@Test
public void testAssertDisplayNameDoesNotExistForTagWithNullTagEntity()
{

    // Setup when clauses
    when(tagDao.getTagByTagTypeAndDisplayName(TAG_CODE, TAG_DISPLAY_NAME)).thenReturn(null);
    // Call method under test
    try
    {
        tagDaoHelper.assertDisplayNameDoesNotExistForTag(TAG_CODE, TAG_DISPLAY_NAME);
    }
    catch (AlreadyExistsException alreadyExistsException)
    {
        // Confirm the exception does not occur
        fail("Should not have caught an exception.");
    }
    // Setup verify clauses
    verify(tagDao).getTagByTagTypeAndDisplayName(TAG_CODE, TAG_DISPLAY_NAME);
    verifyNoMoreInteractions(configurationHelper, tagDao);
}