Bug 494397 - SimpleTest.js |window.onerror| calls |SimpleTest.finish()| while test is still running; (Av1) Tabs cleanup, Improve+Add error messages, Use executeSoon(); r=rcampbell

testing/mochitest/tests/SimpleTest/SimpleTest.js

@@ -180,9 +180,9 @@ SimpleTest.showReport = function() {
     toggleTodo.onclick = partial(SimpleTest.toggleByClass, 'test_todo');
     var body = document.body;  // Handles HTML documents
     if (!body) {
-	// Do the XML thing
+        // Do the XML thing.
         body = document.getElementsByTagNameNS("http://www.w3.org/1999/xhtml",
-					       "body")[0]
+                                               "body")[0];
     }
     var firstChild = body.childNodes[0];
     var addNode;
@@ -464,17 +464,24 @@ var todo = SimpleTest.todo;
 var todo_is = SimpleTest.todo_is;
 var todo_isnot = SimpleTest.todo_isnot;
 var isDeeply = SimpleTest.isDeeply;
-var oldOnError = window.onerror;
+
+const oldOnError = window.onerror;
 window.onerror = function (ev) {
-    is(0, 1, "Error thrown during test: " + ev);
+  // Log the error.
+  ok(false, "[SimpleTest/SimpleTest.js, window.onerror] An error occurred: [ " + ev + " ]");
+
+  // Call previous handler.
   if (oldOnError) {
     try {
       oldOnError(ev);
     } catch (e) {
+      // Log the exception.
+      ok(false, "[SimpleTest/SimpleTest.js, window.onerror] Exception thrown by oldOnError(): [ " + e + " ]");
     }
   }
-    if (SimpleTest._stopOnLoad == false) {
-      // Need to finish() manually here
-      SimpleTest.finish();
+
+  if (!SimpleTest._stopOnLoad) {
+    // Need to finish() manually here, yet let the test actually end first.
+    SimpleTest.executeSoon(SimpleTest.finish);
   }
 }