--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -47,17 +47,16 @@ module.exports = {
     ],
     "rules": {
       "mozilla/no-define-cc-etc": "off",
     }
   }, {
     // XXX Bug 1452706. These directories are still being fixed, so turn off
     //  mozilla/require-expected-throws-or-rejects for now.
     "files": [
-      "browser/components/**",
       "browser/extensions/formautofill/test/unit/test_storage_tombstones.js",
       "browser/modules/test/browser/**",
       "browser/tools/mozscreenshots/browser_boundingbox.js",
       "devtools/client/inspector/extensions/test/head_devtools_inspector_sidebar.js",
       "services/**",
       "storage/test/unit/**",
       "testing/marionette/test/unit/**",
       "toolkit/components/**",

--- a/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js
@@ -196,16 +196,16 @@ add_task(async function testSecureManife
         manifest: {
           [api]: {
             "default_icon": url,
           },
         },
       });
 
       await Assert.rejects(extension.startup(),
-                           null,
+                           /startup failed/,
                            "Manifest rejected");
 
       SimpleTest.endMonitorConsole();
       await waitForConsole;
     }
   }
 });

--- a/browser/components/extensions/test/browser/browser_ext_pageAction_popup.js
+++ b/browser/components/extensions/test/browser/browser_ext_pageAction_popup.js
@@ -231,17 +231,17 @@ add_task(async function testPageActionSe
 
     let extension = ExtensionTestUtils.loadExtension({
       manifest: {
         [api]: {"default_popup": URL},
       },
     });
 
     await Assert.rejects(extension.startup(),
-                         null,
+                         /startup failed/,
                          "Manifest rejected");
 
     SimpleTest.endMonitorConsole();
     await waitForConsole;
   }
 });
 
 add_task(forceGC);

--- a/browser/components/extensions/test/browser/browser_ext_themes_validation.js
+++ b/browser/components/extensions/test/browser/browser_ext_themes_validation.js
@@ -28,17 +28,19 @@ async function testThemeWithInvalidPrope
         manifest[prop] = {"keyword": "test"};
         break;
       default:
         manifest[prop] = {};
     }
   });
 
   let extension = ExtensionTestUtils.loadExtension({manifest});
-  await Assert.rejects(extension.startup(), null, "Theme should fail to load if it contains invalid properties");
+  await Assert.rejects(extension.startup(),
+                       /startup failed/,
+                       "Theme should fail to load if it contains invalid properties");
 }
 
 add_task(async function test_that_theme_with_invalid_properties_fails_to_load() {
   let invalidProps = ["page_action", "browser_action", "background", "permissions", "omnibox", "commands"];
   for (let prop in invalidProps) {
     await testThemeWithInvalidProperties([prop]);
   }
   await testThemeWithInvalidProperties(invalidProps);

--- a/browser/components/migration/tests/unit/test_IE7_passwords.js
+++ b/browser/components/migration/tests/unit/test_IE7_passwords.js
@@ -293,16 +293,17 @@ function getFirstResourceOfType(type) {
 
 function makeURI(aURL) {
   return Services.io.newURI(aURL);
 }
 
 add_task(async function setup() {
   if (AppConstants.isPlatformAndVersionAtLeast("win", "6.2")) {
     Assert.throws(() => getFirstResourceOfType(MigrationUtils.resourceTypes.PASSWORDS),
+                  /failed to find/,
                   "The migrator doesn't exist for win8+");
     return;
   }
   // create the path to Storage2 in the registry if it doest exist.
   createRegistryPath(LOGINS_KEY);
   Storage2Key = Cc["@mozilla.org/windows-registry-key;1"].
                 createInstance(nsIWindowsRegKey);
   Storage2Key.open(nsIWindowsRegKey.ROOT_KEY_CURRENT_USER, LOGINS_KEY,

--- a/browser/components/places/tests/unit/test_browserGlue_prefs.js
+++ b/browser/components/places/tests/unit/test_browserGlue_prefs.js
@@ -47,18 +47,20 @@ add_task(async function test_checkPrefer
   let promiseComplete = promiseTopicObserved("places-browser-init-complete");
   Assert.equal(PlacesUtils.history.databaseStatus,
                PlacesUtils.history.DATABASE_STATUS_CREATE);
   await promiseComplete;
 
   // Ensure preferences status.
   Assert.ok(!Services.prefs.getBoolPref(PREF_AUTO_EXPORT_HTML));
 
