mode 100644
index 0000000000..62c3c141c1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_alias.js
@@ -0,0 +1,31 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const NAME = "Test Alias Engine";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+  let settingsFileWritten = promiseAfterSettings();
+  await Services.search.init();
+  await settingsFileWritten;
+});
+
+add_task(async function upgrade_with_configuration_change_test() {
+  let settingsFileWritten = promiseAfterSettings();
+  await SearchTestUtils.installSearchExtension({
+    name: NAME,
+    keyword: "testalias",
+  });
+  await settingsFileWritten;
+
+  let engine = await Services.search.getEngineByAlias("testalias");
+  Assert.equal(engine?.name, NAME, "Engine can be fetched by alias");
+
+  // Restart the search service but not the AddonManager, we will
+  // load the engines from settings.
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init();
+
+  engine = await Services.search.getEngineByAlias("testalias");
+  Assert.equal(engine?.name, NAME, "Engine can be fetched by alias");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_ids.js b/toolkit/components/search/tests/xpcshell/test_engine_ids.js
new file mode 100644
index 0000000000..c6e5e7e148
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_ids.js
@@ -0,0 +1,144 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests Search Engine IDs are created correctly.
+ */
+
+"use strict";
+
+const { EnterprisePolicyTesting } = ChromeUtils.importESModule(
+  "resource://testing-common/EnterprisePolicyTesting.sys.mjs"
+);
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+add_task(async function setup() {
+  useHttpServer("opensearch");
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_add_on_engine_id() {
+  let addOnEngine = Services.search.defaultEngine;
+
+  Assert.equal(
+    addOnEngine.name,
+    "Test search engine",
+    "Should have installed the Test search engine as default."
+  );
+  Assert.ok(addOnEngine.id, "The Addon Search Engine should have an id.");
+  Assert.equal(
+    addOnEngine.id,
+    "engine@search.mozilla.orgdefault",
+    "The Addon Search Engine id should be the webextension id + the locale."
+  );
+});
+
+add_task(async function test_user_engine_id() {
+  let promiseEngineAdded = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.ADDED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  await Services.search.addUserEngine(
+    "user",
+    "https://example.com/user?q={searchTerms}",
+    "u"
+  );
+
+  await promiseEngineAdded;
+  let userEngine = Services.search.getEngineByName("user");
+
+  Assert.ok(userEngine, "Should have installed the User Search Engine.");
+  Assert.ok(userEngine.id, "The User Search Engine should have an id.");
+  Assert.equal(
+    userEngine.id.length,
+    36,
+    "The User Search Engine id should be a 36 character uuid."
+  );
+});
+
+add_task(async function test_open_search_engine_id() {
+  let promiseEngineAdded = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.ADDED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  let openSearchEngine = await Services.search.addOpenSearchEngine(
+    gDataUrl + "simple.xml",
+    null
+  );
+
+  await promiseEngineAdded;
+
+  Assert.ok(openSearchEngine, "Should have installed the Open Search Engine.");
+  Assert.ok(openSearchEngine.id, "The Open Search Engine should have an id.");
+  Assert.equal(
+    openSearchEngine.id.length,
+    36,
+    "The Open Search Engine id should be a 36 character uuid."
+  );
+});
+
+add_task(async function test_enterprise_policy_engine_id() {
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Add: [
+          {
+            Name: "policy",
+            Description: "Test policy engine",
+            IconURL: "data:image/gif;base64,R0lGODl",
+            Alias: "p",
+            URLTemplate: "https://example.com?q={searchTerms}",
+            SuggestURLTemplate: "https://example.com/suggest/?q={searchTerms}",
+          },
+        ],
+      },
+    },
+  });
+
+  let policyEngine = Services.search.getEngineByName("policy");
+
+  Assert.ok(policyEngine, "Should have installed the Policy Engine.");
+  Assert.ok(policyEngine.id, "The Policy Engine should have an id.");
+  Assert.equal(
+    policyEngine.id,
+    "policy-policy",
+    "The Policy Engine id should be 'policy-' + 'the name of the policy engine'."
+  );
+});
+
+/**
+ * Loads a new enterprise policy, and re-initialise the search service
+ * with the new policy. Also waits for the search service to write the settings
+ * file to disk.
+ *
+ * @param {object} policy
+ *   The enterprise policy to use.
+ */
+async function setupPolicyEngineWithJson(policy) {
+  Services.search.wrappedJSObject.reset();
+
+  await EnterprisePolicyTesting.setupPolicyEngineWithJson(policy);
+
+  let settingsWritten = SearchTestUtils.promiseSearchNotification(
+    "write-settings-to-disk-complete"
+  );
+  await Services.search.init();
+  await settingsWritten;
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_multiple_alias.js b/toolkit/components/search/tests/xpcshell/test_engine_multiple_alias.js
new file mode 100644
index 0000000000..f4a7905d45
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_multiple_alias.js
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const NAME = "Test Alias Engine";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function upgrade_with_configuration_change_test() {
+  let settingsFileWritten = promiseAfterSettings();
+  await SearchTestUtils.installSearchExtension({
+    name: NAME,
+    keyword: [" test", "alias "],
+  });
+  await settingsFileWritten;
+
+  let engine = await Services.search.getEngineByAlias("test");
+  Assert.equal(engine?.name, NAME, "Can be fetched by either alias");
+  engine = await Services.search.getEngineByAlias("alias");
+  Assert.equal(engine?.name, NAME, "Can be fetched by either alias");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector.js b/toolkit/components/search/tests/xpcshell/test_engine_selector.js
new file mode 100644
index 0000000000..7052a7de76
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector.js
@@ -0,0 +1,241 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const TEST_CONFIG = [
+  {
+    engineName: "aol",
+    orderHint: 500,
+    webExtension: {
+      locales: ["default"],
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["us"] },
+        webExtension: {
+          locales: ["baz-$USER_LOCALE"],
+        },
+        telemetryId: "foo-$USER_LOCALE",
+      },
+      {
+        included: { regions: ["fr"] },
+        webExtension: {
+          locales: ["region-$USER_REGION"],
+        },
+        telemetryId: "bar-$USER_REGION",
+      },
+      {
+        included: { regions: ["be"] },
+        webExtension: {
+          locales: ["$USER_LOCALE"],
+        },
+        telemetryId: "$USER_LOCALE",
+      },
+      {
+        included: { regions: ["au"] },
+        webExtension: {
+          locales: ["$USER_REGION"],
+        },
+        telemetryId: "$USER_REGION",
+      },
+    ],
+  },
+  {
+    engineName: "lycos",
+    orderHint: 1000,
+    default: "yes",
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { locales: { matches: ["zh-CN"] } },
+      },
+    ],
+  },
+  {
+    engineName: "altavista",
+    orderHint: 2000,
+    defaultPrivate: "yes",
+    appliesTo: [
+      {
+        included: { locales: { matches: ["en-US"] } },
+      },
+      {
+        included: { regions: ["default"] },
+      },
+    ],
+  },
+  {
+    engineName: "excite",
+    default: "yes-if-no-other",
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["us"] },
+      },
+      {
+        included: { everywhere: true },
+        experiment: "acohortid",
+      },
+    ],
+  },
+  {
+    engineName: "askjeeves",
+  },
+];
+
+const engineSelector = new SearchEngineSelector();
+
+add_task(async function setup() {
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  sinon.stub(settings, "get").returns(TEST_CONFIG);
+});
+
+add_task(async function test_engine_selector() {
+  let { engines, privateDefault } =
+    await engineSelector.fetchEngineConfiguration({
+      locale: "en-US",
+      region: "us",
+    });
+  Assert.equal(
+    privateDefault.engineName,
+    "altavista",
+    "Should set altavista as privateDefault"
+  );
+  let names = engines.map(obj => obj.engineName);
+  Assert.deepEqual(names, ["lycos", "altavista", "aol"], "Correct order");
+  Assert.equal(
+    engines[2].webExtension.locale,
+    "baz-en-US",
+    "Subsequent matches in applies to can override default"
+  );
+
+  ({ engines, privateDefault } = await engineSelector.fetchEngineConfiguration({
+    locale: "zh-CN",
+    region: "kz",
+  }));
+  Assert.equal(engines.length, 2, "Correct engines are returns");
+  Assert.equal(privateDefault, null, "There should be no privateDefault");
+  names = engines.map(obj => obj.engineName);
+  Assert.deepEqual(
+    names,
+    ["excite", "aol"],
+    "The engines should be in the correct order"
+  );
+
+  ({ engines, privateDefault } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+    experiment: "acohortid",
+  }));
+  Assert.deepEqual(
+    engines.map(obj => obj.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Engines are in the correct order and include the experiment engine"
+  );
+
+  ({ engines, privateDefault } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+    experiment: "acohortid",
+  }));
+  Assert.deepEqual(
+    engines.map(obj => obj.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "The engines should be in the correct order"
+  );
+  Assert.equal(
+    privateDefault.engineName,
+    "altavista",
+    "Should set altavista as privateDefault"
+  );
+});
+
+add_task(async function test_locale_region_replacement() {
+  let { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+  });
+  let engine = engines.find(e => e.engineName == "aol");
+  Assert.equal(
+    engine.webExtension.locale,
+    "baz-en-US",
+    "The locale is correctly inserted into the locale field"
+  );
+  Assert.equal(
+    engine.telemetryId,
+    "foo-en-US",
+    "The locale is correctly inserted into the telemetryId"
+  );
+
+  ({ engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "it",
+    region: "us",
+  }));
+  engine = engines.find(e => e.engineName == "aol");
+
+  Assert.equal(
+    engines.find(e => e.engineName == "aol").webExtension.locale,
+    "baz-it",
+    "The locale is correctly inserted into the locale field"
+  );
+  Assert.equal(
+    engine.telemetryId,
+    "foo-it",
+    "The locale is correctly inserted into the telemetryId"
+  );
+
+  ({ engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-CA",
+    region: "fr",
+  }));
+  engine = engines.find(e => e.engineName == "aol");
+  Assert.equal(
+    engine.webExtension.locale,
+    "region-fr",
+    "The region is correctly inserted into the locale field"
+  );
+  Assert.equal(
+    engine.telemetryId,
+    "bar-fr",
+    "The region is correctly inserted into the telemetryId"
+  );
+
+  ({ engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "fy-NL",
+    region: "be",
+  }));
+  engine = engines.find(e => e.engineName == "aol");
+  Assert.equal(
+    engine.webExtension.locale,
+    "fy-NL",
+    "The locale is correctly inserted into the locale field"
+  );
+  Assert.equal(
+    engine.telemetryId,
+    "fy-NL",
+    "The locale is correctly inserted into the telemetryId"
+  );
+  ({ engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "au",
+  }));
+  engine = engines.find(e => e.engineName == "aol");
+  Assert.equal(
+    engine.webExtension.locale,
+    "au",
+    "The region is correctly inserted into the locale field"
+  );
+  Assert.equal(
+    engine.telemetryId,
+    "au",
+    "The region is correctly inserted into the telemetryId"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_application.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_application.js
new file mode 100644
index 0000000000..ef54b763af
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_application.js
@@ -0,0 +1,115 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const TEST_CONFIG = [
+  {
+    webExtension: {
+      id: "aol@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+    default: "yes-if-no-other",
+  },
+  {
+    webExtension: {
+      id: "lycos@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          channel: ["nightly"],
+        },
+      },
+    ],
+    default: "yes",
+  },
+  {
+    webExtension: {
+      id: "altavista@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          channel: ["nightly", "esr"],
+        },
+      },
+    ],
+  },
+  {
+    webExtension: {
+      id: "excite@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { everywhere: true },
+        application: {
+          channel: ["release"],
+        },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+const expectedEnginesPerChannel = {
+  default: ["aol@example.com", "excite@example.com"],
+  nightly: [
+    "lycos@example.com",
+    "aol@example.com",
+    "altavista@example.com",
+    "excite@example.com",
+  ],
+  beta: ["aol@example.com", "excite@example.com"],
+  release: ["excite@example.com", "aol@example.com"],
+  esr: ["aol@example.com", "altavista@example.com", "excite@example.com"],
+};
+
+const expectedDefaultEngine = {
+  default: "aol@example.com",
+  nightly: "lycos@example.com",
+  beta: "aol@example.com",
+  release: "excite@example.com",
+  esr: "aol@example.com",
+};
+
+const engineSelector = new SearchEngineSelector();
+
+add_task(async function test_engine_selector_channels() {
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  sinon.stub(settings, "get").returns(TEST_CONFIG);
+
+  for (let [channel, expected] of Object.entries(expectedEnginesPerChannel)) {
+    const { engines } = await engineSelector.fetchEngineConfiguration({
+      locale: "en-US",
+      region: "us",
+      channel,
+    });
+
+    const engineIds = engines.map(obj => obj.webExtension.id);
+    Assert.deepEqual(
+      engineIds,
+      expected,
+      `Should have the expected engines for channel "${channel}"`
+    );
+
+    Assert.equal(
+      engineIds[0],
+      expectedDefaultEngine[channel],
+      `Should have the correct default for channel "${channel}"`
+    );
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_application_distribution.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_application_distribution.js
new file mode 100644
index 0000000000..2e29eac198
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_application_distribution.js
@@ -0,0 +1,120 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "aol@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+    default: "yes-if-no-other",
+  },
+  {
+    webExtension: {
+      id: "excite@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        // Test with a application/distributions section present but an
+        // empty list.
+        application: {
+          distributions: [],
+        },
+      },
+    ],
+  },
+  {
+    webExtension: {
+      id: "lycos@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          distributions: ["cake"],
+        },
+      },
+    ],
+    default: "yes",
+  },
+  {
+    webExtension: {
+      id: "altavista@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          excludedDistributions: ["apples"],
+        },
+      },
+    ],
+  },
+];
+
+const engineSelector = new SearchEngineSelector();
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_no_distribution_preference() {
+  let { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "default",
+    region: "default",
+    channel: "",
+    distroID: "",
+  });
+  const engineIds = engines.map(obj => obj.webExtension.id);
+  Assert.deepEqual(
+    engineIds,
+    ["aol@example.com", "excite@example.com", "altavista@example.com"],
+    `Should have the expected engines for a normal build.`
+  );
+});
+
+add_task(async function test_distribution_included() {
+  let { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "default",
+    region: "default",
+    channel: "",
+    distroID: "cake",
+  });
+  const engineIds = engines.map(obj => obj.webExtension.id);
+  Assert.deepEqual(
+    engineIds,
+    [
+      "lycos@example.com",
+      "aol@example.com",
+      "excite@example.com",
+      "altavista@example.com",
+    ],
+    `Should have the expected engines for the "cake" distribution.`
+  );
+});
+
+add_task(async function test_distribution_excluded() {
+  let { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "default",
+    region: "default",
+    channel: "",
+    distroID: "apples",
+  });
+  const engineIds = engines.map(obj => obj.webExtension.id);
+  Assert.deepEqual(
+    engineIds,
+    ["aol@example.com", "excite@example.com"],
+    `Should have the expected engines for the "apples" distribution.`
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_application_name.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_application_name.js
new file mode 100644
index 0000000000..fef03c47be
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_application_name.js
@@ -0,0 +1,126 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "aol@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+    default: "yes-if-no-other",
+  },
+  {
+    webExtension: {
+      id: "lycos@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          name: ["firefox"],
+        },
+      },
+    ],
+    default: "yes",
+  },
+  {
+    webExtension: {
+      id: "altavista@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          name: ["fenix"],
+        },
+      },
+    ],
+  },
+  {
+    webExtension: {
+      id: "excite@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        application: {
+          name: ["firefox"],
+          minVersion: "10",
+          maxVersion: "30",
+        },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+const engineSelector = new SearchEngineSelector();
+
+const tests = [
+  {
+    name: "Firefox",
+    version: "1",
+    expected: ["lycos@example.com", "aol@example.com"],
+  },
+  {
+    name: "Firefox",
+    version: "20",
+    expected: ["lycos@example.com", "aol@example.com", "excite@example.com"],
+  },
+  {
+    name: "Fenix",
+    version: "20",
+    expected: ["aol@example.com", "altavista@example.com"],
+  },
+  {
+    name: "Firefox",
+    version: "31",
+    expected: ["lycos@example.com", "aol@example.com"],
+  },
+  {
+    name: "Firefox",
+    version: "30",
+    expected: ["lycos@example.com", "aol@example.com", "excite@example.com"],
+  },
+  {
+    name: "Firefox",
+    version: "10",
+    expected: ["lycos@example.com", "aol@example.com", "excite@example.com"],
+  },
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+
+  let confUrl = `data:application/json,${JSON.stringify(CONFIG)}`;
+  Services.prefs.setStringPref("search.config.url", confUrl);
+});
+
+add_task(async function test_application_name() {
+  for (const { name, version, expected } of tests) {
+    let { engines } = await engineSelector.fetchEngineConfiguration({
+      locale: "default",
+      region: "default",
+      name,
+      version,
+    });
+    const engineIds = engines.map(obj => obj.webExtension.id);
+    Assert.deepEqual(
+      engineIds,
+      expected,
+      `Should have the expected engines for app: "${name}"
+      and version: "${version}"`
+    );
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_order.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_order.js
new file mode 100644
index 0000000000..1de4792af1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_order.js
@@ -0,0 +1,136 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+/**
+ * This constant defines the tests for the order. The input is an array of
+ * engines that will be constructed. The engine definitions are arrays with
+ * fields in order:
+ *   name, orderHint, default, defaultPrivate
+ *
+ * The expected is an array of engine names.
+ */
+const TESTS = [
+  {
+    // Basic tests to ensure correct order for default engine.
+    input: [
+      ["A", 750, "no", "no"],
+      ["B", 3000, "no", "no"],
+      ["C", 2000, "yes", "no"],
+      ["D", 1000, "yes-if-no-other", "no"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["C", "B", "D", "A", "E"],
+    expectedPrivate: undefined,
+  },
+  {
+    input: [
+      ["A", 750, "no", "no"],
+      ["B", 3000, "no", "no"],
+      ["C", 2000, "yes-if-no-other", "no"],
+      ["D", 1000, "yes", "no"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["D", "B", "C", "A", "E"],
+    expectedPrivate: undefined,
+  },
+  // Check that yes-if-no-other works correctly.
+  {
+    input: [
+      ["A", 750, "no", "no"],
+      ["B", 3000, "no", "no"],
+      ["C", 2000, "no", "no"],
+      ["D", 1000, "yes-if-no-other", "no"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["D", "B", "C", "A", "E"],
+    expectedPrivate: undefined,
+  },
+  // Basic tests to ensure correct order with private engine.
+  {
+    input: [
+      ["A", 750, "no", "no"],
+      ["B", 3000, "yes-if-no-other", "no"],
+      ["C", 2000, "no", "yes"],
+      ["D", 1000, "yes", "yes-if-no-other"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["D", "C", "B", "A", "E"],
+    expectedPrivate: "C",
+  },
+  {
+    input: [
+      ["A", 750, "no", "yes-if-no-other"],
+      ["B", 3000, "yes-if-no-other", "no"],
+      ["C", 2000, "no", "yes"],
+      ["D", 1000, "yes", "no"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["D", "C", "B", "A", "E"],
+    expectedPrivate: "C",
+  },
+  // Private engine test for yes-if-no-other.
+  {
+    input: [
+      ["A", 750, "no", "yes-if-no-other"],
+      ["B", 3000, "yes-if-no-other", "no"],
+      ["C", 2000, "no", "no"],
+      ["D", 1000, "yes", "no"],
+      ["E", 500, "no", "no"],
+    ],
+    expected: ["D", "A", "B", "C", "E"],
+    expectedPrivate: "A",
+  },
+];
+
+function getConfigData(testInput) {
+  return testInput.map(info => ({
+    engineName: info[0],
+    orderHint: info[1],
+    default: info[2],
+    defaultPrivate: info[3],
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+  }));
+}
+
+const engineSelector = new SearchEngineSelector();
+
+add_task(async function () {
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  const getStub = sinon.stub(settings, "get");
+
+  let i = 0;
+  for (const test of TESTS) {
+    // Remove the existing configuration and update the stub to return the data
+    // for this test.
+    delete engineSelector._configuration;
+    getStub.returns(getConfigData(test.input));
+
+    const { engines, privateDefault } =
+      await engineSelector.fetchEngineConfiguration({
+        locale: "en-US",
+        region: "us",
+      });
+
+    let names = engines.map(obj => obj.engineName);
+    Assert.deepEqual(
+      names,
+      test.expected,
+      `Should have the correct order for the engines: test ${i}`
+    );
+    Assert.equal(
+      privateDefault && privateDefault.engineName,
+      test.expectedPrivate,
+      `Should have the correct selection for the private engine: test ${i++}`
+    );
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_override.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_override.js
new file mode 100644
index 0000000000..e9aa1c073f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_override.js
@@ -0,0 +1,181 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const TEST_CONFIG = [
+  {
+    webExtension: {
+      id: "aol@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        override: true,
+        application: {
+          distributions: ["distro1"],
+        },
+        params: {
+          searchUrlGetParams: [
+            {
+              name: "field-keywords",
+              value: "{searchTerms}",
+            },
+          ],
+        },
+      },
+    ],
+    default: "yes-if-no-other",
+  },
+  {
+    webExtension: {
+      id: "lycos@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        override: true,
+        experiment: "experiment1",
+        sendAttributionRequest: true,
+      },
+    ],
+    default: "yes",
+  },
+  {
+    webExtension: {
+      id: "altavista@example.com",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        override: true,
+        application: {
+          distributions: ["distro2"],
+        },
+        included: { regions: ["gb"] },
+        params: {
+          searchUrlGetParams: [
+            {
+              name: "field-keywords2",
+              value: "{searchTerms}",
+            },
+          ],
+        },
+      },
+    ],
+    default: "yes",
+  },
+];
+
+const engineSelector = new SearchEngineSelector();
+
+add_task(async function setup() {
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  sinon.stub(settings, "get").returns(TEST_CONFIG);
+});
+
+add_task(async function test_engine_selector_defaults() {
+  // Check that with no override sections matching, we have no overrides active.
+  const { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+  });
+
+  let engine = engines.find(e => e.webExtension.id == "aol@example.com");
+
+  Assert.ok(
+    !("params" in engine),
+    "Should not have overriden the parameters of the engine."
+  );
+
+  engine = engines.find(e => e.webExtension.id == "lycos@example.com");
+
+  Assert.ok(
+    !("sendAttributionRequest" in engine),
+    "Should have overriden the sendAttributionRequest field of the engine."
+  );
+});
+
+add_task(async function test_engine_selector_override_distributions() {
+  const { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+    distroID: "distro1",
+  });
+
+  let engine = engines.find(e => e.webExtension.id == "aol@example.com");
+
+  Assert.deepEqual(
+    engine.params,
+    {
+      searchUrlGetParams: [
+        {
+          name: "field-keywords",
+          value: "{searchTerms}",
+        },
+      ],
+    },
+    "Should have overriden the parameters of the engine."
+  );
+});
+
+add_task(async function test_engine_selector_override_experiments() {
+  const { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+    experiment: "experiment1",
+  });
+
+  let engine = engines.find(e => e.webExtension.id == "lycos@example.com");
+
+  Assert.equal(
+    engine.sendAttributionRequest,
+    true,
+    "Should have overriden the sendAttributionRequest field of the engine."
+  );
+});
+
+add_task(async function test_engine_selector_override_with_included() {
+  let { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "us",
+    distroID: "distro2",
+  });
+
+  let engine = engines.find(e => e.webExtension.id == "altavista@example.com");
+  Assert.ok(
+    !("params" in engine),
+    "Should not have overriden the parameters of the engine."
+  );
+
+  let result = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "gb",
+    distroID: "distro2",
+  });
+  engine = result.engines.find(
+    e => e.webExtension.id == "altavista@example.com"
+  );
+  Assert.deepEqual(
+    engine.params,
+    {
+      searchUrlGetParams: [
+        {
+          name: "field-keywords2",
+          value: "{searchTerms}",
+        },
+      ],
+    },
+    "Should have overriden the parameters of the engine."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_selector_remote_settings.js b/toolkit/components/search/tests/xpcshell/test_engine_selector_remote_settings.js
new file mode 100644
index 0000000000..336ffb1ee5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_selector_remote_settings.js
@@ -0,0 +1,343 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  PromiseUtils: "resource://gre/modules/PromiseUtils.sys.mjs",
+  SearchEngineSelector: "resource://gre/modules/SearchEngineSelector.sys.mjs",
+});
+
+const TEST_CONFIG = [
+  {
+    engineName: "aol",
+    orderHint: 500,
+    webExtension: {
+      locales: ["default"],
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["us"] },
+        webExtension: {
+          locales: ["$USER_LOCALE"],
+        },
+      },
+    ],
+  },
+  {
+    engineName: "lycos",
+    orderHint: 1000,
+    default: "yes",
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { locales: { matches: ["zh-CN"] } },
+      },
+    ],
+  },
+  {
+    engineName: "altavista",
+    orderHint: 2000,
+    defaultPrivate: "yes",
+    appliesTo: [
+      {
+        included: { locales: { matches: ["en-US"] } },
+      },
+      {
+        included: { regions: ["default"] },
+      },
+    ],
+  },
+  {
+    engineName: "excite",
+    default: "yes-if-no-other",
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["us"] },
+      },
+      {
+        included: { everywhere: true },
+        cohort: "acohortid",
+      },
+    ],
+  },
+  {
+    engineName: "askjeeves",
+  },
+];
+
+let getStub;
+
+add_task(async function setup() {
+  const searchConfigSettings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  getStub = sinon.stub(searchConfigSettings, "get");
+
+  // We expect this error from remove settings as we're invalidating the
+  // signature.
+  consoleAllowList.push("Invalid content signature (abc)");
+  // We also test returning an empty configuration.
+  consoleAllowList.push("Received empty search configuration");
+});
+
+add_task(async function test_selector_basic_get() {
+  const listenerSpy = sinon.spy();
+  const engineSelector = new SearchEngineSelector(listenerSpy);
+  getStub.onFirstCall().returns(TEST_CONFIG);
+
+  const { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+  });
+
+  Assert.deepEqual(
+    engines.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have obtained the correct data from the database."
+  );
+  Assert.ok(listenerSpy.notCalled, "Should not have called the listener");
+});
+
+add_task(async function test_selector_get_reentry() {
+  const listenerSpy = sinon.spy();
+  const engineSelector = new SearchEngineSelector(listenerSpy);
+  let promise = PromiseUtils.defer();
+  getStub.resetHistory();
+  getStub.onFirstCall().returns(promise.promise);
+  delete engineSelector._configuration;
+
+  let firstResult;
+  let secondResult;
+
+  const firstCallPromise = engineSelector
+    .fetchEngineConfiguration({
+      locale: "en-US",
+      region: "default",
+    })
+    .then(result => (firstResult = result.engines));
+
+  const secondCallPromise = engineSelector
+    .fetchEngineConfiguration({
+      locale: "en-US",
+      region: "default",
+    })
+    .then(result => (secondResult = result.engines));
+
+  Assert.strictEqual(
+    firstResult,
+    undefined,
+    "Should not have returned the first result yet."
+  );
+
+  Assert.strictEqual(
+    secondResult,
+    undefined,
+    "Should not have returned the second result yet."
+  );
+
+  promise.resolve(TEST_CONFIG);
+
+  await Promise.all([firstCallPromise, secondCallPromise]);
+  Assert.deepEqual(
+    firstResult.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have returned the correct data to the first call"
+  );
+
+  Assert.deepEqual(
+    secondResult.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have returned the correct data to the second call"
+  );
+  Assert.ok(listenerSpy.notCalled, "Should not have called the listener");
+});
+
+add_task(async function test_selector_config_update() {
+  const listenerSpy = sinon.spy();
+  const engineSelector = new SearchEngineSelector(listenerSpy);
+  getStub.resetHistory();
+  getStub.onFirstCall().returns(TEST_CONFIG);
+
+  const { engines } = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+  });
+
+  Assert.deepEqual(
+    engines.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have got the correct configuration"
+  );
+
+  Assert.ok(listenerSpy.notCalled, "Should not have called the listener yet");
+
+  const NEW_DATA = [
+    {
+      default: "yes",
+      engineName: "askjeeves",
+      appliesTo: [{ included: { everywhere: true } }],
+      schema: 1553857697843,
+      last_modified: 1553859483588,
+    },
+  ];
+
+  getStub.resetHistory();
+  getStub.onFirstCall().returns(NEW_DATA);
+  await RemoteSettings(SearchUtils.SETTINGS_KEY).emit("sync", {
+    data: {
+      current: NEW_DATA,
+    },
+  });
+
+  Assert.ok(listenerSpy.called, "Should have called the listener");
+
+  const result = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+  });
+
+  Assert.deepEqual(
+    result.engines.map(e => e.engineName),
+    ["askjeeves"],
+    "Should have updated the configuration with the new data"
+  );
+});
+
+add_task(async function test_selector_db_modification() {
+  const engineSelector = new SearchEngineSelector();
+  // Fill the database with some values that we can use to test that it is cleared.
+  const db = RemoteSettings(SearchUtils.SETTINGS_KEY).db;
+  await db.importChanges(
+    {},
+    Date.now(),
+    [
+      {
+        id: "85e1f268-9ca5-4b52-a4ac-922df5c07264",
+        default: "yes",
+        engineName: "askjeeves",
+        appliesTo: [{ included: { everywhere: true } }],
+      },
+    ],
+    { clear: true }
+  );
+
+  // Stub the get() so that the first call simulates a signature error, and
+  // the second simulates success reading from the dump.
+  getStub.resetHistory();
+  getStub
+    .onFirstCall()
+    .rejects(new RemoteSettingsClient.InvalidSignatureError("abc"));
+  getStub.onSecondCall().returns(TEST_CONFIG);
+
+  let result = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+  });
+
+  Assert.ok(
+    getStub.calledTwice,
+    "Should have called the get() function twice."
+  );
+
+  const databaseEntries = await db.list();
+  Assert.equal(databaseEntries.length, 0, "Should have cleared the database.");
+
+  Assert.deepEqual(
+    result.engines.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have returned the correct data."
+  );
+});
+
+add_task(async function test_selector_db_modification_never_succeeds() {
+  const engineSelector = new SearchEngineSelector();
+  // Fill the database with some values that we can use to test that it is cleared.
+  const db = RemoteSettings(SearchUtils.SETTINGS_KEY).db;
+  await db.importChanges(
+    {},
+    Date.now(),
+    [
+      {
+        id: "b70edfdd-1c3f-4b7b-ab55-38cb048636c0",
+        default: "yes",
+        engineName: "askjeeves",
+        appliesTo: [{ included: { everywhere: true } }],
+      },
+    ],
+    {
+      clear: true,
+    }
+  );
+
+  // Now simulate the condition where for some reason we never get a
+  // valid result.
+  getStub.reset();
+  getStub.rejects(new RemoteSettingsClient.InvalidSignatureError("abc"));
+
+  await Assert.rejects(
+    engineSelector.fetchEngineConfiguration({
+      locale: "en-US",
+      region: "default",
+    }),
+    ex => ex.result == Cr.NS_ERROR_UNEXPECTED,
+    "Should have rejected loading the engine configuration"
+  );
+
+  Assert.ok(
+    getStub.calledTwice,
+    "Should have called the get() function twice."
+  );
+
+  const databaseEntries = await db.list();
+  Assert.equal(databaseEntries.length, 0, "Should have cleared the database.");
+});
+
+add_task(async function test_empty_results() {
+  // Check that returning an empty result re-tries.
+  const engineSelector = new SearchEngineSelector();
+  // Fill the database with some values that we can use to test that it is cleared.
+  const db = RemoteSettings(SearchUtils.SETTINGS_KEY).db;
+  await db.importChanges(
+    {},
+    Date.now(),
+    [
+      {
+        id: "df5655ca-e045-4f8c-a7ee-047eeb654722",
+        default: "yes",
+        engineName: "askjeeves",
+        appliesTo: [{ included: { everywhere: true } }],
+      },
+    ],
+    {
+      clear: true,
+    }
+  );
+
+  // Stub the get() so that the first call simulates an empty database, and
+  // the second simulates success reading from the dump.
+  getStub.resetHistory();
+  getStub.onFirstCall().returns([]);
+  getStub.onSecondCall().returns(TEST_CONFIG);
+
+  let result = await engineSelector.fetchEngineConfiguration({
+    locale: "en-US",
+    region: "default",
+  });
+
+  Assert.ok(
+    getStub.calledTwice,
+    "Should have called the get() function twice."
+  );
+
+  const databaseEntries = await db.list();
+  Assert.equal(databaseEntries.length, 0, "Should have cleared the database.");
+
+  Assert.deepEqual(
+    result.engines.map(e => e.engineName),
+    ["lycos", "altavista", "aol", "excite"],
+    "Should have returned the correct data."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_engine_set_alias.js b/toolkit/components/search/tests/xpcshell/test_engine_set_alias.js
new file mode 100644
index 0000000000..2732183517
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_engine_set_alias.js
@@ -0,0 +1,132 @@
+"use strict";
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_engine_set_alias() {
+  info("Set engine alias");
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: "b",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine1 = await Services.search.getEngineByName("bacon");
+  Assert.ok(engine1.aliases.includes("b"));
+  engine1.alias = "a";
+  Assert.equal(engine1.alias, "a");
+  await extension.unload();
+});
+
+add_task(async function test_engine_set_alias_with_left_space() {
+  info("Set engine alias with left space");
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: "   a",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine2 = await Services.search.getEngineByName("bacon");
+  Assert.ok(engine2.aliases.includes("a"));
+  engine2.alias = "    c";
+  Assert.equal(engine2.alias, "c");
+  await extension.unload();
+});
+
+add_task(async function test_engine_set_alias_with_right_space() {
+  info("Set engine alias with right space");
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: "c   ",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine3 = await Services.search.getEngineByName("bacon");
+  Assert.ok(engine3.aliases.includes("c"));
+  engine3.alias = "o    ";
+  Assert.equal(engine3.alias, "o");
+  await extension.unload();
+});
+
+add_task(async function test_engine_set_alias_with_right_left_space() {
+  info("Set engine alias with left and right space");
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: " o  ",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine4 = await Services.search.getEngineByName("bacon");
+  Assert.ok(engine4.aliases.includes("o"));
+  engine4.alias = "  n ";
+  Assert.equal(engine4.alias, "n");
+  await extension.unload();
+});
+
+add_task(async function test_engine_set_alias_with_space() {
+  info("Set engine alias with space");
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: " ",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine5 = await Services.search.getEngineByName("bacon");
+  Assert.equal(engine5.alias, "");
+  engine5.alias = "b";
+  Assert.equal(engine5.alias, "b");
+  engine5.alias = "  ";
+  Assert.equal(engine5.alias, "");
+  await extension.unload();
+});
+
+add_task(async function test_engine_change_alias() {
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "bacon",
+      keyword: " o  ",
+      search_url: "https://www.bacon.test/find",
+    },
+    { skipUnload: true }
+  );
+  let engine6 = await Services.search.getEngineByName("bacon");
+
+  let promise = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.CHANGED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  engine6.alias = "ba";
+
+  await promise;
+  Assert.equal(
+    engine6.alias,
+    "ba",
+    "Should have correctly notified and changed the alias."
+  );
+
+  let observed = false;
+  Services.obs.addObserver(function observer(aSubject, aTopic, aData) {
+    observed = true;
+  }, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+  engine6.alias = "ba";
+
+  Assert.equal(engine6.alias, "ba", "Should have not changed the alias");
+  Assert.ok(!observed, "Should not have notified for no change in alias");
+
+  await extension.unload();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_getSubmission_encoding.js b/toolkit/components/search/tests/xpcshell/test_getSubmission_encoding.js
new file mode 100644
index 0000000000..b868f1aa8b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_getSubmission_encoding.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const prefix = "https://example.com/?sourceId=Mozilla-search&search=";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("simple-engines");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+function testEncode(engine, charset, query, expected) {
+  engine.wrappedJSObject._queryCharset = charset;
+
+  Assert.equal(
+    engine.getSubmission(query).uri.spec,
+    prefix + expected,
+    `Should have correctly encoded for ${charset}`
+  );
+}
+
+add_task(async function test_getSubmission_encoding() {
+  let engine = await Services.search.getEngineByName("Simple Engine");
+
+  testEncode(engine, "UTF-8", "caff\u00E8", "caff%C3%A8");
+  testEncode(engine, "windows-1252", "caff\u00E8", "caff%E8");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_getSubmission_params.js b/toolkit/components/search/tests/xpcshell/test_getSubmission_params.js
new file mode 100644
index 0000000000..648267e5fc
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_getSubmission_params.js
@@ -0,0 +1,94 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("simple-engines");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+const searchTerms = "fxsearch";
+function checkSubstitution(url, prefix, engine, template, expected) {
+  url.template = prefix + template;
+  equal(engine.getSubmission(searchTerms).uri.spec, prefix + expected);
+}
+
+add_task(async function test_paramSubstitution() {
+  let prefix = "https://example.com/?sourceId=Mozilla-search&search=";
+  let engine = await Services.search.getEngineByName("Simple Engine");
+  let url = engine.wrappedJSObject._getURLOfType("text/html");
+  equal(url.getSubmission("foo", engine).uri.spec, prefix + "foo");
+  // Reset the engine parameters so we can have a clean template to use for
+  // the subsequent tests.
