Use package:stack_trace in unittest.

pkg/unittest/lib/compact_vm_config.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 test configuration that generates a compact 1-line progress bar. The bar is
  * updated in-place before and after each test is executed. If all test pass,
  * you should only see a couple lines in the terminal. If a test fails, the
  * failure is shown and the progress bar continues to be updated below it.
  */
 library compact_vm_config;
 
 import 'dart:io';
+
 import 'unittest.dart';
+import 'src/utils.dart';
 import 'vm_config.dart';
 
 const String _GREEN = '\u001b[32m';
 const String _RED = '\u001b[31m';
 const String _NONE = '\u001b[0m';
 const int MAX_LINE = 80;
 
 class CompactVMConfiguration extends VMConfiguration {
   DateTime _start;
   int _pass = 0;
@@ skipping 16 matching lines @@
   void onTestResult(TestCase test) {
     super.onTestResult(test);
     if (test.result == PASS) {
       _pass++;
       _progressLine(_start, _pass, _fail, test.description);
     } else {
       _fail++;
       _progressLine(_start, _pass, _fail, test.description);
       print('');
       if (test.message != '') {
-        print(_indent(test.message));
+        print(indent(test.message));
       }
 
-      if (test.stackTrace != null && test.stackTrace != '') {
-        print(_indent(test.stackTrace));
+      if (test.stackTrace != null) {
+        print(indent(test.stackTrace.toString()));
       }
     }
   }
 
-  String _indent(String str) {
-    return str.split("\n").map((line) => "  $line").join("\n");
-  }
-
   void onSummary(int passed, int failed, int errors, List<TestCase> results,
       String uncaughtError) {
     var success = false;
     if (passed == 0 && failed == 0 && errors == 0 && uncaughtError == null) {
       print('\nNo tests ran.');
     } else if (failed == 0 && errors == 0 && uncaughtError == null) {
       _progressLine(_start, _pass, _fail, 'All tests pass', _GREEN);
       print('\nAll $passed tests passed.');
       success = true;
     } else {
@@ skipping 94 matching lines @@
     }
     return '...$res';
   }
 }
 
 void useCompactVMConfiguration() {
   unittestConfiguration = _singleton;
 }
 
 final _singleton = new CompactVMConfiguration();