public void testGetServiceComponents() throws AmbariException {
clusters.addCluster("c1");
Cluster c1 = clusters.getCluster("c1");
c1.setDesiredStackVersion(new StackId("HDP-0.2"));
Service s1 = serviceFactory.createNew(c1, "HDFS");
c1.addService(s1);
s1.setDesiredState(State.INSTALLED);
s1.persist();
ServiceComponent sc1 = serviceComponentFactory.createNew(s1, "DATANODE");
s1.addServiceComponent(sc1);
sc1.persist();