@Before
  public void before() {
    resetAll();
    testSubject = new ConfigureClusterTask(clusterTopology, clusterConfigurationRequest, ambariEventPublisher);
  }
Unit test for the ConfigureClusterTask class.
As business methods of this class don't return values, the assertions are made by verifying method calls on mocks.
Thus having strict mocks is essential!
ambari-server/src/test/java/org/apache/ambari/server/topology/ConfigureClusterTaskTest.java