def METHOD_NAME(self, mock_set_options, mock_get_option, mock_template):
    results = self.merge_vars_lookup.run(['__merge_list'], {
        'testlist1__merge_list': ['item1'],
        'testlist2': ['item2'],
        'testlist3__merge_list': ['item3']
    })
    self.assertEqual(results, [['item1', 'item3']])