Unit test improvements.

pkg/unittest/lib/src/test_case.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.
 
 part of unittest;
 
 /**
  * Represents the state for an individual unit test.
  *
  * Create by calling [test] or [solo_test].
@@ skipping 104 matching lines @@
     if (rtn is Future) {
       rtn.then((_) => _runTest())
          .catchError((e) {
           _prepTest();
           // Calling error() will result in the tearDown being done.
           // One could debate whether tearDown should be done after
           // a failed setUp. There is no right answer, but doing it
           // seems to be the more conservative approach, because
           // unittest will not stop at a test failure.
           var stack = getAttachedStackTrace(e);
+          if (stack == null) stack = '';
           error("$description: Test setup failed: $e", "$stack");
         });
     } else {
       var f = _runTest();
       if (f != null) {
         return f;
       }
     }
     if (result == null) { // Not complete.
       _testComplete = new Completer();
       return _testComplete.future;
     }
     return null;
   }
 
   void _notifyComplete() {
     if (_testComplete != null) {
       _testComplete.complete(this);
       _testComplete = null;
     }
   }
 
   // Set the results, notify the config, and return true if this
   // is the first time the result is being set.
   void _setResult(String testResult, String messageText, String stack) {
     _message = messageText;
-    _stackTrace = stack;
+    _stackTrace = _formatStack(stack);
     if (result == null) {
       _result = testResult;
       _config.onTestResult(this);
     } else {
       _result = testResult;
       _config.onTestResultChanged(this);
     }
   }
 
   void _complete(String testResult,
@@ skipping 30 matching lines @@
       }
     }
     _notifyComplete();
   }
 
   void pass() {
     _complete(PASS);
   }
 
   void fail(String messageText, [String stack = '']) {
+    assert(stack != null);
     if (result != null) {
       String newMessage = (result == PASS)
           ? 'Test failed after initially passing: $messageText'
           : 'Test failed more than once: $messageText';
       // TODO(gram): Should we combine the stack with the old one?
       _complete(ERROR, newMessage, stack);
     } else {
       _complete(FAIL, messageText, stack);
     }
   }
 
   void error(String messageText, [String stack = '']) {
+    assert(stack != null);
     _complete(ERROR, messageText, stack);
   }
 
   void _markCallbackComplete() {
     if (--_callbackFunctionsOutstanding == 0 && !isComplete) {
       pass();
     }
   }
 }