--- a/browser/base/content/test/general/browser_contentSearchUI.js
+++ b/browser/base/content/test/general/browser_contentSearchUI.js
@@ -4,16 +4,21 @@
 const TEST_PAGE_BASENAME = "contentSearchUI.html";
 const TEST_CONTENT_SCRIPT_BASENAME = "contentSearchUI.js";
 const TEST_ENGINE_PREFIX = "browser_searchSuggestionEngine";
 const TEST_ENGINE_BASENAME = "searchSuggestionEngine.xml";
 const TEST_ENGINE_2_BASENAME = "searchSuggestionEngine2.xml";
 
 const TEST_MSG = "ContentSearchUIControllerTest";
 
+let {SearchTestUtils} = ChromeUtils.import(
+  "resource://testing-common/SearchTestUtils.jsm", {});
+
+SearchTestUtils.init(Assert, registerCleanupFunction);
+
 requestLongerTimeout(2);
 
 add_task(async function emptyInput() {
   await setUp();
 
   let state = await msg("key", { key: "x", waitForSuggestions: true });
   checkState(state, "x", ["xfoo", "xbar"], -1);
 
@@ -386,16 +391,17 @@ add_task(async function cycleEngines() {
   await msg("key", { key: "VK_DOWN", waitForSuggestions: true });
 
   let promiseEngineChange = function(newEngineName) {
     return new Promise(resolve => {
       Services.obs.addObserver(function resolver(subj, topic, data) {
         if (data != "engine-current") {
           return;
         }
+        subj.QueryInterface(Ci.nsISearchEngine);
         SimpleTest.is(subj.name, newEngineName, "Engine cycled correctly");
         Services.obs.removeObserver(resolver, "browser-search-engine-modified");
         resolve();
       }, "browser-search-engine-modified");
     });
   };
 
   let p = promiseEngineChange(TEST_ENGINE_PREFIX + " " + TEST_ENGINE_2_BASENAME);
@@ -734,18 +740,21 @@ function promiseMsg(name, type, msgMan) 
 }
 
 function setUpEngines() {
   return (async function() {
     info("Removing default search engines");
     let currentEngineName = Services.search.currentEngine.name;
     let currentEngines = Services.search.getVisibleEngines();
     info("Adding test search engines");
-    let engine1 = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
-    await promiseNewSearchEngine(TEST_ENGINE_2_BASENAME);
+    let rootDir = getRootDirectory(gTestPath);
+    let engine1 = await SearchTestUtils.promiseNewSearchEngine(
+      rootDir + TEST_ENGINE_BASENAME);
+    await SearchTestUtils.promiseNewSearchEngine(
+      rootDir + TEST_ENGINE_2_BASENAME);
     Services.search.currentEngine = engine1;
     for (let engine of currentEngines) {
       Services.search.removeEngine(engine);
     }
     registerCleanupFunction(() => {
       Services.search.restoreDefaultEngines();
       Services.search.currentEngine = Services.search.getEngineByName(currentEngineName);
     });

--- a/browser/base/content/test/general/head.js
+++ b/browser/base/content/test/general/head.js
@@ -521,34 +521,16 @@ function promiseNotificationShown(notifi
   if (win.PopupNotifications.panel.state == "open") {
     return Promise.resolve();
   }
   let panelPromise = promisePopupShown(win.PopupNotifications.panel);
   notification.reshow();
   return panelPromise;
 }
 
-function promiseNewSearchEngine(basename) {
-  return new Promise((resolve, reject) => {
-    info("Waiting for engine to be added: " + basename);
-    let url = getRootDirectory(gTestPath) + basename;
-    Services.search.addEngine(url, null, "", false, {
-      onSuccess(engine) {
-        info("Search engine added: " + basename);
-        registerCleanupFunction(() => Services.search.removeEngine(engine));
-        resolve(engine);
-      },
-      onError(errCode) {
-        Assert.ok(false, "addEngine failed with error code " + errCode);
-        reject();
-      },
-    });
-  });
-}
-
 /**
  * Resolves when a bookmark with the given uri is added.
  */
 function promiseOnBookmarkItemAdded(aExpectedURI) {
   return new Promise((resolve, reject) => {
     let bookmarksObserver = {
       onItemAdded(aItemId, aFolderId, aIndex, aItemType, aURI) {
         info("Added a bookmark to " + aURI.spec);