+  url.params = [];
+
+  let check = checkSubstitution.bind(this, url, prefix, engine);
+
+  // The same parameter can be used more than once.
+  check("{searchTerms}/{searchTerms}", searchTerms + "/" + searchTerms);
+
+  // Optional parameters are replaced if we known them.
+  check("{searchTerms?}", searchTerms);
+  check("{unknownOptional?}", "");
+  check("{unknownRequired}", "{unknownRequired}");
+
+  check("{language}", Services.locale.requestedLocale);
+  check("{language?}", Services.locale.requestedLocale);
+
+  engine.wrappedJSObject._queryCharset = "UTF-8";
+  check("{inputEncoding}", "UTF-8");
+  check("{inputEncoding?}", "UTF-8");
+  check("{outputEncoding}", "UTF-8");
+  check("{outputEncoding?}", "UTF-8");
+
+  // 'Unsupported' parameters with hard coded values used only when the parameter is required.
+  check("{count}", "20");
+  check("{count?}", "");
+  check("{startIndex}", "1");
+  check("{startIndex?}", "");
+  check("{startPage}", "1");
+  check("{startPage?}", "");
+
+  check("{moz:locale}", Services.locale.requestedLocale);
+
+  url.template = prefix + "{moz:date}";
+  let params = new URLSearchParams(engine.getSubmission(searchTerms).uri.query);
+  Assert.ok(params.has("search"), "Should have a search option");
+
+  let [, year, month, day, hour] = params
+    .get("search")
+    .match(/^(\d{4})(\d{2})(\d{2})(\d{2})/);
+  let date = new Date(year, month - 1, day, hour);
+
+  // We check the time is within an hour of now as the parameter is only
+  // precise to an hour. Checking the difference also should cope with date
+  // changes etc.
+  let difference = Date.now() - date;
+  Assert.lessOrEqual(
+    difference,
+    60 * 60 * 1000,
+    "Should have set the date within an hour"
+  );
+  Assert.greaterOrEqual(difference, 0, "Should not have a time in the past.");
+});
+
+add_task(async function test_mozParamsFailForNonAppProvided() {
+  await SearchTestUtils.installSearchExtension();
+
+  let prefix = "https://example.com/?q=";
+  let engine = await Services.search.getEngineByName("Example");
+  let url = engine.wrappedJSObject._getURLOfType("text/html");
+  equal(url.getSubmission("foo", engine).uri.spec, prefix + "foo");
+  // Reset the engine parameters so we can have a clean template to use for
+  // the subsequent tests.
+  url.params = [];
+
+  let check = checkSubstitution.bind(this, url, prefix, engine);
+
+  // Test moz: parameters (only supported for built-in engines, ie _isDefault == true).
+  check("{moz:locale}", "{moz:locale}");
+
+  await promiseAfterSettings();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_identifiers.js b/toolkit/components/search/tests/xpcshell/test_identifiers.js
new file mode 100644
index 0000000000..72fa052211
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_identifiers.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test of a search engine's identifier.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("simple-engines");
+  await AddonTestUtils.promiseStartupManager();
+
+  const result = await Services.search.init();
+  Assert.ok(
+    Components.isSuccessCode(result),
+    "Should have initialized the service"
+  );
+
+  useHttpServer();
+  await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+});
+
+function checkIdentifier(engineName, expectedIdentifier, expectedTelemetryId) {
+  const engine = Services.search.getEngineByName(engineName);
+  Assert.ok(
+    engine instanceof Ci.nsISearchEngine,
+    "Should be derived from nsISearchEngine"
+  );
+
+  Assert.equal(
+    engine.identifier,
+    expectedIdentifier,
+    "Should have the correct identifier"
+  );
+
+  Assert.equal(
+    engine.telemetryId,
+    expectedTelemetryId,
+    "Should have the correct telemetry Id"
+  );
+}
+
+add_task(async function test_from_profile() {
+  // An engine loaded from the profile directory won't have an identifier,
+  // because it's not built-in.
+  checkIdentifier(kTestEngineName, null, `other-${kTestEngineName}`);
+});
+
+add_task(async function test_from_telemetry_id() {
+  checkIdentifier("basic", "telemetry", "telemetry");
+});
+
+add_task(async function test_from_webextension_id() {
+  // If not specified, the telemetry Id is derived from the WebExtension prefix,
+  // it should not use the WebExtension display name.
+  checkIdentifier("Simple Engine", "simple", "simple");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_ignorelist.js b/toolkit/components/search/tests/xpcshell/test_ignorelist.js
new file mode 100644
index 0000000000..cf00e7ca30
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_ignorelist.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const kSearchEngineID1 = "ignorelist_test_engine1";
+const kSearchEngineID2 = "ignorelist_test_engine2";
+const kSearchEngineID3 = "ignorelist_test_engine3";
+const kSearchEngineURL1 =
+  "https://example.com/?search={searchTerms}&ignore=true";
+const kSearchEngineURL2 =
+  "https://example.com/?search={searchTerms}&IGNORE=TRUE";
+const kSearchEngineURL3 = "https://example.com/?search={searchTerms}";
+const kExtensionID = "searchignore@mozilla.com";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_ignoreList() {
+  await setupRemoteSettings();
+
+  Assert.ok(
+    !Services.search.isInitialized,
+    "Search service should not be initialized to begin with."
+  );
+
+  let updatePromise = SearchTestUtils.promiseSearchNotification(
+    "settings-update-complete"
+  );
+
+  await SearchTestUtils.installSearchExtension({
+    name: kSearchEngineID1,
+    search_url: kSearchEngineURL1,
+  });
+
+  await updatePromise;
+
+  let engine = Services.search.getEngineByName(kSearchEngineID1);
+  Assert.equal(
+    engine,
+    null,
+    "Engine with ignored search params should not exist"
+  );
+
+  await SearchTestUtils.installSearchExtension({
+    name: kSearchEngineID2,
+    search_url: kSearchEngineURL2,
+  });
+
+  // An ignored engine shouldn't be available at all
+  engine = Services.search.getEngineByName(kSearchEngineID2);
+  Assert.equal(
+    engine,
+    null,
+    "Engine with ignored search params of a different case should not exist"
+  );
+
+  await SearchTestUtils.installSearchExtension({
+    id: kExtensionID,
+    name: kSearchEngineID3,
+    search_url: kSearchEngineURL3,
+  });
+
+  // An ignored engine shouldn't be available at all
+  engine = Services.search.getEngineByName(kSearchEngineID3);
+  Assert.equal(
+    engine,
+    null,
+    "Engine with ignored extension id should not exist"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_ignorelist_update.js b/toolkit/components/search/tests/xpcshell/test_ignorelist_update.js
new file mode 100644
index 0000000000..4a64bd469e
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_ignorelist_update.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const kSearchEngineID1 = "ignorelist_test_engine1";
+const kSearchEngineID2 = "ignorelist_test_engine2";
+const kSearchEngineID3 = "ignorelist_test_engine3";
+const kSearchEngineURL1 =
+  "https://example.com/?search={searchTerms}&ignore=true";
+const kSearchEngineURL2 =
+  "https://example.com/?search={searchTerms}&IGNORE=TRUE";
+const kSearchEngineURL3 = "https://example.com/?search={searchTerms}";
+const kExtensionID = "searchignore@mozilla.com";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_ignoreList() {
+  Assert.ok(
+    !Services.search.isInitialized,
+    "Search service should not be initialized to begin with."
+  );
+
+  let updatePromise = SearchTestUtils.promiseSearchNotification(
+    "settings-update-complete"
+  );
+  await SearchTestUtils.installSearchExtension({
+    name: kSearchEngineID1,
+    search_url: kSearchEngineURL1,
+  });
+  await SearchTestUtils.installSearchExtension({
+    name: kSearchEngineID2,
+    search_url: kSearchEngineURL2,
+  });
+  await SearchTestUtils.installSearchExtension({
+    id: kExtensionID,
+    name: kSearchEngineID3,
+    search_url: kSearchEngineURL3,
+  });
+
+  // Ensure that the initial remote settings update from default values is
+  // complete. The defaults do not include the special inclusions inserted below.
+  await updatePromise;
+
+  for (let engineName of [
+    kSearchEngineID1,
+    kSearchEngineID2,
+    kSearchEngineID3,
+  ]) {
+    Assert.ok(
+      await Services.search.getEngineByName(engineName),
+      `Engine ${engineName} should be present`
+    );
+  }
+
+  // Simulate an ignore list update.
+  await RemoteSettings("hijack-blocklists").emit("sync", {
+    data: {
+      current: [
+        {
+          id: "load-paths",
+          schema: 1553857697843,
+          last_modified: 1553859483588,
+          matches: ["[addon]searchignore@mozilla.com"],
+        },
+        {
+          id: "submission-urls",
+          schema: 1553857697843,
+          last_modified: 1553859435500,
+          matches: ["ignore=true"],
+        },
+      ],
+    },
+  });
+
+  for (let engineName of [
+    kSearchEngineID1,
+    kSearchEngineID2,
+    kSearchEngineID3,
+  ]) {
+    Assert.equal(
+      await Services.search.getEngineByName(engineName),
+      null,
+      `Engine ${engineName} should not be present`
+    );
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_initialization.js b/toolkit/components/search/tests/xpcshell/test_initialization.js
new file mode 100644
index 0000000000..99505bdeb5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_initialization.js
@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that a delayed add-on manager start up does not affect the start up
+// of the search service.
+
+"use strict";
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    orderHint: 30,
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+add_setup(() => {
+  do_get_profile();
+  Services.fog.initializeFOG();
+});
+
+add_task(async function test_initialization_delayed_addon_manager() {
+  let stub = await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  // Wait until the search service gets its configuration before starting
+  // to initialise the add-on manager. This simulates the add-on manager
+  // starting late which used to cause the search service to fail to load any
+  // engines.
+  stub.callsFake(() => {
+    Services.tm.dispatchToMainThread(() => {
+      AddonTestUtils.promiseStartupManager();
+    });
+    return CONFIG;
+  });
+
+  await Services.search.init();
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Test engine shouldn't be the default anymore"
+  );
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "engine",
+      displayName: "Test search engine",
+      loadPath: "[addon]engine@search.mozilla.org",
+      submissionUrl: "https://www.google.com/search?q=",
+      verified: "default",
+    },
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_initialization_with_region.js b/toolkit/components/search/tests/xpcshell/test_initialization_with_region.js
new file mode 100644
index 0000000000..54a5adfc48
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_initialization_with_region.js
@@ -0,0 +1,130 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const SEARCH_SERVICE_TOPIC = "browser-search-service";
+const SEARCH_ENGINE_TOPIC = "browser-search-engine-modified";
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    orderHint: 30,
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["FR"] },
+        default: "yes",
+        defaultPrivate: "yes",
+      },
+    ],
+  },
+  {
+    webExtension: {
+      id: "engine-pref@search.mozilla.org",
+    },
+    orderHint: 20,
+    appliesTo: [
+      {
+        included: { regions: ["FR"] },
+        default: "yes",
+        defaultPrivate: "yes",
+      },
+    ],
+  },
+];
+
+// Default engine with no region defined.
+const DEFAULT = "Test search engine";
+// Default engine with region set to FR.
+const FR_DEFAULT = "engine-pref";
+
+function listenFor(name, key) {
+  let notifyObserved = false;
+  let obs = (subject, topic, data) => {
+    if (data == key) {
+      notifyObserved = true;
+    }
+  };
+  Services.obs.addObserver(obs, name);
+
+  return () => {
+    Services.obs.removeObserver(obs, name);
+    return notifyObserved;
+  };
+}
+
+add_task(async function setup() {
+  Services.prefs.setBoolPref("browser.search.separatePrivateDefault", true);
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  SearchTestUtils.useMockIdleService();
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+});
+
+// This tests what we expect is the normal startup route for a fresh profile -
+// the search service initializes with no region details, then gets a region
+// notified part way through / afterwards.
+add_task(async function test_initialization_with_region() {
+  let reloadObserved = listenFor(SEARCH_SERVICE_TOPIC, "engines-reloaded");
+  let initPromise;
+
+  // Ensure the region lookup completes after init so the
+  // engines are reloaded
+  let srv = useHttpServer();
+  srv.registerPathHandler("/fetch_region", async (req, res) => {
+    res.processAsync();
+    await initPromise;
+    res.setStatusLine("1.1", 200, "OK");
+    res.write(JSON.stringify({ country_code: "FR" }));
+    res.finish();
+  });
+
+  Services.prefs.setCharPref(
+    "browser.region.network.url",
+    `http://localhost:${srv.identity.primaryPort}/fetch_region`
+  );
+
+  Region._setHomeRegion("", false);
+  Region.init();
+
+  initPromise = Services.search.init();
+  await initPromise;
+
+  let otherPromises = [
+    // This test expects settings to be saved twice.
+    promiseAfterSettings().then(promiseAfterSettings),
+    SearchTestUtils.promiseSearchNotification(
+      "engine-default",
+      SEARCH_ENGINE_TOPIC
+    ),
+  ];
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    DEFAULT,
+    "Test engine shouldn't be the default anymore"
+  );
+
+  await Promise.all(otherPromises);
+
+  // Ensure that correct engine is being reported as the default.
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    FR_DEFAULT,
+    "engine-pref should be the default in FR"
+  );
+  Assert.equal(
+    (await Services.search.getDefaultPrivate()).name,
+    FR_DEFAULT,
+    "engine-pref should be the private default in FR"
+  );
+
+  Assert.ok(reloadObserved(), "Engines do reload with delayed region fetch");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_list_json_locale.js b/toolkit/components/search/tests/xpcshell/test_list_json_locale.js
new file mode 100644
index 0000000000..a02e07b9d2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_list_json_locale.js
@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Check default search engine is picked from list.json searchDefault */
+
+"use strict";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines();
+
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "de",
+    "fr",
+  ];
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Region._setHomeRegion("US", false);
+});
+
+add_task(async function test_listJSONlocale() {
+  Services.locale.requestedLocales = ["de"];
+
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  Assert.ok(Services.search.isInitialized, "search initialized");
+
+  let sortedEngines = await Services.search.getEngines();
+  Assert.equal(sortedEngines.length, 1, "Should have only one engine");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Should have the correct default engine"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    // 'de' only displays google, so we'll be using the same engine as the
+    // normal default.
+    "Test search engine",
+    "Should have the correct private default engine"
+  );
+});
+
+// Check that switching locale switches search engines
+add_task(async function test_listJSONlocaleSwitch() {
+  let defaultBranch = Services.prefs.getDefaultBranch(
+    SearchUtils.BROWSER_SEARCH_PREF
+  );
+  defaultBranch.setCharPref("param.code", "good&id=unique");
+
+  await promiseSetLocale("fr");
+
+  Assert.ok(Services.search.isInitialized, "search initialized");
+
+  let sortedEngines = await Services.search.getEngines();
+  Assert.deepEqual(
+    sortedEngines.map(e => e.name),
+    ["Test search engine", "engine-pref", "engine-resourceicon"],
+    "Should have the correct engine list"
+  );
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Should have the correct default engine"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine-pref",
+    "Should have the correct private default engine"
+  );
+});
+
+// Check that region overrides apply
+add_task(async function test_listJSONRegionOverride() {
+  await promiseSetHomeRegion("RU");
+
+  Assert.ok(Services.search.isInitialized, "search initialized");
+
+  let sortedEngines = await Services.search.getEngines();
+  Assert.deepEqual(
+    sortedEngines.map(e => e.name),
+    ["Test search engine", "engine-pref", "engine-chromeicon"],
+    "Should have the correct engine list"
+  );
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Should have the correct default engine"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine-pref",
+    "Should have the correct private default engine"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_list_json_no_private_default.js b/toolkit/components/search/tests/xpcshell/test_list_json_no_private_default.js
new file mode 100644
index 0000000000..8de8ad6a34
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_list_json_no_private_default.js
@@ -0,0 +1,49 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// TODO: Test fallback to normal default when no private set at all.
+
+/* Check default search engine is picked from list.json searchDefault */
+
+"use strict";
+
+// Check that current engine matches with US searchDefault from list.json
+add_task(async function test_searchDefaultEngineUS() {
+  await SearchTestUtils.useTestEngines("data1");
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  Assert.ok(Services.search.isInitialized, "search initialized");
+
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "engine1",
+    "Should have the expected engine as app default"
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine1",
+    "Should have the expected engine as default"
+  );
+  Assert.equal(
+    Services.search.appPrivateDefaultEngine.name,
+    "engine1",
+    "Should have the same engine for the app private default"
+  );
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine1",
+    "Should have the same engine for the private default"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_list_json_searchdefault.js b/toolkit/components/search/tests/xpcshell/test_list_json_searchdefault.js
new file mode 100644
index 0000000000..38c7f302d2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_list_json_searchdefault.js
@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Check default search engine is picked from list.json searchDefault */
+
+"use strict";
+
+// Check that current engine matches with US searchDefault from list.json
+add_task(async function test_searchDefaultEngineUS() {
+  await SearchTestUtils.useTestEngines();
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  Assert.ok(Services.search.isInitialized, "search initialized");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Should have the expected engine as default."
+  );
+  Assert.equal(
+    Services.search.appDefaultEngine.name,
+    "Test search engine",
+    "Should have the expected engine as the app default"
+  );
+
+  // First with the pref off to check using the existing values.
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    Services.search.defaultEngine.name,
+    "Should have the normal default engine when separate private browsing is off."
+  );
+  Assert.equal(
+    Services.search.appPrivateDefaultEngine.name,
+    Services.search.appDefaultEngine.name,
+    "Should have the normal app engine when separate private browsing is off."
+  );
+
+  // Then with the pref on.
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  Assert.equal(
+    Services.search.defaultPrivateEngine.name,
+    "engine-pref",
+    "Should have the private default engine when separate private browsing is on."
+  );
+  Assert.equal(
+    Services.search.appPrivateDefaultEngine.name,
+    "engine-pref",
+    "Should have the app private engine set correctly when separate private browsing is on."
+  );
+
+  Services.prefs.clearUserPref("browser.search.region");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_list_json_searchorder.js b/toolkit/components/search/tests/xpcshell/test_list_json_searchorder.js
new file mode 100644
index 0000000000..21e5b60f0f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_list_json_searchorder.js
@@ -0,0 +1,66 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Check default search engine is picked from list.json searchDefault */
+
+"use strict";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  await SearchTestUtils.useTestEngines();
+  await Services.search.init();
+});
+
+async function checkOrder(expectedOrder) {
+  const sortedEngines = await Services.search.getEngines();
+  Assert.deepEqual(
+    sortedEngines.map(s => s.name),
+    expectedOrder,
+    "Should have the expected engine order"
+  );
+}
+
+add_task(async function test_searchOrderJSON_no_separate_private() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+
+  await checkOrder([
+    // Default engine
+    "Test search engine",
+    // Two engines listed in searchOrder.
+    "engine-resourceicon",
+    "engine-chromeicon",
+    // Rest of the engines in order.
+    "engine-pref",
+    "engine-rel-searchform-purpose",
+    "Test search engine (Reordered)",
+  ]);
+});
+
+add_task(async function test_searchOrderJSON_separate_private() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  await checkOrder([
+    // Default engine
+    "Test search engine",
+    // Default private engine
+    "engine-pref",
+    // Two engines listed in searchOrder.
+    "engine-resourceicon",
+    "engine-chromeicon",
+    // Rest of the engines in order.
+    "engine-rel-searchform-purpose",
+    "Test search engine (Reordered)",
+  ]);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_location_timeout_xhr.js b/toolkit/components/search/tests/xpcshell/test_location_timeout_xhr.js
new file mode 100644
index 0000000000..d76d775dd5
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_location_timeout_xhr.js
@@ -0,0 +1,90 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This is testing the long, last-resort XHR-based timeout for the location
+// search.
+
+function startServer(continuePromise) {
+  let srv = new HttpServer();
+  function lookupCountry(metadata, response) {
+    response.processAsync();
+    // wait for our continuePromise to resolve before writing a valid
+    // response.
+    // This will be resolved after the timeout period, so we can check
+    // the behaviour in that case.
+    continuePromise.then(() => {
+      response.setStatusLine("1.1", 200, "OK");
+      response.write('{"country_code" : "AU"}');
+      response.finish();
+    });
+  }
+  srv.registerPathHandler("/lookup_country", lookupCountry);
+  srv.start(-1);
+  return srv;
+}
+
+function verifyProbeSum(probe, sum) {
+  let histogram = Services.telemetry.getHistogramById(probe);
+  let snapshot = histogram.snapshot();
+  equal(snapshot.sum, sum, probe);
+}
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_location_timeout_xhr() {
+  let resolveContinuePromise;
+  let continuePromise = new Promise(resolve => {
+    resolveContinuePromise = resolve;
+  });
+
+  let server = startServer(continuePromise);
+  let url =
+    "http://localhost:" + server.identity.primaryPort + "/lookup_country";
+  Services.prefs.setCharPref("browser.search.geoip.url", url);
+  // The timeout for the timer.
+  Services.prefs.setIntPref("browser.search.geoip.timeout", 10);
+  let promiseXHRStarted = SearchTestUtils.promiseSearchNotification(
+    "geoip-lookup-xhr-starting"
+  );
+  await Services.search.init();
+  ok(
+    !Services.prefs.prefHasUserValue("browser.search.region"),
+    "should be no region pref"
+  );
+  // should be no result recorded at all.
+  checkCountryResultTelemetry(null);
+
+  // should not have SEARCH_SERVICE_COUNTRY_FETCH_TIME_MS recorded as our
+  // test server is still blocked on our promise.
+  verifyProbeSum("SEARCH_SERVICE_COUNTRY_FETCH_TIME_MS", 0);
+
+  promiseXHRStarted.then(xhr => {
+    // Set the timeout on the xhr object to an extremely low value, so it
+    // should timeout immediately.
+    xhr.timeout = 10;
+    // wait for the xhr timeout to fire.
+    SearchTestUtils.promiseSearchNotification("geoip-lookup-xhr-complete").then(
+      () => {
+        // should have the XHR timeout recorded.
+        checkCountryResultTelemetry(TELEMETRY_RESULT_ENUM.TIMEOUT);
+        // still should not have a report of how long the response took as we
+        // only record that on success responses.
+        verifyProbeSum("SEARCH_SERVICE_COUNTRY_FETCH_TIME_MS", 0);
+        // and we still don't know the country code or region.
+        ok(
+          !Services.prefs.prefHasUserValue("browser.search.region"),
+          "should be no region pref"
+        );
+
+        // unblock the server even though nothing is listening.
+        resolveContinuePromise();
+
+        return new Promise(resolve => {
+          server.stop(resolve);
+        });
+      }
+    );
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_maybereloadengine_order.js b/toolkit/components/search/tests/xpcshell/test_maybereloadengine_order.js
new file mode 100644
index 0000000000..8d0a0891b8
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_maybereloadengine_order.js
@@ -0,0 +1,53 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const TEST_CONFIG = [
+  {
+    webExtension: { id: "plainengine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+  {
+    webExtension: { id: "special-engine@search.mozilla.org" },
+    appliesTo: [{ default: "yes", included: { regions: ["FR"] } }],
+  },
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("test-extensions", null, TEST_CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+
+  registerCleanupFunction(AddonTestUtils.promiseShutdownManager);
+});
+
+add_task(async function basic_multilocale_test() {
+  let resolver;
+  let initPromise = new Promise(resolve => (resolver = resolve));
+  useCustomGeoServer("FR", initPromise);
+
+  await Services.search.init();
+  await Services.search.getAppProvidedEngines();
+  resolver();
+  await SearchTestUtils.promiseSearchNotification("engines-reloaded");
+
+  let engines = await Services.search.getAppProvidedEngines();
+
+  Assert.deepEqual(
+    engines.map(e => e._name),
+    ["Special", "Plain"],
+    "Special engine is default so should be first"
+  );
+
+  engines.forEach(engine => {
+    Assert.ok(!engine._metaData.order, "Order is not defined");
+  });
+
+  Assert.equal(
+    Services.search.wrappedJSObject._settings.getMetaDataAttribute(
+      "useSavedOrder"
+    ),
+    false,
+    "We should not set the engine order during maybeReloadEngines"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_migrateWebExtensionEngine.js b/toolkit/components/search/tests/xpcshell/test_migrateWebExtensionEngine.js
new file mode 100644
index 0000000000..65de325924
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_migrateWebExtensionEngine.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const kExtensionID = "simple@tests.mozilla.org";
+
+add_task(async function setup() {
+  useHttpServer("opensearch");
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines("data1");
+  await Services.search.init();
+});
+
+add_task(async function test_migrateLegacyEngine() {
+  await Services.search.addOpenSearchEngine(gDataUrl + "simple.xml", null);
+
+  // Modify the loadpath so it looks like a legacy plugin loadpath
+  let engine = Services.search.getEngineByName("simple");
+  engine.wrappedJSObject._loadPath = `jar:[profile]/extensions/${kExtensionID}.xpi!/simple.xml`;
+  engine.wrappedJSObject._extensionID = null;
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  // This should replace the existing engine
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      id: "simple",
+      name: "simple",
+      search_url: "https://example.com/",
+    },
+    { skipUnload: true }
+  );
+
+  engine = Services.search.getEngineByName("simple");
+  Assert.equal(engine.wrappedJSObject._loadPath, "[addon]" + kExtensionID);
+  Assert.equal(engine.wrappedJSObject._extensionID, kExtensionID);
+
+  Assert.equal(
+    (await Services.search.getDefault()).name,
+    "simple",
+    "Should have kept the default engine the same"
+  );
+
+  await extension.unload();
+});
+
+add_task(async function test_migrateLegacyEngineDifferentName() {
+  await Services.search.addOpenSearchEngine(gDataUrl + "simple.xml", null);
+
+  // Modify the loadpath so it looks like an legacy plugin loadpath
+  let engine = Services.search.getEngineByName("simple");
+  engine.wrappedJSObject._loadPath = `jar:[profile]/extensions/${kExtensionID}.xpi!/simple.xml`;
+  engine.wrappedJSObject._extensionID = null;
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  // This should replace the existing engine - it has the same id, but a different name.
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      id: "simple",
+      name: "simple search",
+      search_url: "https://example.com/",
+    },
+    { skipUnload: true }
+  );
+
+  engine = Services.search.getEngineByName("simple");
+  Assert.equal(engine, null, "Should have removed the old engine");
+
+  // The engine should have changed its name.
+  engine = Services.search.getEngineByName("simple search");
+  Assert.equal(engine.wrappedJSObject._loadPath, "[addon]" + kExtensionID);
+  Assert.equal(engine.wrappedJSObject._extensionID, kExtensionID);
+
+  Assert.equal(
+    (await Services.search.getDefault()).name,
+    "simple search",
+    "Should have made the new engine default"
+  );
+
+  await extension.unload();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_missing_engine.js b/toolkit/components/search/tests/xpcshell/test_missing_engine.js
new file mode 100644
index 0000000000..9be8c79ae8
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_missing_engine.js
@@ -0,0 +1,104 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test is designed to check the search service keeps working if there's
+// a built-in engine missing from the configuration.
+
+"use strict";
+
+const GOOD_CONFIG = [
+  {
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+  },
+];
+
+const BAD_CONFIG = [
+  ...GOOD_CONFIG,
+  {
+    webExtension: {
+      id: "engine-missing@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+    ],
+  },
+];
+
+add_task(async function setup() {
+  SearchTestUtils.useMockIdleService();
+  await AddonTestUtils.promiseStartupManager();
+
+  // This test purposely attempts to load a missing engine.
+  consoleAllowList.push(
+    "Could not load engine engine-missing@search.mozilla.org"
+  );
+});
+
+add_task(async function test_startup_with_missing() {
+  await SearchTestUtils.useTestEngines("data", null, BAD_CONFIG);
+
+  const result = await Services.search.init();
+  Assert.ok(
+    Components.isSuccessCode(result),
+    "Should have started the search service successfully."
+  );
+
+  const engines = await Services.search.getEngines();
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["Test search engine"],
+    "Should have listed just the good engine"
+  );
+});
+
+add_task(async function test_update_with_missing() {
+  let reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+
+  await RemoteSettings(SearchUtils.SETTINGS_KEY).emit("sync", {
+    data: {
+      current: GOOD_CONFIG,
+    },
+  });
+
+  SearchTestUtils.idleService._fireObservers("idle");
+
+  await reloadObserved;
+
+  const engines = await Services.search.getEngines();
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["Test search engine"],
+    "Should have just the good engine"
+  );
+
+  reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+
+  await RemoteSettings(SearchUtils.SETTINGS_KEY).emit("sync", {
+    data: {
+      current: BAD_CONFIG,
+    },
+  });
+
+  SearchTestUtils.idleService._fireObservers("idle");
+
+  await reloadObserved;
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["Test search engine"],
+    "Should still have just the good engine"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_multipleIcons.js b/toolkit/components/search/tests/xpcshell/test_multipleIcons.js
new file mode 100644
index 0000000000..dc9cc24add
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_multipleIcons.js
@@ -0,0 +1,60 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests getIcons() and getIconURLBySize() on engine with multiple icons.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_multipleIcons() {
+  let engine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineImages.xml`,
+  });
+
+  info("The default should be the 16x16 icon");
+  Assert.ok(engine.iconURI.spec.includes("ico16"));
+
+  Assert.ok(engine.getIconURLBySize(16, 16).includes("ico16"));
+  Assert.ok(engine.getIconURLBySize(32, 32).includes("ico32"));
+  Assert.ok(engine.getIconURLBySize(74, 74).includes("ico74"));
+
+  info("Invalid dimensions should return null.");
+  Assert.equal(null, engine.getIconURLBySize(50, 50));
+
+  let allIcons = engine.getIcons();
+
+  info("Check that allIcons contains expected icon sizes");
+  Assert.equal(allIcons.length, 3);
+  let expectedWidths = [16, 32, 74];
+  Assert.ok(
+    allIcons.every(item => {
+      let width = item.width;
+      Assert.notEqual(expectedWidths.indexOf(width), -1);
+      Assert.equal(width, item.height);
+
+      let icon = item.url.split(",").pop();
+      Assert.equal(icon, "ico" + width);
+
+      return true;
+    })
+  );
+});
+
+add_task(async function test_icon_not_in_file() {
+  let engineUrl = gDataUrl + "engine-fr.xml";
+  let engine = await Services.search.addOpenSearchEngine(
+    engineUrl,
+    "data:image/x-icon;base64,ico16"
+  );
+
+  // Even though the icon wasn't specified inside the XML file, it should be
+  // available both in the iconURI attribute and with getIconURLBySize.
+  Assert.ok(engine.iconURI.spec.includes("ico16"));
+  Assert.ok(engine.getIconURLBySize(16, 16).includes("ico16"));
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_nodb_pluschanges.js b/toolkit/components/search/tests/xpcshell/test_nodb_pluschanges.js
new file mode 100644
index 0000000000..155079ce4b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_nodb_pluschanges.js
@@ -0,0 +1,52 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * test_nodb: Start search service without existing settings file.
+ *
+ * Ensure that :
+ * - nothing explodes;
+ * - if we change the order, search.json.mozlz4 is updated;
+ * - this search.json.mozlz4 can be parsed;
+ * - the order stored in search.json.mozlz4 is consistent.
+ *
+ * Notes:
+ * - we install the search engines of test "test_downloadAndAddEngines.js"
+ * to ensure that this test is independent from locale, commercial agreements
+ * and configuration of Firefox.
+ */
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_nodb_pluschanges() {
+  let engine1 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+  let engine2 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine2.xml`,
+  });
+  await promiseAfterSettings();
+
+  let search = Services.search;
+
+  await search.moveEngine(engine1, 0);
+  await search.moveEngine(engine2, 1);
+
+  // This is needed to avoid some reentrency issues in nsSearchService.
+  info("Next step is forcing flush");
+  await new Promise(resolve => executeSoon(resolve));
+
+  info("Forcing flush");
+  let promiseCommit = promiseAfterSettings();
+  search.QueryInterface(Ci.nsIObserver).observe(null, "quit-application", "");
+  await promiseCommit;
+  info("Commit complete");
+
+  // Check that the entries are placed as specified correctly
+  let metadata = await promiseEngineMetadata();
+  Assert.equal(metadata["Test search engine"].order, 1);
+  Assert.equal(metadata["A second test engine"].order, 2);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_notifications.js b/toolkit/components/search/tests/xpcshell/test_notifications.js
new file mode 100644
index 0000000000..6f7ee3243a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_notifications.js
@@ -0,0 +1,125 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+let engine;
+let appDefaultEngine;
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+  useHttpServer();
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  appDefaultEngine = await Services.search.getDefault();
+});
+
+add_task(async function test_addingEngine_opensearch() {
+  const addEngineObserver = new SearchObserver(
+    [
+      // engine-loaded
+      // Engine was loaded.
+      SearchUtils.MODIFIED_TYPE.LOADED,
+      // engine-added
+      // Engine was added to the store by the search service.
+      SearchUtils.MODIFIED_TYPE.ADDED,
+    ],
+    SearchUtils.MODIFIED_TYPE.ADDED
+  );
+
+  await Services.search.addOpenSearchEngine(gDataUrl + "engine.xml", null);
+
+  engine = await addEngineObserver.promise;
+
+  let retrievedEngine = Services.search.getEngineByName("Test search engine");
+  Assert.equal(engine, retrievedEngine);
+});
+
+add_task(async function test_addingEngine_webExtension() {
+  const addEngineObserver = new SearchObserver(
+    [
+      // engine-added
+      // Engine was added to the store by the search service.
+      SearchUtils.MODIFIED_TYPE.ADDED,
+    ],
+    SearchUtils.MODIFIED_TYPE.ADDED
+  );
+
+  await SearchTestUtils.installSearchExtension({
+    name: "Example Engine",
+  });
+
+  let webExtensionEngine = await addEngineObserver.promise;
+
+  let retrievedEngine = Services.search.getEngineByName("Example Engine");
+  Assert.equal(webExtensionEngine, retrievedEngine);
+});
+
+async function defaultNotificationTest(
+  setPrivateDefault,
+  expectNotificationForPrivate
+) {
+  const defaultObserver = new SearchObserver([
+    expectNotificationForPrivate
+      ? SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE
+      : SearchUtils.MODIFIED_TYPE.DEFAULT,
+  ]);
+
+  Services.search[
+    setPrivateDefault ? "defaultPrivateEngine" : "defaultEngine"
+  ] = engine;
+  await defaultObserver.promise;
+}
+
+add_task(async function test_defaultEngine_notifications() {
+  await defaultNotificationTest(false, false);
+});
+
+add_task(async function test_defaultPrivateEngine_notifications() {
+  await defaultNotificationTest(true, true);
+});
+
+add_task(
+  async function test_defaultPrivateEngine_notifications_when_not_enabled() {
+    await Services.search.setDefault(
+      appDefaultEngine,
+      Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+    );
+
+    Services.prefs.setBoolPref(
+      SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+      false
+    );
+
+    await defaultNotificationTest(true, true);
+  }
+);
+
+add_task(async function test_removeEngine() {
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  await Services.search.setDefaultPrivate(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  const removedObserver = new SearchObserver([
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE,
+    SearchUtils.MODIFIED_TYPE.REMOVED,
+  ]);
+
+  await Services.search.removeEngine(engine);
+
+  await removedObserver;
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch.js b/toolkit/components/search/tests/xpcshell/test_opensearch.js
new file mode 100644
index 0000000000..bdd42860af
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch.js
@@ -0,0 +1,160 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that OpenSearch engines are installed and set up correctly.
+ *
+ * Note: simple.xml, post.xml, suggestion.xml and suggestion-alternate.xml
+ * all use different namespaces to reflect the possibitities that may be
+ * installed.
+ * mozilla-ns.xml uses the mozilla namespace.
+ */
+
+"use strict";
+
+const tests = [
+  {
+    file: "simple.xml",
+    name: "simple",
+    description: "A small test engine",
+    searchForm: "https://example.com/",
+    searchUrl: "https://example.com/search?q=foo",
+  },
+  {
+    file: "post.xml",
+    name: "Post",
+    description: "",
+    // The POST method is not supported for `rel="searchform"` so we fallback
+    // to the `SearchForm` url.
