code: /** 
   * persistence provider is responsible for returning empty collection if relation doesn't exists
   */
  @Test public void testEmptyPersistentCollection(){
    String testClusterName="test_cluster2";
    ClusterEntity clusterEntity=new ClusterEntity();
    clusterEntity.setClusterName(testClusterName);
    ClusterDAO clusterDAO=injector.getInstance(ClusterDAO.class);
    clusterDAO.create(clusterEntity);
    clusterEntity=clusterDAO.findByName(clusterEntity.getClusterName());
    assertTrue("empty relation wasn't instantiated",clusterEntity.getHostEntities() != null);
  }
  