code: @Test public void testCreateServiceComponent() throws AmbariException {
    String componentName="DATANODE2";
    ServiceComponent component=serviceComponentFactory.createNew(service,componentName);
    service.addServiceComponent(component);
    component.persist();
    ServiceComponent sc=service.getServiceComponent(componentName);
    Assert.assertNotNull(sc);
    Assert.assertEquals(componentName,sc.getName());
    Assert.assertEquals(serviceName,sc.getServiceName());
    Assert.assertEquals(cluster.getClusterId(),sc.getClusterId());
    Assert.assertEquals(cluster.getClusterName(),sc.getClusterName());
    Assert.assertEquals(State.INIT,sc.getDesiredState());
    Assert.assertFalse(sc.getDesiredStackVersion().getStackId().isEmpty());
  }
  