@Test
  public void testUpdateContainerParentAccountId() {
    ContainerBuilder containerBuilder = new ContainerBuilder(refContainers.get(0)).setParentAccountId(refAccountId);
    short newParentAccountId = (short) (refAccountId + 1);
    containerBuilder.setParentAccountId(newParentAccountId);
    assertEquals("Container's parent account id is incorrectly updated.", newParentAccountId,
        containerBuilder.build().getParentAccountId());
  }
Tests updating the parent account id for a container.
ambry-api/src/test/java/com/github/ambry/account/AccountContainerTest.java