test_serializers.py

"""
Tests for Discussion API serializers
"""
import itertools
from urlparse import urlparse

import ddt
import httpretty
import mock
from django.test.client import RequestFactory
from nose.plugins.attrib import attr

from discussion_api.serializers import CommentSerializer, ThreadSerializer, get_context
from discussion_api.tests.utils import CommentsServiceMockMixin, make_minimal_cs_comment, make_minimal_cs_thread
from django_comment_client.tests.utils import ForumsEnableMixin
from django_comment_common.models import (
    FORUM_ROLE_ADMINISTRATOR,
    FORUM_ROLE_COMMUNITY_TA,
    FORUM_ROLE_MODERATOR,
    FORUM_ROLE_STUDENT,
    Role
)
from lms.lib.comment_client.comment import Comment
from lms.lib.comment_client.thread import Thread
from openedx.core.djangoapps.course_groups.tests.helpers import CohortFactory
from student.tests.factories import UserFactory
from util.testing import UrlResetMixin
from xmodule.modulestore import ModuleStoreEnum
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory


@ddt.ddt
class SerializerTestMixin(ForumsEnableMixin, CommentsServiceMockMixin, UrlResetMixin):
    @classmethod
    @mock.patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
    def setUpClass(cls):
        super(SerializerTestMixin, cls).setUpClass()
        cls.course = CourseFactory.create()

    @mock.patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
    def setUp(self):
        super(SerializerTestMixin, self).setUp()
        httpretty.reset()
        httpretty.enable()
        self.addCleanup(httpretty.disable)
        self.maxDiff = None  # pylint: disable=invalid-name
        self.user = UserFactory.create()
        self.register_get_user_response(self.user)
        self.request = RequestFactory().get("/dummy")
        self.request.user = self.user
        self.author = UserFactory.create()

    def create_role(self, role_name, users, course=None):
        """Create a Role in self.course with the given name and users"""
        course = course or self.course
        role = Role.objects.create(name=role_name, course_id=course.id)
        role.users = users

    @ddt.data(
        (FORUM_ROLE_ADMINISTRATOR, True, False, True),
        (FORUM_ROLE_ADMINISTRATOR, False, True, False),
        (FORUM_ROLE_MODERATOR, True, False, True),
        (FORUM_ROLE_MODERATOR, False, True, False),
        (FORUM_ROLE_COMMUNITY_TA, True, False, True),
        (FORUM_ROLE_COMMUNITY_TA, False, True, False),
        (FORUM_ROLE_STUDENT, True, False, True),
        (FORUM_ROLE_STUDENT, False, True, True),
    )
    @ddt.unpack
    def test_anonymity(self, role_name, anonymous, anonymous_to_peers, expected_serialized_anonymous):
        """
        Test that content is properly made anonymous.

        Content should be anonymous iff the anonymous field is true or the
        anonymous_to_peers field is true and the requester does not have a
        privileged role.

        role_name is the name of the requester's role.
        anonymous is the value of the anonymous field in the content.
        anonymous_to_peers is the value of the anonymous_to_peers field in the
          content.
        expected_serialized_anonymous is whether the content should actually be
          anonymous in the API output when requested by a user with the given
          role.
        """
        self.create_role(role_name, [self.user])
        serialized = self.serialize(
            self.make_cs_content({"anonymous": anonymous, "anonymous_to_peers": anonymous_to_peers})
        )
        actual_serialized_anonymous = serialized["author"] is None
        self.assertEqual(actual_serialized_anonymous, expected_serialized_anonymous)

    @ddt.data(
        (FORUM_ROLE_ADMINISTRATOR, False, "Staff"),
        (FORUM_ROLE_ADMINISTRATOR, True, None),
        (FORUM_ROLE_MODERATOR, False, "Staff"),
        (FORUM_ROLE_MODERATOR, True, None),
        (FORUM_ROLE_COMMUNITY_TA, False, "Community TA"),
        (FORUM_ROLE_COMMUNITY_TA, True, None),
        (FORUM_ROLE_STUDENT, False, None),
        (FORUM_ROLE_STUDENT, True, None),
    )
    @ddt.unpack
    def test_author_labels(self, role_name, anonymous, expected_label):
        """
        Test correctness of the author_label field.