--- a/browser/base/content/test/urlbar/browser_autocomplete_a11y_label.js
+++ b/browser/base/content/test/urlbar/browser_autocomplete_a11y_label.js
@@ -14,17 +14,18 @@ add_task(async function switchToTab() {
   is(result.label, "about:about about:about Tab", "Result a11y label should be: <title> <url> Tab");
 
   gURLBar.popup.hidePopup();
   await promisePopupHidden(gURLBar.popup);
   gBrowser.removeTab(tab);
 });
 
 add_task(async function searchSuggestions() {
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.currentEngine = engine;
   Services.prefs.setBoolPref(SUGGEST_ALL_PREF, true);
   let suggestionsEnabled = Services.prefs.getBoolPref(SUGGEST_URLBAR_PREF);
   Services.prefs.setBoolPref(SUGGEST_URLBAR_PREF, true);
   registerCleanupFunction(function() {
     Services.search.currentEngine = oldCurrentEngine;
     Services.prefs.clearUserPref(SUGGEST_ALL_PREF);

--- a/browser/base/content/test/urlbar/browser_urlbarOneOffs.js
+++ b/browser/base/content/test/urlbar/browser_urlbarOneOffs.js
@@ -3,17 +3,18 @@ const TEST_ENGINE_BASENAME = "searchSugg
 let gMaxResults;
 
 add_task(async function init() {
   Services.prefs.setBoolPref("browser.urlbar.oneOffSearches", true);
   gMaxResults = Services.prefs.getIntPref("browser.urlbar.maxRichResults");
 
   // Add a search suggestion engine and move it to the front so that it appears
   // as the first one-off.
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   Services.search.moveEngine(engine, 0);
 
   registerCleanupFunction(async function() {
     await hidePopup();
     await PlacesUtils.history.clear();
   });
 
   await PlacesUtils.history.clear();

--- a/browser/base/content/test/urlbar/browser_urlbarOneOffs_searchSuggestions.js
+++ b/browser/base/content/test/urlbar/browser_urlbarOneOffs_searchSuggestions.js
@@ -1,17 +1,18 @@
 const TEST_ENGINE_BASENAME = "searchSuggestionEngine.xml";
 
 add_task(async function init() {
   await PlacesUtils.history.clear();
   await SpecialPowers.pushPrefEnv({
     set: [["browser.urlbar.oneOffSearches", true],
           ["browser.urlbar.suggest.searches", true]],
   });
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.moveEngine(engine, 0);
   Services.search.currentEngine = engine;
   registerCleanupFunction(async function() {
     Services.search.currentEngine = oldCurrentEngine;
 
     await PlacesUtils.history.clear();
     // Make sure the popup is closed for the next test.

--- a/browser/base/content/test/urlbar/browser_urlbarPlaceholder.js
+++ b/browser/base/content/test/urlbar/browser_urlbarPlaceholder.js
@@ -12,17 +12,18 @@ const TEST_ENGINE_BASENAME = "searchSugg
 
 const originalEngine = Services.search.currentEngine;
 const expectedString = gBrowserBundle.formatStringFromName("urlbar.placeholder",
   [originalEngine.name], 1);
 var extraEngine;
 var tabs = [];
 
 add_task(async function setup() {
-  extraEngine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let rootDir = getRootDirectory(gTestPath);
+  extraEngine = await SearchTestUtils.promiseNewSearchEngine(rootDir + TEST_ENGINE_BASENAME);
 
   // Force display of a tab with a URL bar, to clear out any possible placeholder
   // initialization listeners that happen on startup.
   let urlTab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:mozilla");
   BrowserTestUtils.removeTab(urlTab);
 
   registerCleanupFunction(() => {
     Services.search.currentEngine = originalEngine;

--- a/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions.js
@@ -1,16 +1,17 @@
 const SUGGEST_URLBAR_PREF = "browser.urlbar.suggest.searches";
 const TEST_ENGINE_BASENAME = "searchSuggestionEngine.xml";
 
 // Must run first.
 add_task(async function prepare() {
   let suggestionsEnabled = Services.prefs.getBoolPref(SUGGEST_URLBAR_PREF);
   Services.prefs.setBoolPref(SUGGEST_URLBAR_PREF, true);
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.currentEngine = engine;
   registerCleanupFunction(async function() {
     Services.prefs.setBoolPref(SUGGEST_URLBAR_PREF, suggestionsEnabled);
     Services.search.currentEngine = oldCurrentEngine;
 
     // Clicking suggestions causes visits to search results pages, so clear that
     // history now.

