base_test_mixins.py

        if not prevent_discarding_revisions:
            data["prevent_discarding_revisions"] = ["on"]

        if not fetch_update:
            data["update"] = ["Update"]
        else:
            data["fetch_update"] = ["Fetch and update"]

        force_login_user = None
        if force_login_instructor:
            force_login_user = self.get_default_instructor_user(course.identifier)

        with self.temporarily_switch_to_user(force_login_user):
            response = self.c.post(
                self.get_update_course_url(course.identifier), data)
            course.refresh_from_db()

        return response

    def get_page_data_by_page_id(
            self, page_id, course_identifier=None, flow_session_id=None):
        flow_params = self.get_flow_params(course_identifier, flow_session_id)
        return FlowPageData.objects.get(
            flow_session_id=flow_params["flow_session_id"], page_id=page_id)

    def get_page_visits(self, course_identifier=None,
                        flow_session_id=None, page_ordinal=None, page_id=None,
                        **kwargs):
        query_kwargs = {}
        if kwargs.get("answer_visit", False):
            query_kwargs.update({"answer__isnull": False})
        flow_params = self.get_flow_params(course_identifier, flow_session_id)
        query_kwargs.update({"flow_session_id": flow_params["flow_session_id"]})
        if page_ordinal is not None:
            query_kwargs.update({"page_data__page_ordinal": page_ordinal})
        elif page_id is not None:
            query_kwargs.update({"page_data__page_id": page_id})
        return FlowPageVisit.objects.filter(**query_kwargs)

    def get_last_answer_visit(self, course_identifier=None,
                              flow_session_id=None, page_ordinal=None,
                              page_id=None, assert_not_none=True):
        result_qset = self.get_page_visits(course_identifier,
                                           flow_session_id, page_ordinal, page_id,
                                           answer_visit=True).order_by('-pk')[:1]
        if result_qset:
            result = result_qset[0]
        else:
            result = None
        if assert_not_none:
            self.assertIsNotNone(result, "The query returns None")
        return result


class SingleCourseTestMixin(CoursesTestMixinBase):
    courses_setup_list = SINGLE_COURSE_SETUP_LIST

    @classmethod
    def setUpTestData(cls):  # noqa
        super(SingleCourseTestMixin, cls).setUpTestData()
        assert len(cls.course_qset) == 1
        cls.course = cls.course_qset.first()
        cls.instructor_participation = Participation.objects.filter(
            course=cls.course,
            roles__identifier="instructor",
            status=participation_status.active
        ).first()
        assert cls.instructor_participation

        cls.student_participation = Participation.objects.filter(
            course=cls.course,
            roles__identifier="student",
            status=participation_status.active
        ).first()
        assert cls.student_participation

        cls.ta_participation = Participation.objects.filter(
            course=cls.course,
            roles__identifier="ta",
            status=participation_status.active
        ).first()
        assert cls.ta_participation
        cls.c.logout()
        cls.course_page_url = cls.get_course_page_url()

    def setUp(self):  # noqa
        super(SingleCourseTestMixin, self).setUp()

        # reload objects created during setUpTestData in case they were modified in
        # tests. Ref: https://goo.gl/AuzJRC#django.test.TestCase.setUpTestData
        self.course.refresh_from_db()
        self.instructor_participation.refresh_from_db()
        self.student_participation.refresh_from_db()
        self.ta_participation.refresh_from_db()

    @classmethod
    def get_default_course(cls):
        return cls.course

    @classmethod
    def get_default_course_identifier(cls):
        return cls.get_default_course().identifier

    def copy_course_dict_and_set_attrs_for_post(self, attrs_dict={}):
        from course.models import Course
        kwargs = Course.objects.first().__dict__
        kwargs.update(attrs_dict)

        import six
        for k, v in six.iteritems(kwargs):
            if v is None:
                kwargs[k] = ""
        return kwargs


class TwoCourseTestMixin(CoursesTestMixinBase):
    courses_setup_list = []

