diff --git a/accessible/tests/mochitest/attributes/test_obj_group.html b/accessible/tests/mochitest/attributes/test_obj_group.html
index 64afbfcc7e8..3b4be098a4d 100644
--- a/accessible/tests/mochitest/attributes/test_obj_group.html
+++ b/accessible/tests/mochitest/attributes/test_obj_group.html
@@ -193,9 +193,9 @@
       var tree4acc = getAccessible("tree4");
       tree4element.parentNode.removeChild(tree4element);
       waitForEvent(EVENT_REORDER, tree4acc, function() {
-        testGroupAttrs("tree4_ti2", 1, 1, 1);
-        SimpleTest.finish();
-      });
+        testGroupAttrs("tree4_ti2", 1, 1, 1); });
+
+      SimpleTest.finish();
     }
 
     SimpleTest.waitForExplicitFinish();
diff --git a/accessible/tests/mochitest/events.js b/accessible/tests/mochitest/events.js
index 5913a6b3131..9c3f2cc45d8 100644
--- a/accessible/tests/mochitest/events.js
+++ b/accessible/tests/mochitest/events.js
@@ -389,7 +389,7 @@ function eventQueue(aEventType)
 
       var res = this.onFinish();
       if (res != DO_NOT_FINISH_TEST)
-        SimpleTest.executeSoon(SimpleTest.finish);
+        SimpleTest.finish();
 
       return;
     }
diff --git a/browser/base/content/test/general/test_offline_gzip.html b/browser/base/content/test/general/test_offline_gzip.html
index 0824e445185..1b4a6129961 100644
--- a/browser/base/content/test/general/test_offline_gzip.html
+++ b/browser/base/content/test/general/test_offline_gzip.html
@@ -89,7 +89,6 @@ function handleMessageEvents(event) {
       break;
     case 2:    
       is(event.data, "onupdate", "Child was successfully updated.");
-      clearInterval(intervalID);
       finishTest();
       break;
     default:
diff --git a/content/base/test/csp/test_CSP_bug888172.html b/content/base/test/csp/test_CSP_bug888172.html
index b9aa574afe7..d21f7068465 100644
--- a/content/base/test/csp/test_CSP_bug888172.html
+++ b/content/base/test/csp/test_CSP_bug888172.html
@@ -35,10 +35,6 @@ function checkDefaultSrcOnly() {
   ok(getElementColorById(testframe, 'unsafe-inline-script') === green, "Inline script should be allowed");
   ok(getElementColorById(testframe, 'unsafe-eval-script')  === green, "Eval should be allowed");
   ok(getElementColorById(testframe, 'unsafe-inline-style') === green, "Inline style should be allowed");
-
-  document.getElementById('testframe2').src = 'file_CSP_bug888172.sjs?csp=' +
-    escape("default-src 'self' 'unsafe-inline' 'unsafe-eval'; script-src 'self'");
-  document.getElementById('testframe2').addEventListener('load', checkDefaultSrcWithScriptSrc, false);
 }
 
 function checkDefaultSrcWithScriptSrc() {
@@ -47,10 +43,6 @@ function checkDefaultSrcWithScriptSrc() {
   ok(getElementColorById(testframe, 'unsafe-inline-script') === black, "Inline script should be blocked");
   ok(getElementColorById(testframe, 'unsafe-eval-script')  === black, "Eval should be blocked");
   ok(getElementColorById(testframe, 'unsafe-inline-style') === green, "Inline style should be allowed");
-
-  document.getElementById('testframe3').src = 'file_CSP_bug888172.sjs?csp=' +
-    escape("default-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self'");
-  document.getElementById('testframe3').addEventListener('load', checkDefaultSrcWithStyleSrc, false);
 }
 
