Improve browser testing scripts to better handle tests that reload themselves.

tools/testing/dart/browser_controller.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library browser;
 
 import "dart:async";
 import "dart:convert" show LineSplitter, UTF8, JSON;
 import "dart:core";
 import "dart:io";
 
@@ skipping 1448 matching lines @@
     }
   </style>
   <title>Driving page</title>
   <script type='text/javascript'>
     var STATUS_UPDATE_INTERVAL = 10000;
 
     function startTesting() {
       var number_of_tests = 0;
       var current_id;
       var next_id;
-      // Describes a state where we are currently fetching the next test
-      // from the server. We use this to never double request tasks.
+
+      // Has the test in the current iframe reported that it is done?
       var test_completed = true;
+      // Has the test in the current iframe reported that it is started?
+      var test_started = false;
       var testing_window;
 
+      var embedded_iframe_div = document.getElementById('embedded_iframe_div');
       var embedded_iframe = document.getElementById('embedded_iframe');
       var number_div = document.getElementById('number');
       var executing_div = document.getElementById('currently_executing');
       var error_div = document.getElementById('unhandled_error');
       var use_iframe = ${useIframe};
       var start = new Date();
 
       // Object that holds the state of an HTML test
       var html_test;
   
@@ skipping 91 matching lines @@
         number_of_tests++;
         number_div.innerHTML = number_of_tests;
         executing_div.innerHTML = url;
         if (use_iframe) {
           if (html_test) {
             window.addEventListener('detect_errors', setChildHandlers, false);
             embedded_iframe.onload = checkChildHandlersInstalled;
           } else {
             embedded_iframe.onload = null;
           }
+          embedded_iframe_div.removeChild(embedded_iframe);
+          embedded_iframe = document.createElement('iframe');
+          embedded_iframe.id = "embedded_iframe";
+          embedded_iframe.style="width:100%;height:100%";
+          embedded_iframe_div.appendChild(embedded_iframe);
           embedded_iframe.src = url;
         } else {
           if (typeof testing_window != 'undefined') {
             testing_window.close();
           }
           testing_window = window.open(url);
         }
+        test_started = false;
+        test_completed = false;
       }
 
       window.onerror = function (message, url, lineNumber) {
         if (url) {
           reportError(url + ':' + lineNumber + ':' + message);
         } else {
           reportError(message);
         }
       }
 
       function reportError(msg) {
         function handleReady() {
           if (this.readyState == this.DONE && this.status != 200) {
             var error = 'Sending back error did not succeeed: ' + this.status;
             error = error + '. Failed to send msg: ' + msg;
             error_div.innerHTML = error;
           }
         }
         contactBrowserController(
             'POST', '$errorReportingUrl?test=1', handleReady, msg, true);
       }
 
       function reportMessage(msg, isFirstMessage, isStatusUpdate) {
         if (isFirstMessage) {
-          test_completed = false;
+          if (test_started) {
+            reportMessage(
+                "FAIL: test started more than once (test reloads itself) " +
+                msg, false, false);
+            return;
+          }
           current_id = next_id;
+          test_started = true;
           contactBrowserController(
             'POST', '$startedPath/${browserId}?id=' + current_id,
             function () {}, msg, true);
         } else if (isStatusUpdate) {
             contactBrowserController(
               'POST', '$statusUpdatePath/${browserId}?id=' + current_id,
               function() {}, msg, true);
         } else {
           var is_double_report = test_completed;
           var retry = 0;
@@ skipping 31 matching lines @@
         try {
           parsedData = JSON.parse(result);
         } catch(error) { }
         return parsedData;
       }
 
       // Browser tests send JSON messages to the driver window, handled here.
       function messageHandler(e) {
         var msg = e.data;
         if (typeof msg != 'string') return;
-
+        var expectedSource =
+            use_iframe ? embedded_iframe.contentWindow : testing_window;
+        if (e.source != expectedSource) {
+            reportError("Message received from old test window: " + msg);
+            return;
+        }
         var parsedData = parseResult(msg);
         if (parsedData) {
           // Only if the JSON message contains all required parameters,
           // will we handle it and post it back to the test controller.
           if ('message' in parsedData &&
               'is_first_message' in parsedData &&
               'is_status_update' in parsedData &&
               'is_done' in parsedData) {
             var message = parsedData['message'];
             var isFirstMessage = parsedData['is_first_message'];
@@ skipping 57 matching lines @@
       getNextTask();
     }
   </script>
 </head>
   <body onload="startTesting()">
     <div class="controller box">
     Dart test driver, number of tests: <span id="number"></span><br>
     Currently executing: <span id="currently_executing"></span><br>
     Unhandled error: <span id="unhandled_error"></span>
     </div>
-    <div class="test box">
+    <div id="embedded_iframe_div" class="test box">
       <iframe style="width:100%;height:100%;" id="embedded_iframe"></iframe>
     </div>
   </body>
 </html>
 """;
     return driverContent;
   }
 }