+    searchForm: "http://engine-rel-searchform-post.xml/?search",
+    searchUrl: "https://example.com/post",
+    searchPostData: "searchterms=foo",
+  },
+  {
+    file: "suggestion.xml",
+    name: "suggestion",
+    description: "A small engine with suggestions",
+    queryCharset: "windows-1252",
+    searchForm: "http://engine-rel-searchform.xml/?search",
+    searchUrl: "https://example.com/search?q=foo",
+    suggestUrl: "https://example.com/suggest?suggestion=foo",
+  },
+  {
+    file: "suggestion-alternate.xml",
+    name: "suggestion-alternate",
+    description: "A small engine with suggestions",
+    searchForm: "https://example.com/",
+    searchUrl: "https://example.com/search?q=foo",
+    suggestUrl: "https://example.com/suggest?suggestion=foo",
+  },
+  {
+    file: "mozilla-ns.xml",
+    name: "mozilla-ns",
+    description: "An engine using mozilla namespace",
+    searchForm: "https://example.com/",
+    // mozilla-ns.xml also specifies a MozParam. However, they are only
+    // valid for app-provided engines, and hence the param should not show
+    // here.
+    searchUrl: "https://example.com/search?q=foo",
+  },
+];
+
+add_task(async function setup() {
+  Services.fog.initializeFOG();
+  useHttpServer("opensearch");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+for (const test of tests) {
+  add_task(async () => {
+    info(`Testing ${test.file}`);
+    let promiseEngineAdded = SearchTestUtils.promiseSearchNotification(
+      SearchUtils.MODIFIED_TYPE.ADDED,
+      SearchUtils.TOPIC_ENGINE_MODIFIED
+    );
+    let engine = await Services.search.addOpenSearchEngine(
+      gDataUrl + test.file,
+      null
+    );
+    await promiseEngineAdded;
+    Assert.ok(engine, "Should have installed the engine.");
+
+    Assert.equal(engine.name, test.name, "Should have the correct name");
+    Assert.equal(
+      engine.description,
+      test.description,
+      "Should have a description"
+    );
+
+    Assert.equal(
+      engine.wrappedJSObject._loadPath,
+      `[http]localhost/${test.file}`
+    );
+
+    Assert.equal(
+      engine.queryCharset,
+      test.queryCharset ?? SearchUtils.DEFAULT_QUERY_CHARSET,
+      "Should have the expected query charset"
+    );
+
+    let submission = engine.getSubmission("foo");
+    Assert.equal(
+      submission.uri.spec,
+      test.searchUrl,
+      "Should have the correct search url"
+    );
+
+    if (test.searchPostData) {
+      let sis = Cc["@mozilla.org/scriptableinputstream;1"].createInstance(
+        Ci.nsIScriptableInputStream
+      );
+      sis.init(submission.postData);
+      let data = sis.read(submission.postData.available());
+      Assert.equal(
+        decodeURIComponent(data),
+        test.searchPostData,
+        "Should have received the correct POST data"
+      );
+    } else {
+      Assert.equal(
+        submission.postData,
+        null,
+        "Should have not received any POST data"
+      );
+    }
+
+    Assert.equal(
+      engine.searchForm,
+      test.searchForm,
+      "Should have the correct search form url"
+    );
+
+    submission = engine.getSubmission("foo", SearchUtils.URL_TYPE.SUGGEST_JSON);
+    if (test.suggestUrl) {
+      Assert.equal(
+        submission.uri.spec,
+        test.suggestUrl,
+        "Should have the correct suggest url"
+      );
+    } else {
+      Assert.equal(submission, null, "Should not have a suggestion url");
+    }
+  });
+}
+
+add_task(async function test_telemetry_reporting() {
+  // Use an engine from the previous tests.
+  let engine = Services.search.getEngineByName("simple");
+  Services.search.defaultEngine = engine;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-simple",
+      displayName: "simple",
+      loadPath: "[http]localhost/simple.xml",
+      submissionUrl: "blank:",
+      verified: "verified",
+    },
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch_icon.js b/toolkit/components/search/tests/xpcshell/test_opensearch_icon.js
new file mode 100644
index 0000000000..937d1a58b9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch_icon.js
@@ -0,0 +1,63 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function setup() {
+  let server = useHttpServer();
+  server.registerContentType("sjs", "sjs");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+const tests = [
+  {
+    name: "Big Icon",
+    image: "bigIcon.ico",
+    expected: "data:image/png;base64,",
+  },
+  {
+    name: "Remote Icon",
+    image: "remoteIcon.ico",
+    expected: "data:image/x-icon;base64,",
+  },
+  {
+    name: "SVG Icon",
+    image: "svgIcon.svg",
+    expected: "data:image/svg+xml;base64,",
+  },
+];
+
+for (const test of tests) {
+  add_task(async function () {
+    info(`Testing ${test.name}`);
+
+    let promiseEngineAdded = SearchTestUtils.promiseSearchNotification(
+      SearchUtils.MODIFIED_TYPE.ADDED,
+      SearchUtils.TOPIC_ENGINE_MODIFIED
+    );
+    let promiseEngineChanged = SearchTestUtils.promiseSearchNotification(
+      SearchUtils.MODIFIED_TYPE.CHANGED,
+      SearchUtils.TOPIC_ENGINE_MODIFIED
+    );
+    const engineData = {
+      baseURL: gDataUrl,
+      image: test.image,
+      name: test.name,
+      method: "GET",
+    };
+    // The easiest way to test adding the icon is via a generated xml, otherwise
+    // we have to somehow insert the address of the server into it.
+    SearchTestUtils.promiseNewSearchEngine({
+      url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(engineData)}`,
+    });
+    let engine = await promiseEngineAdded;
+    await promiseEngineChanged;
+
+    Assert.ok(engine.iconURI, "the engine has an icon");
+    Assert.ok(
+      engine.iconURI.spec.startsWith(test.expected),
+      "the icon is saved as an x-icon data url"
+    );
+  });
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch_icons_invalid.js b/toolkit/components/search/tests/xpcshell/test_opensearch_icons_invalid.js
new file mode 100644
index 0000000000..4f81b0e9d3
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch_icons_invalid.js
@@ -0,0 +1,49 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Test that an installed engine can't use a resource URL for an icon */
+
+"use strict";
+
+add_task(async function setup() {
+  let server = useHttpServer("");
+  server.registerContentType("sjs", "sjs");
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_installedresourceicon() {
+  let engine1 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}opensearch/resourceicon.xml`,
+  });
+  let engine2 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}opensearch/chromeicon.xml`,
+  });
+
+  Assert.equal(null, engine1.iconURI);
+  Assert.equal(null, engine2.iconURI);
+});
+
+add_task(async function test_installedhttpplace() {
+  let observed = TestUtils.consoleMessageObserved(msg => {
+    return msg.wrappedJSObject.arguments[0].includes(
+      "Content type does not match expected"
+    );
+  });
+
+  // The easiest way to test adding the icon is via a generated xml, otherwise
+  // we have to somehow insert the address of the server into it.
+  let engine = await SearchTestUtils.promiseNewSearchEngine({
+    url:
+      `${gDataUrl}data/engineMaker.sjs?` +
+      JSON.stringify({
+        baseURL: gDataUrl,
+        image: "opensearch/resourceicon.xml",
+        name: "invalidicon",
+        method: "GET",
+      }),
+  });
+
+  await observed;
+
+  Assert.equal(null, engine.iconURI, "Should not have set an iconURI");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch_install_errors.js b/toolkit/components/search/tests/xpcshell/test_opensearch_install_errors.js
new file mode 100644
index 0000000000..62ae7d18ce
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch_install_errors.js
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that various install failures are handled correctly.
+ */
+
+add_task(async function setup() {
+  useHttpServer("opensearch");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  // This test purposely attempts to load an invalid engine.
+  consoleAllowList.push("_onLoad: Failed to init engine!");
+  consoleAllowList.push("Invalid search plugin due to namespace not matching");
+});
+
+add_task(async function test_invalid_path_fails() {
+  await Assert.rejects(
+    Services.search.addOpenSearchEngine("http://invalid/data/engine.xml", null),
+    error => {
+      Assert.equal(
+        error.result,
+        Ci.nsISearchService.ERROR_DOWNLOAD_FAILURE,
+        "Should have returned download failure."
+      );
+      return true;
+    },
+    "Should fail to install an engine with an invalid path."
+  );
+});
+
+add_task(async function test_install_duplicate_fails() {
+  let engine = await Services.search.addOpenSearchEngine(
+    gDataUrl + "simple.xml",
+    null
+  );
+  Assert.equal(engine.name, "simple", "Should have installed the engine.");
+
+  await Assert.rejects(
+    Services.search.addOpenSearchEngine(gDataUrl + "simple.xml", null),
+    error => {
+      Assert.equal(
+        error.result,
+        Ci.nsISearchService.ERROR_DUPLICATE_ENGINE,
+        "Should have returned duplicate failure."
+      );
+      return true;
+    },
+    "Should fail to install a duplicate engine."
+  );
+});
+
+add_task(async function test_invalid_engine_from_dir() {
+  await Assert.rejects(
+    Services.search.addOpenSearchEngine(gDataUrl + "invalid.xml", null),
+    error => {
+      Assert.equal(
+        error.result,
+        Ci.nsISearchService.ERROR_ENGINE_CORRUPTED,
+        "Should have returned corruption failure."
+      );
+      return true;
+    },
+    "Should fail to install an invalid engine."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch_telemetry.js b/toolkit/components/search/tests/xpcshell/test_opensearch_telemetry.js
new file mode 100644
index 0000000000..cd42a47371
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch_telemetry.js
@@ -0,0 +1,62 @@
+/* Any copyright is dedicated to the Public Domain.
+http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const { promiseStartupManager, promiseShutdownManager } = AddonTestUtils;
+
+const openSearchEngineFiles = [
+  "secure-and-securely-updated1.xml",
+  "secure-and-securely-updated2.xml",
+  "secure-and-securely-updated3.xml",
+  // An insecure search form should not affect telemetry.
+  "secure-and-securely-updated-insecure-form.xml",
+  "secure-and-insecurely-updated1.xml",
+  "secure-and-insecurely-updated2.xml",
+  "insecure-and-securely-updated1.xml",
+  "insecure-and-insecurely-updated1.xml",
+  "insecure-and-insecurely-updated2.xml",
+  "secure-and-no-update-url1.xml",
+  "insecure-and-no-update-url1.xml",
+  "secure-localhost.xml",
+  "secure-onionv2.xml",
+  "secure-onionv3.xml",
+];
+
+async function verifyTelemetry(probeNameFragment, engineCount, type) {
+  Services.telemetry.clearScalars();
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertScalar(
+    TelemetryTestUtils.getProcessScalars("parent"),
+    `browser.searchinit.${probeNameFragment}`,
+    engineCount,
+    `Count of ${type} engines: ${engineCount}`
+  );
+}
+
+add_task(async function setup() {
+  useHttpServer("opensearch");
+
+  await promiseStartupManager();
+  await Services.search.init();
+
+  for (let file of openSearchEngineFiles) {
+    await Services.search.addOpenSearchEngine(gDataUrl + file, null);
+  }
+
+  registerCleanupFunction(async () => {
+    await promiseShutdownManager();
+  });
+});
+
+add_task(async function () {
+  verifyTelemetry("secure_opensearch_engine_count", 10, "secure");
+  verifyTelemetry("insecure_opensearch_engine_count", 4, "insecure");
+  verifyTelemetry("secure_opensearch_update_count", 5, "securely updated");
+  verifyTelemetry("insecure_opensearch_update_count", 4, "insecurely updated");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_opensearch_update.js b/toolkit/components/search/tests/xpcshell/test_opensearch_update.js
new file mode 100644
index 0000000000..5d67739b22
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_opensearch_update.js
@@ -0,0 +1,120 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Test that user-set metadata isn't lost on engine update */
+
+"use strict";
+
+const KEYWORD = "keyword";
+let timerManager;
+
+add_task(async function setup() {
+  let server = useHttpServer("");
+  server.registerContentType("sjs", "sjs");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  timerManager = Cc["@mozilla.org/updates/timer-manager;1"].getService(
+    Ci.nsIUpdateTimerManager
+  );
+});
+
+add_task(async function test_installEngine_with_updates_disabled() {
+  const engineData = {
+    baseURL: gDataUrl,
+    name: "test engine",
+    method: "GET",
+    updateFile: "opensearch/simple.xml",
+  };
+
+  Services.prefs.setBoolPref(SearchUtils.BROWSER_SEARCH_PREF + "update", false);
+  Assert.ok(
+    !("search-engine-update-timer" in timerManager.wrappedJSObject._timers),
+    "Should not have registered the update timer already"
+  );
+
+  await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}data/engineMaker.sjs?${JSON.stringify(engineData)}`,
+  });
+
+  Assert.ok(
+    Services.search.getEngineByName("test engine"),
+    "Should have added the test engine."
+  );
+  Assert.ok(
+    !("search-engine-update-timer" in timerManager.wrappedJSObject._timers),
+    "Should have not registered the update timer when updates are disabled"
+  );
+});
+
+add_task(async function test_installEngine_with_updates_enabled() {
+  const engineData = {
+    baseURL: gDataUrl,
+    name: "original engine",
+    method: "GET",
+    updateFile: "opensearch/simple.xml",
+  };
+
+  Services.prefs.setBoolPref(SearchUtils.BROWSER_SEARCH_PREF + "update", true);
+
+  Assert.ok(
+    !("search-engine-update-timer" in timerManager.wrappedJSObject._timers),
+    "Should not have registered the update timer already"
+  );
+
+  let engine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}data/engineMaker.sjs?${JSON.stringify(engineData)}`,
+  });
+
+  Assert.ok(
+    "search-engine-update-timer" in timerManager.wrappedJSObject._timers,
+    "Should have registered the update timer"
+  );
+
+  engine.alias = KEYWORD;
+  await Services.search.moveEngine(engine, 0);
+
+  Assert.ok(
+    !!Services.search.getEngineByName("original engine"),
+    "Should be able to get the engine by the original name"
+  );
+  Assert.ok(
+    !Services.search.getEngineByName("simple"),
+    "Should not be able to get the engine by the new name"
+  );
+});
+
+add_task(async function test_engineUpdate() {
+  const ONE_DAY_IN_MS = 24 * 60 * 60 * 1000;
+
+  let promiseUpdate = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.CHANGED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  // set last update to 8 days ago, since the default interval is 7, then
+  // trigger an update
+  let engine = Services.search.getEngineByName("original engine");
+  engine.wrappedJSObject.setAttr("updateexpir", Date.now() - ONE_DAY_IN_MS * 8);
+  Services.search.QueryInterface(Ci.nsITimerCallback).notify(null);
+
+  await promiseUpdate;
+
+  Assert.equal(engine.name, "simple", "Should have updated the engine's name");
+
+  Assert.equal(engine.alias, KEYWORD, "Should have kept the keyword");
+  Assert.equal(
+    engine.wrappedJSObject.getAttr("order"),
+    1,
+    "Should have kept the order"
+  );
+
+  Assert.ok(
+    !!Services.search.getEngineByName("simple"),
+    "Should be able to get the engine by the new name"
+  );
+  Assert.ok(
+    !Services.search.getEngineByName("original engine"),
+    "Should not be able to get the engine by the old name"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_override_allowlist.js b/toolkit/components/search/tests/xpcshell/test_override_allowlist.js
new file mode 100644
index 0000000000..24a2ecb8e6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_override_allowlist.js
@@ -0,0 +1,391 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const kBaseURL = "https://example.com/";
+const kSearchEngineURL = `${kBaseURL}?q={searchTerms}&foo=myparams`;
+const kOverriddenEngineName = "Simple Engine";
+
+const allowlist = [
+  {
+    thirdPartyId: "test@thirdparty.example.com",
+    overridesId: "simple@search.mozilla.org",
+    urls: [],
+  },
+];
+
+const tests = [
+  {
+    title: "test_not_changing_anything",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: "MozParamsTest2",
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL,
+    },
+    expected: {
+      switchToDefaultAllowed: false,
+      canInstallEngine: true,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_changing_default_engine",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL,
+    },
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_changing_default_engine",
+    startupReason: "ADDON_ENABLE",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL,
+    },
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_overriding_default_engine",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL,
+    },
+    allowlistUrls: [
+      {
+        search_url: kSearchEngineURL,
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: true,
+      searchUrl: kSearchEngineURL,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_enable",
+    startupReason: "ADDON_ENABLE",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL,
+    },
+    allowlistUrls: [
+      {
+        search_url: kSearchEngineURL,
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: true,
+      searchUrl: kSearchEngineURL,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_different_url",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kSearchEngineURL + "a",
+    },
+    allowlistUrls: [
+      {
+        search_url: kSearchEngineURL,
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_get_params",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_url_get_params: "q={searchTerms}&enc=UTF-8",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_url_get_params: "q={searchTerms}&enc=UTF-8",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: true,
+      searchUrl: `${kBaseURL}?q={searchTerms}&enc=UTF-8`,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_different_get_params",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_url_get_params: "q={searchTerms}&enc=UTF-8a",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_url_get_params: "q={searchTerms}&enc=UTF-8",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_post_params",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_url_post_params: "q={searchTerms}&enc=UTF-8",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_url_post_params: "q={searchTerms}&enc=UTF-8",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: true,
+      searchUrl: `${kBaseURL}`,
+      postData: "q={searchTerms}&enc=UTF-8",
+    },
+  },
+  {
+    title: "test_overriding_default_engine_different_post_params",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_url_post_params: "q={searchTerms}&enc=UTF-8a",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_url_post_params: "q={searchTerms}&enc=UTF-8",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+  {
+    title: "test_overriding_default_engine_search_form",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_form: "https://example.com/form",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_form: "https://example.com/form",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: true,
+      searchUrl: `${kBaseURL}`,
+      searchForm: "https://example.com/form",
+    },
+  },
+  {
+    title: "test_overriding_default_engine_different_search_form",
+    startupReason: "ADDON_INSTALL",
+    search_provider: {
+      is_default: true,
+      name: kOverriddenEngineName,
+      keyword: "MozSearch",
+      search_url: kBaseURL,
+      search_form: "https://example.com/forma",
+    },
+    allowlistUrls: [
+      {
+        search_url: kBaseURL,
+        search_form: "https://example.com/form",
+      },
+    ],
+    expected: {
+      switchToDefaultAllowed: true,
+      canInstallEngine: false,
+      overridesEngine: false,
+    },
+  },
+];
+
+let baseExtension;
+let remoteSettingsStub;
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("simple-engines");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  baseExtension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      browser_specific_settings: {
+        gecko: {
+          id: "test@thirdparty.example.com",
+        },
+      },
+    },
+    useAddonManager: "permanent",
+  });
+  await baseExtension.startup();
+
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_ALLOWLIST_KEY);
+  remoteSettingsStub = sinon.stub(settings, "get").returns([]);
+
+  registerCleanupFunction(async () => {
+    await baseExtension.unload();
+  });
+});
+
+for (const test of tests) {
+  add_task(async () => {
+    info(test.title);
+
+    let extension = {
+      ...baseExtension,
+      startupReason: test.startupReason,
+      manifest: {
+        chrome_settings_overrides: {
+          search_provider: test.search_provider,
+        },
+      },
+    };
+
+    if (test.expected.overridesEngine) {
+      remoteSettingsStub.returns([
+        { ...allowlist[0], urls: test.allowlistUrls },
+      ]);
+    }
+
+    let result = await Services.search.maybeSetAndOverrideDefault(extension);
+    Assert.equal(
+      result.canChangeToAppProvided,
+      test.expected.switchToDefaultAllowed,
+      "Should have returned the correct value for allowing switch to default or not."
+    );
+    Assert.equal(
+      result.canInstallEngine,
+      test.expected.canInstallEngine,
+      "Should have returned the correct value for allowing to install the engine or not."
+    );
+
+    let engine = await Services.search.getEngineByName(kOverriddenEngineName);
+    Assert.equal(
+      !!engine.wrappedJSObject.getAttr("overriddenBy"),
+      test.expected.overridesEngine,
+      "Should have correctly overridden or not."
+    );
+
+    Assert.equal(
+      engine.telemetryId,
+      "simple" + (test.expected.overridesEngine ? "-addon" : ""),
+      "Should set the correct telemetry Id"
+    );
+
+    if (test.expected.overridesEngine) {
+      let submission = engine.getSubmission("{searchTerms}");
+      Assert.equal(
+        decodeURI(submission.uri.spec),
+        test.expected.searchUrl,
+        "Should have set the correct url on an overriden engine"
+      );
+
+      if (test.expected.search_form) {
+        Assert.equal(
+          engine.wrappedJSObject._searchForm,
+          test.expected.searchForm,
+          "Should have overridden the search form."
+        );
+      }
+
+      if (test.expected.postData) {
+        let sis = Cc["@mozilla.org/scriptableinputstream;1"].createInstance(
+          Ci.nsIScriptableInputStream
+        );
+        sis.init(submission.postData);
+        let data = sis.read(submission.postData.available());
+        Assert.equal(
+          decodeURIComponent(data),
+          test.expected.postData,
+          "Should have overridden the postData"
+        );
+      }
+
+      // As we're not testing the WebExtension manager as well,
+      // set this engine as default so we can check the telemetry data.
+      let oldDefaultEngine = Services.search.defaultEngine;
+      Services.search.defaultEngine = engine;
+
+      let engineInfo = Services.search.getDefaultEngineInfo();
+      Assert.deepEqual(
+        engineInfo,
+        {
+          defaultSearchEngine: "simple-addon",
+          defaultSearchEngineData: {
+            loadPath: "[addon]simple@search.mozilla.org",
+            name: "Simple Engine",
+            origin: "default",
+            submissionURL: test.expected.searchUrl.replace("{searchTerms}", ""),
+          },
+        },
+        "Should return the extended identifier and alternate submission url to telemetry"
+      );
+      Services.search.defaultEngine = oldDefaultEngine;
+
+      engine.wrappedJSObject.removeExtensionOverride();
+    }
+  });
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_parseSubmissionURL.js b/toolkit/components/search/tests/xpcshell/test_parseSubmissionURL.js
new file mode 100644
index 0000000000..bee90dbb5b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_parseSubmissionURL.js
@@ -0,0 +1,182 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    https://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests getAlternateDomains API.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_parseSubmissionURL() {
+  let engine1 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+  let engine2 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine-fr.xml`,
+  });
+
+  await SearchTestUtils.installSearchExtension({
+    name: "bacon_addParam",
+    keyword: "bacon_addParam",
+    encoding: "windows-1252",
+    search_url: "https://www.bacon.test/find",
+  });
+  await SearchTestUtils.installSearchExtension({
+    name: "idn_addParam",
+    keyword: "idn_addParam",
+    search_url: "https://www.xn--bcher-kva.ch/search",
+  });
+  let engine3 = Services.search.getEngineByName("bacon_addParam");
+  let engine4 = Services.search.getEngineByName("idn_addParam");
+
+  // The following engine provides it's query keyword in
+  // its template in the form of q={searchTerms}
+  let engine5 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine2.xml`,
+  });
+
+  // The following engines cannot identify the search parameter.
+  await SearchTestUtils.installSearchExtension({
+    name: "bacon",
+    keyword: "bacon",
+    search_url: "https://www.bacon.moz/search?q=",
+    search_url_get_params: "",
+  });
+
+  await Services.search.setDefault(
+    engine1,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  // Hide the default engines to prevent them from being used in the search.
+  for (let engine of await Services.search.getAppProvidedEngines()) {
+    await Services.search.removeEngine(engine);
+  }
+
+  // Test the first engine, whose URLs use UTF-8 encoding.
+  // This also tests the query parameter in a different position not being the
+  // first parameter.
+  let url = "https://www.google.com/search?foo=bar&q=caff%C3%A8";
+  let result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // The second engine uses a locale-specific domain that is an alternate domain
+  // of the first one, but the second engine should get priority when matching.
+  // The URL used with this engine uses ISO-8859-1 encoding instead.
+  url = "https://www.google.fr/search?q=caff%E8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine2);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // Test a domain that is an alternate domain of those defined.  In this case,
+  // the first matching engine from the ordered list should be returned.
+  url = "https://www.google.co.uk/search?q=caff%C3%A8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // We support parsing URLs from a dynamically added engine.
+  url = "https://www.bacon.test/find?q=caff%E8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine, engine3);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // Test URLs with unescaped unicode characters.
+  url = "https://www.google.com/search?q=foo+b\u00E4r";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "foo b\u00E4r");
+
+  // Test search engines with unescaped IDNs.
+  url = "https://www.b\u00FCcher.ch/search?q=foo+bar";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine, engine4);
+  Assert.equal(result.terms, "foo bar");
+
+  // Test search engines with escaped IDNs.
+  url = "https://www.xn--bcher-kva.ch/search?q=foo+bar";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine, engine4);
+  Assert.equal(result.terms, "foo bar");
+
+  // Parsing of parameters from an engine template URL is not supported
+  // if no matching parameter value template is provided.
+  Assert.equal(
+    Services.search.parseSubmissionURL("https://www.bacon.moz/search?q=")
+      .engine,
+    null
+  );
+
+  // Parsing of parameters from an engine template URL is supported
+  // if a matching parameter value template is provided.
+  url = "https://duckduckgo.com/?foo=bar&q=caff%C3%A8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine5);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // If the search params are in the template, the query parameter
+  // doesn't need to be separated from the host by a slash, only by
+  // by a question mark.
+  url = "https://duckduckgo.com?foo=bar&q=caff%C3%A8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine5);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // HTTP and HTTPS schemes are interchangeable.
+  url = "https://www.google.com/search?q=caff%C3%A8";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "caff\u00E8");
+
+  // Decoding search terms with multiple spaces should work.
+  result = Services.search.parseSubmissionURL(
+    "https://www.google.com/search?q=+with++spaces+"
+  );
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, " with  spaces ");
+
+  // Parsing search terms with ampersands should work.
+  result = Services.search.parseSubmissionURL(
+    "https://www.google.com/search?q=with%26ampersand"
+  );
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "with&ampersand");
+
+  // Capitals in the path should work
+  result = Services.search.parseSubmissionURL(
+    "https://www.google.com/SEARCH?q=caps"
+  );
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "caps");
+
+  // An empty query parameter should work the same.
+  url = "https://www.google.com/search?q=";
+  result = Services.search.parseSubmissionURL(url);
+  Assert.equal(result.engine.wrappedJSObject, engine1);
+  Assert.equal(result.terms, "");
+
+  // There should be no match when the path is different.
+  result = Services.search.parseSubmissionURL(
+    "https://www.google.com/search/?q=test"
+  );
+  Assert.equal(result.engine, null);
+  Assert.equal(result.terms, "");
+
+  // There should be no match when the argument is different.
+  result = Services.search.parseSubmissionURL(
+    "https://www.google.com/search?q2=test"
+  );
+  Assert.equal(result.engine, null);
+  Assert.equal(result.terms, "");
+
+  // There should be no match for URIs that are not HTTP or HTTPS.
+  result = Services.search.parseSubmissionURL("file://localhost/search?q=test");
+  Assert.equal(result.engine, null);
+  Assert.equal(result.terms, "");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_policyEngine.js b/toolkit/components/search/tests/xpcshell/test_policyEngine.js
new file mode 100644
index 0000000000..4dd58c8fc7
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_policyEngine.js
@@ -0,0 +1,185 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that Enterprise Policy Engines can be installed correctly.
+ */
+
+"use strict";
+
+const { EnterprisePolicyTesting } = ChromeUtils.importESModule(
+  "resource://testing-common/EnterprisePolicyTesting.sys.mjs"
+);
+
+SearchSettings.SETTINGS_INVALIDATION_DELAY = 100;
+
+/**
+ * Loads a new enterprise policy, and re-initialise the search service
+ * with the new policy. Also waits for the search service to write the settings
+ * file to disk.
+ *
+ * @param {object} policy
+ *   The enterprise policy to use.
+ */
+async function setupPolicyEngineWithJson(policy) {
+  Services.search.wrappedJSObject.reset();
+
+  await EnterprisePolicyTesting.setupPolicyEngineWithJson(policy);
+
+  let settingsWritten = SearchTestUtils.promiseSearchNotification(
+    "write-settings-to-disk-complete"
+  );
+  await Services.search.init();
+  await settingsWritten;
+}
+
+add_task(async function setup() {
+  // This initializes the policy engine for xpcshell tests
+  let policies = Cc["@mozilla.org/enterprisepolicies;1"].getService(
+    Ci.nsIObserver
+  );
+  policies.observe(null, "policies-startup", null);
+
+  Services.fog.initializeFOG();
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines();
+
+  SearchUtils.GENERAL_SEARCH_ENGINE_IDS = new Set([
+    "engine-resourceicon@search.mozilla.org",
+  ]);
+});
+
+add_task(async function test_enterprise_policy_engine() {
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Add: [
+          {
+            Name: "policy",
+            Description: "Test policy engine",
+            IconURL: "data:image/gif;base64,R0lGODl",
+            Alias: "p",
+            URLTemplate: "https://example.com?q={searchTerms}",
+            SuggestURLTemplate: "https://example.com/suggest/?q={searchTerms}",
+          },
+        ],
+      },
+    },
+  });
+
+  let engine = Services.search.getEngineByName("policy");
+  Assert.ok(engine, "Should have installed the engine.");
+
+  Assert.equal(engine.name, "policy", "Should have the correct name");
+  Assert.equal(
+    engine.description,
+    "Test policy engine",
+    "Should have a description"
+  );
+  Assert.deepEqual(engine.aliases, ["p"], "Should have the correct alias");
+
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://example.com/?q=foo",
+    "Should have the correct search url"
+  );
+
+  submission = engine.getSubmission("foo", SearchUtils.URL_TYPE.SUGGEST_JSON);
+  Assert.equal(
+    submission.uri.spec,
+    "https://example.com/suggest/?q=foo",
+    "Should have the correct suggest url"
+  );
+
+  Services.search.defaultEngine = engine;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-policy",
+      displayName: "policy",
+      loadPath: "[policy]",
+      submissionUrl: "blank:",
+      verified: "verified",
+    },
+  });
+});
+
+add_task(async function test_enterprise_policy_engine_hidden_persisted() {
+  // Set the engine alias, and wait for the settings to be written.
+  let settingsWritten = SearchTestUtils.promiseSearchNotification(
+    "write-settings-to-disk-complete"
+  );
+  let engine = Services.search.getEngineByName("policy");
+  engine.hidden = "p1";
+  engine.alias = "p1";
+  await settingsWritten;
+
+  // This will reset and re-initialise the search service.
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Add: [
+          {
+            Name: "policy",
+            Description: "Test policy engine",
+            IconURL: "data:image/gif;base64,R0lGODl",
+            Alias: "p",
+            URLTemplate: "https://example.com?q={searchTerms}",
+            SuggestURLTemplate: "https://example.com/suggest/?q={searchTerms}",
+          },
+        ],
+      },
+    },
+  });
+
+  engine = Services.search.getEngineByName("policy");
+  Assert.equal(engine.alias, "p1", "Should have retained the engine alias");
+  Assert.ok(engine.hidden, "Should have kept the engine hidden");
+});
+
+add_task(async function test_enterprise_policy_engine_remove() {
+  // This will reset and re-initialise the search service.
+  await setupPolicyEngineWithJson({
+    policies: {},
+  });
+
+  Assert.ok(
+    !Services.search.getEngineByName("policy"),
+    "Should not have the policy engine installed"
+  );
+
+  let settings = await promiseSettingsData();
+  Assert.ok(
+    !settings.engines.find(e => e.name == "p1"),
+    "Should not have the engine settings stored"
+  );
+});
+
+add_task(async function test_enterprise_policy_hidden_default() {
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Remove: ["Test search engine"],
+      },
+    },
+  });
+
+  Services.search.resetToAppDefaultEngine();
+
+  Assert.equal(Services.search.defaultEngine.name, "engine-resourceicon");
+});
+
+add_task(async function test_enterprise_policy_default() {
+  await setupPolicyEngineWithJson({
+    policies: {
+      SearchEngines: {
+        Default: "engine-pref",
+      },
+    },
+  });
+
+  Services.search.resetToAppDefaultEngine();
+
+  Assert.equal(Services.search.defaultEngine.name, "engine-pref");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_pref.js b/toolkit/components/search/tests/xpcshell/test_pref.js
new file mode 100644
index 0000000000..2445ea2100
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_pref.js
@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Test that MozParam condition="pref" values used in search URLs are from the
+ * default branch, and that their special characters are URL encoded. */
+
+"use strict";
+
+const defaultBranch = Services.prefs.getDefaultBranch(
+  SearchUtils.BROWSER_SEARCH_PREF
+);
+const baseURL = "https://www.google.com/search?q=foo";
+
+add_task(async function setup() {
+  // The test engines used in this test need to be recognized as 'default'
+  // engines, or their MozParams will be ignored.
+  await SearchTestUtils.useTestEngines();
+});
+
+add_task(async function test_pref_initial_value() {
+  defaultBranch.setCharPref("param.code", "good&id=unique");
+  Services.prefs.setCharPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "param.code",
+    "bad"
+  );
+
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  const engine = Services.search.getEngineByName("engine-pref");
+  const base = baseURL + "&code=";
+  Assert.equal(
+    engine.getSubmission("foo").uri.spec,
+    base + "good%26id%3Dunique",
+    "Should have got the submission URL with the correct code"
+  );
+
+  // Now clear the user-set preference. Having a user set preference means
+  // we don't get updates from the pref service of changes on the default
+  // branch. Normally, this won't be an issue, since we don't expect users
+  // to be playing with these prefs, and worst-case, they'll just get the
+  // actual change on restart.
+  Services.prefs.clearUserPref(SearchUtils.BROWSER_SEARCH_PREF + "param.code");
+});
+
+add_task(async function test_pref_updated() {
+  // Update the pref without re-init nor restart.
+  defaultBranch.setCharPref("param.code", "supergood&id=unique123456");
+
+  const engine = Services.search.getEngineByName("engine-pref");
+  const base = baseURL + "&code=";
+  Assert.equal(
+    engine.getSubmission("foo").uri.spec,
+    base + "supergood%26id%3Dunique123456",
+    "Should have got the submission URL with the updated code"
+  );
+});
+
+add_task(async function test_pref_cleared() {
+  // Update the pref without re-init nor restart.
+  // Note you can't delete a preference from the default branch.
+  defaultBranch.setCharPref("param.code", "");
+
+  let engine = Services.search.getEngineByName("engine-pref");
+  Assert.equal(
+    engine.getSubmission("foo").uri.spec,
+    baseURL,
+    "Should have just the base URL after the pref was cleared"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_purpose.js b/toolkit/components/search/tests/xpcshell/test_purpose.js
new file mode 100644
index 0000000000..7320276e4f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_purpose.js
@@ -0,0 +1,83 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that a search purpose can be specified and that query parameters for
+ * that purpose are included in the search URL.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  // The test engines used in this test need to be recognized as 'default'
+  // engines, or their MozParams used to set the purpose will be ignored.
+  await SearchTestUtils.useTestEngines();
+
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_purpose() {
+  let engine = Services.search.getEngineByName("Test search engine");
+
+  function check_submission(aValue, aSearchTerm, aType, aPurpose) {
+    let submissionURL = engine.getSubmission(aSearchTerm, aType, aPurpose).uri
+      .spec;
+    let searchParams = new URLSearchParams(submissionURL.split("?")[1]);
+    if (aValue) {
+      Assert.equal(searchParams.get("channel"), aValue);
+    } else {
+      Assert.ok(!searchParams.has("channel"));
+    }
+    Assert.equal(searchParams.get("q"), aSearchTerm);
+  }
+
+  check_submission("", "foo");
+  check_submission("", "foo", null);
+  check_submission("", "foo", "text/html");
+  check_submission("rcs", "foo", null, "contextmenu");
+  check_submission("rcs", "foo", "text/html", "contextmenu");
+  check_submission("fflb", "foo", null, "keyword");
+  check_submission("fflb", "foo", "text/html", "keyword");
+  check_submission("", "foo", "text/html", "invalid");
+
+  // Tests for a purpose on the search form (ie. empty query).
+  engine = Services.search.getEngineByName("engine-rel-searchform-purpose");
+
+  // See bug 1485508
+  Assert.ok(!engine.searchForm.includes("?&"));
+
+  // verify that the 'system' purpose falls back to the 'searchbar' purpose.
+  check_submission("sb", "foo", "text/html", "system");
+  check_submission("sb", "foo", "text/html", "searchbar");
+});
+
+add_task(async function test_purpose() {
+  let engine = Services.search.getEngineByName(
+    "Test search engine (Reordered)"
+  );
+
+  function check_submission(aValue, aSearchTerm, aType, aPurpose) {
+    let submissionURL = engine.getSubmission(aSearchTerm, aType, aPurpose).uri
+      .spec;
+    let searchParams = new URLSearchParams(submissionURL.split("?")[1]);
+    if (aValue) {
+      Assert.equal(searchParams.get("channel"), aValue);
+    } else {
+      Assert.ok(!searchParams.has("channel"));
+    }
+    Assert.equal(searchParams.get("q"), aSearchTerm);
+  }
+
+  check_submission("", "foo");
+  check_submission("", "foo", null);
+  check_submission("", "foo", "text/html");
+  check_submission("rcs", "foo", null, "contextmenu");
+  check_submission("rcs", "foo", "text/html", "contextmenu");
+  check_submission("fflb", "foo", null, "keyword");
+  check_submission("fflb", "foo", "text/html", "keyword");
+  check_submission("", "foo", "text/html", "invalid");
+
+  // See bug 1485508
+  Assert.ok(!engine.searchForm.includes("?&"));
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_reload_engines.js b/toolkit/components/search/tests/xpcshell/test_reload_engines.js
new file mode 100644
index 0000000000..4d3a3d3659
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_reload_engines.js
@@ -0,0 +1,316 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const CONFIG = [
+  {
+    // Engine initially default, but the defaults will be changed to engine-pref.
