@Test(expected = IllegalArgumentException.class)
  public void testCreateClusterWithInvalidRequest2() throws Exception {
    ClusterRequest r = new ClusterRequest(1L, null, null, null);
    controller.createCluster(r);
  }
Allows to set maintenanceStateHelper. For use when there is anything to test
with maintenance mode.
ambari-server/src/test/java/org/apache/ambari/server/controller/AmbariManagementControllerTest.java