private static void injectField(MaintenanceStateHelper maintenanceStateHelper, Clusters clusters)
          throws NoSuchFieldException, IllegalAccessException {
    Class<?> maintenanceHelperClass = MaintenanceStateHelper.class;
    Field f = maintenanceHelperClass.getDeclaredField("clusters");
    f.setAccessible(true);
    f.set(maintenanceStateHelper, clusters);
  }
Tests that the service MM state is calculated correctly for an alert.

@throws Exception
ambari-server/src/test/java/org/apache/ambari/server/controller/MaintenanceStateHelperTest.java