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+        defaultPrivate: "yes",
+      },
+      {
+        included: { regions: ["FR"] },
+        default: "no",
+        defaultPrivate: "no",
+      },
+    ],
+  },
+  {
+    // This will become defaults when region is changed to FR.
+    webExtension: {
+      id: "engine-pref@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["FR"] },
+        default: "yes",
+        defaultPrivate: "yes",
+      },
+    ],
+  },
+  {
+    // This engine will get an update when region is changed to FR.
+    webExtension: {
+      id: "engine-chromeicon@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["FR"] },
+        extraParams: [
+          { name: "c", value: "my-test" },
+          { name: "q1", value: "{searchTerms}" },
+        ],
+      },
+    ],
+  },
+  {
+    // This engine will be removed when the region is changed to FR.
+    webExtension: {
+      id: "engine-rel-searchform-purpose@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["FR"] },
+      },
+    ],
+  },
+  {
+    // This engine will be added when the region is changed to FR.
+    webExtension: {
+      id: "engine-reordered@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { regions: ["FR"] },
+      },
+    ],
+  },
+  {
+    // This engine will be re-ordered and have a changed name, when moved to FR.
+    webExtension: {
+      id: "engine-resourceicon@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["FR"] },
+      },
+      {
+        included: { regions: ["FR"] },
+        webExtension: {
+          locales: ["gd"],
+        },
+        orderHint: 30,
+      },
+    ],
+  },
+  {
+    // This engine has the same name, but still should be replaced correctly.
+    webExtension: {
+      id: "engine-same-name@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["FR"] },
+      },
+      {
+        included: { regions: ["FR"] },
+        webExtension: {
+          locales: ["gd"],
+        },
+      },
+    ],
+  },
+];
+
+async function visibleEngines() {
+  return (await Services.search.getVisibleEngines()).map(e => e.identifier);
+}
+
+add_task(async function setup() {
+  Services.prefs.setBoolPref("browser.search.separatePrivateDefault", true);
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+
+  SearchTestUtils.useMockIdleService();
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+});
+
+// This is to verify that the loaded configuration matches what we expect for
+// the test.
+add_task(async function test_initial_config_correct() {
+  Region._setHomeRegion("", false);
+
+  await Services.search.init();
+
+  const installedEngines = await Services.search.getAppProvidedEngines();
+  Assert.deepEqual(
+    installedEngines.map(e => e.identifier),
+    [
+      "engine",
+      "engine-chromeicon",
+      "engine-pref",
+      "engine-rel-searchform-purpose",
+      "engine-resourceicon",
+      "engine-same-name",
+    ],
+    "Should have the correct list of engines installed."
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).identifier,
+    "engine",
+    "Should have loaded the expected default engine"
+  );
+
+  Assert.equal(
+    (await Services.search.getDefaultPrivate()).identifier,
+    "engine",
+    "Should have loaded the expected private default engine"
+  );
+});
+
+add_task(async function test_config_updated_engine_changes() {
+  // Update the config.
+  const reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  const defaultEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+  const defaultPrivateEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT_PRIVATE,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  const enginesAdded = [];
+  const enginesModified = [];
+  const enginesRemoved = [];
+
+  function enginesObs(subject, topic, data) {
+    if (data == SearchUtils.MODIFIED_TYPE.ADDED) {
+      enginesAdded.push(subject.QueryInterface(Ci.nsISearchEngine).identifier);
+    } else if (data == SearchUtils.MODIFIED_TYPE.CHANGED) {
+      enginesModified.push(
+        subject.QueryInterface(Ci.nsISearchEngine).identifier
+      );
+    } else if (data == SearchUtils.MODIFIED_TYPE.REMOVED) {
+      enginesRemoved.push(subject.QueryInterface(Ci.nsISearchEngine).name);
+    }
+  }
+  Services.obs.addObserver(enginesObs, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+  Region._setHomeRegion("FR", false);
+
+  await Services.search.wrappedJSObject._maybeReloadEngines();
+
+  await reloadObserved;
+  Services.obs.removeObserver(enginesObs, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+  Assert.deepEqual(
+    enginesAdded,
+    ["engine-resourceicon-gd", "engine-reordered"],
+    "Should have added the correct engines"
+  );
+
+  Assert.deepEqual(
+    enginesModified.sort(),
+    ["engine", "engine-chromeicon", "engine-pref", "engine-same-name-gd"],
+    "Should have modified the expected engines"
+  );
+
+  Assert.deepEqual(
+    enginesRemoved,
+    ["engine-rel-searchform-purpose", "engine-resourceicon"],
+    "Should have removed the expected engine"
+  );
+
+  const installedEngines = await Services.search.getAppProvidedEngines();
+
+  Assert.deepEqual(
+    installedEngines.map(e => e.identifier),
+    [
+      "engine-pref",
+      "engine-resourceicon-gd",
+      "engine-chromeicon",
+      "engine-same-name-gd",
+      "engine",
+      "engine-reordered",
+    ],
+    "Should have the correct list of engines installed in the expected order."
+  );
+
+  const newDefault = await defaultEngineChanged;
+  Assert.equal(
+    newDefault.QueryInterface(Ci.nsISearchEngine).name,
+    "engine-pref",
+    "Should have correctly notified the new default engine"
+  );
+
+  const newDefaultPrivate = await defaultPrivateEngineChanged;
+  Assert.equal(
+    newDefaultPrivate.QueryInterface(Ci.nsISearchEngine).name,
+    "engine-pref",
+    "Should have correctly notified the new default private engine"
+  );
+
+  const engineWithParams = await Services.search.getEngineByName(
+    "engine-chromeicon"
+  );
+  Assert.equal(
+    engineWithParams.getSubmission("test").uri.spec,
+    "https://www.google.com/search?c=my-test&q1=test",
+    "Should have updated the parameters"
+  );
+
+  const engineWithSameName = await Services.search.getEngineByName(
+    "engine-same-name"
+  );
+  Assert.equal(
+    engineWithSameName.getSubmission("test").uri.spec,
+    "https://www.example.com/search?q=test",
+    "Should have correctly switched to the engine of the same name"
+  );
+
+  Assert.equal(
+    Services.search.wrappedJSObject._settings.getMetaDataAttribute(
+      "useSavedOrder"
+    ),
+    false,
+    "Should not have set the useSavedOrder preference"
+  );
+});
+
+add_task(async function test_user_settings_persist() {
+  let reload = SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Region._setHomeRegion("");
+  await reload;
+
+  Assert.ok(
+    (await visibleEngines()).includes("engine-rel-searchform-purpose"),
+    "Rel Searchform engine should be included by default"
+  );
+
+  let settingsFileWritten = promiseAfterSettings();
+  let engine = await Services.search.getEngineByName(
+    "engine-rel-searchform-purpose"
+  );
+  await Services.search.removeEngine(engine);
+  await settingsFileWritten;
+
+  Assert.ok(
+    !(await visibleEngines()).includes("engine-rel-searchform-purpose"),
+    "Rel Searchform engine has been removed"
+  );
+
+  reload = SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Region._setHomeRegion("FR");
+  await reload;
+
+  reload = SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Region._setHomeRegion("");
+  await reload;
+
+  Assert.ok(
+    !(await visibleEngines()).includes("engine-rel-searchform-purpose"),
+    "Rel Searchform removal should be remembered"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_reload_engines_experiment.js b/toolkit/components/search/tests/xpcshell/test_reload_engines_experiment.js
new file mode 100644
index 0000000000..ded610ca56
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_reload_engines_experiment.js
@@ -0,0 +1,133 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const CONFIG = [
+  {
+    // Just a basic engine that won't be changed.
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+    ],
+  },
+  {
+    // This engine will have the locale swapped when the experiment is set.
+    webExtension: {
+      id: "engine-same-name@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        webExtension: {
+          locales: ["en"],
+        },
+      },
+      {
+        included: { everywhere: true },
+        webExtension: {
+          locales: ["gd"],
+        },
+        experiment: "xpcshell",
+      },
+    ],
+  },
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+});
+
+// This is to verify that the loaded configuration matches what we expect for
+// the test.
+add_task(async function test_initial_config_correct() {
+  await Services.search.init();
+
+  const installedEngines = await Services.search.getAppProvidedEngines();
+  Assert.deepEqual(
+    installedEngines.map(e => e.identifier),
+    ["engine", "engine-same-name-en"],
+    "Should have the correct list of engines installed."
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).identifier,
+    "engine",
+    "Should have loaded the expected default engine"
+  );
+});
+
+add_task(async function test_config_updated_engine_changes() {
+  // Update the config.
+  const reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  const enginesAdded = [];
+  const enginesModified = [];
+  const enginesRemoved = [];
+
+  function enginesObs(subject, topic, data) {
+    if (data == SearchUtils.MODIFIED_TYPE.ADDED) {
+      enginesAdded.push(subject.QueryInterface(Ci.nsISearchEngine).identifier);
+    } else if (data == SearchUtils.MODIFIED_TYPE.CHANGED) {
+      enginesModified.push(
+        subject.QueryInterface(Ci.nsISearchEngine).identifier
+      );
+    } else if (data == SearchUtils.MODIFIED_TYPE.REMOVED) {
+      enginesRemoved.push(subject.QueryInterface(Ci.nsISearchEngine).name);
+    }
+  }
+  Services.obs.addObserver(enginesObs, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+  Services.prefs.setCharPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "experiment",
+    "xpcshell"
+  );
+
+  await reloadObserved;
+  Services.obs.removeObserver(enginesObs, SearchUtils.TOPIC_ENGINE_MODIFIED);
+
+  Assert.deepEqual(enginesAdded, [], "Should have added the correct engines");
+
+  Assert.deepEqual(
+    enginesModified.sort(),
+    ["engine", "engine-same-name-gd"],
+    "Should have modified the expected engines"
+  );
+
+  Assert.deepEqual(
+    enginesRemoved,
+    [],
+    "Should have removed the expected engine"
+  );
+
+  const installedEngines = await Services.search.getAppProvidedEngines();
+
+  Assert.deepEqual(
+    installedEngines.map(e => e.identifier),
+    ["engine", "engine-same-name-gd"],
+    "Should have the correct list of engines installed in the expected order."
+  );
+
+  const engineWithSameName = await Services.search.getEngineByName(
+    "engine-same-name"
+  );
+  Assert.equal(
+    engineWithSameName.getSubmission("test").uri.spec,
+    "https://www.example.com/search?q=test",
+    "Should have correctly switched to the engine of the same name"
+  );
+
+  Assert.equal(
+    Services.search.wrappedJSObject._settings.getMetaDataAttribute(
+      "useSavedOrder"
+    ),
+    false,
+    "Should not have set the useSavedOrder preference"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_reload_engines_locales.js b/toolkit/components/search/tests/xpcshell/test_reload_engines_locales.js
new file mode 100644
index 0000000000..9e98e5e73a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_reload_engines_locales.js
@@ -0,0 +1,95 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests reloading engines when changing the in-use locale of a WebExtension,
+ * where the name of the engine changes as well.
+ */
+
+"use strict";
+
+const CONFIG = [
+  {
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+    ],
+  },
+  {
+    webExtension: {
+      id: "engine-diff-name@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { locales: { matches: ["gd"] } },
+      },
+      {
+        included: { locales: { matches: ["gd"] } },
+        webExtension: {
+          locales: ["gd"],
+        },
+      },
+    ],
+  },
+];
+
+add_setup(async () => {
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "en",
+    "gd",
+  ];
+  Services.locale.requestedLocales = ["gd"];
+
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_config_updated_engine_changes() {
+  let engines = await Services.search.getEngines();
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["Test search engine", "engine-diff-name-gd"],
+    "Should have the correct engines installed"
+  );
+
+  let engine = await Services.search.getEngineByName("engine-diff-name-gd");
+  Assert.equal(
+    engine.name,
+    "engine-diff-name-gd",
+    "Should have the correct engine name"
+  );
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    "https://gd.wikipedia.com/search",
+    "Should have the gd search url"
+  );
+
+  await promiseSetLocale("en");
+
+  engines = await Services.search.getEngines();
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["Test search engine", "engine-diff-name-en"],
+    "Should have the correct engines installed after locale change"
+  );
+
+  engine = await Services.search.getEngineByName("engine-diff-name-en");
+  Assert.equal(
+    engine.name,
+    "engine-diff-name-en",
+    "Should have the correct engine name"
+  );
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    "https://en.wikipedia.com/search",
+    "Should have the en search url"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_remove_engine_notification_box.js b/toolkit/components/search/tests/xpcshell/test_remove_engine_notification_box.js
new file mode 100644
index 0000000000..867412a771
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_remove_engine_notification_box.js
@@ -0,0 +1,392 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+Cu.importGlobalProperties(["structuredClone"]);
+
+const CONFIG = [
+  {
+    // Engine initially default, but the defaults will be changed to engine-pref.
+    webExtension: {
+      id: "engine@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+      {
+        included: { regions: ["FR"] },
+        default: "no",
+      },
+    ],
+  },
+  {
+    // This will become defaults when region is changed to FR.
+    webExtension: {
+      id: "engine-pref@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["FR"] },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+const CONFIG_UPDATED = [
+  {
+    webExtension: {
+      id: "engine-pref@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+      },
+      {
+        included: { regions: ["FR"] },
+        default: "yes",
+      },
+    ],
+  },
+];
+
+let stub;
+let settingsFilePath;
+let userSettings;
+
+add_task(async function setup() {
+  SearchSettings.SETTINGS_INVALIDATION_DELAY = 100;
+  SearchTestUtils.useMockIdleService();
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+
+  stub = sinon.stub(
+    await Services.search.wrappedJSObject,
+    "_showRemovalOfSearchEngineNotificationBox"
+  );
+
+  settingsFilePath = PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME);
+
+  Region._setHomeRegion("", false);
+
+  let promiseSaved = promiseAfterSettings();
+  await Services.search.init();
+  await promiseSaved;
+
+  userSettings = await Services.search.wrappedJSObject._settings.get();
+});
+
+// Verify the loaded configuration matches what we expect for the test.
+add_task(async function test_initial_config_correct() {
+  const installedEngines = await Services.search.getAppProvidedEngines();
+  Assert.deepEqual(
+    installedEngines.map(e => e.identifier),
+    ["engine", "engine-pref"],
+    "Should have the correct list of engines installed."
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).identifier,
+    "engine",
+    "Should have loaded the expected default engine"
+  );
+});
+
+add_task(async function test_metadata_undefined() {
+  let defaultEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  info("Update region to FR.");
+  Region._setHomeRegion("FR", false);
+
+  let settings = structuredClone(userSettings);
+  settings.metaData = undefined;
+  await reloadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_reloadEngines should not have shown the notification box."
+  );
+
+  settings = structuredClone(userSettings);
+  settings.metaData = undefined;
+  await loadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not have shown the notification box."
+  );
+
+  const newDefault = await defaultEngineChanged;
+  Assert.equal(
+    newDefault.QueryInterface(Ci.nsISearchEngine).name,
+    "engine-pref",
+    "Should have correctly notified the new default engine."
+  );
+});
+
+add_task(async function test_metadata_changed() {
+  let metaDataProperties = [
+    "locale",
+    "region",
+    "channel",
+    "experiment",
+    "distroID",
+  ];
+
+  for (let name of metaDataProperties) {
+    let settings = structuredClone(userSettings);
+    settings.metaData[name] = "test";
+    await assert_metadata_changed(settings);
+  }
+});
+
+add_task(async function test_default_engine_unchanged() {
+  let currentEngineName =
+    Services.search.wrappedJSObject._getEngineDefault(false).name;
+
+  Assert.equal(
+    currentEngineName,
+    "Test search engine",
+    "Default engine should be unchanged."
+  );
+
+  await reloadEngines(structuredClone(userSettings));
+  Assert.ok(
+    stub.notCalled,
+    "_reloadEngines should not have shown the notification box."
+  );
+
+  await loadEngines(structuredClone(userSettings));
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not have shown the notification box."
+  );
+});
+
+add_task(async function test_new_current_engine_is_undefined() {
+  consoleAllowList.push("No default engine");
+  let settings = structuredClone(userSettings);
+  let getEngineDefaultStub = sinon.stub(
+    await Services.search.wrappedJSObject,
+    "_getEngineDefault"
+  );
+  getEngineDefaultStub.returns(undefined);
+
+  await loadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not have shown the notification box."
+  );
+
+  getEngineDefaultStub.restore();
+});
+
+add_task(async function test_current_engine_is_null() {
+  Services.search.wrappedJSObject._currentEngine = null;
+
+  await reloadEngines(structuredClone(userSettings));
+  Assert.ok(
+    stub.notCalled,
+    "_reloadEngines should not have shown the notification box."
+  );
+
+  let settings = structuredClone(userSettings);
+  settings.metaData.current = null;
+  await loadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not have shown the notification box."
+  );
+});
+
+add_task(async function test_default_changed_and_metadata_unchanged_exists() {
+  info("Update region to FR to change engine.");
+  Region._setHomeRegion("FR", false);
+
+  info("Set user settings metadata to the same properties as cached metadata.");
+  await Services.search.wrappedJSObject._fetchEngineSelectorEngines();
+  userSettings.metaData = {
+    ...Services.search.wrappedJSObject._settings.getSettingsMetaData(),
+    appDefaultEngine: "Test search engine",
+  };
+
+  await reloadEngines(structuredClone(userSettings));
+  Assert.ok(
+    stub.notCalled,
+    "_reloadEngines should not show the notification box as the engine still exists."
+  );
+
+  // Reset.
+  Region._setHomeRegion("US", false);
+  await reloadEngines(structuredClone(userSettings));
+});
+
+add_task(async function test_default_engine_changed_and_metadata_unchanged() {
+  info("Update region to FR to change engine.");
+  Region._setHomeRegion("FR", false);
+
+  const defaultEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  info("Set user settings metadata to the same properties as cached metadata.");
+  await Services.search.wrappedJSObject._fetchEngineSelectorEngines();
+  userSettings.metaData = {
+    ...Services.search.wrappedJSObject._settings.getSettingsMetaData(),
+    appDefaultEngineId: "engine@search.mozilla.orgdefault",
+  };
+
+  // Update config by removing the app default engine
+  await setConfigToLoad(CONFIG_UPDATED);
+
+  await reloadEngines(structuredClone(userSettings));
+  Assert.ok(
+    stub.calledOnce,
+    "_reloadEngines should show the notification box."
+  );
+
+  Assert.deepEqual(
+    stub.firstCall.args,
+    ["Test search engine", "engine-pref"],
+    "_showRemovalOfSearchEngineNotificationBox should display " +
+      "'Test search engine' as the engine removed and 'engine-pref' as the new " +
+      "default engine."
+  );
+
+  const newDefault = await defaultEngineChanged;
+  Assert.equal(
+    newDefault.QueryInterface(Ci.nsISearchEngine).name,
+    "engine-pref",
+    "Should have correctly notified the new default engine"
+  );
+
+  info("Reset userSettings.metaData.current engine.");
+  let settings = structuredClone(userSettings);
+  settings.metaData.current = Services.search.wrappedJSObject._currentEngine;
+
+  await loadEngines(settings);
+  Assert.ok(stub.calledTwice, "_loadEngines should show the notification box.");
+
+  Assert.deepEqual(
+    stub.secondCall.args,
+    ["Test search engine", "engine-pref"],
+    "_showRemovalOfSearchEngineNotificationBox should display " +
+      "'Test search engine' as the engine removed and 'engine-pref' as the new " +
+      "default engine."
+  );
+});
+
+add_task(async function test_app_default_engine_changed_on_start_up() {
+  let settings = structuredClone(userSettings);
+
+  // Set the current engine to "" so we can use the app default engine as
+  // default
+  settings.metaData.current = "";
+
+  // Update config by removing the app default engine
+  await setConfigToLoad(CONFIG_UPDATED);
+
+  await loadEngines(settings);
+  Assert.ok(
+    stub.calledThrice,
+    "_loadEngines should show the notification box."
+  );
+});
+
+add_task(async function test_app_default_engine_change_start_up_still_exists() {
+  stub.resetHistory();
+  let settings = structuredClone(userSettings);
+
+  // Set the current engine to "" so we can use the app default engine as
+  // default
+  settings.metaData.current = "";
+  settings.metaData.appDefaultEngine = "Test search engine";
+
+  await setConfigToLoad(CONFIG);
+
+  await loadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not show the notification box."
+  );
+});
+
+async function setConfigToLoad(config) {
+  let searchSettingsObj = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  // Restore the get method in order to stub it again in useTestEngines
+  searchSettingsObj.get.restore();
+  Services.search.wrappedJSObject.resetEngineSelector();
+  await SearchTestUtils.useTestEngines("data", null, config);
+}
+
+function writeSettings(settings) {
+  return IOUtils.writeJSON(settingsFilePath, settings, { compress: true });
+}
+
+async function reloadEngines(settings) {
+  let promiseSaved = promiseAfterSettings();
+
+  await Services.search.wrappedJSObject._reloadEngines(settings);
+
+  await promiseSaved;
+}
+
+async function loadEngines(settings) {
+  await writeSettings(settings);
+
+  let promiseSaved = promiseAfterSettings();
+
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init();
+
+  await promiseSaved;
+}
+
+async function assert_metadata_changed(settings) {
+  info("Update region.");
+  Region._setHomeRegion("FR", false);
+  await reloadEngines(settings);
+  Region._setHomeRegion("", false);
+
+  let defaultEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.DEFAULT,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  await reloadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_reloadEngines should not have shown the notification box."
+  );
+
+  let newDefault = await defaultEngineChanged;
+  Assert.equal(
+    newDefault.QueryInterface(Ci.nsISearchEngine).name,
+    "Test search engine",
+    "Should have correctly notified the new default engine."
+  );
+
+  Region._setHomeRegion("FR", false);
+  await reloadEngines(settings);
+  Region._setHomeRegion("", false);
+
+  await loadEngines(settings);
+  Assert.ok(
+    stub.notCalled,
+    "_loadEngines should not have shown the notification box."
+  );
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Test search engine",
+    "Should have correctly notified the new default engine."
+  );
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_remove_profile_engine.js b/toolkit/components/search/tests/xpcshell/test_remove_profile_engine.js
new file mode 100644
index 0000000000..76a67b39c2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_remove_profile_engine.js
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// This test is to ensure that we remove xml files from searchplugins/ in the
+// profile directory when a user removes the actual engine from their profile.
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function run_test() {
+  // Copy an engine to [profile]/searchplugin/
+  let dir = do_get_profile().clone();
+  dir.append("searchplugins");
+  if (!dir.exists()) {
+    dir.create(dir.DIRECTORY_TYPE, FileUtils.PERMS_DIRECTORY);
+  }
+  do_get_file("data/engine.xml").copyTo(dir, "test-search-engine.xml");
+
+  let file = dir.clone();
+  file.append("test-search-engine.xml");
+  Assert.ok(file.exists());
+
+  let data = await readJSONFile(do_get_file("data/search-legacy.json"));
+
+  // Put the filePath inside the settings file, to simulate what a pre-58 version
+  // of Firefox would have done.
+  for (let engine of data.engines) {
+    if (engine._name == "Test search engine") {
+      engine.filePath = file.path;
+    }
+  }
+
+  await promiseSaveSettingsData(data);
+
+  await Services.search.init();
+
+  // test the engine is loaded ok.
+  let engine = Services.search.getEngineByName("Test search engine");
+  Assert.notEqual(engine, null, "Should have found the engine");
+
+  // remove the engine and verify the file has been removed too.
+  await Services.search.removeEngine(engine);
+  Assert.ok(!file.exists(), "Should have removed the file.");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_save_sorted_engines.js b/toolkit/components/search/tests/xpcshell/test_save_sorted_engines.js
new file mode 100644
index 0000000000..b609960d1f
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_save_sorted_engines.js
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Ensure that metadata are stored correctly on disk after:
+ * - moving an engine
+ * - removing an engine
+ * - adding a new engine
+ *
+ * Notes:
+ * - we install the search engines of test "test_downloadAndAddEngines.js"
+ * to ensure that this test is independent from locale, commercial agreements
+ * and configuration of Firefox.
+ */
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_save_sorted_engines() {
+  let engine1 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+  let engine2 = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine2.xml`,
+  });
+  await promiseAfterSettings();
+
+  let search = Services.search;
+
+  // Test moving the engines
+  await search.moveEngine(engine1, 0);
+  await search.moveEngine(engine2, 1);
+
+  // Changes should be commited immediately
+  await promiseAfterSettings();
+  info("Commit complete after moveEngine");
+
+  // Check that the entries are placed as specified correctly
+  let metadata = await promiseEngineMetadata();
+  Assert.equal(metadata["Test search engine"].order, 1);
+  Assert.equal(metadata["A second test engine"].order, 2);
+
+  // Test removing an engine
+  search.removeEngine(engine1);
+  await promiseAfterSettings();
+  info("Commit complete after removeEngine");
+
+  // Check that the order of the remaining engine was updated correctly
+  metadata = await promiseEngineMetadata();
+  Assert.equal(metadata["A second test engine"].order, 1);
+
+  // Test adding a new engine
+  await SearchTestUtils.installSearchExtension({
+    name: "foo",
+    keyword: "foo",
+  });
+
+  let engine = Services.search.getEngineByName("foo");
+  await promiseAfterSettings();
+  info("Commit complete after addEngineWithDetails");
+
+  metadata = await promiseEngineMetadata();
+  Assert.ok(engine.aliases.includes("foo"));
+  Assert.ok(metadata.foo.order > 0);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_searchSuggest.js b/toolkit/components/search/tests/xpcshell/test_searchSuggest.js
new file mode 100644
index 0000000000..161e7d6c63
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchSuggest.js
@@ -0,0 +1,891 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+
+/**
+ * Testing search suggestions from SearchSuggestionController.jsm.
+ */
+
+"use strict";
+
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const { FormHistory } = ChromeUtils.importESModule(
+  "resource://gre/modules/FormHistory.sys.mjs"
+);
+const { SearchSuggestionController } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchSuggestionController.sys.mjs"
+);
+const { PromiseUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/PromiseUtils.sys.mjs"
+);
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const ENGINE_NAME = "other";
+const SEARCH_TELEMETRY_LATENCY = "SEARCH_SUGGESTIONS_LATENCY_MS";
+
+// We must make sure the FormHistoryStartup component is
+// initialized in order for it to respond to FormHistory
+// requests from nsFormAutoComplete.js.
+var formHistoryStartup = Cc[
+  "@mozilla.org/satchel/form-history-startup;1"
+].getService(Ci.nsIObserver);
+formHistoryStartup.observe(null, "profile-after-change", null);
+
+var getEngine, postEngine, unresolvableEngine, alternateJSONEngine;
+
+add_task(async function setup() {
+  Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+  // These tests intentionally test broken connections.
+  consoleAllowList = consoleAllowList.concat([
+    "Non-200 status or empty HTTP response: 404",
+    "Non-200 status or empty HTTP response: 500",
+    "Unexpected response, searchString does not match remote response",
+    "HTTP request timeout",
+    "HTTP error",
+  ]);
+
+  let server = useHttpServer();
+  server.registerContentType("sjs", "sjs");
+
+  await AddonTestUtils.promiseStartupManager();
+
+  registerCleanupFunction(async () => {
+    // Remove added form history entries
+    await updateSearchHistory("remove", null);
+    Services.prefs.clearUserPref("browser.search.suggest.enabled");
+  });
+});
+
+add_task(async function add_test_engines() {
+  let getEngineData = {
+    baseURL: gDataUrl,
+    name: "GET suggestion engine",
+    method: "GET",
+  };
+
+  let postEngineData = {
+    baseURL: gDataUrl,
+    name: "POST suggestion engine",
+    method: "POST",
+  };
+
+  let unresolvableEngineData = {
+    baseURL: "http://example.invalid/",
+    name: "Offline suggestion engine",
+    method: "GET",
+  };
+
+  let alternateJSONSuggestEngineData = {
+    baseURL: gDataUrl,
+    name: "Alternative JSON suggestion type",
+    method: "GET",
+    alternativeJSONType: true,
+  };
+
+  getEngine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(getEngineData)}`,
+  });
+  postEngine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(postEngineData)}`,
+  });
+  unresolvableEngine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(unresolvableEngineData)}`,
+  });
+  alternateJSONEngine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(
+      alternateJSONSuggestEngineData
+    )}`,
+  });
+});
+
+// Begin tests
+
+add_task(async function simple_no_result_promise() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("no remote", false, getEngine);
+  Assert.equal(result.term, "no remote");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 0);
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function simple_remote_no_local_result() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, getEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "Mozilla");
+  Assert.equal(result.remote[1].value, "modern");
+  Assert.equal(result.remote[2].value, "mom");
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function simple_remote_no_local_result_telemetry() {
+  Services.telemetry.clearScalars();
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  await controller.fetch("mo", false, getEngine);
+
+  let scalars = {};
+  const key = "browser.search.data_transferred";
+
+  await TestUtils.waitForCondition(() => {
+    scalars =
+      Services.telemetry.getSnapshotForKeyedScalars("main", false).parent || {};
+    return key in scalars;
+  }, "should have the expected keyed scalars");
+
+  const scalar = scalars[key];
+  Assert.ok(`sggt-${ENGINE_NAME}` in scalar, "correct telemetry category");
+  Assert.notEqual(scalar[`sggt-${ENGINE_NAME}`], 0, "bandwidth logged");
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function simple_remote_no_local_result_alternative_type() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, alternateJSONEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "Mozilla");
+  Assert.equal(result.remote[1].value, "modern");
+  Assert.equal(result.remote[2].value, "mom");
+});
+
+add_task(async function remote_term_case_mismatch() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("Query Case Mismatch", false, getEngine);
+  Assert.equal(result.term, "Query Case Mismatch");
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "Query Case Mismatch");
+});
+
+add_task(async function simple_local_no_remote_result() {
+  await updateSearchHistory("bump", "no remote entries");
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("no remote", false, getEngine);
+  Assert.equal(result.term, "no remote");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "no remote entries");
+  Assert.equal(result.remote.length, 0);
+
+  await updateSearchHistory("remove", "no remote entries");
+});
+
+add_task(async function simple_non_ascii() {
+  await updateSearchHistory("bump", "I ❤️ XUL");
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("I ❤️", false, getEngine);
+  Assert.equal(result.term, "I ❤️");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "I ❤️ XUL");
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "I ❤️ Mozilla");
+});
+
+add_task(async function both_local_remote_result_dedupe() {
+  await updateSearchHistory("bump", "Mozilla");
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, getEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "Mozilla");
+  Assert.equal(result.remote.length, 2);
+  Assert.equal(result.remote[0].value, "modern");
+  Assert.equal(result.remote[1].value, "mom");
+});
+
+add_task(async function POST_both_local_remote_result_dedupe() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, postEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "Mozilla");
+  Assert.equal(result.remote.length, 2);
+  Assert.equal(result.remote[0].value, "modern");
+  Assert.equal(result.remote[1].value, "mom");
+});
+
+add_task(async function both_local_remote_result_dedupe2() {
+  await updateSearchHistory("bump", "mom");
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, getEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 2);
+  Assert.equal(result.local[0].value, "mom");
+  Assert.equal(result.local[1].value, "Mozilla");
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "modern");
+});
+
+add_task(async function both_local_remote_result_dedupe3() {
+  // All of the server entries also exist locally
+  await updateSearchHistory("bump", "modern");
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("mo", false, getEngine);
+  Assert.equal(result.term, "mo");
+  Assert.equal(result.local.length, 3);
+  Assert.equal(result.local[0].value, "modern");
+  Assert.equal(result.local[1].value, "mom");
+  Assert.equal(result.local[2].value, "Mozilla");
+  Assert.equal(result.remote.length, 0);
+});
+
+add_task(async function valid_tail_results() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("tail query", false, getEngine);
+  Assert.equal(result.term, "tail query");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "tail query normal");
+  Assert.ok(!result.remote[0].matchPrefix);
+  Assert.ok(!result.remote[0].tail);
+  Assert.equal(result.remote[1].value, "tail query tail 1");
+  Assert.equal(result.remote[1].matchPrefix, "… ");
+  Assert.equal(result.remote[1].tail, "tail 1");
+  Assert.equal(result.remote[2].value, "tail query tail 2");
+  Assert.equal(result.remote[2].matchPrefix, "… ");
+  Assert.equal(result.remote[2].tail, "tail 2");
+});
+
+add_task(async function alt_tail_results() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("tailalt query", false, getEngine);
+  Assert.equal(result.term, "tailalt query");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "tailalt query normal");
+  Assert.ok(!result.remote[0].matchPrefix);
+  Assert.ok(!result.remote[0].tail);
+  Assert.equal(result.remote[1].value, "tailalt query tail 1");
+  Assert.equal(result.remote[1].matchPrefix, "… ");
+  Assert.equal(result.remote[1].tail, "tail 1");
+  Assert.equal(result.remote[2].value, "tailalt query tail 2");
+  Assert.equal(result.remote[2].matchPrefix, "… ");
+  Assert.equal(result.remote[2].tail, "tail 2");
+});
+
+add_task(async function invalid_tail_results() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("tailjunk query", false, getEngine);
+  Assert.equal(result.term, "tailjunk query");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "tailjunk query normal");
+  Assert.ok(!result.remote[0].matchPrefix);
+  Assert.ok(!result.remote[0].tail);
+  Assert.equal(result.remote[1].value, "tailjunk query tail 1");
+  Assert.ok(!result.remote[1].matchPrefix);
+  Assert.ok(!result.remote[1].tail);
+  Assert.equal(result.remote[2].value, "tailjunk query tail 2");
+  Assert.ok(!result.remote[2].matchPrefix);
+  Assert.ok(!result.remote[2].tail);
+});
+
+add_task(async function too_few_tail_results() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("tailjunk few query", false, getEngine);
+  Assert.equal(result.term, "tailjunk few query");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "tailjunk few query normal");
+  Assert.ok(!result.remote[0].matchPrefix);
+  Assert.ok(!result.remote[0].tail);
+  Assert.equal(result.remote[1].value, "tailjunk few query tail 1");
+  Assert.ok(!result.remote[1].matchPrefix);
+  Assert.ok(!result.remote[1].tail);
+  Assert.equal(result.remote[2].value, "tailjunk few query tail 2");
+  Assert.ok(!result.remote[2].matchPrefix);
+  Assert.ok(!result.remote[2].tail);
+});
+
+add_task(async function empty_rich_results() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("richempty query", false, getEngine);
+  Assert.equal(result.term, "richempty query");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[0].value, "richempty query normal");
+  Assert.ok(!result.remote[0].matchPrefix);
+  Assert.ok(!result.remote[0].tail);
+  Assert.equal(result.remote[1].value, "richempty query tail 1");
+  Assert.ok(!result.remote[1].matchPrefix);
+  Assert.ok(!result.remote[1].tail);
+  Assert.equal(result.remote[2].value, "richempty query tail 2");
+  Assert.ok(!result.remote[2].matchPrefix);
+  Assert.ok(!result.remote[2].tail);
+});
+
+add_task(async function tail_offset_index() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("tail tail 1 t", false, getEngine);
+  Assert.equal(result.term, "tail tail 1 t");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 3);
+  Assert.equal(result.remote[1].value, "tail tail 1 t tail 1");
+  Assert.equal(result.remote[1].matchPrefix, "… ");
+  Assert.equal(result.remote[1].tail, "tail 1");
+  Assert.equal(result.remote[1].tailOffsetIndex, 14);
+});
+
+add_task(async function fetch_twice_in_a_row() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  // Two entries since the first will match the first fetch but not the second.
+  await updateSearchHistory("bump", "delay local");
+  await updateSearchHistory("bump", "delayed local");
+
+  let controller = new SearchSuggestionController();
+  let resultPromise1 = controller.fetch("delay", false, getEngine);
+
+  // A second fetch while the server is still waiting to return results leads to an abort.
+  let resultPromise2 = controller.fetch("delayed ", false, getEngine);
+  await resultPromise1.then(results => Assert.equal(null, results));
+
+  let result = await resultPromise2;
+  Assert.equal(result.term, "delayed ");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "delayed local");
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "delayed ");
+
+  // Only the second fetch's latency should be recorded since the first fetch
+  // was aborted and latencies for aborted fetches are not recorded.
