@Test
public void testGetEntityByClusterAndApp() throws Exception {

  // Cluster and AppId should be enough to get an entity.
  TimelineEntity result = reader.getEntity(
      new TimelineReaderContext("cluster1", null, null, null, "app1", "app",
      "id_1"),
      new TimelineDataToRetrieve(null, null, null, null, null, null));
  Assert.assertEquals(
      (new TimelineEntity.Identifier("app", "id_1")).toString(),
      result.getIdentifier().toString());
  Assert.assertEquals((Long)1425016502000L, result.getCreatedTime());
  Assert.assertEquals(0, result.getConfigs().size());
  Assert.assertEquals(0, result.getMetrics().size());
}