@Test
public void testPerformHostOrdered() throws Exception {

  final HostMaintenanceModeCheck hostMaintenanceModeCheck = new HostMaintenanceModeCheck();
  hostMaintenanceModeCheck.clustersProvider = new Provider<Clusters>() {
    @Override
    public Clusters get() {
      return clusters;
    }
  };
  final Cluster cluster = Mockito.mock(Cluster.class);
  Mockito.when(cluster.getClusterId()).thenReturn(1L);
  Mockito.when(cluster.getCurrentStackVersion()).thenReturn(new StackId("HDP", "2.2"));
  Mockito.when(clusters.getCluster("cluster")).thenReturn(cluster);
  final List<Host> hosts = new ArrayList<>();
  final Host host1 = Mockito.mock(Host.class);
  final Host host2 = Mockito.mock(Host.class);
  final Host host3 = Mockito.mock(Host.class);
  Mockito.when(host1.getMaintenanceState(1L)).thenReturn(MaintenanceState.OFF);
  Mockito.when(host2.getMaintenanceState(1L)).thenReturn(MaintenanceState.OFF);
  Mockito.when(host3.getMaintenanceState(1L)).thenReturn(MaintenanceState.OFF);
  Mockito.when(host1.getHostName()).thenReturn("h1");
  Mockito.when(host2.getHostName()).thenReturn("h2");
  Mockito.when(host3.getHostName()).thenReturn("h3");
  hosts.add(host1);
  hosts.add(host2);
  hosts.add(host3);
  Mockito.when(cluster.getHosts()).thenReturn(hosts);
  PrerequisiteCheck check = new PrerequisiteCheck(null, null);
  hostMaintenanceModeCheck.perform(check, new PrereqCheckRequest("cluster"));
  Assert.assertEquals(PrereqCheckStatus.PASS, check.getStatus());
  // put a host into MM in order to trigger the warning
  check = new PrerequisiteCheck(null, null);
  Mockito.when(host3.getMaintenanceState(1L)).thenReturn(MaintenanceState.ON);
  hostMaintenanceModeCheck.perform(check, new PrereqCheckRequest("cluster", UpgradeType.HOST_ORDERED));
  Assert.assertEquals(PrereqCheckStatus.FAIL, check.getStatus());
  Assert.assertEquals("The following hosts cannot be in Maintenance Mode: h3.", check.getFailReason());
}