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function both_identical_with_more_than_max_results() {
+  // Add letters A through Z to form history which will match the server
+  for (
+    let charCode = "A".charCodeAt();
+    charCode <= "Z".charCodeAt();
+    charCode++
+  ) {
+    await updateSearchHistory(
+      "bump",
+      "letter " + String.fromCharCode(charCode)
+    );
+  }
+
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 7;
+  controller.maxRemoteResults = 10;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 7);
+  for (let i = 0; i < controller.maxLocalResults; i++) {
+    Assert.equal(
+      result.local[i].value,
+      "letter " + String.fromCharCode("A".charCodeAt() + i)
+    );
+  }
+  Assert.equal(result.local.length + result.remote.length, 10);
+  for (let i = 0; i < result.remote.length; i++) {
+    Assert.equal(
+      result.remote[i].value,
+      "letter " +
+        String.fromCharCode("A".charCodeAt() + controller.maxLocalResults + i)
+    );
+  }
+});
+
+add_task(async function noremote_maxLocal() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 2; // (should be ignored because no remote results)
+  controller.maxRemoteResults = 0;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 26);
+  for (let i = 0; i < result.local.length; i++) {
+    Assert.equal(
+      result.local[i].value,
+      "letter " + String.fromCharCode("A".charCodeAt() + i)
+    );
+  }
+  Assert.equal(result.remote.length, 0);
+
+  assertLatencyHistogram(histogram, false);
+});
+
+add_task(async function someremote_maxLocal() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 2;
+  controller.maxRemoteResults = 4;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 2);
+  for (let i = 0; i < result.local.length; i++) {
+    Assert.equal(
+      result.local[i].value,
+      "letter " + String.fromCharCode("A".charCodeAt() + i)
+    );
+  }
+  Assert.equal(result.remote.length, 2);
+  // "A" and "B" will have been de-duped, start at C for remote results
+  for (let i = 0; i < result.remote.length; i++) {
+    Assert.equal(
+      result.remote[i].value,
+      "letter " + String.fromCharCode("C".charCodeAt() + i)
+    );
+  }
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function one_of_each() {
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 1;
+  controller.maxRemoteResults = 2;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "letter A");
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "letter B");
+});
+
+add_task(async function local_result_returned_remote_result_disabled() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  Services.prefs.setBoolPref("browser.search.suggest.enabled", false);
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 1;
+  controller.maxRemoteResults = 1;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 26);
+  for (let i = 0; i < 26; i++) {
+    Assert.equal(
+      result.local[i].value,
+      "letter " + String.fromCharCode("A".charCodeAt() + i)
+    );
+  }
+  Assert.equal(result.remote.length, 0);
+  assertLatencyHistogram(histogram, false);
+  Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+});
+
+add_task(
+  async function local_result_returned_remote_result_disabled_after_creation_of_controller() {
+    let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+      SEARCH_TELEMETRY_LATENCY
+    );
+    let controller = new SearchSuggestionController();
+    controller.maxLocalResults = 1;
+    controller.maxRemoteResults = 1;
+    Services.prefs.setBoolPref("browser.search.suggest.enabled", false);
+    let result = await controller.fetch("letter ", false, getEngine);
+    Assert.equal(result.term, "letter ");
+    Assert.equal(result.local.length, 26);
+    for (let i = 0; i < 26; i++) {
+      Assert.equal(
+        result.local[i].value,
+        "letter " + String.fromCharCode("A".charCodeAt() + i)
+      );
+    }
+    Assert.equal(result.remote.length, 0);
+    assertLatencyHistogram(histogram, false);
+    Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+  }
+);
+
+add_task(
+  async function one_of_each_disabled_before_creation_enabled_after_creation_of_controller() {
+    let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+      SEARCH_TELEMETRY_LATENCY
+    );
+
+    Services.prefs.setBoolPref("browser.search.suggest.enabled", false);
+    let controller = new SearchSuggestionController();
+    controller.maxLocalResults = 1;
+    controller.maxRemoteResults = 2;
+    Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+    let result = await controller.fetch("letter ", false, getEngine);
+    Assert.equal(result.term, "letter ");
+    Assert.equal(result.local.length, 1);
+    Assert.equal(result.local[0].value, "letter A");
+    Assert.equal(result.remote.length, 1);
+    Assert.equal(result.remote[0].value, "letter B");
+
+    assertLatencyHistogram(histogram, true);
+
+    Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+  }
+);
+
+add_task(async function one_local_zero_remote() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 1;
+  controller.maxRemoteResults = 0;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 26);
+  for (let i = 0; i < 26; i++) {
+    Assert.equal(
+      result.local[i].value,
+      "letter " + String.fromCharCode("A".charCodeAt() + i)
+    );
+  }
+  Assert.equal(result.remote.length, 0);
+  assertLatencyHistogram(histogram, false);
+});
+
+add_task(async function zero_local_one_remote() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 0;
+  controller.maxRemoteResults = 1;
+  let result = await controller.fetch("letter ", false, getEngine);
+  Assert.equal(result.term, "letter ");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 1);
+  Assert.equal(result.remote[0].value, "letter A");
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function stop_search() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+  let controller = new SearchSuggestionController(result => {
+    do_throw("The callback shouldn't be called after stop()");
+  });
+  let resultPromise = controller.fetch("mo", false, getEngine);
+  controller.stop();
+  await resultPromise.then(result => {
+    Assert.equal(null, result);
+  });
+  assertLatencyHistogram(histogram, false);
+});
+
+add_task(async function empty_searchTerm() {
+  // Empty searches don't go to the server but still get form history.
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("", false, getEngine);
+  Assert.equal(result.term, "");
+  Assert.ok(!!result.local.length);
+  Assert.equal(result.remote.length, 0);
+  assertLatencyHistogram(histogram, false);
+});
+
+add_task(async function slow_timeout() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  // Make the server return suggestions on a delay longer than the timeout of
+  // the suggestion controller.
+  let delayMs = 3 * SearchSuggestionController.REMOTE_TIMEOUT_DEFAULT;
+  let searchString = `delay${delayMs} `;
+
+  // Add a local result.
+  let localValue = searchString + " local result";
+  await updateSearchHistory("bump", localValue);
+
+  // Do a search. The remote fetch should time out but the local result should
+  // be returned.
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch(searchString, false, getEngine);
+  Assert.equal(result.term, searchString);
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, localValue);
+  Assert.equal(result.remote.length, 0);
+
+  // The remote fetch isn't done yet, so the latency histogram should not be
+  // updated.
+  assertLatencyHistogram(histogram, false);
+
+  // Wait for the remote fetch to finish.
+  await new Promise(r => setTimeout(r, delayMs));
+
+  // Now the latency histogram should be updated.
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function slow_timeout_2() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  // Make the server return suggestions on a delay longer the timeout of the
+  // suggestion controller.
+  let delayMs = 3 * SearchSuggestionController.REMOTE_TIMEOUT_DEFAULT;
+  let searchString = `delay${delayMs} `;
+
+  // Add a local result.
+  let localValue = searchString + " local result";
+  await updateSearchHistory("bump", localValue);
+
+  // Do two searches using the same controller. Both times, the remote fetches
+  // should time out and only the local result should be returned. The second
+  // search should abort the remote fetch of the first search, and the remote
+  // fetch of the second search should be ongoing when the second search
+  // finishes.
+  let controller = new SearchSuggestionController();
+  for (let i = 0; i < 2; i++) {
+    let result = await controller.fetch(searchString, false, getEngine);
+    Assert.equal(result.term, searchString);
+    Assert.equal(result.local.length, 1);
+    Assert.equal(result.local[0].value, localValue);
+    Assert.equal(result.remote.length, 0);
+  }
+
+  // The remote fetch of the second search isn't done yet, so the latency
+  // histogram should not be updated.
+  assertLatencyHistogram(histogram, false);
+
+  // Wait for the second remote fetch to finish.
+  await new Promise(r => setTimeout(r, delayMs));
+
+  // Now the latency histogram should be updated, and only the remote fetch of
+  // the second search should be recorded.
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function slow_stop() {
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  // Make the server return suggestions on a delay longer the timeout of the
+  // suggestion controller.
+  let delayMs = 3 * SearchSuggestionController.REMOTE_TIMEOUT_DEFAULT;
+  let searchString = `delay${delayMs} `;
+
+  // Do a search but stop it before it finishes. Wait a tick before stopping it
+  // to better simulate the real world.
+  let controller = new SearchSuggestionController();
+  let resultPromise = controller.fetch(searchString, false, getEngine);
+  await TestUtils.waitForTick();
+  controller.stop();
+  let result = await resultPromise;
+  Assert.equal(result, null, "No result should be returned");
+
+  // The remote fetch should have been aborted by stopping the controller, but
+  // wait for the timeout period just to make sure it's done.
+  await new Promise(r => setTimeout(r, delayMs));
+
+  // Since the latencies of aborted fetches are not recorded, the latency
+  // histogram should not be updated.
+  assertLatencyHistogram(histogram, false);
+});
+
+// Error handling
+
+add_task(async function remote_term_mismatch() {
+  await updateSearchHistory("bump", "Query Mismatch Entry");
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("Query Mismatch", false, getEngine);
+  Assert.equal(result.term, "Query Mismatch");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "Query Mismatch Entry");
+  Assert.equal(result.remote.length, 0);
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function http_404() {
+  await updateSearchHistory("bump", "HTTP 404 Entry");
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("HTTP 404", false, getEngine);
+  Assert.equal(result.term, "HTTP 404");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "HTTP 404 Entry");
+  Assert.equal(result.remote.length, 0);
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function http_500() {
+  await updateSearchHistory("bump", "HTTP 500 Entry");
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("HTTP 500", false, getEngine);
+  Assert.equal(result.term, "HTTP 500");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "HTTP 500 Entry");
+  Assert.equal(result.remote.length, 0);
+
+  assertLatencyHistogram(histogram, true);
+});
+
+add_task(async function unresolvable_server() {
+  await updateSearchHistory("bump", "Unresolvable Server Entry");
+
+  let histogram = TelemetryTestUtils.getAndClearKeyedHistogram(
+    SEARCH_TELEMETRY_LATENCY
+  );
+
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch(
+    "Unresolvable Server",
+    false,
+    unresolvableEngine
+  );
+  Assert.equal(result.term, "Unresolvable Server");
+  Assert.equal(result.local.length, 1);
+  Assert.equal(result.local[0].value, "Unresolvable Server Entry");
+  Assert.equal(result.remote.length, 0);
+
+  // This latency assert fails on Windows 7 (NT version 6.1), so skip it there.
+  if (!AppConstants.isPlatformAndVersionAtMost("win", "6.1")) {
+    assertLatencyHistogram(histogram, true);
+  }
+});
+
+// Exception handling
+
+add_task(async function missing_pb() {
+  Assert.throws(() => {
+    let controller = new SearchSuggestionController();
+    controller.fetch("No privacy");
+  }, /priva/i);
+});
+
+add_task(async function missing_engine() {
+  Assert.throws(() => {
+    let controller = new SearchSuggestionController();
+    controller.fetch("No engine", false);
+  }, /engine/i);
+});
+
+add_task(async function invalid_engine() {
+  Assert.throws(() => {
+    let controller = new SearchSuggestionController();
+    controller.fetch("invalid engine", false, {});
+  }, /engine/i);
+});
+
+add_task(async function no_results_requested() {
+  Assert.throws(() => {
+    let controller = new SearchSuggestionController();
+    controller.maxLocalResults = 0;
+    controller.maxRemoteResults = 0;
+    controller.fetch("No results requested", false, getEngine);
+  }, /result/i);
+});
+
+add_task(async function minus_one_results_requested() {
+  Assert.throws(() => {
+    let controller = new SearchSuggestionController();
+    controller.maxLocalResults = -1;
+    controller.fetch("-1 results requested", false, getEngine);
+  }, /result/i);
+});
+
+add_task(async function test_userContextId() {
+  let controller = new SearchSuggestionController();
+  controller._fetchRemote = function (
+    searchTerm,
+    engine,
+    privateMode,
+    userContextId
+  ) {
+    Assert.equal(userContextId, 1);
+    return PromiseUtils.defer();
+  };
+
+  controller.fetch("test", false, getEngine, 1);
+});
+
+// Non-English characters
+
+add_task(async function suggestions_contain_escaped_unicode() {
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("stü", false, getEngine);
+  Assert.equal(result.term, "stü");
+  Assert.equal(result.local.length, 0);
+  Assert.equal(result.remote.length, 2);
+  Assert.equal(result.remote[0].value, "stühle");
+  Assert.equal(result.remote[1].value, "stüssy");
+});
+
+// Helpers
+
+function updateSearchHistory(operation, value) {
+  return FormHistory.update({
+    op: operation,
+    fieldname: "searchbar-history",
+    value,
+  });
+}
+
+function assertLatencyHistogram(histogram, shouldRecord) {
+  let snapshot = histogram.snapshot();
+  info("Checking latency snapshot: " + JSON.stringify(snapshot));
+
+  // Build a map from engine ID => number of non-zero values recorded for it.
+  let valueCountByEngineId = Object.entries(snapshot).reduce(
+    (memo, [key, data]) => {
+      memo[key] = Object.values(data.values).filter(v => v != 0);
+      return memo;
+    },
+    {}
+  );
+
+  let expected = shouldRecord ? { [ENGINE_NAME]: [1] } : {};
+  Assert.deepEqual(
+    valueCountByEngineId,
+    expected,
+    shouldRecord ? "Latency histogram updated" : "Latency histogram not updated"
+  );
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_searchSuggest_cookies.js b/toolkit/components/search/tests/xpcshell/test_searchSuggest_cookies.js
new file mode 100644
index 0000000000..78d4fde8f1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchSuggest_cookies.js
@@ -0,0 +1,143 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test that search suggestions from SearchSuggestionController.jsm don't store
+ * cookies.
+ */
+
+"use strict";
+
+const { SearchSuggestionController } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchSuggestionController.sys.mjs"
+);
+
+// We must make sure the FormHistoryStartup component is
+// initialized in order for it to respond to FormHistory
+// requests from nsFormAutoComplete.js.
+var formHistoryStartup = Cc[
+  "@mozilla.org/satchel/form-history-startup;1"
+].getService(Ci.nsIObserver);
+formHistoryStartup.observe(null, "profile-after-change", null);
+
+function countCacheEntries() {
+  info("Enumerating cache entries");
+  return new Promise(resolve => {
+    let storage = Services.cache2.diskCacheStorage(
+      Services.loadContextInfo.default
+    );
+    storage.asyncVisitStorage(
+      {
+        onCacheStorageInfo(num, consumption) {
+          this._num = num;
+        },
+        onCacheEntryInfo(uri) {
+          info("Found cache entry: " + uri.asciiSpec);
+        },
+        onCacheEntryVisitCompleted() {
+          resolve(this._num || 0);
+        },
+      },
+      true /* Do walk entries */
+    );
+  });
+}
+
+function countCookieEntries() {
+  info("Enumerating cookies");
+  let cookies = Services.cookies.cookies;
+  let cookieCount = 0;
+  for (let cookie of cookies) {
+    info(
+      "Cookie:" + cookie.rawHost + " " + JSON.stringify(cookie.originAttributes)
+    );
+    cookieCount++;
+    break;
+  }
+  return cookieCount;
+}
+
+let engines;
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+  Services.prefs.setBoolPref("browser.search.suggest.enabled.private", true);
+
+  registerCleanupFunction(async () => {
+    // Clean up all the data.
+    await new Promise(resolve =>
+      Services.clearData.deleteData(Ci.nsIClearDataService.CLEAR_ALL, resolve)
+    );
+    Services.prefs.clearUserPref("browser.search.suggest.enabled");
+    Services.prefs.clearUserPref("browser.search.suggest.enabled.private");
+  });
+
+  let server = useHttpServer();
+  server.registerContentType("sjs", "sjs");
+
+  let unicodeName = ["\u30a8", "\u30c9"].join("");
+  engines = [
+    await SearchTestUtils.promiseNewSearchEngine({
+      url: `${gDataUrl}engineMaker.sjs?${JSON.stringify({
+        baseURL: gDataUrl,
+        name: unicodeName,
+        method: "GET",
+      })}`,
+    }),
+    await SearchTestUtils.promiseNewSearchEngine({
+      url: `${gDataUrl}engineMaker.sjs?${JSON.stringify({
+        baseURL: gDataUrl,
+        name: "engine two",
+        method: "GET",
+      })}`,
+    }),
+  ];
+
+  // Clean up all the data.
+  await new Promise(resolve =>
+    Services.clearData.deleteData(Ci.nsIClearDataService.CLEAR_ALL, resolve)
+  );
+  Assert.equal(await countCacheEntries(), 0, "The cache should be empty");
+  Assert.equal(await countCookieEntries(), 0, "Should not find any cookie");
+});
+
+add_task(async function test_private_mode() {
+  await test_engine(true);
+});
+add_task(async function test_normal_mode() {
+  await test_engine(false);
+});
+
+async function test_engine(privateMode) {
+  info(`Testing ${privateMode ? "private" : "normal"} mode`);
+  let controller = new SearchSuggestionController();
+  let result = await controller.fetch("no results", privateMode, engines[0]);
+  Assert.equal(result.local.length, 0, "Should have no local suggestions");
+  Assert.equal(result.remote.length, 0, "Should have no remote suggestions");
+
+  result = await controller.fetch("cookie", privateMode, engines[1]);
+  Assert.equal(result.local.length, 0, "Should have no local suggestions");
+  Assert.equal(result.remote.length, 0, "Should have no remote suggestions");
+  Assert.equal(await countCacheEntries(), 0, "The cache should be empty");
+  Assert.equal(await countCookieEntries(), 0, "Should not find any cookie");
+
+  let firstPartyDomain1 = controller.firstPartyDomains.get(engines[0].name);
+  Assert.ok(
+    /^[\.a-z0-9-]+\.search\.suggestions\.mozilla/.test(firstPartyDomain1),
+    "Check firstPartyDomain1"
+  );
+
+  let firstPartyDomain2 = controller.firstPartyDomains.get(engines[1].name);
+  Assert.ok(
+    /^[\.a-z0-9-]+\.search\.suggestions\.mozilla/.test(firstPartyDomain2),
+    "Check firstPartyDomain2"
+  );
+
+  Assert.notEqual(
+    firstPartyDomain1,
+    firstPartyDomain2,
+    "Check firstPartyDomain id unique per engine"
+  );
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_searchSuggest_extraParams.js b/toolkit/components/search/tests/xpcshell/test_searchSuggest_extraParams.js
new file mode 100644
index 0000000000..8bac7d39cb
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchSuggest_extraParams.js
@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const TEST_CONFIG = [
+  {
+    webExtension: { id: "get@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+    suggestExtraParams: [
+      {
+        name: "custom_param",
+        pref: "test_pref_param",
+        condition: "pref",
+      },
+    ],
+  },
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("method-extensions", null, TEST_CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_custom_suggest_param() {
+  let engine = Services.search.getEngineByName("Get Engine");
+  Assert.notEqual(engine, null, "Should have found an engine");
+
+  let submissionSuggest = engine.getSubmission(
+    "bar",
+    SearchUtils.URL_TYPE.SUGGEST_JSON
+  );
+  Assert.equal(
+    submissionSuggest.uri.spec,
+    "https://example.com/?webExtension=1&suggest=bar",
+    "Suggest URLs should match"
+  );
+
+  let defaultBranch = Services.prefs.getDefaultBranch("browser.search.");
+  defaultBranch.setCharPref("param.test_pref_param", "good");
+
+  let nextSubmissionSuggest = engine.getSubmission(
+    "bar",
+    SearchUtils.URL_TYPE.SUGGEST_JSON
+  );
+  Assert.equal(
+    nextSubmissionSuggest.uri.spec,
+    "https://example.com/?custom_param=good&webExtension=1&suggest=bar",
+    "Suggest URLs should include custom param"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_searchSuggest_private.js b/toolkit/components/search/tests/xpcshell/test_searchSuggest_private.js
new file mode 100644
index 0000000000..3337bf9a27
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchSuggest_private.js
@@ -0,0 +1,54 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Test that search suggestions from SearchSuggestionController.jsm operate
+ * correctly in private mode.
+ */
+
+"use strict";
+
+const { SearchSuggestionController } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchSuggestionController.sys.mjs"
+);
+
+let engine;
+
+add_task(async function setup() {
+  Services.prefs.setBoolPref("browser.search.suggest.enabled", true);
+
+  let server = useHttpServer();
+  server.registerContentType("sjs", "sjs");
+
+  await AddonTestUtils.promiseStartupManager();
+
+  const engineData = {
+    baseURL: gDataUrl,
+    name: "GET suggestion engine",
+    method: "GET",
+  };
+
+  engine = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engineMaker.sjs?${JSON.stringify(engineData)}`,
+  });
+});
+
+add_task(async function test_suggestions_in_private_mode_enabled() {
+  Services.prefs.setBoolPref("browser.search.suggest.enabled.private", true);
+
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 0;
+  controller.maxRemoteResults = 1;
+  let result = await controller.fetch("mo", true, engine);
+  Assert.equal(result.remote.length, 1);
+});
+
+add_task(async function test_suggestions_in_private_mode_disabled() {
+  Services.prefs.setBoolPref("browser.search.suggest.enabled.private", false);
+
+  let controller = new SearchSuggestionController();
+  controller.maxLocalResults = 0;
+  controller.maxRemoteResults = 1;
+  let result = await controller.fetch("mo", true, engine);
+  Assert.equal(result.remote.length, 0);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_searchTermFromResult.js b/toolkit/components/search/tests/xpcshell/test_searchTermFromResult.js
new file mode 100644
index 0000000000..f2693efc3b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchTermFromResult.js
@@ -0,0 +1,303 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Tests searchTermFromResult API.
+ */
+
+let defaultEngine;
+
+// The test string contains special characters to ensure
+// that they are encoded/decoded properly.
+const TERM = "c;,?:@&=+$-_.!~*'()# d\u00E8f";
+const TERM_ENCODED = "c%3B%2C%3F%3A%40%26%3D%2B%24-_.!~*'()%23+d%C3%A8f";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null, [
+    {
+      webExtension: {
+        id: "engine-purposes@search.mozilla.org",
+      },
+      appliesTo: [
+        {
+          included: { everywhere: true },
+          default: "yes",
+        },
+      ],
+    },
+  ]);
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+
+  defaultEngine = Services.search.getEngineByName("Test Engine With Purposes");
+});
+
+add_task(async function test_searchTermFromResult_withAllPurposes() {
+  for (let purpose of Object.values(SearchUtils.PARAM_PURPOSES)) {
+    let uri = defaultEngine.getSubmission(TERM, null, purpose).uri;
+    let searchTerm = defaultEngine.searchTermFromResult(uri);
+    Assert.equal(
+      searchTerm,
+      TERM,
+      `Should return the correct url for purpose: ${purpose}`
+    );
+  }
+});
+
+add_task(async function test_searchTermFromResult() {
+  // Internationalized Domain Name search engine.
+  await SearchTestUtils.installSearchExtension({
+    name: "idn_addParam",
+    keyword: "idn_addParam",
+    search_url: "https://www.xn--bcher-kva.ch/search",
+  });
+  let engineEscapedIDN = Services.search.getEngineByName("idn_addParam");
+
+  // Setup server for french engine.
+  await useHttpServer();
+
+  // For ISO-8859-1 encoding testing.
+  let engineISOCharset = await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine-fr.xml`,
+  });
+
+  // For Windows-1252 encoding testing.
+  await SearchTestUtils.installSearchExtension({
+    name: "bacon_addParam",
+    keyword: "bacon_addParam",
+    encoding: "windows-1252",
+    search_url: "https://www.bacon.test/find",
+  });
+  let engineWinCharset = Services.search.getEngineByName("bacon_addParam");
+
+  // Verify getValidEngineUrl returns a URL that can return a search term.
+  let testUrl = getValidEngineUrl();
+  Assert.equal(
+    getTerm(testUrl),
+    TERM,
+    "Should get term from a url generated by getSubmission."
+  );
+
+  testUrl = getValidEngineUrl();
+  testUrl.pathname = "/SEARCH";
+  Assert.equal(
+    getTerm(testUrl),
+    TERM,
+    "Should get term even if path is not the same case as the engine."
+  );
+
+  let url = `https://www.xn--bcher-kva.ch/search?q=${TERM_ENCODED}`;
+  Assert.equal(
+    getTerm(url, engineEscapedIDN),
+    TERM,
+    "Should get term from IDNs urls."
+  );
+
+  url = `http://www.google.fr/search?q=caf%E8+au+lait&ie=iso-8859-1&oe=iso-8859-1`;
+  Assert.equal(
+    getTerm(url, engineISOCharset),
+    "caf\u00E8 au lait",
+    "Should get term from ISO-8859-1 encoded url containing a search term."
+  );
+
+  url = `http://www.google.fr/search?&ie=iso-8859-1&oe=iso-8859-1&q=`;
+  Assert.equal(
+    getTerm(url, engineISOCharset),
+    "",
+    "Should get a blank string from ISO-8859-1 encoded url missing a search term"
+  );
+
+  url = "https://www.bacon.test/find?q=caf%E8+au+lait";
+  Assert.equal(
+    getTerm(url, engineWinCharset),
+    "caf\u00E8 au lait",
+    "Should get term from Windows-1252 encoded url containing a search term."
+  );
+
+  url = "https://www.bacon.test/find?q=";
+  Assert.equal(
+    getTerm(url, engineWinCharset),
+    "",
+    "Should get a blank string from Windows-1252 encoded url missing a search term."
+  );
+
+  url = "about:blank";
+  Assert.equal(getTerm(url), "", "Should get a blank string from about:blank.");
+
+  url = "about:newtab";
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from about:newtab."
+  );
+});
+
+// Use a version of the url that should return a term and make minute
+// modifications that should cause it to return a blank value.
+add_task(async function test_searchTermFromResult_blank() {
+  let url = getValidEngineUrl();
+  url.searchParams.set("hello", "world");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from url containing query param name not recognized by the engine."
+  );
+
+  url = getValidEngineUrl();
+  url.protocol = "http";
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from url that has a different scheme from the engine."
+  );
+
+  url = getValidEngineUrl();
+  url.protocol = "http";
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from url that has a different path from the engine."
+  );
+
+  url = getValidEngineUrl();
+  url.host = "images.example.com";
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from url that has a different host from the engine."
+  );
+
+  url = getValidEngineUrl();
+  url.host = "example.com";
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from url that has a different host from the engine."
+  );
+
+  url = getValidEngineUrl();
+  url.searchParams.set("form", "MOZUNKNOWN");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from a url that has an un-recognized form value."
+  );
+
+  url = getValidEngineUrl();
+  url.searchParams.set("q", "");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from a url with a missing search query value."
+  );
+
+  url = getValidEngineUrl();
+  url.searchParams.delete("q");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from a url with a missing search query name."
+  );
+
+  url = getValidEngineUrl();
+  url.searchParams.delete("pc");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from a url with a missing a query parameter."
+  );
+
+  url = getValidEngineUrl();
+  url.searchParams.delete("form");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string from a url with a missing a query parameter."
+  );
+});
+
+add_task(async function test_searchTermFromResult_prefParam() {
+  const defaultBranch = Services.prefs.getDefaultBranch(
+    SearchUtils.BROWSER_SEARCH_PREF
+  );
+
+  defaultBranch.setCharPref("param.testChannelEnabled", "yes");
+
+  let url = getValidEngineUrl(true);
+  Assert.equal(getTerm(url), TERM, "Should get term after pref is turned on.");
+
+  url.searchParams.delete("channel");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string if pref is on and channel param is missing."
+  );
+
+  defaultBranch.setCharPref("param.testChannelEnabled", "");
+  url = getValidEngineUrl(true);
+  Assert.equal(getTerm(url), TERM, "Should get term after pref is turned off.");
+
+  url.searchParams.set("channel", "yes");
+  Assert.equal(
+    getTerm(url),
+    "",
+    "Should get a blank string if pref is turned off but channel param is present."
+  );
+});
+
+// searchTermFromResult attempts to look into the template of a search
+// engine if query params aren't present in the url.params, so make sure
+// it works properly and fails gracefully.
+add_task(async function test_searchTermFromResult_paramsInSearchUrl() {
+  await SearchTestUtils.installSearchExtension({
+    name: "engine_params_in_search_url",
+    search_url: "https://example.com/?q={searchTerms}&pc=firefox",
+    search_url_get_params: "",
+  });
+  let testEngine = Services.search.getEngineByName(
+    "engine_params_in_search_url"
+  );
+  let url = `https://example.com/?q=${TERM_ENCODED}&pc=firefox`;
+  Assert.equal(
+    getTerm(url, testEngine),
+    TERM,
+    "Should get term from an engine with params in its search url."
+  );
+
+  url = `https://example.com/?q=${TERM_ENCODED}`;
+  Assert.equal(
+    getTerm(url, testEngine),
+    "",
+    "Should get a blank string when not all params are present."
+  );
+
+  await SearchTestUtils.installSearchExtension({
+    name: "engine_params_in_search_url_without_delimiter",
+    search_url: "https://example.com/q={searchTerms}",
+    search_url_get_params: "",
+  });
+  testEngine = Services.search.getEngineByName(
+    "engine_params_in_search_url_without_delimiter"
+  );
+  url = `https://example.com/?q=${TERM_ENCODED}&pc=firefox&page=1`;
+  Assert.equal(
+    getTerm(url, testEngine),
+    "",
+    "Should get a blank string from an engine with no params and no delimiter in its url."
+  );
+});
+
+function getTerm(url, searchEngine = defaultEngine) {
+  return searchEngine.searchTermFromResult(Services.io.newURI(url.toString()));
+}
+
+// Return a new instance of a submission URL so that it can modified
+// and tested again. Allow callers to force the cache to update, especially
+// if the engine is expected to have updated.
+function getValidEngineUrl(updateCache = false) {
+  if (updateCache || !this._submissionUrl) {
+    this._submissionUrl = defaultEngine.getSubmission(TERM, null).uri.spec;
+  }
+  return new URL(this._submissionUrl);
+}
diff --git a/toolkit/components/search/tests/xpcshell/test_searchUrlDomain.js b/toolkit/components/search/tests/xpcshell/test_searchUrlDomain.js
new file mode 100644
index 0000000000..6cec77043a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_searchUrlDomain.js
@@ -0,0 +1,21 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests searchUrlDomain API.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null);
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_resultDomain() {
+  await Services.search.init();
+
+  let engine = Services.search.getEngineByName("Test search engine");
+
+  Assert.equal(engine.searchUrlDomain, "www.google.com");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_selectedEngine.js b/toolkit/components/search/tests/xpcshell/test_selectedEngine.js
new file mode 100644
index 0000000000..4a5d42211a
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_selectedEngine.js
@@ -0,0 +1,155 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const kDefaultEngineName = "engine1";
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines("data1");
+  Assert.ok(!Services.search.isInitialized);
+  Services.prefs.setBoolPref(
+    "browser.search.removeEngineInfobar.enabled",
+    false
+  );
+});
+
+// Check that the default engine matches the defaultenginename pref
+add_task(async function test_defaultEngine() {
+  await Services.search.init();
+  await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+});
+
+// Setting the search engine should be persisted across restarts.
+add_task(async function test_persistAcrossRestarts() {
+  // Set the engine through the API.
+  await Services.search.setDefault(
+    Services.search.getEngineByName(kTestEngineName),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(Services.search.defaultEngine.name, kTestEngineName);
+  await promiseAfterSettings();
+
+  // Check that the a hash was saved.
+  let metadata = await promiseGlobalMetadata();
+  Assert.equal(metadata.defaultEngineIdHash.length, 44);
+
+  // Re-init and check the engine is still the same.
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init(true);
+  Assert.equal(Services.search.defaultEngine.name, kTestEngineName);
+
+  // Cleanup (set the engine back to default).
+  Services.search.resetToAppDefaultEngine();
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+});
+
+// An engine set without a valid hash should be ignored.
+add_task(async function test_ignoreInvalidHash() {
+  // Set the engine through the API.
+  await Services.search.setDefault(
+    Services.search.getEngineByName(kTestEngineName),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(Services.search.defaultEngine.name, kTestEngineName);
+  await promiseAfterSettings();
+
+  // Then mess with the file (make the hash invalid).
+  let metadata = await promiseGlobalMetadata();
+  metadata.defaultEngineIdHash = "invalid";
+  await promiseSaveGlobalMetadata(metadata);
+
+  // Re-init the search service, and check that the json file is ignored.
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init(true);
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+});
+
+// Resetting the engine to the default should remove the saved value.
+add_task(async function test_settingToDefault() {
+  // Set the engine through the API.
+  await Services.search.setDefault(
+    Services.search.getEngineByName(kTestEngineName),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(Services.search.defaultEngine.name, kTestEngineName);
+  await promiseAfterSettings();
+
+  // Check that the current engine was saved.
+  let metadata = await promiseGlobalMetadata();
+  let currentEngine = Services.search.getEngineByName(kTestEngineName);
+  Assert.equal(metadata.defaultEngineId, currentEngine.id);
+
+  // Then set the engine back to the default through the API.
+  await Services.search.setDefault(
+    Services.search.getEngineByName(kDefaultEngineName),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  await promiseAfterSettings();
+
+  // Check that the current engine is no longer saved in the JSON file.
+  metadata = await promiseGlobalMetadata();
+  Assert.equal(metadata.defaultEngineId, "");
+});
+
+add_task(async function test_resetToOriginalDefaultEngine() {
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+
+  await Services.search.setDefault(
+    Services.search.getEngineByName(kTestEngineName),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(Services.search.defaultEngine.name, kTestEngineName);
+  await promiseAfterSettings();
+
+  Services.search.resetToAppDefaultEngine();
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+  await promiseAfterSettings();
+});
+
+add_task(async function test_fallback_kept_after_restart() {
+  // Set current engine to a default engine that isn't the original default.
+  let builtInEngines = await Services.search.getAppProvidedEngines();
+  let nonDefaultBuiltInEngine;
+  for (let engine of builtInEngines) {
+    if (engine.name != kDefaultEngineName) {
+      nonDefaultBuiltInEngine = engine;
+      break;
+    }
+  }
+  await Services.search.setDefault(
+    nonDefaultBuiltInEngine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    nonDefaultBuiltInEngine.name
+  );
+  await promiseAfterSettings();
+
+  // Remove that engine...
+  await Services.search.removeEngine(nonDefaultBuiltInEngine);
+  // The engine being a default (built-in) one, it should be hidden
+  // rather than actually removed.
+  Assert.ok(nonDefaultBuiltInEngine.hidden);
+
+  // Using the defaultEngine getter should force a fallback to the
+  // original default engine.
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+
+  // Restoring the default engines should unhide our built-in test
+  // engine, but not change the value of defaultEngine.
+  Services.search.restoreDefaultEngines();
+  Assert.ok(!nonDefaultBuiltInEngine.hidden);
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+  await promiseAfterSettings();
+
+  // After a restart, the defaultEngine value should still be unchanged.
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init(true);
+  Assert.equal(Services.search.defaultEngine.name, kDefaultEngineName);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_sendSubmissionURL.js b/toolkit/components/search/tests/xpcshell/test_sendSubmissionURL.js
new file mode 100644
index 0000000000..26052c1bea
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_sendSubmissionURL.js
@@ -0,0 +1,90 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests covering sending submission URLs for major engines
+ */
+
+const SUBMISSION_YES = [
+  ["Google1 Test", "https://www.google.com/search", "q={searchTerms}"],
+  ["Google2 Test", "https://www.google.co.uk/search", "q={searchTerms}"],
+  ["Yahoo1 Test", "https://search.yahoo.com/search", "p={searchTerms}"],
+  ["Yahoo2 Test", "https://uk.search.yahoo.com/search", "p={searchTerms}"],
+  ["AOL1 Test", "https://search.aol.com/aol/search", "q={searchTerms}"],
+  ["AOL2 Test", "https://search.aol.co.uk/aol/search", "q={searchTerms}"],
+  ["Yandex1 Test", "https://yandex.ru/search/", "text={searchTerms}"],
+  ["Yandex2 Test", "https://yandex.com/search/", "text={searchTerms}"],
+  ["Ask1 Test", "https://www.ask.com/web", "q={searchTerms}"],
+  ["Ask2 Test", "https://fr.ask.com/web", "q={searchTerms}"],
+  ["Bing Test", "https://www.bing.com/search", "q={searchTerms}"],
+  [
+    "Startpage Test",
+    "https://www.startpage.com/do/search",
+    "query={searchTerms}",
+  ],
+  ["DuckDuckGo Test", "https://duckduckgo.com/", "q={searchTerms}"],
+  ["Baidu Test", "https://www.baidu.com/s", "wd={searchTerms}"],
+];
+
+const SUBMISSION_NO = [
+  ["Other1 Test", "https://example.com", "q={searchTerms}"],
+  ["Other2 Test", "https://googlebutnotgoogle.com", "q={searchTerms}"],
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+});
+
+async function addAndMakeDefault(name, search_url, search_url_get_params) {
+  await SearchTestUtils.installSearchExtension({
+    name,
+    search_url,
+    search_url_get_params,
+  });
+
+  let engine = Services.search.getEngineByName(name);
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  return engine;
+}
+
+add_task(async function test_submission_url_matching() {
+  Assert.ok(!Services.search.isInitialized);
+  let engineInfo;
+  let engine;
+
+  for (let [name, searchURL, searchParams] of SUBMISSION_YES) {
+    engine = await addAndMakeDefault(name, searchURL, searchParams);
+    engineInfo = Services.search.getDefaultEngineInfo();
+    Assert.equal(
+      engineInfo.defaultSearchEngineData.submissionURL,
+      (searchURL + "?" + searchParams).replace("{searchTerms}", "")
+    );
+    await Services.search.removeEngine(engine);
+  }
+
+  for (let [name, searchURL, searchParams] of SUBMISSION_NO) {
+    engine = await addAndMakeDefault(name, searchURL, searchParams);
+    engineInfo = Services.search.getDefaultEngineInfo();
+    Assert.equal(engineInfo.defaultSearchEngineData.submissionURL, null);
+    await Services.search.removeEngine(engine);
+  }
+});
+
+add_task(async function test_submission_url_built_in() {
+  const engine = await Services.search.getEngineByName("engine1");
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  const engineInfo = Services.search.getDefaultEngineInfo();
+  Assert.equal(
+    engineInfo.defaultSearchEngineData.submissionURL,
+    "https://1.example.com/search?q=",
+    "Should have given the submission url for a built-in engine."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings.js b/toolkit/components/search/tests/xpcshell/test_settings.js
new file mode 100644
index 0000000000..3be00f460e
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings.js
@@ -0,0 +1,616 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test initializing from the search settings.
