import importlib import unittest from io import StringIO from django.core import management, serializers from django.core.serializers.base import DeserializationError from django.test import SimpleTestCase, TestCase, TransactionTestCase from .models import Author from .tests import SerializersTestBase, SerializersTransactionTestBase try: import yaml HAS_YAML = True except ImportError: HAS_YAML = False YAML_IMPORT_ERROR_MESSAGE = r"No module named yaml" class YamlImportModuleMock: """Provides a wrapped import_module function to simulate yaml ImportError In order to run tests that verify the behavior of the YAML serializer when run on a system that has yaml installed (like the django CI server), mock import_module, so that it raises an ImportError when the yaml serializer is being imported. The importlib.import_module() call is being made in the serializers.register_serializer(). Refs: #12756 """ def __init__(self): self._import_module = importlib.import_module def import_module(self, module_path): if module_path == serializers.BUILTIN_SERIALIZERS["yaml"]: raise ImportError(YAML_IMPORT_ERROR_MESSAGE) return self._import_module(module_path) class NoYamlSerializerTestCase(SimpleTestCase): """Not having pyyaml installed provides a misleading error Refs: #12756 """ @classmethod def setUpClass(cls): """Removes imported yaml and stubs importlib.import_module""" super().setUpClass() cls._import_module_mock = YamlImportModuleMock() importlib.import_module = cls._import_module_mock.import_module # clear out cached serializers to emulate yaml missing serializers._serializers = {} @classmethod def tearDownClass(cls): """Puts yaml back if necessary""" super().tearDownClass() importlib.import_module = cls._import_module_mock._import_module # clear out cached serializers to clean out BadSerializer instances serializers._serializers = {} def test_serializer_pyyaml_error_message(self): """Using yaml serializer without pyyaml raises ImportError""" jane = Author(name="Jane") with self.assertRaises(ImportError): serializers.serialize("yaml", [jane]) def test_deserializer_pyyaml_error_message(self): """Using yaml deserializer without pyyaml raises ImportError""" with self.assertRaises(ImportError): serializers.deserialize("yaml", "") def test_dumpdata_pyyaml_error_message(self): """Calling dumpdata produces an error when yaml package missing""" with self.assertRaisesMessage( management.CommandError, YAML_IMPORT_ERROR_MESSAGE ): management.call_command("dumpdata", format="yaml") @unittest.skipUnless(HAS_YAML, "No yaml library detected") class YamlSerializerTestCase(SerializersTestBase, TestCase): serializer_name = "yaml" pkless_str = """- model: serializers.category pk: null fields: name: Reference - model: serializers.category fields: name: Non-fiction""" mapping_ordering_str = ( """- model: serializers.article pk: %(article_pk)s fields: author: %(author_pk)s headline: Poker has no place on ESPN pub_date: 2006-06-16 11:00:00 categories:""" + ( " [%(first_category_pk)s, %(second_category_pk)s]" if HAS_YAML and yaml.__version__ < "5.1" else "\n - %(first_category_pk)s\n - %(second_category_pk)s" ) + """ meta_data: [] topics: [] """ ) @staticmethod def _validate_output(serial_str): try: yaml.safe_load(StringIO(serial_str)) except Exception: return False else: return True @staticmethod def _get_pk_values(serial_str): ret_list = [] stream = StringIO(serial_str) for obj_dict in yaml.safe_load(stream): ret_list.append(obj_dict["pk"]) return ret_list @staticmethod def _get_field_values(serial_str, field_name): ret_list = [] stream = StringIO(serial_str) for obj_dict in yaml.safe_load(stream): if "fields" in obj_dict and field_name in obj_dict["fields"]: field_value = obj_dict["fields"][field_name] # yaml.safe_load will return non-string objects for some # of the fields we are interested in, this ensures that # everything comes back as a string if isinstance(field_value, str): ret_list.append(field_value) else: ret_list.append(str(field_value)) return ret_list def test_yaml_deserializer_exception(self): with self.assertRaises(DeserializationError): for obj in serializers.deserialize("yaml", "{"): pass @unittest.skipUnless(HAS_YAML, "No yaml library detected") class YamlSerializerTransactionTestCase( SerializersTransactionTestBase, TransactionTestCase ): serializer_name = "yaml" fwd_ref_str = """- model: serializers.article pk: 1 fields: headline: Forward references pose no problem pub_date: 2006-06-16 15:00:00 categories: [1] author: 1 - model: serializers.category pk: 1 fields: name: Reference - model: serializers.author pk: 1 fields: name: Agnes"""