    @classmethod
    def setUpTestData(cls):  # noqa
        super(TwoCourseTestMixin, cls).setUpTestData()
        assert len(cls.course_qset) == 2, (
            "'courses_setup_list' should contain two courses")
        cls.course1 = cls.course_qset.first()
        cls.course1_instructor_participation = Participation.objects.filter(
            course=cls.course1,
            roles__identifier="instructor",
            status=participation_status.active
        ).first()
        assert cls.course1_instructor_participation

        cls.course1_student_participation = Participation.objects.filter(
            course=cls.course1,
            roles__identifier="student",
            status=participation_status.active
        ).first()
        assert cls.course1_student_participation

        cls.course1_ta_participation = Participation.objects.filter(
            course=cls.course1,
            roles__identifier="ta",
            status=participation_status.active
        ).first()
        assert cls.course1_ta_participation
        cls.course1_page_url = cls.get_course_page_url(cls.course1.identifier)

        cls.course2 = cls.course_qset.last()
        cls.course2_instructor_participation = Participation.objects.filter(
            course=cls.course2,
            roles__identifier="instructor",
            status=participation_status.active
        ).first()
        assert cls.course2_instructor_participation

        cls.course2_student_participation = Participation.objects.filter(
            course=cls.course2,
            roles__identifier="student",
            status=participation_status.active
        ).first()
        assert cls.course2_student_participation

        cls.course2_ta_participation = Participation.objects.filter(
            course=cls.course2,
            roles__identifier="ta",
            status=participation_status.active
        ).first()
        assert cls.course2_ta_participation
        cls.course2_page_url = cls.get_course_page_url(cls.course2.identifier)

        cls.c.logout()

    def setUp(self):  # noqa
        super(TwoCourseTestMixin, self).setUp()
        # reload objects created during setUpTestData in case they were modified in
        # tests. Ref: https://goo.gl/AuzJRC#django.test.TestCase.setUpTestData
        self.course1.refresh_from_db()
        self.course1_instructor_participation.refresh_from_db()
        self.course1_student_participation.refresh_from_db()
        self.course1_ta_participation.refresh_from_db()

        self.course2.refresh_from_db()
        self.course2_instructor_participation.refresh_from_db()
        self.course2_student_participation.refresh_from_db()
        self.course2_ta_participation.refresh_from_db()


class SingleCoursePageTestMixin(SingleCourseTestMixin):
    # This serves as cache
    _default_session_id = None

    @property
    def flow_id(self):
        raise NotImplementedError

    @classmethod
    def update_default_flow_session_id(cls, course_identifier):
        cls._default_session_id = cls.default_flow_params["flow_session_id"]

    def get_default_flow_session_id(self, course_identifier):
        if self._default_session_id is not None:
            return self._default_session_id
        self._default_session_id = self.get_latest_session_id(course_identifier)
        return self._default_session_id


class TwoCoursePageTestMixin(TwoCourseTestMixin):
    _course1_default_session_id = None
    _course2_default_session_id = None

    @property
    def flow_id(self):
        raise NotImplementedError

    def get_default_flow_session_id(self, course_identifier):
        if course_identifier == self.course1.identifier:
            if self._course1_default_session_id is not None:
                return self._course1_default_session_id
            self._course1_default_session_id = (
                self.get_last_session_id(course_identifier))
            return self._course1_default_session_id
        if course_identifier == self.course2.identifier:
            if self._course2_default_session_id is not None:
                return self._course2_default_session_id
            self._course2_default_session_id = (
                self.get_last_session_id(course_identifier))
            return self._course2_default_session_id

    @classmethod
    def update_default_flow_session_id(cls, course_identifier):
        new_session_id = cls.default_flow_params["flow_session_id"]
        if course_identifier == cls.course1.identifier:
            cls._course1_default_session_id = new_session_id
        elif course_identifier == cls.course2.identifier:
            cls._course2_default_session_id = new_session_id


class FallBackStorageMessageTestMixin(object):
    # In case other message storage are used, the following is the default
    # storage used by django and RELATE. Tests which concerns the message
    # should not include this mixin.
    storage = 'django.contrib.messages.storage.fallback.FallbackStorage'

    def setUp(self):  # noqa
        super(FallBackStorageMessageTestMixin, self).setUp()
        self.settings_override = override_settings(MESSAGE_STORAGE=self.storage)
        self.settings_override.enable()

    def tearDown(self):  # noqa
        self.settings_override.disable()

    def get_listed_storage_from_response(self, response):
        return list(self.get_response_context_value_by_name(response, 'messages'))