--- a/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
@@ -4,17 +4,18 @@
 const SUGGEST_ALL_PREF = "browser.search.suggest.enabled";
 const SUGGEST_URLBAR_PREF = "browser.urlbar.suggest.searches";
 const CHOICE_PREF = "browser.urlbar.userMadeSearchSuggestionsChoice";
 const TIMES_PREF = "browser.urlbar.timesBeforeHidingSuggestionsHint";
 const TEST_ENGINE_BASENAME = "searchSuggestionEngine.xml";
 const ONEOFF_PREF = "browser.urlbar.oneOffSearches";
 
 add_task(async function prepare() {
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.currentEngine = engine;
   let suggestionsEnabled = Services.prefs.getBoolPref(SUGGEST_URLBAR_PREF);
   let defaults = Services.prefs.getDefaultBranch("browser.urlbar.");
   let searchSuggestionsDefault = defaults.getBoolPref("suggest.searches");
   defaults.setBoolPref("suggest.searches", true);
   let suggestionsChoice = Services.prefs.getBoolPref(CHOICE_PREF);
   Services.prefs.setBoolPref(CHOICE_PREF, false);

--- a/browser/base/content/test/urlbar/browser_urlbarSearchTelemetry.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchTelemetry.js
@@ -4,17 +4,18 @@ ChromeUtils.import("resource:///modules/
 
 const SUGGEST_URLBAR_PREF = "browser.urlbar.suggest.searches";
 const TEST_ENGINE_BASENAME = "searchSuggestionEngine.xml";
 
 // Must run first.
 add_task(async function prepare() {
   let suggestionsEnabled = Services.prefs.getBoolPref(SUGGEST_URLBAR_PREF);
   Services.prefs.setBoolPref(SUGGEST_URLBAR_PREF, true);
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.currentEngine = engine;
 
   registerCleanupFunction(async function() {
     Services.prefs.setBoolPref(SUGGEST_URLBAR_PREF, suggestionsEnabled);
     Services.search.currentEngine = oldCurrentEngine;
 
     // Clicking urlbar results causes visits to their associated pages, so clear

--- a/browser/base/content/test/urlbar/browser_urlbarStopSearchOnSelection.js
+++ b/browser/base/content/test/urlbar/browser_urlbarStopSearchOnSelection.js
@@ -14,17 +14,18 @@ const TEST_ENGINE_SUGGESTIONS_TIMEOUT = 
 const TEST_ENGINE_NUM_EXPECTED_RESULTS = 2;
 
 add_task(async function init() {
   await PlacesUtils.history.clear();
   await SpecialPowers.pushPrefEnv({
     set: [["browser.urlbar.suggest.searches", true]],
   });
   // Add a test search engine that returns suggestions on a delay.
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.moveEngine(engine, 0);
   Services.search.currentEngine = engine;
   registerCleanupFunction(async () => {
     Services.search.currentEngine = oldCurrentEngine;
     await PlacesUtils.history.clear();
     // Make sure the popup is closed for the next test.
     gURLBar.blur();

--- a/browser/base/content/test/urlbar/browser_urlbar_search_speculative_connect_engine.js
+++ b/browser/base/content/test/urlbar/browser_urlbar_search_speculative_connect_engine.js
@@ -24,17 +24,18 @@ add_task(async function setup() {
           ["browser.urlbar.speculativeConnect.enabled", true],
           // In mochitest this number is 0 by default but we have to turn it on.
           ["network.http.speculative-parallel-limit", 6],
           // The http server is using IPv4, so it's better to disable IPv6 to avoid weird
           // networking problem.
           ["network.dns.disableIPv6", true]],
   });
 
-  let engine = await promiseNewSearchEngine(TEST_ENGINE_BASENAME);
+  let engine = await SearchTestUtils.promiseNewSearchEngine(
+    getRootDirectory(gTestPath) + TEST_ENGINE_BASENAME);
   let oldCurrentEngine = Services.search.currentEngine;
   Services.search.currentEngine = engine;
 
   registerCleanupFunction(async function() {
     await PlacesUtils.history.clear();
     Services.search.currentEngine = oldCurrentEngine;
     gHttpServer.identity.remove(gScheme, gHost, gPort);
     gHttpServer.stop(() => {
@@ -48,9 +49,8 @@ add_task(async function connect_search_e
   await promiseAutocompleteResultPopup("foo", window, true);
   // Check if the first result is with type "searchengine"
   let controller = gURLBar.popup.input.controller;
   let style = controller.getStyleAt(0);
   is(style.includes("searchengine"), true, "The first result type is searchengine");
   await promiseSpeculativeConnection(gHttpServer);
   is(gHttpServer.connectionNumber, 1, `${gHttpServer.connectionNumber} speculative connection has been setup.`);
 });
-

