TestCase times out after 20 seconds.

dart/pkg/unittest/lib/test_controller.js

 // Copyright (c) 2011, 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.
 
 /**
  * Test controller logic - used by unit test harness to embed tests in
  * conent shell.
  */
 
 // Clear the console before every test run - this is Firebug specific code.
@@ skipping 134 matching lines @@
 // [print] with the secret messages "unittest-suite-success" and
 // "unittest-suite-wait-for-done". These messages are then posted so
 // processMessage above will see them.
 function dartPrint(msg) {
   if ((msg === 'unittest-suite-success')
       || (msg === 'unittest-suite-done')
       || (msg === 'unittest-suite-wait-for-done')) {
     window.postMessage(msg, '*');
     return;
   }
+  if (typeof console === 'object') console.warn(msg);
   var pre = document.createElement("pre");
   pre.appendChild(document.createTextNode(String(msg)));
   document.body.appendChild(pre);
 }
 
 // dart2js will generate code to call this function instead of calling
 // Dart [main] directly. The argument is a closure that invokes main.
 function dartMainRunner(main) {
   window.postMessage('dart-calling-main', '*');
   try {
     main();
   } catch (e) {
     dartPrint(e);
     if (e.stack) dartPrint(e.stack);
     window.postMessage('unittest-suite-fail', '*');
     return;
   }
   window.postMessage('dart-main-done', '*');
 }