        The label should be "Staff", "Staff", or "Community TA" for the
        Administrator, Moderator, and Community TA roles, respectively, but
        the label should not be present if the content is anonymous.

        role_name is the name of the author's role.
        anonymous is the value of the anonymous field in the content.
        expected_label is the expected value of the author_label field in the
          API output.
        """
        self.create_role(role_name, [self.author])
        serialized = self.serialize(self.make_cs_content({"anonymous": anonymous}))
        self.assertEqual(serialized["author_label"], expected_label)

    def test_abuse_flagged(self):
        serialized = self.serialize(self.make_cs_content({"abuse_flaggers": [str(self.user.id)]}))
        self.assertEqual(serialized["abuse_flagged"], True)

    def test_voted(self):
        thread_id = "test_thread"
        self.register_get_user_response(self.user, upvoted_ids=[thread_id])
        serialized = self.serialize(self.make_cs_content({"id": thread_id}))
        self.assertEqual(serialized["voted"], True)


@attr(shard=3)
@ddt.ddt
class ThreadSerializerSerializationTest(SerializerTestMixin, SharedModuleStoreTestCase):
    """Tests for ThreadSerializer serialization."""
    def make_cs_content(self, overrides):
        """
        Create a thread with the given overrides, plus some useful test data.
        """
        merged_overrides = {
            "course_id": unicode(self.course.id),
            "user_id": str(self.author.id),
            "username": self.author.username,
            "read": True,
            "endorsed": True,
            "resp_total": 0,
        }
        merged_overrides.update(overrides)
        return make_minimal_cs_thread(merged_overrides)

    def serialize(self, thread):
        """
        Create a serializer with an appropriate context and use it to serialize
        the given thread, returning the result.
        """
        return ThreadSerializer(thread, context=get_context(self.course, self.request)).data

    def test_basic(self):
        thread = make_minimal_cs_thread({
            "id": "test_thread",
            "course_id": unicode(self.course.id),
            "commentable_id": "test_topic",
            "user_id": str(self.author.id),
            "username": self.author.username,
            "title": "Test Title",
            "body": "Test body",
            "pinned": True,
            "votes": {"up_count": 4},
            "comments_count": 5,
            "unread_comments_count": 3,
        })
        expected = self.expected_thread_data({
            "author": self.author.username,
            "vote_count": 4,
            "comment_count": 6,
            "unread_comment_count": 3,
            "pinned": True,
            "editable_fields": ["abuse_flagged", "following", "read", "voted"],
        })
        self.assertEqual(self.serialize(thread), expected)

        thread["thread_type"] = "question"
        expected.update({
            "type": "question",
            "comment_list_url": None,
            "endorsed_comment_list_url": (
                "http://testserver/api/discussion/v1/comments/?thread_id=test_thread&endorsed=True"
            ),
            "non_endorsed_comment_list_url": (
                "http://testserver/api/discussion/v1/comments/?thread_id=test_thread&endorsed=False"
            ),
        })
        self.assertEqual(self.serialize(thread), expected)

    def test_pinned_missing(self):
        """
        Make sure that older threads in the comments service without the pinned
        field do not break serialization
        """
        thread_data = self.make_cs_content({})
        del thread_data["pinned"]
        self.register_get_thread_response(thread_data)
        serialized = self.serialize(thread_data)
        self.assertEqual(serialized["pinned"], False)

    def test_group(self):
        self.course.cohort_config = {"cohorted": True}
        modulestore().update_item(self.course, ModuleStoreEnum.UserID.test)
        cohort = CohortFactory.create(course_id=self.course.id)
        serialized = self.serialize(self.make_cs_content({"group_id": cohort.id}))
        self.assertEqual(serialized["group_id"], cohort.id)
        self.assertEqual(serialized["group_name"], cohort.name)

    def test_following(self):
        thread_id = "test_thread"
        self.register_get_user_response(self.user, subscribed_thread_ids=[thread_id])
        serialized = self.serialize(self.make_cs_content({"id": thread_id}))
        self.assertEqual(serialized["following"], True)

    def test_response_count(self):
        thread_data = self.make_cs_content({"resp_total": 2})
        self.register_get_thread_response(thread_data)
        serialized = self.serialize(thread_data)
        self.assertEqual(serialized["response_count"], 2)

    def test_response_count_missing(self):
        thread_data = self.make_cs_content({})
        del thread_data["resp_total"]
        self.register_get_thread_response(thread_data)
        serialized = self.serialize(thread_data)
        self.assertNotIn("response_count", serialized)