 function checkDefaultSrcWithStyleSrc() {
@@ -67,6 +59,14 @@ function checkDefaultSrcWithStyleSrc() {
 document.getElementById('testframe1').src = 'file_CSP_bug888172.sjs?csp=' +
   escape("default-src 'self' 'unsafe-inline' 'unsafe-eval'");
 document.getElementById('testframe1').addEventListener('load', checkDefaultSrcOnly, false);
+
+document.getElementById('testframe2').src = 'file_CSP_bug888172.sjs?csp=' +
+  escape("default-src 'self' 'unsafe-inline' 'unsafe-eval'; script-src 'self'");
+document.getElementById('testframe2').addEventListener('load', checkDefaultSrcWithScriptSrc, false);
+
+document.getElementById('testframe3').src = 'file_CSP_bug888172.sjs?csp=' +
+  escape("default-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self'");
+document.getElementById('testframe3').addEventListener('load', checkDefaultSrcWithStyleSrc, false);
 </script>
 </pre>
 </body>
diff --git a/content/media/test/test_autoplay_contentEditable.html b/content/media/test/test_autoplay_contentEditable.html
index 171f14e5fbc..e8b5e97610f 100644
--- a/content/media/test/test_autoplay_contentEditable.html
+++ b/content/media/test/test_autoplay_contentEditable.html
@@ -28,12 +28,6 @@ function gotPlayEvent(event) {
      " tokens["+v._state+"]=" + tokens[v._state] +
      " tokens["+v._state+"].indexOf(event.type)=" + tokens[v._state].indexOf(event.type));
   v._state = event.type;
-  if (event.type == 'canplaythrough') {
-    //canplaythrough event can fire multiple times on Windows
-    v.removeEventListener('canplaythrough', gotPlayEvent, false);
-    v.pause();
-    goToNext(v);
-  }
 }
 
 function goToNext(v) {
@@ -52,6 +46,8 @@ function initTest(test, token) {
     v.addEventListener(e, gotPlayEvent, false);
   });
 
+  setTimeout(function() goToNext(v), 500);
+
   v.src = test.name;
   v.autoplay = true;
   document.body.appendChild(v); // Causes load.
diff --git a/content/media/test/test_mediarecorder_getencodeddata.html b/content/media/test/test_mediarecorder_getencodeddata.html
index dba8300081f..e4b646873e0 100644
--- a/content/media/test/test_mediarecorder_getencodeddata.html
+++ b/content/media/test/test_mediarecorder_getencodeddata.html
@@ -25,9 +25,6 @@ SpecialPowers.pushPrefEnv({"set": [["media.ogg.enabled", false]]},
         ok(onErrorFired, 'onStop after onError');
         ok(ondataavailableFired, 'ondataavailableFired');
 
-        //Apparently, as soon as the document is unloading, mediaRecorder.ondataavailable
-        //fires again, so set it to null to avoid failures
-        mediaRecorder.ondataavailable = null;
         SimpleTest.finish();
       }
       mediaRecorder.ondataavailable = function(evt) {
diff --git a/content/media/test/test_mediatrack_events.html b/content/media/test/test_mediatrack_events.html
index 39d4d01cf09..90eea9dbd2c 100644
--- a/content/media/test/test_mediatrack_events.html
+++ b/content/media/test/test_mediatrack_events.html
@@ -67,14 +67,6 @@ function startTest() {
         element.onended = null;
         element.onplaying = null;
         element.onpause = null;
-        //This helps to prevent these events from firing after SimpleTest.finish()
-        //on B2G ICS Emulator, but not sure they have been run at all, then
-        element.audioTracks.onremovetrack = null;
-        element.audioTracks.onaddtrack = null;
-        element.audioTracks.onchange = null;
-        element.videoTracks.onremovetrack = null;
-        element.videoTracks.onaddtrack = null;
-        element.videoTracks.onchange = null;
         SimpleTest.finish();
       }
 
diff --git a/content/media/webspeech/recognition/test/test_call_start_from_end_handler.html b/content/media/webspeech/recognition/test/test_call_start_from_end_handler.html
index aaa7e506a7d..468a860a169 100644
--- a/content/media/webspeech/recognition/test/test_call_start_from_end_handler.html
+++ b/content/media/webspeech/recognition/test/test_call_start_from_end_handler.html
@@ -20,9 +20,8 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=650295
 <script type="text/javascript">
   SimpleTest.waitForExplicitFinish();
 
