Changes to how we handle fancy stacks:

pkg/unittest/lib/unittest.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.
 
 /**
  * A library for writing dart unit tests.
  *
  * ## Installing ##
  *
  * Use [pub][] to install this package. Add the following to your `pubspec.yaml`
@@ skipping 832 matching lines @@
 typedef dynamic TestFunction();
 
 /**
  * A flag that controls whether we hide unittest and core library details in
  * exception stacks.
  *
  * Useful to disable when debugging unittest or matcher customizations.
  */
 bool formatStacks = true;
 
-/** Returns a Trace object from a StackTrace object or a String. */
+/**
+ * A flag that controls whether we try to filter out irrelevant frames from 
+ * the stack trce. Requires formatStacks to be set.
+ */
+bool filterStacks = true;
+
+/**
+ * Returns a Trace object from a StackTrace object or a String, or the 
+ * unchanged input if formatStacks is false;
+ */
 Trace _getTrace(stack) {
   Trace trace;
-  if (stack == null) return null;
+  if (stack == null || !formatStacks) return null;
   if (stack is String) {
     trace = new Trace.parse(stack);
   } else if (stack is StackTrace) {
     trace = new Trace.from(stack);
   } else {
     throw new Exception('Invalid stack type ${stack.runtimeType} for $stack.');
   }
 
-  if (!formatStacks) return trace;
+  if (!filterStacks) return trace;
 
   // Format the stack trace by removing everything above TestCase._runTest,
   // which is usually going to be irrelevant. Also fold together unittest and
   // core library calls so only the function the user called is visible.
   return new Trace(trace.frames.takeWhile((frame) {
     return frame.package != 'unittest' || frame.member != 'TestCase._runTest';
   })).terse.foldFrames((frame) => frame.package == 'unittest' || frame.isCore);
 }