@Test
public void getClusterToManageFromZoneTestListOfClustersEmpty() {

    List<ClusterVO> clusters = new ArrayList<>();
    Mockito.doReturn(clusters).when(clusterService).listAllClustersOnZone(Mockito.anyLong());
    ClusterVO result = administrationAgent.getClusterToManageFromZone(clusterAdministrationHeuristicAlgorithm, null);
    Assert.assertNull(result);
    verifyGetClusterToManageFromZoneCalledMethods(0, 0, 0);
}