-  Assert.throws(() => Services.prefs.getBoolPref(PREF_IMPORT_BOOKMARKS_HTML));
-  Assert.throws(() => Services.prefs.getBoolPref(PREF_RESTORE_DEFAULT_BOOKMARKS));
+  Assert.throws(() => Services.prefs.getBoolPref(PREF_IMPORT_BOOKMARKS_HTML),
+    /NS_ERROR_UNEXPECTED/);
+  Assert.throws(() => Services.prefs.getBoolPref(PREF_RESTORE_DEFAULT_BOOKMARKS),
+    /NS_ERROR_UNEXPECTED/);
 });
 
 add_task(async function test_import() {
   info("Import from bookmarks.html if importBookmarksHTML is true.");
 
   await PlacesUtils.bookmarks.eraseEverything();
 
   // Sanity check: we should not have any bookmark on the toolbar.

--- a/browser/components/places/tests/unit/test_browserGlue_smartBookmarks.js
+++ b/browser/components/places/tests/unit/test_browserGlue_smartBookmarks.js
@@ -44,17 +44,18 @@ add_task(async function setup() {
   let promiseComplete = promiseTopicObserved("places-browser-init-complete");
   Assert.equal(PlacesUtils.history.databaseStatus,
                PlacesUtils.history.DATABASE_STATUS_CREATE);
   await promiseComplete;
 
   // Ensure preferences status.
   Assert.ok(!Services.prefs.getBoolPref(PREF_AUTO_EXPORT_HTML));
   Assert.ok(!Services.prefs.getBoolPref(PREF_RESTORE_DEFAULT_BOOKMARKS));
-  Assert.throws(() => Services.prefs.getBoolPref(PREF_IMPORT_BOOKMARKS_HTML));
+  Assert.throws(() => Services.prefs.getBoolPref(PREF_IMPORT_BOOKMARKS_HTML),
+    /NS_ERROR_UNEXPECTED/);
 });
 
 add_task(async function test_version_0() {
   info("All smart bookmarks are created if smart bookmarks version is 0.");
 
   // Sanity check: we should have default bookmark.
   Assert.ok(await PlacesUtils.bookmarks.fetch({
     parentGuid: PlacesUtils.bookmarks.toolbarGuid,

--- a/browser/components/sessionstore/test/browser_dying_cache.js
+++ b/browser/components/sessionstore/test/browser_dying_cache.js
@@ -32,18 +32,20 @@ add_task(async function test() {
 
   // SessionStore should no longer track our window
   // but it should still report the same state.
   ok(!("__SSi" in win), "sessionstore does no longer track our window");
   checkWindowState(win);
 
   // Make sure we're not allowed to modify state data.
   Assert.throws(() => ss.setWindowState(win, {}),
+    /Window is not tracked/,
     "we're not allowed to modify state data anymore");
   Assert.throws(() => ss.setWindowValue(win, "foo", "baz"),
+    /Window is not tracked/,
     "we're not allowed to modify state data anymore");
 });
 
 function checkWindowState(window) {
   let {windows: [{tabs}]} = JSON.parse(ss.getWindowState(window));
   is(tabs.length, 1, "the window has a single tab");
   is(tabs[0].entries[0].url, "about:mozilla", "the tab is about:mozilla");
 

--- a/browser/components/sessionstore/test/browser_not_collect_when_idle.js
+++ b/browser/components/sessionstore/test/browser_not_collect_when_idle.js
@@ -83,22 +83,21 @@ add_task(async function testIntervalChan
 
   let p1 = promiseSaveState();
 
   // Schedule a state write, which is expeced to be postponed after about
   // `browser.sessionstore.interval.idle` ms, since the idle flag was just set.
   SessionSaver.runDelayed(0);
 
   // We expect `p1` hits the timeout.
-  await Assert.rejects(p1, null, "[Test 1A] No state write during idle.");
+  await Assert.rejects(p1, /Save state timeout/, "[Test 1A] No state write during idle.");
 
   // Test again for better reliability. Same, we expect following promise hits
   // the timeout.
-  await Assert.rejects(promiseSaveState(), null, "[Test 1B] Again: No state write during idle.");
+  await Assert.rejects(promiseSaveState(), /Save state timeout/, "[Test 1B] Again: No state write during idle.");
 
   // Back to the active mode.
   info("Start to test active mode...");
   idleService._fireObservers("active");
 
   info("[Test 2] Waiting for sessionstore-state-write-complete during active");
   await TestUtils.topicObserved("sessionstore-state-write-complete");
 });
-