+ */
+
+"use strict";
+
+const legacyUseSavedOrderPrefName =
+  SearchUtils.BROWSER_SEARCH_PREF + "useDBForOrder";
+
+var settingsTemplate;
+
+/**
+ * Test reading from search.json.mozlz4
+ */
+add_task(async function setup() {
+  Services.prefs
+    .getDefaultBranch(SearchUtils.BROWSER_SEARCH_PREF + "param.")
+    .setCharPref("test", "expected");
+
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+async function loadSettingsFile(settingsFile, setVersion, setHashes) {
+  settingsTemplate = await readJSONFile(do_get_file(settingsFile));
+  if (setVersion) {
+    settingsTemplate.version = SearchUtils.SETTINGS_VERSION;
+  }
+
+  if (setHashes) {
+    settingsTemplate.metaData.hash = SearchUtils.getVerificationHash(
+      settingsTemplate.metaData.current
+    );
+    settingsTemplate.metaData.privateHash = SearchUtils.getVerificationHash(
+      settingsTemplate.metaData.private
+    );
+  }
+
+  delete settingsTemplate.visibleDefaultEngines;
+
+  await promiseSaveSettingsData(settingsTemplate);
+}
+
+/**
+ * Start the search service and confirm the engine properties match the expected values.
+ *
+ * @param {string} settingsFile
+ *   The path to the settings file to use.
+ * @param {boolean} setVersion
+ *   True if to set the version in the copied settings file.
+ * @param {boolean} expectedUseDBValue
+ *   The value expected for the `useSavedOrder` metadata attribute.
+ */
+async function checkLoadSettingProperties(
+  settingsFile,
+  setVersion,
+  expectedUseDBValue
+) {
+  info("init search service");
+  let ss = Services.search.wrappedJSObject;
+
+  await loadSettingsFile(settingsFile, setVersion);
+
+  const settingsFileWritten = promiseAfterSettings();
+
+  await ss.reset();
+  await Services.search.init();
+
+  await settingsFileWritten;
+
+  let engines = await ss.getEngines();
+
+  Assert.equal(
+    engines[0].name,
+    "engine1",
+    "Should have loaded the correct first engine"
+  );
+  Assert.equal(engines[0].alias, "testAlias", "Should have set the alias");
+  Assert.equal(engines[0].hidden, false, "Should have not hidden the engine");
+  Assert.equal(engines[0].id, "engine1@search.mozilla.orgdefault");
+
+  Assert.equal(
+    engines[1].name,
+    "engine2",
+    "Should have loaded the correct second engine"
+  );
+  Assert.equal(engines[1].alias, "", "Should have not set the alias");
+  Assert.equal(engines[1].hidden, true, "Should have hidden the engine");
+  Assert.equal(engines[1].id, "engine2@search.mozilla.orgdefault");
+
+  // The extra engine is the second in the list.
+  isSubObjectOf(EXPECTED_ENGINE.engine, engines[2]);
+  Assert.ok(engines[2].id, "test-addon-id@mozilla.orgdefault");
+
+  let engineFromSS = ss.getEngineByName(EXPECTED_ENGINE.engine.name);
+  Assert.ok(!!engineFromSS);
+  isSubObjectOf(EXPECTED_ENGINE.engine, engineFromSS);
+
+  Assert.equal(
+    engineFromSS.getSubmission("foo").uri.spec,
+    "http://www.google.com/search?q=foo",
+    "Should have the correct URL with no mozparams"
+  );
+
+  Assert.equal(
+    ss._settings.getMetaDataAttribute("useSavedOrder"),
+    expectedUseDBValue,
+    "Should have set the useSavedOrder metadata correctly."
+  );
+
+  let migratedSettingsFile = await promiseSettingsData();
+
+  Assert.equal(
+    migratedSettingsFile.engines[0].id,
+    "engine1@search.mozilla.orgdefault"
+  );
+
+  removeSettingsFile();
+}
+
+add_task(async function test_legacy_setting_engine_properties() {
+  Services.prefs.setBoolPref(legacyUseSavedOrderPrefName, true);
+
+  let legacySettings = await readJSONFile(
+    do_get_file("data/search-legacy.json")
+  );
+
+  // Assert the engine ids have not been migrated yet
+  for (let engine of legacySettings.engines) {
+    Assert.ok(!("id" in engine));
+  }
+  Assert.ok(!("defaultEngineId" in legacySettings.metaData));
+  Assert.ok(!("privateDefaultEngineId" in legacySettings.metaData));
+
+  await checkLoadSettingProperties("data/search-legacy.json", false, true);
+
+  Assert.ok(
+    !Services.prefs.prefHasUserValue(legacyUseSavedOrderPrefName),
+    "Should have cleared the legacy pref."
+  );
+});
+
+add_task(
+  async function test_legacy_setting_migration_with_undefined_metaData_current_and_private() {
+    let ss = Services.search.wrappedJSObject;
+
+    await loadSettingsFile("data/search-legacy.json", false);
+    const settingsFileWritten = promiseAfterSettings();
+
+    await ss.reset();
+    await Services.search.init();
+
+    await settingsFileWritten;
+
+    let migratedSettingsFile = await promiseSettingsData();
+
+    Assert.equal(
+      migratedSettingsFile.metaData.defaultEngineId,
+      "",
+      "When there is no metaData.current attribute in settings file, the migration should set the defaultEngineId to an empty string."
+    );
+    Assert.equal(
+      migratedSettingsFile.metaData.privateDefaultEngineId,
+      "",
+      "When there is no metaData.private attribute in settings file, the migration should set the privateDefaultEngineId to an empty string."
+    );
+
+    removeSettingsFile();
+  }
+);
+
+add_task(
+  async function test_legacy_setting_migration_with_correct_metaData_current_and_private_hashes() {
+    let ss = Services.search.wrappedJSObject;
+
+    await loadSettingsFile(
+      "data/search-legacy-correct-default-engine-hashes.json",
+      false,
+      true
+    );
+    const settingsFileWritten = promiseAfterSettings();
+
+    await ss.reset();
+    await Services.search.init();
+
+    await settingsFileWritten;
+
+    let migratedSettingsFile = await promiseSettingsData();
+
+    Assert.equal(
+      migratedSettingsFile.metaData.defaultEngineId,
+      "engine2@search.mozilla.orgdefault",
+      "When the metaData.current and associated hash are correct, the migration should set the defaultEngineId to the engine id."
+    );
+    Assert.equal(
+      migratedSettingsFile.metaData.privateDefaultEngineId,
+      "engine2@search.mozilla.orgdefault",
+      "When the metaData.private and associated hash are correct, the migration should set the privateDefaultEngineId to the private engine id."
+    );
+
+    removeSettingsFile();
+  }
+);
+
+add_task(
+  async function test_legacy_setting_migration_with_incorrect_metaData_current_and_private_hashes_app_provided() {
+    let ss = Services.search.wrappedJSObject;
+
+    // Here we are testing correct migration for the case that a user has set
+    // their default engine to an application provided engine (but not the app
+    // default).
+    //
+    // In this case we should ignore invalid hashes for the default engines,
+    // and allow the select default to remain. This covers the case where
+    // a user has copied a profile from a different directory.
+    // See SearchService._getEngineDefault for more details.
+
+    await loadSettingsFile(
+      "data/search-legacy-wrong-default-engine-hashes.json",
+      false,
+      false
+    );
+    const settingsFileWritten = promiseAfterSettings();
+
+    await ss.reset();
+    await Services.search.init();
+
+    await settingsFileWritten;
+
+    let migratedSettingsFile = await promiseSettingsData();
+
+    Assert.equal(
+      migratedSettingsFile.metaData.defaultEngineId,
+      "engine2@search.mozilla.orgdefault",
+      "Should ignore invalid metaData.hash when the default engine is application provided."
+    );
+    Assert.equal(
+      Services.search.defaultEngine.name,
+      "engine2",
+      "Should have the correct engine set as default"
+    );
+
+    Assert.equal(
+      migratedSettingsFile.metaData.privateDefaultEngineId,
+      "engine2@search.mozilla.orgdefault",
+      "Should ignore invalid metaData.privateHash when the default private engine is application provided."
+    );
+    Assert.equal(
+      Services.search.defaultPrivateEngine.name,
+      "engine2",
+      "Should have the correct engine set as default private"
+    );
+
+    removeSettingsFile();
+  }
+);
+
+add_task(
+  async function test_legacy_setting_migration_with_incorrect_metaData_current_and_private_hashes_third_party() {
+    let ss = Services.search.wrappedJSObject;
+
+    // This test is checking that if the user has set a third-party engine as
+    // default, and the verification hash is invalid, then we do not copy
+    // the default engine setting.
+
+    await loadSettingsFile(
+      "data/search-legacy-wrong-third-party-engine-hashes.json",
+      false,
+      false
+    );
+    const settingsFileWritten = promiseAfterSettings();
+
+    await ss.reset();
+    await Services.search.init();
+
+    await settingsFileWritten;
+
+    let migratedSettingsFile = await promiseSettingsData();
+
+    Assert.equal(
+      migratedSettingsFile.metaData.defaultEngineId,
+      "",
+      "Should reset the default engine when metaData.hash is invalid and the engine is not application provided."
+    );
+    Assert.equal(
+      Services.search.defaultEngine.name,
+      "engine1",
+      "Should have reset the default engine"
+    );
+
+    Assert.equal(
+      migratedSettingsFile.metaData.privateDefaultEngineId,
+      "",
+      "Should reset the default engine when metaData.privateHash is invalid and the engine is not application provided."
+    );
+    Assert.equal(
+      Services.search.defaultPrivateEngine.name,
+      "engine1",
+      "Should have reset the default private engine"
+    );
+
+    removeSettingsFile();
+  }
+);
+
+add_task(async function test_current_setting_engine_properties() {
+  await checkLoadSettingProperties("data/search.json", true, false);
+});
+
+add_task(async function test_settings_metadata_properties() {
+  let ss = Services.search.wrappedJSObject;
+
+  await loadSettingsFile("data/search.json");
+
+  const settingsFileWritten = promiseAfterSettings();
+  await ss.reset();
+  await Services.search.init();
+
+  await settingsFileWritten;
+
+  let metaDataProperties = [
+    "locale",
+    "region",
+    "channel",
+    "experiment",
+    "distroID",
+  ];
+
+  for (let name of metaDataProperties) {
+    Assert.notEqual(
+      ss._settings.getMetaDataAttribute(`${name}`),
+      undefined,
+      `Search settings should have ${name} property defined.`
+    );
+  }
+
+  removeSettingsFile();
+});
+
+add_task(async function test_settings_write_when_settings_changed() {
+  let ss = Services.search.wrappedJSObject;
+  await loadSettingsFile("data/search.json");
+
+  const settingsFileWritten = promiseAfterSettings();
+  await ss.reset();
+  await Services.search.init();
+  await settingsFileWritten;
+
+  Assert.ok(
+    ss._settings.isCurrentAndCachedSettingsEqual(),
+    "Settings and cached settings should be the same after search service initializaiton."
+  );
+
+  const settingsFileWritten2 = promiseAfterSettings();
+  ss._settings.setMetaDataAttribute("value", "test");
+
+  Assert.ok(
+    !ss._settings.isCurrentAndCachedSettingsEqual(),
+    "Settings should differ from cached settings after a new attribute is set."
+  );
+
+  await settingsFileWritten2;
+  info("Settings write complete");
+
+  Assert.ok(
+    ss._settings.isCurrentAndCachedSettingsEqual(),
+    "Settings and cached settings should be the same after new attribte on settings is written."
+  );
+
+  removeSettingsFile();
+});
+
+add_task(async function test_set_and_get_engine_metadata_attribute() {
+  let ss = Services.search.wrappedJSObject;
+  await loadSettingsFile("data/search.json");
+
+  const settingsFileWritten = promiseAfterSettings();
+  await ss.reset();
+  await Services.search.init();
+  await settingsFileWritten;
+
+  let engines = await ss.getEngines();
+  const settingsFileWritten2 = promiseAfterSettings();
+  ss._settings.setEngineMetaDataAttribute(engines[0].name, "value", "test");
+  await settingsFileWritten2;
+
+  Assert.equal(
+    "test",
+    ss._settings.getEngineMetaDataAttribute(engines[0].name, "value"),
+    `${engines[0].name}'s metadata property "value" should be set as "test" after calling getEngineMetaDataAttribute.`
+  );
+
+  let userSettings = await ss._settings.get();
+  let engine = userSettings.engines.find(e => e._name == engines[0].name);
+
+  Assert.equal(
+    "test",
+    engine._metaData.value,
+    `${engines[0].name}'s metadata property "value" should be set as "test" from settings file.`
+  );
+
+  removeSettingsFile();
+});
+
+add_task(
+  async function test_settings_write_prevented_when_settings_unchanged() {
+    let ss = Services.search.wrappedJSObject;
+    await loadSettingsFile("data/search.json");
+
+    const settingsFileWritten = promiseAfterSettings();
+    await ss.reset();
+    await Services.search.init();
+    await settingsFileWritten;
+
+    Assert.ok(
+      ss._settings.isCurrentAndCachedSettingsEqual(),
+      "Settings and cached settings should be the same after search service initializaiton."
+    );
+
+    // Update settings.
+    const settingsFileWritten2 = promiseAfterSettings();
+    ss._settings.setMetaDataAttribute("value", "test");
+
+    Assert.ok(
+      !ss._settings.isCurrentAndCachedSettingsEqual(),
+      "Settings should differ from cached settings after a new attribute is set."
+    );
+    await settingsFileWritten2;
+
+    // Set the same attribute as before to ensure there was no change.
+    // Settings write should be prevented.
+    let promiseWritePrevented = SearchTestUtils.promiseSearchNotification(
+      "write-prevented-when-settings-unchanged"
+    );
+    ss._settings.setMetaDataAttribute("value", "test");
+
+    Assert.ok(
+      ss._settings.isCurrentAndCachedSettingsEqual(),
+      "Settings and cached settings should be the same."
+    );
+    await promiseWritePrevented;
+
+    removeSettingsFile();
+  }
+);
+
+/**
+ * Test that the JSON settings written in the profile is correct.
+ */
+add_task(async function test_settings_write() {
+  let ss = Services.search.wrappedJSObject;
+  info("test settings writing");
+
+  await loadSettingsFile("data/search.json");
+
+  const settingsFileWritten = promiseAfterSettings();
+  await ss.reset();
+  await Services.search.init();
+  await settingsFileWritten;
+
+  let settingsData = await promiseSettingsData();
+
+  // Remove buildID and locale, as they are no longer used.
+  delete settingsTemplate.buildID;
+  delete settingsTemplate.locale;
+
+  for (let engine of settingsTemplate.engines) {
+    // Remove _shortName from the settings template, as it is no longer supported,
+    // but older settings used to have it, so we keep it in the template as an
+    // example.
+    if ("_shortName" in engine) {
+      delete engine._shortName;
+    }
+    if ("_urls" in engine) {
+      // Only app-provided engines support purpose & mozparams, others do not,
+      // so filter them out of the expected template.
+      for (let urls of engine._urls) {
+        urls.params = urls.params.filter(p => !p.purpose && !p.mozparam);
+        // resultDomain is also no longer supported.
+        if ("resultDomain" in urls) {
+          delete urls.resultDomain;
+        }
+      }
+    }
+    // Remove queryCharset, if it is the same as the default, as we don't save
+    // it in that case.
+    if (engine?.queryCharset == SearchUtils.DEFAULT_QUERY_CHARSET) {
+      delete engine.queryCharset;
+    }
+  }
+
+  // Note: the file is copied with an old version number, which should have
+  // been updated on write.
+  settingsTemplate.version = SearchUtils.SETTINGS_VERSION;
+
+  isSubObjectOf(settingsTemplate, settingsData, (prop, value) => {
+    if (prop != "_iconURL" && prop != "{}") {
+      return false;
+    }
+    // Skip items that are to do with icons for extensions, as we can't
+    // control the uuid.
+    return value.startsWith("moz-extension://");
+  });
+});
+
+async function settings_write_check(disableFn) {
+  let ss = Services.search.wrappedJSObject;
+
+  sinon.stub(ss._settings, "_write").returns(Promise.resolve());
+
+  // Simulate the search service being initialized.
+  disableFn(true);
+
+  ss._settings.setMetaDataAttribute("value", "test");
+
+  Assert.ok(
+    ss._settings._write.notCalled,
+    "Should not have attempted to _write"
+  );
+
+  // Wait for two periods of the normal delay to ensure we still do not write.
+  await new Promise(r =>
+    // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+    setTimeout(r, SearchSettings.SETTNGS_INVALIDATION_DELAY * 2)
+  );
+
+  Assert.ok(
+    ss._settings._write.notCalled,
+    "Should not have attempted to _write"
+  );
+
+  disableFn(false);
+
+  await TestUtils.waitForCondition(
+    () => ss._settings._write.calledOnce,
+    "Should attempt to write the settings."
+  );
+
+  sinon.restore();
+}
+
+add_task(async function test_settings_write_prevented_during_init() {
+  await settings_write_check(disable => {
+    let status = disable ? "success" : "failed";
+    Services.search.wrappedJSObject.forceInitializationStatusForTests(status);
+  });
+});
+
+add_task(async function test_settings_write_prevented_during_reload() {
+  await settings_write_check(
+    disable => (Services.search.wrappedJSObject._reloadingEngines = disable)
+  );
+});
+
+var EXPECTED_ENGINE = {
+  engine: {
+    name: "Test search engine",
+    alias: "",
+    description: "A test search engine (based on Google search)",
+    searchForm: "http://www.google.com/",
+    wrappedJSObject: {
+      _extensionID: "test-addon-id@mozilla.org",
+      _iconURL:
+        "data:image/png;base64,AAABAAEAEBAAAAEAGABoAwAAFgAAACgAAAAQAAA" +
+        "AIAAAAAEAGAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADs9Pt8xetPtu9F" +
+        "sfFNtu%2BTzvb2%2B%2Fne4dFJeBw0egA%2FfAJAfAA8ewBBegAAAAD%2B%2F" +
+        "Ptft98Mp%2BwWsfAVsvEbs%2FQeqvF8xO7%2F%2F%2F63yqkxdgM7gwE%2Fgg" +
+        "M%2BfQA%2BegBDeQDe7PIbotgQufcMufEPtfIPsvAbs%2FQvq%2Bfz%2Bf%2F" +
+        "%2B%2B%2FZKhR05hgBBhQI8hgBAgAI9ewD0%2B%2Fg3pswAtO8Cxf4Kw%2FsJ" +
+        "vvYAqupKsNv%2B%2Fv7%2F%2FP5VkSU0iQA7jQA9hgBDgQU%2BfQH%2F%2Ff%" +
+        "2FQ6fM4sM4KsN8AteMCruIqqdbZ7PH8%2Fv%2Fg6Nc%2Fhg05kAA8jAM9iQI%" +
+        "2BhQA%2BgQDQu6b97uv%2F%2F%2F7V8Pqw3eiWz97q8%2Ff%2F%2F%2F%2F7%" +
+        "2FPptpkkqjQE4kwA7kAA5iwI8iAA8hQCOSSKdXjiyflbAkG7u2s%2F%2B%2F%" +
+        "2F39%2F%2F7r8utrqEYtjQE8lgA7kwA7kwA9jwA9igA9hACiWSekVRyeSgiYS" +
+        "BHx6N%2F%2B%2Fv7k7OFRmiYtlAA5lwI7lwI4lAA7kgI9jwE9iwI4iQCoVhWc" +
+        "TxCmb0K%2BooT8%2Fv%2F7%2F%2F%2FJ2r8fdwI1mwA3mQA3mgA8lAE8lAE4j" +
+        "wA9iwE%2BhwGfXifWvqz%2B%2Ff%2F58u%2Fev6Dt4tr%2B%2F%2F2ZuIUsgg" +
+        "A7mgM6mAM3lgA5lgA6kQE%2FkwBChwHt4dv%2F%2F%2F728ei1bCi7VAC5XQ7" +
+        "kz7n%2F%2F%2F6bsZkgcB03lQA9lgM7kwA2iQktZToPK4r9%2F%2F%2F9%2F%" +
+        "2F%2FSqYK5UwDKZAS9WALIkFn%2B%2F%2F3%2F%2BP8oKccGGcIRJrERILYFE" +
+        "MwAAuEAAdX%2F%2Ff7%2F%2FP%2B%2BfDvGXQLIZgLEWgLOjlf7%2F%2F%2F%" +
+        "2F%2F%2F9QU90EAPQAAf8DAP0AAfMAAOUDAtr%2F%2F%2F%2F7%2B%2Fu2bCT" +
+        "IYwDPZgDBWQDSr4P%2F%2Fv%2F%2F%2FP5GRuABAPkAA%2FwBAfkDAPAAAesA" +
+        "AN%2F%2F%2B%2Fz%2F%2F%2F64g1C5VwDMYwK8Yg7y5tz8%2Fv%2FV1PYKDOc" +
+        "AAP0DAf4AAf0AAfYEAOwAAuAAAAD%2F%2FPvi28ymXyChTATRrIb8%2F%2F3v" +
+        "8fk6P8MAAdUCAvoAAP0CAP0AAfYAAO4AAACAAQAAAAAAAAAAAAAAAAAAAAAAA" +
+        "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAA",
+      _urls: [
+        {
+          type: "application/x-suggestions+json",
+          method: "GET",
+          template:
+            "http://suggestqueries.google.com/complete/search?output=firefox&client=firefox" +
+            "&hl={moz:locale}&q={searchTerms}",
+          params: "",
+        },
+        {
+          type: "text/html",
+          method: "GET",
+          template: "http://www.google.com/search",
+          params: [
+            {
+              name: "q",
+              value: "{searchTerms}",
+              purpose: undefined,
+            },
+          ],
+        },
+      ],
+    },
+  },
+};
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_broken.js b/toolkit/components/search/tests/xpcshell/test_settings_broken.js
new file mode 100644
index 0000000000..12298155f1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_broken.js
@@ -0,0 +1,131 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test initializing from broken search settings. This is one where the engines
+ * array for some reason has lost all the default engines, but retained either
+ * one or two, or a user-supplied engine. We don't know why this happens, but
+ * we have seen it (bug 1578807).
+ */
+
+"use strict";
+
+const { getAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+
+const enginesSettings = {
+  version: SearchUtils.SETTINGS_VERSION,
+  buildID: "TBD",
+  appVersion: "TBD",
+  locale: "en-US",
+  metaData: {
+    searchDefault: "Test search engine",
+    searchDefaultHash: "TBD",
+    // Intentionally in the past, but shouldn't actually matter for this test.
+    searchDefaultExpir: 1567694909002,
+    current: "",
+    hash: "TBD",
+    visibleDefaultEngines:
+      "engine,engine-pref,engine-rel-searchform-purpose,engine-chromeicon,engine-resourceicon,engine-reordered",
+    visibleDefaultEnginesHash: "TBD",
+  },
+  engines: [
+    // This is a user-installed engine - the only one that was listed due to the
+    // original issue.
+    {
+      _name: "A second test engine",
+      _shortName: "engine2",
+      _loadPath: "[profile]/searchplugins/engine2.xml",
+      description: "A second test search engine (based on DuckDuckGo)",
+      _iconURL:
+        "data:image/x-icon;base64,AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAEAgQAhIOEAMjHyABIR0gA6ejpAGlqaQCpqKkAKCgoAPz9/AAZGBkAmJiYANjZ2ABXWFcAent6ALm6uQA8OjwAiIiIiIiIiIiIiI4oiL6IiIiIgzuIV4iIiIhndo53KIiIiB/WvXoYiIiIfEZfWBSIiIEGi/foqoiIgzuL84i9iIjpGIoMiEHoiMkos3FojmiLlUipYliEWIF+iDe0GoRa7D6GPbjcu1yIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+      _iconMapObj: {
+        '{"width":16,"height":16}':
+          "data:image/x-icon;base64,AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAEAgQAhIOEAMjHyABIR0gA6ejpAGlqaQCpqKkAKCgoAPz9/AAZGBkAmJiYANjZ2ABXWFcAent6ALm6uQA8OjwAiIiIiIiIiIiIiI4oiL6IiIiIgzuIV4iIiIhndo53KIiIiB/WvXoYiIiIfEZfWBSIiIEGi/foqoiIgzuL84i9iIjpGIoMiEHoiMkos3FojmiLlUipYliEWIF+iDe0GoRa7D6GPbjcu1yIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+      },
+      _isBuiltin: false,
+      _metaData: {
+        order: 1,
+      },
+      _urls: [
+        {
+          template: "https://duckduckgo.com/?q={searchTerms}",
+          rels: [],
+          resultDomain: "duckduckgo.com",
+          params: [],
+        },
+      ],
+      queryCharset: "UTF-8",
+      filePath: "TBD",
+    },
+  ],
+};
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  // Allow telemetry probes which may otherwise be disabled for some applications (e.g. Thunderbird)
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  await SearchTestUtils.useTestEngines();
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+  Services.locale.availableLocales = ["en-US"];
+  Services.locale.requestedLocales = ["en-US"];
+
+  // We dynamically generate the hashes because these depend on the profile.
+  enginesSettings.metaData.searchDefaultHash = SearchUtils.getVerificationHash(
+    enginesSettings.metaData.searchDefault
+  );
+  enginesSettings.metaData.hash = SearchUtils.getVerificationHash(
+    enginesSettings.metaData.current
+  );
+  enginesSettings.metaData.visibleDefaultEnginesHash =
+    SearchUtils.getVerificationHash(
+      enginesSettings.metaData.visibleDefaultEngines
+    );
+  const appInfo = getAppInfo();
+  enginesSettings.buildID = appInfo.platformBuildID;
+  enginesSettings.appVersion = appInfo.version;
+
+  await IOUtils.writeJSON(
+    PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME),
+    enginesSettings,
+    { compress: true }
+  );
+});
+
+add_task(async function test_cached_engine_properties() {
+  info("init search service");
+
+  const initResult = await Services.search.init();
+
+  info("init'd search service");
+  Assert.ok(
+    Components.isSuccessCode(initResult),
+    "Should have successfully created the search service"
+  );
+
+  const engines = await Services.search.getEngines();
+
+  const expectedEngines = [
+    // Default engines
+    "Test search engine",
+    // Rest of engines in order
+    "engine-resourceicon",
+    "engine-chromeicon",
+    "engine-pref",
+    "engine-rel-searchform-purpose",
+    "Test search engine (Reordered)",
+    "A second test engine",
+  ];
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    expectedEngines,
+    "Should have the expected default engines"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_duplicate.js b/toolkit/components/search/tests/xpcshell/test_settings_duplicate.js
new file mode 100644
index 0000000000..b269fcafca
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_duplicate.js
@@ -0,0 +1,134 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test initializing with an engine that's a duplicate of an app-provided
+ * engine.
+ */
+
+"use strict";
+
+const { getAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+
+const enginesSettings = {
+  version: SearchUtils.SETTINGS_VERSION,
+  buildID: "TBD",
+  appVersion: "TBD",
+  locale: "en-US",
+  metaData: {
+    searchDefault: "Test search engine",
+    searchDefaultHash: "TBD",
+    // Intentionally in the past, but shouldn't actually matter for this test.
+    searchDefaultExpir: 1567694909002,
+    current: "",
+    hash: "TBD",
+    visibleDefaultEngines:
+      "engine,engine-pref,engine-rel-searchform-purpose,engine-chromeicon,engine-resourceicon,engine-reordered",
+    visibleDefaultEnginesHash: "TBD",
+  },
+  engines: [
+    {
+      _metaData: { alias: null },
+      _isAppProvided: true,
+      _name: "engine1",
+    },
+    {
+      _metaData: { alias: null },
+      _isAppProvided: true,
+      _name: "engine2",
+    },
+    // This is a user-installed engine - the only one that was listed due to the
+    // original issue.
+    {
+      _name: "engine1",
+      _shortName: "engine1",
+      _loadPath: "[test]oldduplicateversion",
+      description: "An old near duplicate version of engine1",
+      _iconURL:
+        "data:image/x-icon;base64,AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAEAgQAhIOEAMjHyABIR0gA6ejpAGlqaQCpqKkAKCgoAPz9/AAZGBkAmJiYANjZ2ABXWFcAent6ALm6uQA8OjwAiIiIiIiIiIiIiI4oiL6IiIiIgzuIV4iIiIhndo53KIiIiB/WvXoYiIiIfEZfWBSIiIEGi/foqoiIgzuL84i9iIjpGIoMiEHoiMkos3FojmiLlUipYliEWIF+iDe0GoRa7D6GPbjcu1yIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+      _iconMapObj: {
+        '{"width":16,"height":16}':
+          "data:image/x-icon;base64,AAABAAEAEBAQAAEABAAoAQAAFgAAACgAAAAQAAAAIAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAAAAAEAgQAhIOEAMjHyABIR0gA6ejpAGlqaQCpqKkAKCgoAPz9/AAZGBkAmJiYANjZ2ABXWFcAent6ALm6uQA8OjwAiIiIiIiIiIiIiI4oiL6IiIiIgzuIV4iIiIhndo53KIiIiB/WvXoYiIiIfEZfWBSIiIEGi/foqoiIgzuL84i9iIjpGIoMiEHoiMkos3FojmiLlUipYliEWIF+iDe0GoRa7D6GPbjcu1yIiIiIiIiIiIiIiIiIiIiIiIiIiIiIiIgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+      },
+      _metaData: {
+        order: 1,
+      },
+      _urls: [
+        {
+          template: "https://example.com/?myquery={searchTerms}",
+          rels: [],
+          resultDomain: "example.com",
+          params: [],
+        },
+      ],
+      queryCharset: "UTF-8",
+      filePath: "TBD",
+    },
+  ],
+};
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  // Allow telemetry probes which may otherwise be disabled for some applications (e.g. Thunderbird)
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  await SearchTestUtils.useTestEngines("data1");
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+  Services.locale.availableLocales = ["en-US"];
+  Services.locale.requestedLocales = ["en-US"];
+
+  // We dynamically generate the hashes because these depend on the profile.
+  enginesSettings.metaData.searchDefaultHash = SearchUtils.getVerificationHash(
+    enginesSettings.metaData.searchDefault
+  );
+  enginesSettings.metaData.hash = SearchUtils.getVerificationHash(
+    enginesSettings.metaData.current
+  );
+  enginesSettings.metaData.visibleDefaultEnginesHash =
+    SearchUtils.getVerificationHash(
+      enginesSettings.metaData.visibleDefaultEngines
+    );
+  let appInfo = getAppInfo();
+  enginesSettings.buildID = appInfo.platformBuildID;
+  enginesSettings.appVersion = appInfo.version;
+
+  await IOUtils.write(
+    PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME),
+    new TextEncoder().encode(JSON.stringify(enginesSettings)),
+    { compress: true }
+  );
+});
+
+add_task(async function test_cached_duplicate() {
+  info("init search service");
+
+  let initResult = await Services.search.init();
+
+  info("init'd search service");
+  Assert.ok(
+    Components.isSuccessCode(initResult),
+    "Should have successfully created the search service"
+  );
+
+  let engine = await Services.search.getEngineByName("engine1");
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://1.example.com/search?q=foo",
+    "Should have not changed the app provided engine."
+  );
+
+  let engines = await Services.search.getEngines();
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["engine1", "engine2"],
+    "Should have the expected default engines"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_good.js b/toolkit/components/search/tests/xpcshell/test_settings_good.js
new file mode 100644
index 0000000000..2c69889c09
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_good.js
@@ -0,0 +1,103 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test initializing from good search settings.
+ */
+
+"use strict";
+
+const { getAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+
+const enginesSettings = {
+  version: SearchUtils.SETTINGS_VERSION,
+  buildID: "TBD",
+  appVersion: "TBD",
+  locale: "en-US",
+  metaData: {
+    searchDefault: "Test search engine",
+    searchDefaultHash: "TBD",
+    // Intentionally in the past, but shouldn't actually matter for this test.
+    searchDefaultExpir: 1567694909002,
+    // We use the second engine here so that the user's default is set
+    // to something different, and hence so that we exercise the appropriate
+    // code paths.
+    defaultEngineId: "engine2@search.mozilla.orgdefault",
+    defaultEngineIdHash: "TBD",
+    visibleDefaultEngines: "engine1,engine2",
+    visibleDefaultEnginesHash: "TBD",
+  },
+  engines: [
+    {
+      _metaData: { alias: null },
+      _isAppProvided: true,
+      _name: "engine1",
+    },
+    {
+      _metaData: { alias: null },
+      _isAppProvided: true,
+      _name: "engine2",
+    },
+  ],
+};
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  // Allow telemetry probes which may otherwise be disabled for some applications (e.g. Thunderbird)
+  Services.prefs.setBoolPref(
+    "toolkit.telemetry.testing.overrideProductsCheck",
+    true
+  );
+
+  await SearchTestUtils.useTestEngines("data1");
+  Services.prefs.setCharPref(SearchUtils.BROWSER_SEARCH_PREF + "region", "US");
+  Services.locale.availableLocales = ["en-US"];
+  Services.locale.requestedLocales = ["en-US"];
+
+  // We dynamically generate the hashes because these depend on the profile.
+  enginesSettings.metaData.searchDefaultHash = SearchUtils.getVerificationHash(
+    enginesSettings.metaData.searchDefault
+  );
+  enginesSettings.metaData.defaultEngineIdHash =
+    SearchUtils.getVerificationHash(enginesSettings.metaData.defaultEngineId);
+  enginesSettings.metaData.visibleDefaultEnginesHash =
+    SearchUtils.getVerificationHash(
+      enginesSettings.metaData.visibleDefaultEngines
+    );
+  const appInfo = getAppInfo();
+  enginesSettings.buildID = appInfo.platformBuildID;
+  enginesSettings.appVersion = appInfo.version;
+
+  await IOUtils.writeJSON(
+    PathUtils.join(PathUtils.profileDir, SETTINGS_FILENAME),
+    enginesSettings,
+    { compress: true }
+  );
+});
+
+add_task(async function test_cached_engine_properties() {
+  info("init search service");
+
+  const initResult = await Services.search.init();
+
+  info("init'd search service");
+  Assert.ok(
+    Components.isSuccessCode(initResult),
+    "Should have successfully created the search service"
+  );
+
+  const engines = await Services.search.getEngines();
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "engine2",
+    "Should have the expected default engine"
+  );
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["engine1", "engine2"],
+    "Should have the expected application provided engines"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_ignorelist.js b/toolkit/components/search/tests/xpcshell/test_settings_ignorelist.js
new file mode 100644
index 0000000000..b02775bbd9
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_ignorelist.js
@@ -0,0 +1,62 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test initializing from the search settings.
+ */
+
+"use strict";
+
+var { getAppInfo } = ChromeUtils.importESModule(
+  "resource://testing-common/AppInfo.sys.mjs"
+);
+
+var settingsTemplate;
+
+/**
+ * Test reading from search.json.mozlz4
+ */
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  await setupRemoteSettings();
+
+  settingsTemplate = await readJSONFile(
+    do_get_file("data/search_ignorelist.json")
+  );
+  settingsTemplate.buildID = getAppInfo().platformBuildID;
+
+  await promiseSaveSettingsData(settingsTemplate);
+});
+
+/**
+ * Start the search service and confirm the settings were reset
+ */
+add_task(async function test_settings_rest() {
+  info("init search service");
+
+  let updatePromise = SearchTestUtils.promiseSearchNotification(
+    "settings-update-complete"
+  );
+
+  let result = await Services.search.init();
+
+  Assert.ok(
+    Components.isSuccessCode(result),
+    "Search service should be successfully initialized"
+  );
+  await updatePromise;
+
+  const engines = await Services.search.getEngines();
+
+  // Engine list will have been reset to the default,
+  // Not the one engine in the settings.
+  // It should have more than one engine.
