@Test
  public void testGetApplicationContainerContext() {
    ApplicationContainerContext applicationContainerContext = mock(ApplicationContainerContext.class);
    Context context = buildWithApplicationContainerContext(applicationContainerContext);
    assertEquals(applicationContainerContext, context.getApplicationContainerContext());
  }
Given a concrete context, getApplicationContainerContext should return it.
samza-core/src/test/java/org/apache/samza/context/TestContextImpl.java