--- a/browser/components/tests/unit/test_distribution.js
+++ b/browser/components/tests/unit/test_distribution.js
@@ -99,43 +99,52 @@ add_task(async function() {
   Assert.equal(defaultBranch.getStringPref("distribution.about"), "Tèƨƭ δïƨƭřïβúƭïôñ ƒïℓè");
 
   Assert.equal(defaultBranch.getCharPref("distribution.test.string"), "Test String");
   Assert.equal(defaultBranch.getCharPref("distribution.test.string.noquotes"), "Test String");
   Assert.equal(defaultBranch.getIntPref("distribution.test.int"), 777);
   Assert.equal(defaultBranch.getBoolPref("distribution.test.bool.true"), true);
   Assert.equal(defaultBranch.getBoolPref("distribution.test.bool.false"), false);
 
-  Assert.throws(() => defaultBranch.getCharPref("distribution.test.empty"));
-  Assert.throws(() => defaultBranch.getIntPref("distribution.test.empty"));
-  Assert.throws(() => defaultBranch.getBoolPref("distribution.test.empty"));
+  Assert.throws(() => defaultBranch.getCharPref("distribution.test.empty"),
+    /NS_ERROR_UNEXPECTED/);
+  Assert.throws(() => defaultBranch.getIntPref("distribution.test.empty"),
+    /NS_ERROR_UNEXPECTED/);
+  Assert.throws(() => defaultBranch.getBoolPref("distribution.test.empty"),
+    /NS_ERROR_UNEXPECTED/);
 
   Assert.equal(defaultBranch.getCharPref("distribution.test.pref.locale"), "en-US");
   Assert.equal(defaultBranch.getCharPref("distribution.test.pref.language.en"), "en");
   Assert.equal(defaultBranch.getCharPref("distribution.test.pref.locale.en-US"), "en-US");
-  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.language.de"));
+  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.language.de"),
+    /NS_ERROR_UNEXPECTED/);
   // This value was never set because of the empty language specific pref
-  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.language.reset"));
+  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.language.reset"),
+    /NS_ERROR_UNEXPECTED/);
   // This value was never set because of the empty locale specific pref
-  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.locale.reset"));
+  Assert.throws(() => defaultBranch.getCharPref("distribution.test.pref.locale.reset"),
+    /NS_ERROR_UNEXPECTED/);
   // This value was overridden by a locale specific setting
   Assert.equal(defaultBranch.getCharPref("distribution.test.pref.locale.set"), "Locale Set");
   // This value was overridden by a language specific setting
   Assert.equal(defaultBranch.getCharPref("distribution.test.pref.language.set"), "Language Set");
   // Language should not override locale
   Assert.notEqual(defaultBranch.getCharPref("distribution.test.pref.locale.set"), "Language Set");
 
   Assert.equal(defaultBranch.getComplexValue("distribution.test.locale", Ci.nsIPrefLocalizedString).data, "en-US");
   Assert.equal(defaultBranch.getComplexValue("distribution.test.language.en", Ci.nsIPrefLocalizedString).data, "en");
   Assert.equal(defaultBranch.getComplexValue("distribution.test.locale.en-US", Ci.nsIPrefLocalizedString).data, "en-US");
-  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.language.de", Ci.nsIPrefLocalizedString));
+  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.language.de", Ci.nsIPrefLocalizedString),
+    /NS_ERROR_UNEXPECTED/);
   // This value was never set because of the empty language specific pref
-  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.language.reset", Ci.nsIPrefLocalizedString));
+  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.language.reset", Ci.nsIPrefLocalizedString),
+    /NS_ERROR_UNEXPECTED/);
   // This value was never set because of the empty locale specific pref
-  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.locale.reset", Ci.nsIPrefLocalizedString));
+  Assert.throws(() => defaultBranch.getComplexValue("distribution.test.locale.reset", Ci.nsIPrefLocalizedString),
+    /NS_ERROR_UNEXPECTED/);
   // This value was overridden by a locale specific setting
   Assert.equal(defaultBranch.getComplexValue("distribution.test.locale.set", Ci.nsIPrefLocalizedString).data, "Locale Set");
   // This value was overridden by a language specific setting
   Assert.equal(defaultBranch.getComplexValue("distribution.test.language.set", Ci.nsIPrefLocalizedString).data, "Language Set");
   // Language should not override locale
   Assert.notEqual(defaultBranch.getComplexValue("distribution.test.locale.set", Ci.nsIPrefLocalizedString).data, "Language Set");
 
   do_test_pending();