Use package:stack_trace in unittest.

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 23 matching lines @@
   String _message = '';
   /** Error or failure message. */
   String get message => _message;
 
   String _result;
   /**
    * One of [PASS], [FAIL], [ERROR], or [null] if the test hasn't run yet.
    */
   String get result => _result;
 
-  String _stackTrace;
+  Trace _stackTrace;
   /** Stack trace associated with this test, or [null] if it succeeded. */
-  String get stackTrace => _stackTrace;
+  Trace get stackTrace => _stackTrace;
 
   /** The group (or groups) under which this test is running. */
   final String currentGroup;
 
   DateTime _startTime;
   DateTime get startTime => _startTime;
 
   Duration _runningTime;
   Duration get runningTime => _runningTime;
 
@@ skipping 18 matching lines @@
 
   Future _runTest() {
     _prepTest();
     // Increment/decrement callbackFunctionsOutstanding to prevent
     // synchronous 'async' callbacks from causing the  test to be
     // marked as complete before the body is completely executed.
     ++_callbackFunctionsOutstanding;
     var f = testFunction();
     --_callbackFunctionsOutstanding;
     if (f is Future) {
-      return f.then((_) => _finishTest())
-        .catchError((error) {
-          var stack = getAttachedStackTrace(error);
-          _registerException(this, error, stack);
-        });
+      return f.then((_) => _finishTest()).catchError((error) {
+        _registerException(this, error, getAttachedStackTrace(error));
+      });
     } else {
       _finishTest();
       return null;
     }
   }
 
   void _finishTest() {
     if (result == null && _callbackFunctionsOutstanding == 0) {
       pass();
     }
   }
 
   /**
    * Perform any associated [_setUp] function and run the test. Returns
    * a [Future] that can be used to schedule the next test. If the test runs
    * to completion synchronously, or is disabled, null is returned, to
    * tell unittest to schedule the next test immediately.
    */
   Future _run() {
     if (!enabled) return null;
 
     _result = _stackTrace = null;
     _message = '';
     _doneTeardown = false;
     var rtn = setUp == null ? null : setUp();
     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");
-        });
+      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.
+        error(
+            "$description: Test setup failed: $e",
+            getAttachedStackTrace(e));
+      });
     } 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) {
+  void _setResult(String testResult, String messageText, stack) {
     _message = messageText;
-    _stackTrace = _formatStack(stack);
+    _stackTrace = _getTrace(stack);
     if (result == null) {
       _result = testResult;
       _config.onTestResult(this);
     } else {
       _result = testResult;
       _config.onTestResultChanged(this);
     }
   }
 
-  void _complete(String testResult,
-                [String messageText = '',
-                 String stack = '']) {
+  void _complete(String testResult, [String messageText = '', stack]) {
     if (runningTime == null) {
       // The startTime can be `null` if an error happened during setup. In this
       // case we simply report a running time of 0.
       if (startTime != null) {
         _runningTime = new DateTime.now().difference(startTime);
       } else {
         _runningTime = const Duration(seconds: 0);
       }
     }
     _setResult(testResult, messageText, stack);
@@ skipping 17 matching lines @@
         }
       }
     }
     _notifyComplete();
   }
 
   void pass() {
     _complete(PASS);
   }
 
-  void fail(String messageText, [String stack = '']) {
-    assert(stack != null);
+  void fail(String messageText, [stack]) {
     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);
+  void error(String messageText, [stack]) {
     _complete(ERROR, messageText, stack);
   }
 
   void _markCallbackComplete() {
     if (--_callbackFunctionsOutstanding == 0 && !isComplete) {
       pass();
     }
   }
 }