--- a/browser/base/content/test/urlbar/head.js
+++ b/browser/base/content/test/urlbar/head.js
@@ -5,16 +5,20 @@ ChromeUtils.import("resource://gre/modul
 ChromeUtils.defineModuleGetter(this, "PlacesUtils",
   "resource://gre/modules/PlacesUtils.jsm");
 ChromeUtils.defineModuleGetter(this, "PlacesTestUtils",
   "resource://testing-common/PlacesTestUtils.jsm");
 ChromeUtils.defineModuleGetter(this, "Preferences",
   "resource://gre/modules/Preferences.jsm");
 ChromeUtils.defineModuleGetter(this, "HttpServer",
   "resource://testing-common/httpd.js");
+ChromeUtils.defineModuleGetter(this, "SearchTestUtils",
+  "resource://testing-common/SearchTestUtils.jsm");
+
+SearchTestUtils.init(Assert, registerCleanupFunction);
 
 /**
  * Waits for the next top-level document load in the current browser.  The URI
  * of the document is compared against aExpectedURL.  The load is then stopped
  * before it actually starts.
  *
  * @param aExpectedURL
  *        The URL of the document that is expected to load.
@@ -199,34 +203,16 @@ function promiseAutocompleteResultPopup(
       win.gURLBar.dispatchEvent(event);
     }
     win.gURLBar.controller.startSearch(inputText);
   }, win);
 
   return promiseSearchComplete(win, dontAnimate);
 }
 
-function promiseNewSearchEngine(basename) {
-  return new Promise((resolve, reject) => {
-    info("Waiting for engine to be added: " + basename);
-    let url = getRootDirectory(gTestPath) + basename;
-    Services.search.addEngine(url, null, "", false, {
-      onSuccess(engine) {
-        info("Search engine added: " + basename);
-        registerCleanupFunction(() => Services.search.removeEngine(engine));
-        resolve(engine);
-      },
-      onError(errCode) {
-        Assert.ok(false, "addEngine failed with error code " + errCode);
-        reject();
-      },
-    });
-  });
-}
-
 function promisePageActionPanelOpen() {
   let dwu = window.QueryInterface(Ci.nsIInterfaceRequestor)
                   .getInterface(Ci.nsIDOMWindowUtils);
   return BrowserTestUtils.waitForCondition(() => {
     // Wait for the main page action button to become visible.  It's hidden for
     // some URIs, so depending on when this is called, it may not yet be quite
     // visible.  It's up to the caller to make sure it will be visible.
     info("Waiting for main page action button to have non-0 size");

--- a/browser/components/search/moz.build
+++ b/browser/components/search/moz.build
@@ -5,12 +5,16 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 BROWSER_CHROME_MANIFESTS += [
     'test/browser.ini',
     'test/google_codes/browser.ini',
     'test/google_nocodes/browser.ini',
 ]
 
+TESTING_JS_MODULES += [
+    'test/SearchTestUtils.jsm',
+]
+
 JAR_MANIFESTS += ['jar.mn']
 
 with Files('**'):
     BUG_COMPONENT = ('Firefox', 'Search')

new file mode 100644
--- /dev/null
+++ b/browser/components/search/test/SearchTestUtils.jsm
@@ -0,0 +1,43 @@
+"use strict";
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+var EXPORTED_SYMBOLS = [
+  "SearchTestUtils",
+];
+
+var gTestGlobals;
+
+var SearchTestUtils = Object.freeze({
+  init(Assert, registerCleanupFunction) {
+    gTestGlobals = {
+      Assert,
+      registerCleanupFunction
+    };
+  },
+
+  /**
+   * Adds a search engine to the search service. It will remove the engine
+   * at the end of the test.
+   *
+   * @param {String}   url                     The URL of the engine to add.
+   * @param {Function} registerCleanupFunction Pass the registerCleanupFunction
+   *                                           from the test's scope.
+   * @returns {Promise} Returns a promise that is resolved with the new engine
+   *                    or rejected if it fails.
+   */
+  promiseNewSearchEngine(url) {
+    return new Promise((resolve, reject) => {
+      Services.search.addEngine(url, null, "", false, {
+        onSuccess(engine) {
+          gTestGlobals.registerCleanupFunction(() => Services.search.removeEngine(engine));
+          resolve(engine);
+        },
+        onError(errCode) {
+          gTestGlobals.Assert.ok(false, `addEngine failed with error code ${errCode}`);
+          reject();
+        },
+      });
+    });
+  }
+});