@ddt.ddt
class CommentSerializerTest(SerializerTestMixin, SharedModuleStoreTestCase):
    """Tests for CommentSerializer."""
    def setUp(self):
        super(CommentSerializerTest, self).setUp()
        self.endorser = UserFactory.create()
        self.endorsed_at = "2015-05-18T12:34:56Z"

    def make_cs_content(self, overrides=None, with_endorsement=False):
        """
        Create a comment with the given overrides, plus some useful test data.
        """
        merged_overrides = {
            "user_id": str(self.author.id),
            "username": self.author.username
        }
        if with_endorsement:
            merged_overrides["endorsement"] = {
                "user_id": str(self.endorser.id),
                "time": self.endorsed_at
            }
        merged_overrides.update(overrides or {})
        return make_minimal_cs_comment(merged_overrides)

    def serialize(self, comment, thread_data=None):
        """
        Create a serializer with an appropriate context and use it to serialize
        the given comment, returning the result.
        """
        context = get_context(self.course, self.request, make_minimal_cs_thread(thread_data))
        return CommentSerializer(comment, context=context).data

    def test_basic(self):
        comment = {
            "type": "comment",
            "id": "test_comment",
            "thread_id": "test_thread",
            "user_id": str(self.author.id),
            "username": self.author.username,
            "anonymous": False,
            "anonymous_to_peers": False,
            "created_at": "2015-04-28T00:00:00Z",
            "updated_at": "2015-04-28T11:11:11Z",
            "body": "Test body",
            "endorsed": False,
            "abuse_flaggers": [],
            "votes": {"up_count": 4},
            "children": [],
            "child_count": 0,
        }
        expected = {
            "id": "test_comment",
            "thread_id": "test_thread",
            "parent_id": None,
            "author": self.author.username,
            "author_label": None,
            "created_at": "2015-04-28T00:00:00Z",
            "updated_at": "2015-04-28T11:11:11Z",
            "raw_body": "Test body",
            "rendered_body": "<p>Test body</p>",
            "endorsed": False,
            "endorsed_by": None,
            "endorsed_by_label": None,
            "endorsed_at": None,
            "abuse_flagged": False,
            "voted": False,
            "vote_count": 4,
            "children": [],
            "editable_fields": ["abuse_flagged", "voted"],
            "child_count": 0,
        }
        self.assertEqual(self.serialize(comment), expected)

    @ddt.data(
        *itertools.product(
            [
                FORUM_ROLE_ADMINISTRATOR,
                FORUM_ROLE_MODERATOR,
                FORUM_ROLE_COMMUNITY_TA,
                FORUM_ROLE_STUDENT,
            ],
            [True, False]
        )
    )
    @ddt.unpack
    def test_endorsed_by(self, endorser_role_name, thread_anonymous):
        """
        Test correctness of the endorsed_by field.

        The endorser should be anonymous iff the thread is anonymous to the
        requester, and the endorser is not a privileged user.

        endorser_role_name is the name of the endorser's role.
        thread_anonymous is the value of the anonymous field in the thread.
        """
        self.create_role(endorser_role_name, [self.endorser])
        serialized = self.serialize(
            self.make_cs_content(with_endorsement=True),
            thread_data={"anonymous": thread_anonymous}
        )
        actual_endorser_anonymous = serialized["endorsed_by"] is None
        expected_endorser_anonymous = endorser_role_name == FORUM_ROLE_STUDENT and thread_anonymous
        self.assertEqual(actual_endorser_anonymous, expected_endorser_anonymous)

    @ddt.data(
        (FORUM_ROLE_ADMINISTRATOR, "Staff"),
        (FORUM_ROLE_MODERATOR, "Staff"),
        (FORUM_ROLE_COMMUNITY_TA, "Community TA"),
        (FORUM_ROLE_STUDENT, None),
    )
    @ddt.unpack
    def test_endorsed_by_labels(self, role_name, expected_label):
        """
        Test correctness of the endorsed_by_label field.