    def clear_message_response_storage(self, response):
        # this should only be used for debug, because we are using private method
        # which might change
        try:
            storage = self.get_response_context_value_by_name(response, 'messages')
        except AssertionError:
            # message doesn't exist in response context
            return
        if hasattr(storage, '_loaded_data'):
            storage._loaded_data = []
        elif hasattr(storage, '_loaded_message'):
            storage._loaded_messages = []

        if hasattr(storage, '_queued_messages'):
            storage._queued_messages = []

        self.assertEqual(len(storage), 0)

    def assertResponseMessagesCount(self, response, expected_count):  # noqa
        storage = self.get_listed_storage_from_response(response)
        self.assertEqual(len(storage), expected_count)

    def assertResponseMessagesEqual(self, response, expected_messages):  # noqa
        storage = self.get_listed_storage_from_response(response)
        if not isinstance(expected_messages, list):
            expected_messages = [expected_messages]
        self.assertEqual(len([m for m in storage]), len(expected_messages))
        self.assertEqual([m.message for m in storage], expected_messages)

    def assertResponseMessagesEqualRegex(self, response, expected_message_regexs):  # noqa
        storage = self.get_listed_storage_from_response(response)
        if not isinstance(expected_message_regexs, list):
            expected_message_regexs = [expected_message_regexs]
        self.assertEqual(len([m for m in storage]), len(expected_message_regexs))
        messages = [m.message for m in storage]
        for idx, m in enumerate(messages):
            six.assertRegex(self, m, expected_message_regexs[idx])

    def assertResponseMessagesContains(self, response, expected_messages):  # noqa
        storage = self.get_listed_storage_from_response(response)
        if isinstance(expected_messages, str):
            expected_messages = [expected_messages]
        messages = [m.message for m in storage]
        for em in expected_messages:
            self.assertIn(em, messages)

    def assertResponseMessageLevelsEqual(self, response, expected_levels):  # noqa
        storage = self.get_listed_storage_from_response(response)
        self.assertEqual([m.level for m in storage], expected_levels)

    def debug_print_response_messages(self, response):
        """
        For debugging :class:`django.contrib.messages` objects in post response
        :param response: response
        """
        try:
            storage = self.get_listed_storage_from_response(response)
            print("\n-----------message start (%i total)-------------"
                  % len(storage))
            for m in storage:
                print(m.message)
            print("-----------message end-------------\n")
        except KeyError:
            print("\n-------no message----------")


class SubprocessRunpyContainerMixin(object):
    """
    This mixin is used to fake a runpy container, only needed when
    the TestCase include test(s) for code questions
    """
    @classmethod
    def setUpClass(cls):  # noqa
        if six.PY2:
            from unittest import SkipTest
            raise SkipTest("In process fake container is configured for "
                           "PY3 only, since currently runpy docker only "
                           "provide PY3 envrionment")

        super(SubprocessRunpyContainerMixin, cls).setUpClass()
        cls.faked_container_patch = mock.patch(
            "course.page.code.SPAWN_CONTAINERS_FOR_RUNPY", False)
        cls.faked_container_patch.start()

        python_executable = os.getenv("PY_EXE")

        if not python_executable:
            import sys
            python_executable = sys.executable

        import subprocess
        args = [python_executable,
                os.path.abspath(
                    os.path.join(
                        os.path.dirname(__file__), os.pardir,
                        "docker-image-run-py", "runpy")),
                ]
        cls.faked_container_process = subprocess.Popen(
            args,
            stdout=subprocess.DEVNULL,

            # because runpy prints to stderr
            stderr=subprocess.DEVNULL
        )

        cls.faked_container_patch.start()

    @classmethod
    def tearDownClass(cls):  # noqa
        super(SubprocessRunpyContainerMixin, cls).tearDownClass()
        cls.faked_container_patch.stop()
        cls.faked_container_process.kill()


def improperly_configured_cache_patch():
    # can be used as context manager or decorator
    if six.PY3:
        built_in_import_path = "builtins.__import__"
        import builtins  # noqa
    else:
        built_in_import_path = "__builtin__.__import__"
        import __builtin__ as builtins  # noqa
    built_in_import = builtins.__import__

    def my_disable_cache_import(name, globals=None, locals=None, fromlist=(),
                                level=0):
        if name == "django.core.cache":
            raise ImproperlyConfigured()
        return built_in_import(name, globals, locals, fromlist, level)

    return mock.patch(built_in_import_path, side_effect=my_disable_cache_import)

# vim: fdm=marker