+  Assert.greater(
+    engines.length,
+    1,
+    "Should have more than one engine in the list"
+  );
+
+  removeSettingsFile();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_migration_ids.js b/toolkit/components/search/tests/xpcshell/test_settings_migration_ids.js
new file mode 100644
index 0000000000..f5ccb8a301
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_migration_ids.js
@@ -0,0 +1,122 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test migration of user, enterprise policy and OpenSearch engines
+ * from when engines were referenced by name rather than id.
+ *
+ * Add-ons and default engine ids are tested in test_settings.js.
+ */
+
+"use strict";
+
+const { EnterprisePolicyTesting } = ChromeUtils.importESModule(
+  "resource://testing-common/EnterprisePolicyTesting.sys.mjs"
+);
+
+const enterprisePolicy = {
+  policies: {
+    SearchEngines: {
+      Add: [
+        {
+          Name: "Policy",
+          Encoding: "windows-1252",
+          URLTemplate: "http://example.com/?q={searchTerms}",
+        },
+      ],
+    },
+  },
+};
+
+/**
+ * Loads the settings file and ensures it has not already been migrated.
+ *
+ * @param {string} settingsFile The settings file to load
+ */
+async function loadSettingsFile(settingsFile) {
+  let settingsTemplate = await readJSONFile(do_get_file(settingsFile));
+
+  Assert.less(
+    settingsTemplate.version,
+    7,
+    "Should be a version older than when indexing engines by id was introduced"
+  );
+  for (let engine of settingsTemplate.engines) {
+    Assert.ok(!("id" in engine));
+  }
+
+  await promiseSaveSettingsData(settingsTemplate);
+}
+
+/**
+ * Test reading from search.json.mozlz4
+ */
+add_task(async function setup() {
+  // This initializes the policy engine for xpcshell tests
+  let policies = Cc["@mozilla.org/enterprisepolicies;1"].getService(
+    Ci.nsIObserver
+  );
+  policies.observe(null, "policies-startup", null);
+
+  Services.prefs
+    .getDefaultBranch(SearchUtils.BROWSER_SEARCH_PREF + "param.")
+    .setCharPref("test", "expected");
+
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+  await EnterprisePolicyTesting.setupPolicyEngineWithJson(enterprisePolicy);
+  // Setting the enterprise policy starts the search service initialising,
+  // so we wait for that to complete before starting the test.
+  await Services.search.init();
+});
+
+/**
+ * Tests that an installed engine matches the expected data.
+ *
+ * @param {object} expectedData The expected data for the engine
+ */
+async function assertInstalledEngineMatches(expectedData) {
+  let engine = await Services.search.getEngineByName(expectedData.name);
+
+  Assert.ok(engine, `Should have found the ${expectedData.type} engine`);
+  if (expectedData.idLength) {
+    Assert.equal(
+      engine.id.length,
+      expectedData.idLength,
+      "Should have been given an id"
+    );
+  } else {
+    Assert.equal(engine.id, expectedData.id, "Should have the expected id");
+  }
+  Assert.equal(engine.alias, expectedData.alias, "Should have kept the alias");
+}
+
+add_task(async function test_migration_from_pre_ids() {
+  await loadSettingsFile("data/search-legacy-no-ids.json");
+
+  const settingsFileWritten = promiseAfterSettings();
+
+  await Services.search.wrappedJSObject.reset();
+  await Services.search.init();
+
+  await settingsFileWritten;
+
+  await assertInstalledEngineMatches({
+    type: "OpenSearch",
+    name: "Bugzilla@Mozilla",
+    idLength: 36,
+    alias: "bugzillaAlias",
+  });
+  await assertInstalledEngineMatches({
+    type: "Enterprise Policy",
+    name: "Policy",
+    id: "policy-Policy",
+    alias: "PolicyAlias",
+  });
+  await assertInstalledEngineMatches({
+    type: "User",
+    name: "User",
+    idLength: 36,
+    alias: "UserAlias",
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_migration_loadPath.js b/toolkit/components/search/tests/xpcshell/test_settings_migration_loadPath.js
new file mode 100644
index 0000000000..e6a7cbce00
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_migration_loadPath.js
@@ -0,0 +1,130 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test migration load path for user, enterprise policy and add-on
+ * engines.
+ */
+
+"use strict";
+
+const { EnterprisePolicyTesting } = ChromeUtils.importESModule(
+  "resource://testing-common/EnterprisePolicyTesting.sys.mjs"
+);
+
+const enterprisePolicy = {
+  policies: {
+    SearchEngines: {
+      Add: [
+        {
+          Name: "Policy",
+          Encoding: "windows-1252",
+          URLTemplate: "http://example.com/?q={searchTerms}",
+        },
+      ],
+    },
+  },
+};
+
+add_task(async function setup() {
+  // This initializes the policy engine for xpcshell tests
+  let policies = Cc["@mozilla.org/enterprisepolicies;1"].getService(
+    Ci.nsIObserver
+  );
+  policies.observe(null, "policies-startup", null);
+
+  Services.prefs
+    .getDefaultBranch(SearchUtils.BROWSER_SEARCH_PREF + "param.")
+    .setCharPref("test", "expected");
+
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+  await EnterprisePolicyTesting.setupPolicyEngineWithJson(enterprisePolicy);
+  // Setting the enterprise policy starts the search service initialising,
+  // so we wait for that to complete before starting the test, we can
+  // then also add an extra add-on engine.
+  await Services.search.init();
+  let settingsFileWritten = promiseAfterSettings();
+  await SearchTestUtils.installSearchExtension();
+  await settingsFileWritten;
+});
+
+/**
+ * Loads the settings file and ensures it has not already been migrated.
+ */
+add_task(async function test_load_and_check_settings() {
+  let settingsTemplate = await readJSONFile(
+    do_get_file("data/search-legacy-old-loadPaths.json")
+  );
+
+  Assert.less(
+    settingsTemplate.version,
+    8,
+    "Should be a version older than when indexing engines by id was introduced"
+  );
+  let engine = settingsTemplate.engines.find(e => e.id == "policy-Policy");
+  Assert.equal(
+    engine._loadPath,
+    "[other]addEngineWithDetails:set-via-policy",
+    "Should have a old style load path for the policy engine"
+  );
+  engine = settingsTemplate.engines.find(
+    e => e.id == "bbc163e7-7b1a-47aa-a32c-c59062de2754"
+  );
+  Assert.equal(
+    engine._loadPath,
+    "[other]addEngineWithDetails:set-via-user",
+    "Should have a old style load path for the user engine"
+  );
+  engine = settingsTemplate.engines.find(
+    e => e.id == "example@tests.mozilla.orgdefault"
+  );
+  Assert.equal(
+    engine._loadPath,
+    "[other]addEngineWithDetails:example@tests.mozilla.org",
+    "Should have a old style load path for the add-on engine"
+  );
+
+  await promiseSaveSettingsData(settingsTemplate);
+});
+
+/**
+ * Tests that an installed engine matches the expected data.
+ *
+ * @param {object} expectedData The expected data for the engine
+ */
+async function assertInstalledEngineMatches(expectedData) {
+  let engine = await Services.search.getEngineByName(expectedData.name);
+
+  Assert.ok(engine, `Should have found the ${expectedData.type} engine`);
+  Assert.equal(
+    engine.wrappedJSObject._loadPath,
+    expectedData.loadPath,
+    "Should have migrated the loadPath"
+  );
+}
+
+add_task(async function test_migration_from_pre_ids() {
+  const settingsFileWritten = promiseAfterSettings();
+
+  await Services.search.wrappedJSObject.reset();
+  await Services.search.init();
+
+  await settingsFileWritten;
+
+  await assertInstalledEngineMatches({
+    type: "Policy",
+    name: "Policy",
+    loadPath: "[policy]",
+  });
+  await assertInstalledEngineMatches({
+    type: "User",
+    name: "User",
+    loadPath: "[user]",
+  });
+  await assertInstalledEngineMatches({
+    type: "Add-on",
+    name: "Example",
+    loadPath: "[addon]example@tests.mozilla.org",
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_none.js b/toolkit/components/search/tests/xpcshell/test_settings_none.js
new file mode 100644
index 0000000000..14d3bb8e51
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_none.js
@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * test_nosettings: Start search engine
+ * - without search.json.mozlz4
+ *
+ * Ensure that :
+ * - nothing explodes;
+ * - search.json.mozlz4 is created.
+ */
+
+add_task(async function setup() {
+  useHttpServer();
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_nosettings() {
+  let search = Services.search;
+
+  let afterSettingsPromise = promiseAfterSettings();
+
+  await search.init();
+
+  // Check that the settings is created at startup
+  await afterSettingsPromise;
+
+  // Check that search.json.mozlz4 has been created.
+  let settingsFile = do_get_profile().clone();
+  settingsFile.append(SETTINGS_FILENAME);
+  Assert.ok(settingsFile.exists());
+
+  await SearchTestUtils.promiseNewSearchEngine({
+    url: `${gDataUrl}engine.xml`,
+  });
+
+  info("Engine has been added, let's wait for the settings to be built");
+  await promiseAfterSettings();
+
+  info("Searching test engine in settings");
+  let settings = await promiseSettingsData();
+  let found = false;
+  for (let engine of settings.engines) {
+    if (engine._name == "Test search engine") {
+      found = true;
+      break;
+    }
+  }
+  Assert.ok(found);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_obsolete.js b/toolkit/components/search/tests/xpcshell/test_settings_obsolete.js
new file mode 100644
index 0000000000..459a9d8aa1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_obsolete.js
@@ -0,0 +1,83 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test removing obsolete engine types on upgrade of settings.
+ */
+
+"use strict";
+
+async function loadSettingsFile(settingsFile, name) {
+  let settings = await readJSONFile(do_get_file(settingsFile));
+
+  settings.metaData.current = name;
+  settings.metaData.hash = SearchUtils.getVerificationHash(name);
+
+  await promiseSaveSettingsData(settings);
+}
+
+/**
+ * Start the search service and confirm the engine properties match the expected values.
+ *
+ * @param {string} settingsFile
+ *   The path to the settings file to use.
+ * @param {string} engineName
+ *   The engine name that should be default and is being removed.
+ */
+async function checkLoadSettingProperties(settingsFile, engineName) {
+  await loadSettingsFile(settingsFile, engineName);
+
+  const settingsFileWritten = promiseAfterSettings();
+  let ss = new SearchService();
+  let result = await ss.init();
+
+  Assert.ok(
+    Components.isSuccessCode(result),
+    "Should have successfully initialized the search service"
+  );
+
+  await settingsFileWritten;
+
+  let engines = await ss.getEngines();
+
+  Assert.deepEqual(
+    engines.map(e => e.name),
+    ["engine1", "engine2"],
+    "Should have only loaded the app-provided engines"
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).name,
+    "engine1",
+    "Should have used the configured default engine"
+  );
+
+  removeSettingsFile();
+  ss._removeObservers();
+}
+
+/**
+ * Test reading from search.json.mozlz4
+ */
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data1");
+  await AddonTestUtils.promiseStartupManager();
+});
+
+add_task(async function test_obsolete_distribution_engine() {
+  await checkLoadSettingProperties(
+    "data/search-obsolete-distribution.json",
+    "Distribution"
+  );
+});
+
+add_task(async function test_obsolete_langpack_engine() {
+  await checkLoadSettingProperties(
+    "data/search-obsolete-langpack.json",
+    "Langpack"
+  );
+});
+
+add_task(async function test_obsolete_app_engine() {
+  await checkLoadSettingProperties("data/search-obsolete-app.json", "App");
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_persist.js b/toolkit/components/search/tests/xpcshell/test_settings_persist.js
new file mode 100644
index 0000000000..f4ef840838
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_persist.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const CONFIG_DEFAULT = [
+  {
+    webExtension: { id: "plainengine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+  {
+    webExtension: { id: "special-engine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+];
+
+const CONFIG_UPDATED = [
+  {
+    webExtension: { id: "plainengine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+];
+
+async function startup() {
+  let settingsFileWritten = promiseAfterSettings();
+  let ss = new SearchService();
+  await AddonTestUtils.promiseRestartManager();
+  await ss.init(false);
+  await settingsFileWritten;
+  return ss;
+}
+
+async function updateConfig(config) {
+  const settings = await RemoteSettings(SearchUtils.SETTINGS_KEY);
+  settings.get.restore();
+  sinon.stub(settings, "get").returns(config);
+}
+
+async function visibleEngines(ss) {
+  return (await ss.getVisibleEngines()).map(e => e._name);
+}
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("test-extensions", null, CONFIG_DEFAULT);
+  registerCleanupFunction(AddonTestUtils.promiseShutdownManager);
+  await AddonTestUtils.promiseStartupManager();
+  // This is only needed as otherwise events will not be properly notified
+  // due to https://searchfox.org/mozilla-central/source/toolkit/components/search/SearchUtils.jsm#186
+  let settingsFileWritten = promiseAfterSettings();
+  await Services.search.init(false);
+  Services.search.wrappedJSObject._removeObservers();
+  await settingsFileWritten;
+});
+
+add_task(async function () {
+  let ss = await startup();
+  Assert.ok(
+    (await visibleEngines(ss)).includes("Special"),
+    "Should have both engines on first startup"
+  );
+
+  let settingsFileWritten = promiseAfterSettings();
+  let engine = await ss.getEngineByName("Special");
+  await ss.removeEngine(engine);
+  await settingsFileWritten;
+
+  Assert.ok(
+    !(await visibleEngines(ss)).includes("Special"),
+    "Special has been remove, only Plain should remain"
+  );
+
+  ss._removeObservers();
+  updateConfig(CONFIG_UPDATED);
+  ss = await startup();
+
+  Assert.ok(
+    !(await visibleEngines(ss)).includes("Special"),
+    "Updated to new configuration that doesnt have Special"
+  );
+
+  ss._removeObservers();
+  updateConfig(CONFIG_DEFAULT);
+  ss = await startup();
+
+  Assert.ok(
+    !(await visibleEngines(ss)).includes("Special"),
+    "Configuration now includes Special but we should remember its removal"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_settings_persist_diff_locale_same_name.js b/toolkit/components/search/tests/xpcshell/test_settings_persist_diff_locale_same_name.js
new file mode 100644
index 0000000000..3c0b930bc8
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_settings_persist_diff_locale_same_name.js
@@ -0,0 +1,68 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const CONFIG = [
+  {
+    webExtension: { id: "engine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+  {
+    // This engine has the same name, but still should be replaced correctly.
+    webExtension: {
+      id: "engine-same-name@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        excluded: { regions: ["FR"] },
+      },
+      {
+        included: { regions: ["FR"] },
+        webExtension: {
+          locales: ["gd"],
+        },
+      },
+    ],
+  },
+];
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data", null, CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+  let settingsFileWritten = promiseAfterSettings();
+  Region._setHomeRegion("US", false);
+  await Services.search.init();
+  await settingsFileWritten;
+});
+
+add_task(async function test_settings_persist_diff_locale_same_name() {
+  let settingsFileWritten = promiseAfterSettings();
+  let engine1 = Services.search.getEngineByName("engine-same-name");
+  Services.search.moveEngine(engine1, 0);
+
+  let engine2 = Services.search.getEngineByName("Test search engine");
+  Services.search.moveEngine(engine2, 1);
+  // Ensure we have saved the settings before we restart below.
+  await settingsFileWritten;
+
+  Assert.deepEqual(
+    (await Services.search.getEngines()).map(e => e.name),
+    ["engine-same-name", "Test search engine"],
+    "Should have set the engines to the expected order"
+  );
+
+  // Setting the region to FR will change the engine id, but use the same name.
+  Region._setHomeRegion("FR", false);
+
+  // Pretend we are restarting.
+  Services.search.wrappedJSObject.reset();
+  await Services.search.init();
+
+  Assert.deepEqual(
+    (await Services.search.getEngines()).map(e => e.name),
+    ["engine-same-name", "Test search engine"],
+    "Should have retained the engines in the expected order"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_sort_orders-no-hints.js b/toolkit/components/search/tests/xpcshell/test_sort_orders-no-hints.js
new file mode 100644
index 0000000000..71b75fcdc1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_sort_orders-no-hints.js
@@ -0,0 +1,69 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Check the correct default engines are picked from the configuration list,
+ * when we have some with the same orderHint, and some without any.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  await SearchTestUtils.useTestEngines(
+    "data",
+    null,
+    (
+      await readJSONFile(do_get_file("data/engines-no-order-hint.json"))
+    ).data
+  );
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+});
+
+async function checkOrder(type, expectedOrder) {
+  // Reset the sorted list.
+  Services.search.wrappedJSObject._cachedSortedEngines = null;
+
+  const sortedEngines = await Services.search[type]();
+  Assert.deepEqual(
+    sortedEngines.map(s => s.name),
+    expectedOrder,
+    `Should have the expected engine order from ${type}`
+  );
+}
+
+add_task(async function test_engine_sort_with_non_builtins_sort() {
+  await SearchTestUtils.installSearchExtension({ name: "nonbuiltin1" });
+
+  // As we've added an engine, the pref will have been set to true, but
+  // we do really want to test the default sort.
+  Services.search.wrappedJSObject._settings.setMetaDataAttribute(
+    "useSavedOrder",
+    false
+  );
+
+  const EXPECTED_ORDER = [
+    // Default engine.
+    "Test search engine",
+    // Alphabetical order for the two with orderHint = 1000.
+    "engine-chromeicon",
+    "engine-rel-searchform-purpose",
+    // Alphabetical order for the remaining engines without orderHint.
+    "engine-pref",
+    "engine-resourceicon",
+    "Test search engine (Reordered)",
+  ];
+
+  // We should still have the same built-in engines listed.
+  await checkOrder("getAppProvidedEngines", EXPECTED_ORDER);
+
+  const expected = [...EXPECTED_ORDER];
+  // This is inserted in alphabetical order for the last three.
+  expected.splice(expected.length - 1, 0, "nonbuiltin1");
+  await checkOrder("getEngines", expected);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_sort_orders.js b/toolkit/components/search/tests/xpcshell/test_sort_orders.js
new file mode 100644
index 0000000000..4609c7f4fb
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_sort_orders.js
@@ -0,0 +1,91 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Check the correct default engines are picked from the configuration list,
+ * and have the correct orders.
+ */
+
+"use strict";
+
+const EXPECTED_ORDER = [
+  // Default engines
+  "Test search engine",
+  "engine-pref",
+  // Now the engines in orderHint order.
+  "engine-resourceicon",
+  "engine-chromeicon",
+  "engine-rel-searchform-purpose",
+  "Test search engine (Reordered)",
+];
+
+add_task(async function setup() {
+  await AddonTestUtils.promiseStartupManager();
+
+  await SearchTestUtils.useTestEngines();
+
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "gd",
+  ];
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+});
+
+async function checkOrder(type, expectedOrder) {
+  // Reset the sorted list.
+  Services.search.wrappedJSObject._cachedSortedEngines = null;
+
+  const sortedEngines = await Services.search[type]();
+  Assert.deepEqual(
+    sortedEngines.map(s => s.name),
+    expectedOrder,
+    `Should have the expected engine order from ${type}`
+  );
+}
+
+add_task(async function test_engine_sort_only_builtins() {
+  await checkOrder("getAppProvidedEngines", EXPECTED_ORDER);
+  await checkOrder("getEngines", EXPECTED_ORDER);
+});
+
+add_task(async function test_engine_sort_with_non_builtins_sort() {
+  await SearchTestUtils.installSearchExtension({ name: "nonbuiltin1" });
+
+  // As we've added an engine, the pref will have been set to true, but
+  // we do really want to test the default sort.
+  Services.search.wrappedJSObject._settings.setMetaDataAttribute(
+    "useSavedOrder",
+    false
+  );
+
+  // We should still have the same built-in engines listed.
+  await checkOrder("getAppProvidedEngines", EXPECTED_ORDER);
+
+  const expected = [...EXPECTED_ORDER];
+  expected.splice(EXPECTED_ORDER.length, 0, "nonbuiltin1");
+  await checkOrder("getEngines", expected);
+});
+
+add_task(async function test_engine_sort_with_locale() {
+  await promiseSetLocale("gd");
+
+  const expected = [
+    "engine-resourceicon-gd",
+    "engine-pref",
+    "engine-rel-searchform-purpose",
+    "engine-chromeicon",
+    "Test search engine (Reordered)",
+  ];
+
+  await checkOrder("getAppProvidedEngines", expected);
+  expected.push("nonbuiltin1");
+  await checkOrder("getEngines", expected);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_telemetry_event_default.js b/toolkit/components/search/tests/xpcshell/test_telemetry_event_default.js
new file mode 100644
index 0000000000..a73ef6be58
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_telemetry_event_default.js
@@ -0,0 +1,293 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests for the default engine telemetry event that can be tested via xpcshell,
+ * related to changing or selecting a different configuration.
+ * Other tests are typically in browser mochitests.
+ */
+
+"use strict";
+
+ChromeUtils.defineESModuleGetters(this, {
+  NimbusFeatures: "resource://nimbus/ExperimentAPI.sys.mjs",
+  TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
+});
+
+const BASE_CONFIG = [
+  {
+    webExtension: { id: "engine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+    default: "yes",
+  },
+];
+const MAIN_CONFIG = [
+  {
+    webExtension: { id: "engine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+    default: "no",
+  },
+  {
+    webExtension: { id: "engine-chromeicon@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+    default: "yes-if-no-other",
+  },
+  {
+    webExtension: { id: "engine-fr@search.mozilla.org" },
+    appliesTo: [
+      { included: { everywhere: true } },
+      {
+        included: { locales: { matches: ["fr"] } },
+        excluded: { regions: ["DE"] },
+        default: "yes",
+      },
+    ],
+    default: "no",
+  },
+  {
+    webExtension: { id: "engine-pref@search.mozilla.org" },
+    appliesTo: [
+      { included: { everywhere: true } },
+      { included: { regions: ["DE"] }, default: "yes" },
+    ],
+    default: "no",
+  },
+  {
+    webExtension: { id: "engine2@search.mozilla.org" },
+    appliesTo: [
+      { included: { everywhere: true } },
+      { included: { everywhere: true }, experiment: "test1", default: "yes" },
+    ],
+    default: "no",
+  },
+];
+
+const testSearchEngine = {
+  id: "engine",
+  name: "Test search engine",
+  loadPath: "[addon]engine@search.mozilla.org",
+  submissionUrl: "https://www.google.com/search?q=",
+};
+const testChromeIconEngine = {
+  id: "engine-chromeicon",
+  name: "engine-chromeicon",
+  loadPath: "[addon]engine-chromeicon@search.mozilla.org",
+  submissionUrl: "https://www.google.com/search?q=",
+};
+const testFrEngine = {
+  id: "engine-fr",
+  name: "Test search engine (fr)",
+  loadPath: "[addon]engine-fr@search.mozilla.org",
+  submissionUrl: "https://www.google.fr/search?q=&ie=iso-8859-1&oe=iso-8859-1",
+};
+const testPrefEngine = {
+  id: "engine-pref",
+  name: "engine-pref",
+  loadPath: "[addon]engine-pref@search.mozilla.org",
+  submissionUrl: "https://www.google.com/search?q=",
+};
+const testEngine2 = {
+  id: "engine2",
+  name: "A second test engine",
+  loadPath: "[addon]engine2@search.mozilla.org",
+  submissionUrl: "https://duckduckgo.com/?q=",
+};
+
+function clearTelemetry() {
+  Services.telemetry.clearEvents();
+  Services.fog.testResetFOG();
+}
+
+async function checkTelemetry(
+  source,
+  prevEngine,
+  newEngine,
+  checkPrivate = false
+) {
+  TelemetryTestUtils.assertEvents(
+    [
+      {
+        object: checkPrivate ? "change_private" : "change_default",
+        value: source,
+        extra: {
+          prev_id: prevEngine?.id ?? "",
+          new_id: newEngine?.id ?? "",
+          new_name: newEngine?.name ?? "",
+          new_load_path: newEngine?.loadPath ?? "",
+          // Telemetry has a limit of 80 characters.
+          new_sub_url: newEngine?.submissionUrl.slice(0, 80) ?? "",
+        },
+      },
+    ],
+    { category: "search", method: "engine" }
+  );
+
+  let snapshot;
+  if (checkPrivate) {
+    snapshot = await Glean.searchEnginePrivate.changed.testGetValue();
+  } else {
+    snapshot = await Glean.searchEngineDefault.changed.testGetValue();
+  }
+  delete snapshot[0].timestamp;
+  Assert.deepEqual(
+    snapshot[0],
+    {
+      category: checkPrivate
+        ? "search.engine.private"
+        : "search.engine.default",
+      name: "changed",
+      extra: {
+        change_source: source,
+        previous_engine_id: prevEngine?.id ?? "",
+        new_engine_id: newEngine?.id ?? "",
+        new_display_name: newEngine?.name ?? "",
+        new_load_path: newEngine?.loadPath ?? "",
+        new_submission_url: newEngine?.submissionUrl ?? "",
+      },
+    },
+    "Should have received the correct event details"
+  );
+}
+
+let getVariableStub;
+
+add_setup(async () => {
+  Region._setHomeRegion("US", false);
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "en",
+    "fr",
+  ];
+  Services.locale.requestedLocales = ["en"];
+
+  sinon.spy(NimbusFeatures.searchConfiguration, "onUpdate");
+  sinon.stub(NimbusFeatures.searchConfiguration, "ready").resolves();
+  getVariableStub = sinon.stub(
+    NimbusFeatures.searchConfiguration,
+    "getVariable"
+  );
+  getVariableStub.returns(null);
+
+  SearchTestUtils.useMockIdleService();
+  Services.fog.initializeFOG();
+  sinon.stub(
+    Services.search.wrappedJSObject,
+    "_showRemovalOfSearchEngineNotificationBox"
+  );
+
+  await SearchTestUtils.useTestEngines("data", null, BASE_CONFIG);
+  await AddonTestUtils.promiseStartupManager();
+
+  await Services.search.init();
+});
+
+add_task(async function test_configuration_changes_default() {
+  clearTelemetry();
+
+  await SearchTestUtils.updateRemoteSettingsConfig(MAIN_CONFIG);
+
+  await checkTelemetry("config", testSearchEngine, testChromeIconEngine);
+});
+
+add_task(async function test_experiment_changes_default() {
+  clearTelemetry();
+
+  let reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  getVariableStub.callsFake(name => (name == "experiment" ? "test1" : null));
+  NimbusFeatures.searchConfiguration.onUpdate.firstCall.args[0]();
+  await reloadObserved;
+
+  await checkTelemetry("experiment", testChromeIconEngine, testEngine2);
+
+  // Reset the stub so that we are no longer in an experiment.
+  getVariableStub.returns(null);
+});
+
+add_task(async function test_locale_changes_default() {
+  clearTelemetry();
+
+  let reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Services.locale.requestedLocales = ["fr"];
+  await reloadObserved;
+
+  await checkTelemetry("locale", testEngine2, testFrEngine);
+});
+
+add_task(async function test_region_changes_default() {
+  clearTelemetry();
+
+  let reloadObserved =
+    SearchTestUtils.promiseSearchNotification("engines-reloaded");
+  Region._setHomeRegion("DE", true);
+  await reloadObserved;
+
+  await checkTelemetry("region", testFrEngine, testPrefEngine);
+});
+
+add_task(async function test_user_changes_separate_private_pref() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    true
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  await Services.search.setDefaultPrivate(
+    Services.search.getEngineByName("engine-chromeicon"),
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  Assert.notEqual(
+    await Services.search.getDefault(),
+    await Services.search.getDefaultPrivate(),
+    "Should have different engines for the pre-condition"
+  );
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    false
+  );
+
+  clearTelemetry();
+
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    false
+  );
+
+  await checkTelemetry("user_private_split", testChromeIconEngine, null, true);
+
+  getVariableStub.returns(null);
+});
+
+add_task(async function test_experiment_with_separate_default_notifies() {
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault.ui.enabled",
+    false
+  );
+  Services.prefs.setBoolPref(
+    SearchUtils.BROWSER_SEARCH_PREF + "separatePrivateDefault",
+    true
+  );
+
+  clearTelemetry();
+
+  getVariableStub.callsFake(name =>
+    name == "seperatePrivateDefaultUIEnabled" ? true : null
+  );
+  NimbusFeatures.searchConfiguration.onUpdate.firstCall.args[0]();
+
+  await checkTelemetry("experiment", null, testChromeIconEngine, true);
+
+  clearTelemetry();
+
+  // Reset the stub so that we are no longer in an experiment.
+  getVariableStub.returns(null);
+  NimbusFeatures.searchConfiguration.onUpdate.firstCall.args[0]();
+
+  await checkTelemetry("experiment", testChromeIconEngine, null, true);
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_userEngine.js b/toolkit/components/search/tests/xpcshell/test_userEngine.js
new file mode 100644
index 0000000000..659baf10ab
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_userEngine.js
@@ -0,0 +1,56 @@
+/* Any copyright is dedicated to the Public Domain.
+ *    http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that User Engines can be installed correctly.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  Services.fog.initializeFOG();
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+});
+
+add_task(async function test_user_engine() {
+  let promiseEngineAdded = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.ADDED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+  await Services.search.addUserEngine(
+    "user",
+    "https://example.com/user?q={searchTerms}",
+    "u"
+  );
+  await promiseEngineAdded;
+
+  let engine = Services.search.getEngineByName("user");
+  Assert.ok(engine, "Should have installed the engine.");
+
+  Assert.equal(engine.name, "user", "Should have the correct name");
+  Assert.equal(engine.description, null, "Should not have a description");
+  Assert.deepEqual(engine.aliases, ["u"], "Should have the correct alias");
+
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://example.com/user?q=foo",
+    "Should have the correct search url"
+  );
+
+  submission = engine.getSubmission("foo", SearchUtils.URL_TYPE.SUGGEST_JSON);
+  Assert.equal(submission, null, "Should not have a suggest url");
+
+  Services.search.defaultEngine = engine;
+
+  await assertGleanDefaultEngine({
+    normal: {
+      engineId: "other-user",
+      displayName: "user",
+      loadPath: "[user]",
+      submissionUrl: "blank:",
+      verified: "verified",
+    },
+  });
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_validate_engines.js b/toolkit/components/search/tests/xpcshell/test_validate_engines.js
new file mode 100644
index 0000000000..1f95b1e14b
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_validate_engines.js
@@ -0,0 +1,36 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Ensure all the engines defined in the configuration are valid by
+// creating a refined configuration that includes all the engines everywhere.
+
+"use strict";
+
+const { SearchService } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchService.sys.mjs"
+);
+
+const ss = new SearchService();
+
+add_task(async function test_validate_engines() {
+  let settings = RemoteSettings(SearchUtils.SETTINGS_KEY);
+  let config = await settings.get();
+  config = config.map(e => {
+    return {
+      appliesTo: [
+        {
+          included: {
+            everywhere: true,
+          },
+        },
+      ],
+      webExtension: {
+        id: e.webExtension.id,
+      },
+    };
+  });
+
+  sinon.stub(settings, "get").returns(config);
+  await AddonTestUtils.promiseStartupManager();
+  await ss.init();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_validate_manifests.js b/toolkit/components/search/tests/xpcshell/test_validate_manifests.js
new file mode 100644
index 0000000000..c840009ab6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_validate_manifests.js
@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+Cu.importGlobalProperties(["fetch"]);
+
+const { ExtensionData } = ChromeUtils.importESModule(
+  "resource://gre/modules/Extension.sys.mjs"
+);
+
+const SEARCH_EXTENSIONS_PATH = "resource://search-extensions";
+
+function getFileURI(resourceURI) {
+  let resHandler = Services.io
+    .getProtocolHandler("resource")
+    .QueryInterface(Ci.nsIResProtocolHandler);
+  let filePath = resHandler.resolveURI(Services.io.newURI(resourceURI));
+  return Services.io.newURI(filePath);
+}
+
+async function getSearchExtensions() {
+  // Fetching the root will give us the directory listing which we can parse
+  // for each file name
+  let list = await fetch(`${SEARCH_EXTENSIONS_PATH}/`).then(req => req.text());
+  return list
+    .split("\n")
+    .slice(2)
+    .reduce((acc, line) => {
+      let parts = line.split(" ");
+      if (parts.length > 2 && !parts[1].endsWith(".json")) {
+        // When the directory listing comes from omni jar each engine
+        // has a trailing slash (engine/) which we dont get locally, or want.
+        acc.push(parts[1].split("/")[0]);
+      }
+      return acc;
+    }, []);
+}
+
+add_task(async function test_validate_manifest() {
+  let searchExtensions = await getSearchExtensions();
+  ok(
+    !!searchExtensions.length,
+    `Found ${searchExtensions.length} search extensions`
+  );
+  for (const xpi of searchExtensions) {
+    info(`loading: ${SEARCH_EXTENSIONS_PATH}/${xpi}/`);
+    let fileURI = getFileURI(`${SEARCH_EXTENSIONS_PATH}/${xpi}/`);
+    let extension = new ExtensionData(fileURI, false);
+    await extension.loadManifest();
+    let locales = await extension.promiseLocales();
+    for (let locale of locales.keys()) {
+      try {
+        let manifest = await extension.getLocalizedManifest(locale);
+        ok(!!manifest, `parsed manifest ${xpi.leafName} in ${locale}`);
+      } catch (e) {
+        ok(
+          false,
+          `FAIL manifest for ${xpi.leafName} in locale ${locale} failed ${e} :: ${e.stack}`
+        );
+      }
+    }
+  }
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_builtin_upgrade.js b/toolkit/components/search/tests/xpcshell/test_webextensions_builtin_upgrade.js
new file mode 100644
index 0000000000..41a7c0c0b2
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_builtin_upgrade.js
@@ -0,0 +1,252 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Enable SCOPE_APPLICATION for builtin testing.  Default in tests is only SCOPE_PROFILE.
+// AddonManager.SCOPE_PROFILE | AddonManager.SCOPE_APPLICATION == 5;
+Services.prefs.setIntPref("extensions.enabledScopes", 5);
+
+const { promiseShutdownManager, promiseStartupManager } = AddonTestUtils;
+
+const TEST_CONFIG = [
+  {
+    webExtension: {
+      id: "multilocale@search.mozilla.org",
+      locales: ["af", "an"],
+    },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+  {
+    webExtension: {
+      id: "plainengine@search.mozilla.org",
+    },
+    appliesTo: [{ included: { everywhere: true } }],
+    params: {
+      searchUrlGetParams: [
+        {
+          name: "config",
+          value: "applied",
+        },
+      ],
+    },
+  },
+];
+
+async function getEngineNames() {
+  let engines = await Services.search.getEngines();
+  return engines.map(engine => engine._name);
+}
+
+function makePlainExtension(version, name = "Plain") {
+  return {
+    useAddonManager: "permanent",
+    manifest: {
+      name,
+      version,
+      browser_specific_settings: {
+        gecko: {
+          id: "plainengine@search.mozilla.org",
+        },
+      },
+      chrome_settings_overrides: {
+        search_provider: {
+          name,
+          search_url: "https://duckduckgo.com/",
+          params: [
+            {
+              name: "q",
+              value: "{searchTerms}",
+            },
+            {
+              name: "t",
+              condition: "purpose",
+              purpose: "contextmenu",
+              value: "ffcm",
+            },
+            {
+              name: "t",
+              condition: "purpose",
+              purpose: "keyword",
+              value: "ffab",
+            },
+            {
+              name: "t",
+              condition: "purpose",
+              purpose: "searchbar",
+              value: "ffsb",
+            },
+            {
+              name: "t",
+              condition: "purpose",
+              purpose: "homepage",
+              value: "ffhp",
+            },
+            {
+              name: "t",
+              condition: "purpose",
+              purpose: "newtab",
+              value: "ffnt",
+            },
+          ],
+          suggest_url: "https://ac.duckduckgo.com/ac/q={searchTerms}&type=list",
+        },
+      },
+    },
+  };
+}
+
+function makeMultiLocaleExtension(version) {
+  return {
+    useAddonManager: "permanent",
+    manifest: {
+      name: "__MSG_searchName__",
+      version,
+      browser_specific_settings: {
+        gecko: {
+          id: "multilocale@search.mozilla.org",
+        },
+      },
+      default_locale: "an",
+      chrome_settings_overrides: {
+        search_provider: {
+          name: "__MSG_searchName__",
+          search_url: "__MSG_searchUrl__",
+        },
+      },
+    },
+    files: {
+      "_locales/af/messages.json": {
+        searchUrl: {
+          message: `https://example.af/?q={searchTerms}&version=${version}`,
+          description: "foo",
+        },
+        searchName: {
+          message: `Multilocale AF`,
+          description: "foo",
+        },
+      },
+      "_locales/an/messages.json": {
+        searchUrl: {
+          message: `https://example.an/?q={searchTerms}&version=${version}`,
+          description: "foo",
+        },
+        searchName: {
+          message: `Multilocale AN`,
+          description: "foo",
+        },
+      },
+    },
+  };
+}
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("test-extensions", null, TEST_CONFIG);
+  await promiseStartupManager();
+
+  registerCleanupFunction(promiseShutdownManager);
+  await Services.search.init();
+});
+
+add_task(async function basic_multilocale_test() {
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain",
+  ]);
+
+  let ext = ExtensionTestUtils.loadExtension(makeMultiLocaleExtension("2.0"));
+  await ext.startup();
+  await AddonTestUtils.waitForSearchProviderStartup(ext);
+
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain",
+  ]);
+
+  let engine = await Services.search.getEngineByName("Multilocale AF");
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    "https://example.af/?q=test&version=2.0",
+    "Engine got update"
+  );
+  engine = await Services.search.getEngineByName("Multilocale AN");
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    "https://example.an/?q=test&version=2.0",
+    "Engine got update"
+  );
+
+  await ext.unload();
+});
+
+add_task(async function upgrade_with_configuration_change_test() {
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain",
+  ]);
+
+  let engine = await Services.search.getEngineByName("Plain");
+  Assert.ok(engine.isAppProvided);
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    // This test engine specifies the q and t params in its search_url, therefore
+    // we get both those and the extra parameter specified in the test config.