        The label should be "Staff", "Staff", or "Community TA" for the
        Administrator, Moderator, and Community TA roles, respectively.

        role_name is the name of the author's role.
        expected_label is the expected value of the author_label field in the
          API output.
        """
        self.create_role(role_name, [self.endorser])
        serialized = self.serialize(self.make_cs_content(with_endorsement=True))
        self.assertEqual(serialized["endorsed_by_label"], expected_label)

    def test_endorsed_at(self):
        serialized = self.serialize(self.make_cs_content(with_endorsement=True))
        self.assertEqual(serialized["endorsed_at"], self.endorsed_at)

    def test_children(self):
        comment = self.make_cs_content({
            "id": "test_root",
            "children": [
                self.make_cs_content({
                    "id": "test_child_1",
                    "parent_id": "test_root",
                }),
                self.make_cs_content({
                    "id": "test_child_2",
                    "parent_id": "test_root",
                    "children": [
                        self.make_cs_content({
                            "id": "test_grandchild",
                            "parent_id": "test_child_2"
                        })
                    ],
                }),
            ],
        })
        serialized = self.serialize(comment)
        self.assertEqual(serialized["children"][0]["id"], "test_child_1")
        self.assertEqual(serialized["children"][0]["parent_id"], "test_root")
        self.assertEqual(serialized["children"][1]["id"], "test_child_2")
        self.assertEqual(serialized["children"][1]["parent_id"], "test_root")
        self.assertEqual(serialized["children"][1]["children"][0]["id"], "test_grandchild")
        self.assertEqual(serialized["children"][1]["children"][0]["parent_id"], "test_child_2")


@ddt.ddt
class ThreadSerializerDeserializationTest(
        ForumsEnableMixin,
        CommentsServiceMockMixin,
        UrlResetMixin,
        SharedModuleStoreTestCase
):
    """Tests for ThreadSerializer deserialization."""
    @classmethod
    @mock.patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
    def setUpClass(cls):
        super(ThreadSerializerDeserializationTest, cls).setUpClass()
        cls.course = CourseFactory.create()

    @mock.patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
    def setUp(self):
        super(ThreadSerializerDeserializationTest, self).setUp()
        httpretty.reset()
        httpretty.enable()
        self.addCleanup(httpretty.disable)
        self.user = UserFactory.create()
        self.register_get_user_response(self.user)
        self.request = RequestFactory().get("/dummy")
        self.request.user = self.user
        self.minimal_data = {
            "course_id": unicode(self.course.id),
            "topic_id": "test_topic",
            "type": "discussion",
            "title": "Test Title",
            "raw_body": "Test body",
        }
        self.existing_thread = Thread(**make_minimal_cs_thread({
            "id": "existing_thread",
            "course_id": unicode(self.course.id),
            "commentable_id": "original_topic",
            "thread_type": "discussion",
            "title": "Original Title",
            "body": "Original body",
            "user_id": str(self.user.id),
            "username": self.user.username,
            "read": "False",
            "endorsed": "False"
        }))

    def save_and_reserialize(self, data, instance=None):
        """
        Create a serializer with the given data and (if updating) instance,
        ensure that it is valid, save the result, and return the full thread
        data from the serializer.
        """
        serializer = ThreadSerializer(
            instance,
            data=data,
            partial=(instance is not None),
            context=get_context(self.course, self.request)
        )
        self.assertTrue(serializer.is_valid())
        serializer.save()
        return serializer.data

