public Set<String> excludedTopics(ClusterModel clusterModel, Pattern requestedExcludedTopics) {
    Pattern topicsToExclude = requestedExcludedTopics != null ? requestedExcludedTopics : _defaultExcludedTopics;
    return Utils.getTopicNamesMatchedWithPattern(topicsToExclude, clusterModel::topics);
  }
@Test
  public void testGetNoExcludedTopics() {
    GoalOptimizer goalOptimizer = createGoalOptimizer();
    ClusterModel clusterModel = EasyMock.mock(ClusterModel.class);
    EasyMock.expect(clusterModel.topics()).andThrow(new AssertionFailedError("Not expect this method gets called")).anyTimes();
    EasyMock.replay(clusterModel);
    Set<String> excludedTopics = goalOptimizer.excludedTopics(clusterModel, null);
    Assert.assertTrue(excludedTopics.isEmpty());
    EasyMock.verify(clusterModel);

    EasyMock.reset(clusterModel);
    EasyMock.replay(clusterModel);
    Pattern matchNothingPattern = Pattern.compile("");
    excludedTopics = goalOptimizer.excludedTopics(clusterModel, matchNothingPattern);
    Assert.assertTrue(excludedTopics.isEmpty());
    EasyMock.verify(clusterModel);
  }