@Test
  public void testGroupNotExists() {

    DBUserGroupCallbackImpl callback = new DBUserGroupCallbackImpl(props);
    boolean exists = callback.existsGroup("HR");
    assertFalse(exists);
  }
  @Test
  public void testGroupExists() {

    DBUserGroupCallbackImpl callback = new DBUserGroupCallbackImpl(props);
    boolean exists = callback.existsGroup("PM");
    assertTrue(exists);
  }