anchor.diff:      manager.addBuildTarget(target, channel);
       var targets = manager.targetsForChanges(
           [WatchEvent(ChangeType.ADD, 'foo/bar/blah/some_file.dart')]);
  -    expect(targets.map((target) => target.target).toList().contains('foo'),
  -        isTrue);
  +    expect(targets.map((target) => target.target), contains('foo'));
       targets = manager.targetsForChanges(
           [WatchEvent(ChangeType.ADD, 'foo/bar/blah/some_test.dart')]);
       expect(targets.isEmpty, isTrue);
  
positive.code:     var channelB = DummyChannel();
      var targetA = DefaultBuildTarget((b) => b..target = 'foo');
      manager.addBuildTarget(targetA, channelA);
      expect(
          manager.targets.map((target) => target.target).toList().contains('foo'),
          isTrue);
      var targetB = DefaultBuildTarget((b) => b..target = 'bar');
      manager.addBuildTarget(targetB, channelB);
      expect(manager.targets.isNotEmpty, isTrue);
  
negative.code:     var target = DefaultBuildTarget((b) => b..target = 'foo');
      expect(manager.targets.isEmpty, isTrue);
      manager.addBuildTarget(target, channel);
      expect(manager.targets.map((target) => target.target), contains('foo'));
    });
  
    test('returns an empty set when no channels are interested', () {
  