-  var audioTag;
   function createAudioStream() {
-    audioTag = document.createElement("audio");
+    var audioTag = document.createElement("audio");
     audioTag.src = DEFAULT_AUDIO_SAMPLE_FILE;
 
     var stream = audioTag.mozCaptureStreamUntilEnded();
@@ -65,12 +64,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=650295
       'result': buildResultCallback("Mock final result"),
       'end': endHandler,
     },
-    doneFunc: function() {
-      //Pause the audio element, before unloading the document, otherwise
-      //it will cause more results to fire after SimpleTest.finish
-      audioTag.pause();
-      SimpleTest.finish();
-    },
+    doneFunc: SimpleTest.finish,
     prefs: [["media.webspeech.test.fake_fsm_events", true], ["media.webspeech.test.fake_recognition_service", true]]
   });
 
diff --git a/dom/base/test/test_domcursor.html b/dom/base/test/test_domcursor.html
index bb975a67f37..7d6ae2fa996 100644
--- a/dom/base/test/test_domcursor.html
+++ b/dom/base/test/test_domcursor.html
@@ -85,6 +85,12 @@ var tests = [
       next();
     }
     req.continue();
+    try {
+      req.continue();
+      ok(false, "calling continue twice should fail");
+    } catch (e) {
+      ok(true, "calling continue twice should fail");
+    }
   },
   function() {
     // FireDone
diff --git a/dom/browser-element/mochitest/browserElement_KeyEvents.js b/dom/browser-element/mochitest/browserElement_KeyEvents.js
index e3dd6a88142..f6367e1bcb2 100644
--- a/dom/browser-element/mochitest/browserElement_KeyEvents.js
+++ b/dom/browser-element/mochitest/browserElement_KeyEvents.js
@@ -82,11 +82,6 @@ function eventHandler(e) {
   }
 
   if (nbEvents == 0) {
-    //removeEventListener, otherwise a key event is fired
-    //for some reason, with keyCode 95
-    removeEventListener('keydown', eventHandler);
-    removeEventListener('keypress', eventHandler);
-    removeEventListener('keyup', eventHandler);
     SimpleTest.finish();
     return;
   }
diff --git a/dom/browser-element/mochitest/browserElement_TopBarrier.js b/dom/browser-element/mochitest/browserElement_TopBarrier.js
index 670f1472e3f..a86cf980d9a 100644
--- a/dom/browser-element/mochitest/browserElement_TopBarrier.js
+++ b/dom/browser-element/mochitest/browserElement_TopBarrier.js
@@ -28,8 +28,6 @@ function runTest() {
 
 var numMsgReceived = 0;
 function outerIframeLoaded() {
-  // If you're changing the amount of is() calls in injectedScript,
-  // also change the number in waitForMessages accordingly
   var injectedScript =
     "data:,function is(a, b, desc) {                                     \
       if (a == b) {                                                      \
@@ -65,8 +63,7 @@ function outerIframeLoaded() {
 
   mm.loadFrameScript(injectedScript, /* allowDelayedLoad = */ false);
 
-  // 8 is the number of is() calls in injectedScript
-  waitForMessages(8);
+  waitForMessages(6);
 }
 
 function waitForMessages(num) {
diff --git a/dom/inputmethod/mochitest/test_bug960946.html b/dom/inputmethod/mochitest/test_bug960946.html
index 716b7962267..6feecaf669a 100644
--- a/dom/inputmethod/mochitest/test_bug960946.html
+++ b/dom/inputmethod/mochitest/test_bug960946.html
@@ -18,7 +18,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=960946
 // The input context.
 var gContext = null;
 var gCounter = 0;
-var gBackSpaceCounter = 0;
 var result = ["keydown", "keypress", "keydown","keypress",
               "keydown", "keypress", "keyup"
              ];
@@ -27,12 +26,11 @@ inputmethod_setup(function() {
   runTest();
 });
 
