Use the new test runner.

test/error_group_test.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 error_group_test;
 
 import 'dart:async';
 
 import 'package:pub/src/error_group.dart';
 import 'package:pub/src/utils.dart';
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 
 ErrorGroup errorGroup;
 
 // TODO(nweiz): once there's a global error handler, we should test that it does
 // and does not get called at appropriate times. See issue 5958.
 //
 // One particular thing we should test that has no tests now is that a stream
 // that has a subscription added and subsequently canceled counts as having no
 // listeners.
 
@@ skipping 414 matching lines @@
              completion(equals(['value1', 'value2'])));
       controller..add('value1')..add('value2')..close();
 
       expect(signal.future.then((_) {
         // shouldn't cause a top-level exception
         completer.completeError(new FormatException());
       }), completes);
     });
   });
 }