Use the stack_trace library in scheduled_test.

pkg/scheduled_test/lib/src/utils.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 utils;
 
 import 'dart:async';
 
+import 'package:stack_trace/stack_trace.dart';
+
 /// A pair of values.
 class Pair<E, F> {
   E first;
   F last;
 
   Pair(this.first, this.last);
 
   String toString() => '($first, $last)';
 
   bool operator==(other) {
@@ skipping 156 matching lines @@
     return map;
   });
 }
 
 /// Returns whether [pattern] matches all of [string].
 bool fullMatch(String string, Pattern pattern) {
   var matches = pattern.allMatches(string);
   if (matches.isEmpty) return false;
   return matches.first.start == 0 && matches.first.end == string.length;
 }
+
+/// Returns a string representation of [trace] that has the core and test frames
+/// folded together.
+String terseTraceString(StackTrace trace) {
+  return new Trace.from(trace).terse.foldFrames((frame) {
+    return frame.package == 'scheduled_test' || frame.package == 'unittest' ||
+        frame.isCore;
+  }).toString().trim();
+}