-var input;
 // The frame script running in file_test_backspace_event.html.
 function appFrameScript() {
   let input = content.document.getElementById('test-input');
   input.onkeydown = input.onkeypress = input.onkeyup = function(event) {
-    dump('key event was fired in file_test_backspace_event.html: ' + event.type +'\n');
+    dump('key event was fired in file_test_backspace_event.html.\n');
     sendAsyncMessage('test:KeyBoard:keyEvent', {'type':event.type});
   };
 }
@@ -69,6 +67,9 @@ function runTest() {
       ok(true, 'Keyboard input was received.');
       is(SpecialPowers.wrap(event).json.type, result[gCounter], "expected event");
       gCounter++;
+      if (gCounter == 7) {
+        inputmethod_cleanup();
+      }
     });
   });
 }
@@ -92,10 +93,6 @@ function test_sendBackspace(repeat) {
   // Send backspace
   gContext.sendKey(KeyEvent.DOM_VK_BACK_SPACE, 0, 0, repeat).then(function() {
     ok(true, 'sendKey success');
-    gBackSpaceCounter++;
-    if (gBackSpaceCounter == 3) {
-      inputmethod_cleanup();
-    }
   }, function(e) {
     ok(false, 'sendKey failed:' + e.name);
     inputmethod_cleanup();
diff --git a/dom/tests/mochitest/chrome/test_docshell_swap.xul b/dom/tests/mochitest/chrome/test_docshell_swap.xul
index b80e402cd5a..48a1b5b5157 100644
--- a/dom/tests/mochitest/chrome/test_docshell_swap.xul
+++ b/dom/tests/mochitest/chrome/test_docshell_swap.xul
@@ -46,6 +46,8 @@
 
     let mm1 = flo1.frameLoader.messageManager;
     let mm2 = flo2.frameLoader.messageManager;
+    mm1.addMessageListener("pong", () => { gotPong(true); });
+    mm2.addMessageListener("pong", () => { gotPong(false); });
 
     // Swap docshells. Everything should be identical to before, since there was nothing to
     // distinguish these docshells.
diff --git a/dom/workers/test/test_bug883784.jsm b/dom/workers/test/test_bug883784.jsm
index 03a6e228229..096272d3169 100644
--- a/dom/workers/test/test_bug883784.jsm
+++ b/dom/workers/test/test_bug883784.jsm
@@ -4,7 +4,10 @@ this.Test = {
   start: function(ok, is, finish) {
     let worker = new ChromeWorker("jsm_url_worker.js");
     worker.onmessage = function(event) {
-      if (event.data.type == 'status') {
+
+      if (event.data.type == 'finish') {
+        finish();
+      } else if (event.data.type == 'status') {
         ok(event.data.status, event.data.msg);
       } else if (event.data.type == 'url') {
         var xhr = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
@@ -13,13 +16,8 @@ this.Test = {
         xhr.onreadystatechange = function() {
           if (xhr.readyState == 4) {
             ok(true, "Blob readable!");
-            finish();
           }
         }
-        xhr.onerror = function() {
-          ok(true, "Blob unreadable, should not happen!");
-          finish();
-        }
         xhr.send();
       }
     };
diff --git a/layout/base/tests/test_bug607529.html b/layout/base/tests/test_bug607529.html
index ed0cc0c3220..6eee1097668 100644
--- a/layout/base/tests/test_bug607529.html
+++ b/layout/base/tests/test_bug607529.html
@@ -45,7 +45,6 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=607529
       // Protect against calling SimpleTest.finish() more than once.
       if (!done) {
 	w.close();
-        window.onmessage = null;
 	SimpleTest.finish();
 	done = true;
       }