    def test_create_minimal(self):
        self.register_post_thread_response({"id": "test_id", "username": self.user.username})
        saved = self.save_and_reserialize(self.minimal_data)
        self.assertEqual(
            urlparse(httpretty.last_request().path).path,
            "/api/v1/test_topic/threads"
        )
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "commentable_id": ["test_topic"],
                "thread_type": ["discussion"],
                "title": ["Test Title"],
                "body": ["Test body"],
                "user_id": [str(self.user.id)],
            }
        )
        self.assertEqual(saved["id"], "test_id")

    def test_create_all_fields(self):
        self.register_post_thread_response({"id": "test_id", "username": self.user.username})
        data = self.minimal_data.copy()
        data["group_id"] = 42
        self.save_and_reserialize(data)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "commentable_id": ["test_topic"],
                "thread_type": ["discussion"],
                "title": ["Test Title"],
                "body": ["Test body"],
                "user_id": [str(self.user.id)],
                "group_id": ["42"],
            }
        )

    def test_create_missing_field(self):
        for field in self.minimal_data:
            data = self.minimal_data.copy()
            data.pop(field)
            serializer = ThreadSerializer(data=data)
            self.assertFalse(serializer.is_valid())
            self.assertEqual(
                serializer.errors,
                {field: ["This field is required."]}
            )

    @ddt.data("", " ")
    def test_create_empty_string(self, value):
        data = self.minimal_data.copy()
        data.update({field: value for field in ["topic_id", "title", "raw_body"]})
        serializer = ThreadSerializer(data=data, context=get_context(self.course, self.request))
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {field: ["This field may not be blank."] for field in ["topic_id", "title", "raw_body"]}
        )

    def test_create_type(self):
        self.register_post_thread_response({"id": "test_id", "username": self.user.username})
        data = self.minimal_data.copy()
        data["type"] = "question"
        self.save_and_reserialize(data)

        data["type"] = "invalid_type"
        serializer = ThreadSerializer(data=data)
        self.assertFalse(serializer.is_valid())

    def test_update_empty(self):
        self.register_put_thread_response(self.existing_thread.attributes)
        self.save_and_reserialize({}, self.existing_thread)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "commentable_id": ["original_topic"],
                "thread_type": ["discussion"],
                "title": ["Original Title"],
                "body": ["Original body"],
                "anonymous": ["False"],
                "anonymous_to_peers": ["False"],
                "closed": ["False"],
                "pinned": ["False"],
                "user_id": [str(self.user.id)],
                "read": ["False"],
            }
        )

    @ddt.data(True, False)
    def test_update_all(self, read):
        self.register_put_thread_response(self.existing_thread.attributes)
        data = {
            "topic_id": "edited_topic",
            "type": "question",
            "title": "Edited Title",
            "raw_body": "Edited body",
            "read": read,
        }
        saved = self.save_and_reserialize(data, self.existing_thread)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "commentable_id": ["edited_topic"],
                "thread_type": ["question"],
                "title": ["Edited Title"],
                "body": ["Edited body"],
                "anonymous": ["False"],
                "anonymous_to_peers": ["False"],
                "closed": ["False"],
                "pinned": ["False"],
                "user_id": [str(self.user.id)],
                "read": [str(read)],
            }
        )
        for key in data:
            self.assertEqual(saved[key], data[key])

    @ddt.data("", " ")
    def test_update_empty_string(self, value):
        serializer = ThreadSerializer(
            self.existing_thread,
            data={field: value for field in ["topic_id", "title", "raw_body"]},
            partial=True,
            context=get_context(self.course, self.request)
        )
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {field: ["This field may not be blank."] for field in ["topic_id", "title", "raw_body"]}
        )

    def test_update_course_id(self):
        serializer = ThreadSerializer(
            self.existing_thread,
            data={"course_id": "some/other/course"},
            partial=True,
            context=get_context(self.course, self.request)
        )
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {"course_id": ["This field is not allowed in an update."]}
        )


