tests: import unittest via package: url

tests/lib/async/stream_from_iterable_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.
 
 // Test merging streams.
 library dart.test.stream_from_iterable;
 
 import "package:expect/expect.dart";
 import "dart:async";
-import '../../../pkg/unittest/lib/unittest.dart';
+import 'package:unittest/unittest.dart';
 import 'event_helper.dart';
 
 class IterableTest<T> {
   static int counter = 0;
   Iterable<T> iterable;
   IterableTest(this.iterable);
   void run() {
     test("stream from iterable ${counter++}", () {
       Events expected = new Events.fromIterable(iterable);
       Stream<T> stream = new Stream<T>.fromIterable(iterable);
@@ skipping 121 matching lines @@
       Expect.listEquals([1, 3, 5], data);
       Expect.listEquals([2, 4], errors);
       done();
     });
     c.addStream(from, cancelOnError: false).then((_) {
       c.close();
       done();
     });
   });
 }