source, reference = data['citations'][0], data['reference_fixture'][0]
mismatch = [key for key in ['author', 'year'] if source[key] != reference[key]]
check('差异字段与参考fixture逐项比较一致', sorted(output['issues'][0]['mismatch_fields']) == sorted(mismatch))
result = {'fixture_only': True, 'reference_lookup_performed': False, 'issues': output['issues']}
