@Test
  public void manyToOne_setAccount() {
    Document many = new Document();

    // init
    Account one = new Account();

    one.setId(ValueGenerator.getUniqueString(32));
    many.setAccount(one);

    // make sure it is propagated properly
    assertNotNull(many.getAccountId());
    assertEquals(one, many.getAccount());
    assertSame(many.getAccountId(), one.getId());
    // now set it to back to null
    many.setAccount(null);

    // make sure null is propagated properly
    assertNull(many.getAccount());

    // make sure it is propagated on fk column as well
    assertNull(many.getAccountId());
  }