@Test
public void testPerform() throws Exception {

  final HostsHeartbeatCheck hostHeartbeatCheck = new HostsHeartbeatCheck();
  hostHeartbeatCheck.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);
  final HostHealthStatus status1 = Mockito.mock(HostHealthStatus.class);
  final HostHealthStatus status2 = Mockito.mock(HostHealthStatus.class);
  final HostHealthStatus status3 = Mockito.mock(HostHealthStatus.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.getHealthStatus()).thenReturn(status1);
  Mockito.when(host2.getHealthStatus()).thenReturn(status2);
  Mockito.when(host3.getHealthStatus()).thenReturn(status3);
  Mockito.when(status1.getHealthStatus()).thenReturn(HealthStatus.HEALTHY);
  Mockito.when(status2.getHealthStatus()).thenReturn(HealthStatus.HEALTHY);
  Mockito.when(status3.getHealthStatus()).thenReturn(HealthStatus.UNKNOWN);
  hosts.add(host1);
  hosts.add(host2);
  hosts.add(host3);
  Mockito.when(cluster.getHosts()).thenReturn(hosts);
  PrerequisiteCheck check = new PrerequisiteCheck(null, null);
  hostHeartbeatCheck.perform(check, new PrereqCheckRequest("cluster"));
  Assert.assertEquals(PrereqCheckStatus.FAIL, check.getStatus());
  // put the unhealthy host into MM which will allow this check to pass
  check = new PrerequisiteCheck(null, null);
  Mockito.when(host3.getMaintenanceState(1L)).thenReturn(MaintenanceState.ON);
  hostHeartbeatCheck.perform(check, new PrereqCheckRequest("cluster"));
  Assert.assertEquals(PrereqCheckStatus.PASS, check.getStatus());
  // make the host healthy and take it out of MM to produce a PASS result
  Mockito.when(status3.getHealthStatus()).thenReturn(HealthStatus.HEALTHY);
  check = new PrerequisiteCheck(null, null);
  Mockito.when(host3.getMaintenanceState(1L)).thenReturn(MaintenanceState.OFF);
  hostHeartbeatCheck.perform(check, new PrereqCheckRequest("cluster"));
  Assert.assertEquals(PrereqCheckStatus.PASS, check.getStatus());
}