+    "https://duckduckgo.com/?q=test&t=ffsb&config=applied",
+    "Should have the configuration applied before update."
+  );
+
+  let ext = ExtensionTestUtils.loadExtension(makePlainExtension("2.0"));
+  await ext.startup();
+  await AddonTestUtils.waitForSearchProviderStartup(ext);
+
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain",
+  ]);
+
+  engine = await Services.search.getEngineByName("Plain");
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    // This test engine specifies the q and t params in its search_url, therefore
+    // we get both those and the extra parameter specified in the test config.
+    "https://duckduckgo.com/?q=test&t=ffsb&config=applied",
+    "Should still have the configuration applied after update."
+  );
+
+  await ext.unload();
+});
+
+add_task(async function test_upgrade_with_name_change() {
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain",
+  ]);
+
+  let ext = ExtensionTestUtils.loadExtension(
+    makePlainExtension("2.0", "Plain2")
+  );
+  await ext.startup();
+  await AddonTestUtils.waitForSearchProviderStartup(ext);
+
+  Assert.deepEqual(await getEngineNames(), [
+    "Multilocale AF",
+    "Multilocale AN",
+    "Plain2",
+  ]);
+
+  let engine = await Services.search.getEngineByName("Plain2");
+  Assert.equal(
+    engine.getSubmission("test").uri.spec,
+    // This test engine specifies the q and t params in its search_url, therefore
+    // we get both those and the extra parameter specified in the test config.
+    "https://duckduckgo.com/?q=test&t=ffsb&config=applied",
+    "Should still have the configuration applied after update."
+  );
+
+  await ext.unload();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_install.js b/toolkit/components/search/tests/xpcshell/test_webextensions_install.js
new file mode 100644
index 0000000000..4b006edd6c
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_install.js
@@ -0,0 +1,205 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { promiseShutdownManager, promiseStartupManager } = AddonTestUtils;
+
+async function getEngineNames() {
+  let engines = await Services.search.getEngines();
+  return engines.map(engine => engine._name);
+}
+
+add_task(async function setup() {
+  let server = useHttpServer();
+  server.registerContentType("sjs", "sjs");
+  await SearchTestUtils.useTestEngines("test-extensions");
+  await promiseStartupManager();
+
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "af",
+  ];
+
+  registerCleanupFunction(async () => {
+    await promiseShutdownManager();
+    Services.prefs.clearUserPref("browser.search.region");
+  });
+});
+
+add_task(async function basic_install_test() {
+  await Services.search.init();
+  await promiseAfterSettings();
+
+  // On first boot, we get the configuration defaults
+  Assert.deepEqual(await getEngineNames(), ["Plain", "Special"]);
+
+  // User installs a new search engine
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      encoding: "windows-1252",
+    },
+    { skipUnload: true }
+  );
+  Assert.deepEqual((await getEngineNames()).sort(), [
+    "Example",
+    "Plain",
+    "Special",
+  ]);
+
+  let engine = await Services.search.getEngineByName("Example");
+  Assert.equal(
+    engine.wrappedJSObject.queryCharset,
+    "windows-1252",
+    "Should have the correct charset"
+  );
+
+  // User uninstalls their engine
+  await extension.awaitStartup();
+  await extension.unload();
+  await promiseAfterSettings();
+  Assert.deepEqual(await getEngineNames(), ["Plain", "Special"]);
+});
+
+add_task(async function test_install_duplicate_engine() {
+  let name = "Plain";
+  consoleAllowList.push(`An engine called ${name} already exists`);
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name,
+      search_url: "https://example.com/plain",
+    },
+    { skipUnload: true }
+  );
+
+  let engine = await Services.search.getEngineByName("Plain");
+  let submission = engine.getSubmission("foo");
+  Assert.equal(
+    submission.uri.spec,
+    "https://duckduckgo.com/?q=foo&t=ffsb",
+    "Should have not changed the app provided engine."
+  );
+
+  // User uninstalls their engine
+  await extension.unload();
+});
+
+add_task(async function basic_multilocale_test() {
+  await promiseSetHomeRegion("an");
+
+  Assert.deepEqual(await getEngineNames(), [
+    "Plain",
+    "Special",
+    "Multilocale AN",
+  ]);
+});
+
+add_task(async function complex_multilocale_test() {
+  await promiseSetHomeRegion("af");
+
+  Assert.deepEqual(await getEngineNames(), [
+    "Plain",
+    "Special",
+    "Multilocale AF",
+    "Multilocale AN",
+  ]);
+});
+
+add_task(async function test_manifest_selection() {
+  // Sets the home region without updating.
+  Region._setHomeRegion("an", false);
+  await promiseSetLocale("af");
+
+  let engine = await Services.search.getEngineByName("Multilocale AN");
+  Assert.ok(
+    engine.iconURI.spec.endsWith("favicon-an.ico"),
+    "Should have the correct favicon for an extension of one locale using a different locale."
+  );
+  Assert.equal(
+    engine.description,
+    "A enciclopedia Libre",
+    "Should have the correct engine name for an extension of one locale using a different locale."
+  );
+});
+
+add_task(async function test_load_favicon_invalid() {
+  let observed = TestUtils.consoleMessageObserved(msg => {
+    return msg.wrappedJSObject.arguments[0].includes(
+      "Content type does not match expected"
+    );
+  });
+
+  // User installs a new search engine
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      favicon_url: `${gDataUrl}engine.xml`,
+    },
+    { skipUnload: true }
+  );
+
+  await observed;
+
+  let engine = await Services.search.getEngineByName("Example");
+  Assert.equal(null, engine.iconURI, "Should not have set an iconURI");
+
+  // User uninstalls their engine
+  await extension.awaitStartup();
+  await extension.unload();
+  await promiseAfterSettings();
+});
+
+add_task(async function test_load_favicon_invalid_redirect() {
+  let observed = TestUtils.consoleMessageObserved(msg => {
+    return msg.wrappedJSObject.arguments[0].includes(
+      "Content type does not match expected"
+    );
+  });
+
+  // User installs a new search engine
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      favicon_url: `${gDataUrl}/iconsRedirect.sjs?type=invalid`,
+    },
+    { skipUnload: true }
+  );
+
+  await observed;
+
+  let engine = await Services.search.getEngineByName("Example");
+  Assert.equal(null, engine.iconURI, "Should not have set an iconURI");
+
+  // User uninstalls their engine
+  await extension.awaitStartup();
+  await extension.unload();
+  await promiseAfterSettings();
+});
+
+add_task(async function test_load_favicon_redirect() {
+  let promiseEngineChanged = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.CHANGED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+
+  // User installs a new search engine
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      favicon_url: `${gDataUrl}/iconsRedirect.sjs`,
+    },
+    { skipUnload: true }
+  );
+
+  let engine = await Services.search.getEngineByName("Example");
+
+  await promiseEngineChanged;
+
+  Assert.ok(engine.iconURI, "Should have set an iconURI");
+  Assert.ok(
+    engine.iconURI.spec.startsWith("data:image/x-icon;base64,"),
+    "Should have saved the expected content type for the icon"
+  );
+
+  // User uninstalls their engine
+  await extension.awaitStartup();
+  await extension.unload();
+  await promiseAfterSettings();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_language_switch.js b/toolkit/components/search/tests/xpcshell/test_webextensions_language_switch.js
new file mode 100644
index 0000000000..e23a2ff433
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_language_switch.js
@@ -0,0 +1,110 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { promiseShutdownManager, promiseStartupManager } = AddonTestUtils;
+
+add_task(async function setup() {
+  Services.locale.availableLocales = [
+    ...Services.locale.availableLocales,
+    "en",
+    "de",
+    "fr",
+  ];
+  Services.locale.requestedLocales = ["en"];
+
+  await SearchTestUtils.useTestEngines("data1");
+  await promiseStartupManager();
+  await Services.search.init();
+  await promiseAfterSettings();
+
+  registerCleanupFunction(promiseShutdownManager);
+});
+
+add_task(async function test_language_switch_changes_name() {
+  await SearchTestUtils.installSearchExtension(
+    {
+      name: "__MSG_engineName__",
+      id: "engine@tests.mozilla.org",
+      search_url_get_params: `q={searchTerms}&version=1.0`,
+      default_locale: "en",
+      version: "1.0",
+    },
+    { skipUnload: false },
+    {
+      "_locales/en/messages.json": {
+        engineName: {
+          message: "English Name",
+          description: "The Name",
+        },
+      },
+      "_locales/fr/messages.json": {
+        engineName: {
+          message: "French Name",
+          description: "The Name",
+        },
+      },
+    }
+  );
+
+  let engine = Services.search.getEngineById("engine@tests.mozilla.orgdefault");
+  Assert.ok(!!engine, "Should have loaded the engine");
+  Assert.equal(
+    engine.name,
+    "English Name",
+    "Should have loaded the English version of the name"
+  );
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  let promiseChanged = TestUtils.topicObserved(
+    "browser-search-engine-modified",
+    (eng, verb) => verb == "engine-changed"
+  );
+
+  await promiseSetLocale("fr");
+
+  await promiseChanged;
+
+  engine = Services.search.getEngineById("engine@tests.mozilla.orgdefault");
+  Assert.ok(!!engine, "Should still be available");
+  Assert.equal(
+    engine.name,
+    "French Name",
+    "Should have updated to the French version of the name"
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).id,
+    engine.id,
+    "Should have kept the default engine the same"
+  );
+
+  promiseChanged = TestUtils.topicObserved(
+    "browser-search-engine-modified",
+    (eng, verb) => verb == "engine-changed"
+  );
+
+  // Check for changing to a locale the add-on doesn't have.
+  await promiseSetLocale("de");
+
+  await promiseChanged;
+
+  engine = Services.search.getEngineById("engine@tests.mozilla.orgdefault");
+  Assert.ok(!!engine, "Should still be available");
+  Assert.equal(
+    engine.name,
+    "English Name",
+    "Should have fallen back to the default locale (English) version of the name"
+  );
+
+  Assert.equal(
+    (await Services.search.getDefault()).id,
+    engine.id,
+    "Should have kept the default engine the same"
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_migrate_to.js b/toolkit/components/search/tests/xpcshell/test_webextensions_migrate_to.js
new file mode 100644
index 0000000000..b9e78203ca
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_migrate_to.js
@@ -0,0 +1,66 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test migrating legacy add-on engines in background.
+ */
+
+"use strict";
+
+add_task(async function setup() {
+  useHttpServer("opensearch");
+  await AddonTestUtils.promiseStartupManager();
+  await SearchTestUtils.useTestEngines("data1");
+
+  let data = await readJSONFile(do_get_file("data/search-migration.json"));
+
+  await promiseSaveSettingsData(data);
+
+  await Services.search.init();
+
+  // We need the extension installed for this test, but we do not want to
+  // trigger the functions that happen on installation, so stub that out.
+  // The manifest already has details of this engine.
+  let oldFunc = Services.search.wrappedJSObject.addEnginesFromExtension;
+  Services.search.wrappedJSObject.addEnginesFromExtension = () => {};
+
+  // Add the add-on so add-on manager has a valid item.
+  await SearchTestUtils.installSearchExtension({
+    id: "simple",
+    name: "simple search",
+    search_url: "https://example.com/",
+  });
+
+  Services.search.wrappedJSObject.addEnginesFromExtension = oldFunc;
+});
+
+add_task(async function test_migrateLegacyEngineDifferentName() {
+  await Services.search.init();
+
+  let engine = Services.search.getEngineByName("simple");
+  Assert.ok(engine, "Should have the legacy add-on engine.");
+
+  // Set this engine as default, the new engine should become the default
+  // after migration.
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  engine = Services.search.getEngineByName("simple search");
+  Assert.ok(engine, "Should have the WebExtension engine.");
+
+  await Services.search.runBackgroundChecks();
+
+  engine = Services.search.getEngineByName("simple");
+  Assert.ok(!engine, "Should have removed the legacy add-on engine");
+
+  engine = Services.search.getEngineByName("simple search");
+  Assert.ok(engine, "Should have kept the WebExtension engine.");
+
+  Assert.equal(
+    (await Services.search.getDefault()).name,
+    engine.name,
+    "Should have switched to the WebExtension engine as default."
+  );
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_normandy_upgrade.js b/toolkit/components/search/tests/xpcshell/test_webextensions_normandy_upgrade.js
new file mode 100644
index 0000000000..faf57c1807
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_normandy_upgrade.js
@@ -0,0 +1,93 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+SearchTestUtils.initXPCShellAddonManager(this, "system");
+
+async function restart() {
+  Services.search.wrappedJSObject.reset();
+  await AddonTestUtils.promiseRestartManager();
+  await Services.search.init(false);
+}
+
+const CONFIG_DEFAULT = [
+  {
+    webExtension: { id: "plainengine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+];
+
+const CONFIG_UPDATED = [
+  {
+    webExtension: { id: "plainengine@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+  {
+    webExtension: { id: "example@search.mozilla.org" },
+    appliesTo: [{ included: { everywhere: true } }],
+  },
+];
+
+async function getEngineNames() {
+  let engines = await Services.search.getAppProvidedEngines();
+  return engines.map(engine => engine._name);
+}
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("test-extensions", null, CONFIG_DEFAULT);
+  await AddonTestUtils.promiseStartupManager();
+  registerCleanupFunction(AddonTestUtils.promiseShutdownManager);
+  SearchTestUtils.useMockIdleService();
+  await Services.search.init();
+});
+
+// Test the situation where we receive an updated configuration
+// that references an engine that doesnt exist locally as it
+// will be installed by Normandy.
+add_task(async function test_config_before_normandy() {
+  // Ensure initial default setup.
+  await SearchTestUtils.updateRemoteSettingsConfig(CONFIG_DEFAULT);
+  await restart();
+  Assert.deepEqual(await getEngineNames(), ["Plain"]);
+  // Updated configuration references nonexistant engine.
+  await SearchTestUtils.updateRemoteSettingsConfig(CONFIG_UPDATED);
+  Assert.deepEqual(
+    await getEngineNames(),
+    ["Plain"],
+    "Updated engine hasnt been installed yet"
+  );
+  // Normandy then installs the engine.
+  let addon = await SearchTestUtils.installSystemSearchExtension();
+  Assert.deepEqual(
+    await getEngineNames(),
+    ["Plain", "Example"],
+    "Both engines are now enabled"
+  );
+  await addon.unload();
+});
+
+// Test the situation where we receive a newly installed
+// engine from Normandy followed by the update to the
+// configuration that uses that engine.
+add_task(async function test_normandy_before_config() {
+  // Ensure initial default setup.
+  await SearchTestUtils.updateRemoteSettingsConfig(CONFIG_DEFAULT);
+  await restart();
+  Assert.deepEqual(await getEngineNames(), ["Plain"]);
+  // Normandy installs the enigne.
+  let addon = await SearchTestUtils.installSystemSearchExtension();
+  Assert.deepEqual(
+    await getEngineNames(),
+    ["Plain"],
+    "Normandy engine ignored as not in config yet"
+  );
+  // Configuration is updated to use the engine.
+  await SearchTestUtils.updateRemoteSettingsConfig(CONFIG_UPDATED);
+  Assert.deepEqual(
+    await getEngineNames(),
+    ["Plain", "Example"],
+    "Both engines are now enabled"
+  );
+  await addon.unload();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_startup_remove.js b/toolkit/components/search/tests/xpcshell/test_webextensions_startup_remove.js
new file mode 100644
index 0000000000..0b55bca424
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_startup_remove.js
@@ -0,0 +1,83 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const ENGINE_ID = "enginetest@example.com";
+let xpi;
+let profile = do_get_profile().clone();
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data1");
+  xpi = AddonTestUtils.createTempWebExtensionFile({
+    manifest: {
+      version: "1.0",
+      browser_specific_settings: {
+        gecko: { id: ENGINE_ID },
+      },
+      chrome_settings_overrides: {
+        search_provider: {
+          name: "Test Engine",
+          search_url: `https://example.com/?q={searchTerms}`,
+        },
+      },
+    },
+  });
+  await AddonTestUtils.manuallyInstall(xpi);
+});
+
+add_task(async function test_removeAddonOnStartup() {
+  // First startup the add-on manager and ensure the engine is installed.
+  await AddonTestUtils.promiseStartupManager();
+  let promise = promiseAfterSettings();
+  await Services.search.init();
+
+  let engine = Services.search.getEngineByName("Test Engine");
+  let allEngines = await Services.search.getEngines();
+
+  Assert.ok(!!engine, "Should have installed the test engine");
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+  await promise;
+
+  await AddonTestUtils.promiseShutdownManager();
+
+  // Now remove it, reset the search service and start up the add-on manager.
+  // Note: the saved settings will have the engine in. If this didn't work,
+  // the engine would still be present.
+  await IOUtils.remove(
+    PathUtils.join(profile.path, "extensions", `${ENGINE_ID}.xpi`)
+  );
+
+  let removePromise = SearchTestUtils.promiseSearchNotification(
+    SearchUtils.MODIFIED_TYPE.REMOVED,
+    SearchUtils.TOPIC_ENGINE_MODIFIED
+  );
+  Services.search.wrappedJSObject.reset();
+  await AddonTestUtils.promiseStartupManager();
+  await Services.search.init();
+  await removePromise;
+
+  Assert.ok(
+    !Services.search.getEngineByName("Test Engine"),
+    "Should have removed the test engine"
+  );
+
+  let newEngines = await Services.search.getEngines();
+  Assert.deepEqual(
+    newEngines.map(e => e.name),
+    allEngines.map(e => e.name).filter(n => n != "Test Engine"),
+    "Should no longer have the test engine in the full list"
+  );
+  let newDefault = await Services.search.getDefault();
+  Assert.equal(
+    newDefault.name,
+    "engine1",
+    "Should have changed the default engine back to the configuration default"
+  );
+
+  await AddonTestUtils.promiseShutdownManager();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_upgrade.js b/toolkit/components/search/tests/xpcshell/test_webextensions_upgrade.js
new file mode 100644
index 0000000000..555e2ae2f1
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_upgrade.js
@@ -0,0 +1,188 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { promiseShutdownManager, promiseStartupManager } = AddonTestUtils;
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("data1");
+  await promiseStartupManager();
+  await Services.search.init();
+  await promiseAfterSettings();
+
+  registerCleanupFunction(promiseShutdownManager);
+});
+
+add_task(async function test_basic_upgrade() {
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      version: "1.0",
+      search_url_get_params: `q={searchTerms}&version=1.0`,
+      keyword: "foo",
+    },
+    { skipUnload: true }
+  );
+
+  let engine = await Services.search.getEngineByAlias("foo");
+  Assert.ok(engine, "Can fetch engine with alias");
+  engine.alias = "testing";
+
+  engine = await Services.search.getEngineByAlias("testing");
+  Assert.ok(engine, "Can fetch engine by alias");
+  let params = engine.getSubmission("test").uri.query.split("&");
+  Assert.ok(params.includes("version=1.0"), "Correct version installed");
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  let promiseChanged = TestUtils.topicObserved(
+    "browser-search-engine-modified",
+    (eng, verb) => verb == "engine-changed"
+  );
+
+  let manifest = SearchTestUtils.createEngineManifest({
+    version: "2.0",
+    search_url_get_params: `q={searchTerms}&version=2.0`,
+    keyword: "bar",
+  });
+  await extension.upgrade({
+    useAddonManager: "permanent",
+    manifest,
+  });
+  await AddonTestUtils.waitForSearchProviderStartup(extension);
+  await promiseChanged;
+
+  engine = await Services.search.getEngineByAlias("testing");
+  Assert.ok(engine, "Engine still has alias set");
+
+  params = engine.getSubmission("test").uri.query.split("&");
+  Assert.ok(params.includes("version=2.0"), "Correct version installed");
+
+  Assert.equal(
+    Services.search.defaultEngine.name,
+    "Example",
+    "Should have retained the same default engine"
+  );
+
+  await extension.unload();
+  await promiseAfterSettings();
+});
+
+add_task(async function test_upgrade_changes_name() {
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "engine",
+      id: "engine@tests.mozilla.org",
+      search_url_get_params: `q={searchTerms}&version=1.0`,
+      version: "1.0",
+    },
+    { skipUnload: true }
+  );
+
+  let engine = Services.search.getEngineByName("engine");
+  Assert.ok(!!engine, "Should have loaded the engine");
+
+  await Services.search.setDefault(
+    engine,
+    Ci.nsISearchService.CHANGE_REASON_UNKNOWN
+  );
+
+  // When we add engines currently, we normally force using the saved order.
+  // Reset that here, so we can check the order is reset in the case this
+  // is a application provided engine change.
+  Services.search.wrappedJSObject._settings.setMetaDataAttribute(
+    "useSavedOrder",
+    false
+  );
+  Services.search.getEngineByName("engine1").wrappedJSObject._orderHint = null;
+  Services.search.getEngineByName("engine2").wrappedJSObject._orderHint = null;
+
+  Assert.deepEqual(
+    (await Services.search.getVisibleEngines()).map(e => e.name),
+    ["engine1", "engine2", "engine"],
+    "Should have the expected order initially"
+  );
+
+  let promiseChanged = TestUtils.topicObserved(
+    "browser-search-engine-modified",
+    (eng, verb) => verb == "engine-changed"
+  );
+
+  let manifest = SearchTestUtils.createEngineManifest({
+    name: "Bar",
+    id: "engine@tests.mozilla.org",
+    search_url_get_params: `q={searchTerms}&version=2.0`,
+    version: "2.0",
+  });
+  await extension.upgrade({
+    useAddonManager: "permanent",
+    manifest,
+  });
+  await AddonTestUtils.waitForSearchProviderStartup(extension);
+
+  await promiseChanged;
+
+  engine = Services.search.getEngineByName("Bar");
+  Assert.ok(!!engine, "Should be able to get the new engine");
+
+  Assert.equal(
+    (await Services.search.getDefault()).name,
+    "Bar",
+    "Should have kept the default engine the same"
+  );
+
+  Assert.deepEqual(
+    (await Services.search.getVisibleEngines()).map(e => e.name),
+    // Expected order: Default, then others in alphabetical.
+    ["engine1", "Bar", "engine2"],
+    "Should have updated the engine order"
+  );
+
+  await extension.unload();
+  await promiseAfterSettings();
+});
+
+add_task(async function test_upgrade_to_existing_name_not_allowed() {
+  let extension = await SearchTestUtils.installSearchExtension(
+    {
+      name: "engine",
+      search_url_get_params: `q={searchTerms}&version=1.0`,
+      version: "1.0",
+    },
+    { skipUnload: true }
+  );
+
+  let engine = Services.search.getEngineByName("engine");
+  Assert.ok(!!engine, "Should have loaded the engine");
+
+  let promise = AddonTestUtils.waitForSearchProviderStartup(extension);
+  let name = "engine1";
+  consoleAllowList.push(`An engine called ${name} already exists`);
+  let manifest = SearchTestUtils.createEngineManifest({
+    name,
+    search_url_get_params: `q={searchTerms}&version=2.0`,
+    version: "2.0",
+  });
+  await extension.upgrade({
+    useAddonManager: "permanent",
+    manifest,
+  });
+  await promise;
+
+  Assert.equal(
+    Services.search.getEngineByName("engine1").getSubmission("").uri.spec,
+    "https://1.example.com/",
+    "Should have not changed the original engine"
+  );
+
+  console.log((await Services.search.getEngines()).map(e => e.name));
+
+  engine = Services.search.getEngineByName("engine");
+  Assert.ok(!!engine, "Should still be able to get the engine by the old name");
+
+  await extension.unload();
+  await promiseAfterSettings();
+});
diff --git a/toolkit/components/search/tests/xpcshell/test_webextensions_valid.js b/toolkit/components/search/tests/xpcshell/test_webextensions_valid.js
new file mode 100644
index 0000000000..b5e71d2560
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/test_webextensions_valid.js
@@ -0,0 +1,165 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const { promiseShutdownManager, promiseStartupManager } = AddonTestUtils;
+
+let extension;
+let oldRemoveEngineFunc;
+
+add_task(async function setup() {
+  await SearchTestUtils.useTestEngines("simple-engines");
+  await promiseStartupManager();
+
+  Services.telemetry.canRecordExtended = true;
+
+  await Services.search.init();
+  await promiseAfterSettings();
+
+  extension = await SearchTestUtils.installSearchExtension(
+    {},
+    { skipUnload: true }
+  );
+  await extension.awaitStartup();
+
+  // For these tests, stub-out the removeEngine function, so that when we
+  // remove it from the add-on manager, the engine is left in the search
+  // settings.
+  oldRemoveEngineFunc = Services.search.wrappedJSObject.removeEngine.bind(
+    Services.search.wrappedJSObject
+  );
+  Services.search.wrappedJSObject.removeEngine = () => {};
+
+  registerCleanupFunction(async () => {
+    await promiseShutdownManager();
+  });
+});
+
+add_task(async function test_valid_extensions_do_nothing() {
+  Services.telemetry.clearScalars();
+
+  Assert.ok(
+    Services.search.getEngineByName("Example"),
+    "Should have installed the engine"
+  );
+
+  await Services.search.runBackgroundChecks();
+
+  let scalars = TelemetryTestUtils.getProcessScalars("parent", true, true);
+
+  Assert.deepEqual(scalars, {}, "Should not have recorded any issues");
+});
+
+add_task(async function test_different_name() {
+  Services.telemetry.clearScalars();
+
+  let engine = Services.search.getEngineByName("Example");
+
+  engine.wrappedJSObject._name = "Example Test";
+
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertKeyedScalar(
+    TelemetryTestUtils.getProcessScalars("parent", true, true),
+    "browser.searchinit.engine_invalid_webextension",
+    extension.id,
+    5
+  );
+
+  engine.wrappedJSObject._name = "Example";
+});
+
+add_task(async function test_different_url() {
+  Services.telemetry.clearScalars();
+
+  let engine = Services.search.getEngineByName("Example");
+
+  engine.wrappedJSObject._urls = [];
+  engine.wrappedJSObject._setUrls({
+    search_url: "https://example.com/123",
+    search_url_get_params: "?q={searchTerms}",
+  });
+
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertKeyedScalar(
+    TelemetryTestUtils.getProcessScalars("parent", true, true),
+    "browser.searchinit.engine_invalid_webextension",
+    extension.id,
+    6
+  );
+});
+
+add_task(async function test_extension_no_longer_specifies_engine() {
+  Services.telemetry.clearScalars();
+
+  let extensionInfo = {
+    useAddonManager: "permanent",
+    manifest: {
+      version: "2.0",
+      browser_specific_settings: {
+        gecko: {
+          id: "example@tests.mozilla.org",
+        },
+      },
+    },
+  };
+
+  await extension.upgrade(extensionInfo);
+
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertKeyedScalar(
+    TelemetryTestUtils.getProcessScalars("parent", true, true),
+    "browser.searchinit.engine_invalid_webextension",
+    extension.id,
+    4
+  );
+});
+
+add_task(async function test_disabled_extension() {
+  // We don't clear scalars between tests to ensure the scalar gets set
+  // to the new value, rather than added.
+
+  // Disable the extension, this won't remove the search engine because we've
+  // stubbed removeEngine.
+  await extension.addon.disable();
+
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertKeyedScalar(
+    TelemetryTestUtils.getProcessScalars("parent", true, true),
+    "browser.searchinit.engine_invalid_webextension",
+    extension.id,
+    2
+  );
+
+  extension.addon.enable();
+  await extension.awaitStartup();
+});
+
+add_task(async function test_missing_extension() {
+  // We don't clear scalars between tests to ensure the scalar gets set
+  // to the new value, rather than added.
+
+  let extensionId = extension.id;
+  // Remove the extension, this won't remove the search engine because we've
+  // stubbed removeEngine.
+  await extension.unload();
+
+  await Services.search.runBackgroundChecks();
+
+  TelemetryTestUtils.assertKeyedScalar(
+    TelemetryTestUtils.getProcessScalars("parent", true, true),
+    "browser.searchinit.engine_invalid_webextension",
+    extensionId,
+    1
+  );
+
+  await oldRemoveEngineFunc(Services.search.getEngineByName("Example"));
+});
diff --git a/toolkit/components/search/tests/xpcshell/xpcshell.ini b/toolkit/components/search/tests/xpcshell/xpcshell.ini
new file mode 100644
index 0000000000..4f0be19aa6
--- /dev/null
+++ b/toolkit/components/search/tests/xpcshell/xpcshell.ini
@@ -0,0 +1,196 @@
+[DEFAULT]
+firefox-appdir = browser
+head = head_search.js
+dupe-manifest =
+tags=searchmain
+skip-if = toolkit == 'android'
+prefs =
+  browser.search.removeEngineInfobar.enabled=true
+
+support-files =
+  data/engine.xml
+  data/engine/manifest.json
+  data/engine2.xml
+  data/engine2/manifest.json
+  data/engine-app/manifest.json
+  data/engine-diff-name/manifest.json
+  data/engine-diff-name/_locales/en/messages.json
+  data/engine-diff-name/_locales/gd/messages.json
+  data/engine-fr.xml
+  data/engine-fr/manifest.json
+  data/engine-reordered/manifest.json
+  data/engineMaker.sjs
+  data/engine-pref/manifest.json
+  data/engine-rel-searchform-purpose/manifest.json
+  data/engine-system-purpose/manifest.json
+  data/engineImages.xml
+  data/engine-chromeicon/manifest.json
+  data/engine-purposes/manifest.json
+  data/engine-resourceicon/manifest.json
+  data/engine-resourceicon/_locales/en/messages.json
+  data/engine-resourceicon/_locales/gd/messages.json
+  data/engine-same-name/manifest.json
+  data/engine-same-name/_locales/en/messages.json
+  data/engine-same-name/_locales/gd/messages.json
+  data/engines-no-order-hint.json
+  data/engines.json
+  data/iconsRedirect.sjs
+  data/search.json
+  data/search-legacy.json
+  data/search-legacy-correct-default-engine-hashes.json
+  data/search-legacy-no-ids.json
+  data/search-legacy-old-loadPaths.json
+  data/search-legacy-wrong-default-engine-hashes.json
+  data/search-legacy-wrong-third-party-engine-hashes.json
+  data/search-obsolete-app.json
+  data/search-obsolete-distribution.json
+  data/search-obsolete-langpack.json
+  data/searchSuggestions.sjs
+  data/geolookup-extensions/multilocale/favicon.ico
+  data/geolookup-extensions/multilocale/manifest.json
+  data/geolookup-extensions/multilocale/_locales/af/messages.json
+  data/geolookup-extensions/multilocale/_locales/an/messages.json
+  data1/engine1/manifest.json
+  data1/engine2/manifest.json
+  data1/exp2/manifest.json
+  data1/exp3/manifest.json
+  data1/engines.json
+  simple-engines/engines.json
+  simple-engines/basic/manifest.json
+  simple-engines/hidden/manifest.json
+  simple-engines/simple/manifest.json
+  test-extensions/engines.json
+  test-extensions/plainengine/favicon.ico
+  test-extensions/plainengine/manifest.json
+  test-extensions/special-engine/favicon.ico
+  test-extensions/special-engine/manifest.json
+  test-extensions/multilocale/favicon-af.ico
+  test-extensions/multilocale/favicon-an.ico
+  test-extensions/multilocale/manifest.json
+  test-extensions/multilocale/_locales/af/messages.json
+  test-extensions/multilocale/_locales/an/messages.json
+
+[test_async.js]
+[test_config_attribution.js]
+[test_config_engine_params.js]
+support-files =
+  method-extensions/get/manifest.json
+  method-extensions/post/manifest.json
+  method-extensions/engines.json
+[test_defaultEngine_fallback.js]
+[test_defaultEngine_experiments.js]
+[test_defaultEngine.js]
+[test_defaultPrivateEngine.js]
+[test_engine_alias.js]
+[test_engine_ids.js]
+[test_engine_multiple_alias.js]
+[test_engine_selector_application_distribution.js]
+[test_engine_selector_application_name.js]
+[test_engine_selector_application.js]
+[test_engine_selector_order.js]
+[test_engine_selector_override.js]
+[test_engine_selector_remote_settings.js]
+tag = remotesettings searchmain
+[test_engine_selector.js]
+[test_engine_set_alias.js]
+[test_getSubmission_encoding.js]
+[test_getSubmission_params.js]
+[test_identifiers.js]
+[test_ignorelist_update.js]
+[test_ignorelist.js]
+[test_initialization.js]
+[test_initialization_with_region.js]
+[test_list_json_locale.js]
+[test_list_json_no_private_default.js]
+[test_list_json_searchdefault.js]
+[test_list_json_searchorder.js]
+[test_maybereloadengine_order.js]
+[test_migrateWebExtensionEngine.js]
+[test_missing_engine.js]
+[test_multipleIcons.js]
+[test_nodb_pluschanges.js]
+[test_notifications.js]
+[test_opensearch_icon.js]
+support-files =
+  data/bigIcon.ico
+  data/remoteIcon.ico
+  data/svgIcon.svg
+[test_opensearch_icons_invalid.js]
+support-files =
+  opensearch/chromeicon.xml
+  opensearch/resourceicon.xml
+[test_opensearch_install_errors.js]
+support-files = opensearch/invalid.xml
+[test_opensearch_telemetry.js]
+support-files =
+  opensearch/secure-and-securely-updated1.xml
+  opensearch/secure-and-securely-updated2.xml
+  opensearch/secure-and-securely-updated3.xml
+  opensearch/secure-and-securely-updated-insecure-form.xml
+  opensearch/secure-and-insecurely-updated1.xml
+  opensearch/secure-and-insecurely-updated2.xml
+  opensearch/insecure-and-securely-updated1.xml
+  opensearch/insecure-and-insecurely-updated1.xml
+  opensearch/insecure-and-insecurely-updated2.xml
+  opensearch/secure-and-no-update-url1.xml
+  opensearch/insecure-and-no-update-url1.xml
+  opensearch/secure-localhost.xml
+  opensearch/secure-onionv2.xml
+  opensearch/secure-onionv3.xml
+[test_opensearch_update.js]
+[test_opensearch.js]
+support-files =
+  opensearch/mozilla-ns.xml
+  opensearch/post.xml
+  opensearch/simple.xml
+  opensearch/suggestion.xml
+  opensearch/suggestion-alternate.xml
+[test_appDefaultEngine.js]
+[test_override_allowlist.js]
+[test_parseSubmissionURL.js]
+[test_policyEngine.js]
+[test_pref.js]
+skip-if = nightly_build
+[test_purpose.js]
+[test_reload_engines_experiment.js]
+[test_reload_engines_locales.js]
+[test_reload_engines.js]
+[test_remove_profile_engine.js]
+[test_remove_engine_notification_box.js]
+[test_searchUrlDomain.js]
+[test_save_sorted_engines.js]
+[test_SearchStaticData.js]
+[test_searchSuggest_cookies.js]
+[test_searchSuggest_extraParams.js]
+[test_searchSuggest_private.js]
+[test_searchSuggest.js]
+[test_searchTermFromResult.js]
+[test_selectedEngine.js]
+[test_sendSubmissionURL.js]
+[test_settings_broken.js]
+[test_settings_duplicate.js]
+[test_settings_good.js]
+[test_settings_ignorelist.js]
+support-files = data/search_ignorelist.json
+[test_settings_migration_ids.js]
+[test_settings_migration_loadPath.js]
+[test_settings_none.js]
+[test_settings_obsolete.js]
+[test_settings_persist_diff_locale_same_name.js]
+[test_settings_persist.js]
+[test_settings.js]
+[test_sort_orders-no-hints.js]
+[test_sort_orders.js]
+[test_telemetry_event_default.js]
+[test_userEngine.js]
+[test_validate_engines.js]
+[test_validate_manifests.js]
+[test_webextensions_builtin_upgrade.js]
+[test_webextensions_install.js]
+[test_webextensions_language_switch.js]
+[test_webextensions_migrate_to.js]
+support-files = data/search-migration.json
+[test_webextensions_normandy_upgrade.js]
+[test_webextensions_startup_remove.js]
+[test_webextensions_upgrade.js]
+[test_webextensions_valid.js]