@ddt.ddt
class CommentSerializerDeserializationTest(ForumsEnableMixin, CommentsServiceMockMixin, SharedModuleStoreTestCase):
    """Tests for ThreadSerializer deserialization."""
    @classmethod
    def setUpClass(cls):
        super(CommentSerializerDeserializationTest, cls).setUpClass()
        cls.course = CourseFactory.create()

    def setUp(self):
        super(CommentSerializerDeserializationTest, self).setUp()
        httpretty.reset()
        httpretty.enable()
        self.addCleanup(httpretty.disable)
        self.user = UserFactory.create()
        self.register_get_user_response(self.user)
        self.request = RequestFactory().get("/dummy")
        self.request.user = self.user
        self.minimal_data = {
            "thread_id": "test_thread",
            "raw_body": "Test body",
        }
        self.existing_comment = Comment(**make_minimal_cs_comment({
            "id": "existing_comment",
            "thread_id": "existing_thread",
            "body": "Original body",
            "user_id": str(self.user.id),
            "username": self.user.username,
            "course_id": unicode(self.course.id),
        }))

    def save_and_reserialize(self, data, instance=None):
        """
        Create a serializer with the given data, ensure that it is valid, save
        the result, and return the full comment data from the serializer.
        """
        context = get_context(
            self.course,
            self.request,
            make_minimal_cs_thread({"course_id": unicode(self.course.id)})
        )
        serializer = CommentSerializer(
            instance,
            data=data,
            partial=(instance is not None),
            context=context
        )
        self.assertTrue(serializer.is_valid())
        serializer.save()
        return serializer.data

    @ddt.data(None, "test_parent")
    def test_create_success(self, parent_id):
        data = self.minimal_data.copy()
        if parent_id:
            data["parent_id"] = parent_id
            self.register_get_comment_response({"thread_id": "test_thread", "id": parent_id})
        self.register_post_comment_response(
            {"id": "test_comment", "username": self.user.username},
            thread_id="test_thread",
            parent_id=parent_id
        )
        saved = self.save_and_reserialize(data)
        expected_url = (
            "/api/v1/comments/{}".format(parent_id) if parent_id else
            "/api/v1/threads/test_thread/comments"
        )
        self.assertEqual(urlparse(httpretty.last_request().path).path, expected_url)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "body": ["Test body"],
                "user_id": [str(self.user.id)],
            }
        )
        self.assertEqual(saved["id"], "test_comment")
        self.assertEqual(saved["parent_id"], parent_id)

    def test_create_all_fields(self):
        data = self.minimal_data.copy()
        data["parent_id"] = "test_parent"
        data["endorsed"] = True
        self.register_get_comment_response({"thread_id": "test_thread", "id": "test_parent"})
        self.register_post_comment_response(
            {"id": "test_comment", "username": self.user.username},
            thread_id="test_thread",
            parent_id="test_parent"
        )
        self.save_and_reserialize(data)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "body": ["Test body"],
                "user_id": [str(self.user.id)],
                "endorsed": ["True"],
            }
        )

    def test_create_parent_id_nonexistent(self):
        self.register_get_comment_error_response("bad_parent", 404)
        data = self.minimal_data.copy()
        data["parent_id"] = "bad_parent"
        context = get_context(self.course, self.request, make_minimal_cs_thread())
        serializer = CommentSerializer(data=data, context=context)
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {
                "non_field_errors": [
                    "parent_id does not identify a comment in the thread identified by thread_id."
                ]
            }
        )

    def test_create_parent_id_wrong_thread(self):
        self.register_get_comment_response({"thread_id": "different_thread", "id": "test_parent"})
        data = self.minimal_data.copy()
        data["parent_id"] = "test_parent"
        context = get_context(self.course, self.request, make_minimal_cs_thread())
        serializer = CommentSerializer(data=data, context=context)
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {
                "non_field_errors": [
                    "parent_id does not identify a comment in the thread identified by thread_id."
                ]
            }
        )

    @ddt.data(None, -1, 0, 2, 5)
    def test_create_parent_id_too_deep(self, max_depth):
        with mock.patch("django_comment_client.utils.MAX_COMMENT_DEPTH", max_depth):
            data = self.minimal_data.copy()
            context = get_context(self.course, self.request, make_minimal_cs_thread())
            if max_depth is None or max_depth >= 0:
                if max_depth != 0:
                    self.register_get_comment_response({
                        "id": "not_too_deep",
                        "thread_id": "test_thread",
                        "depth": max_depth - 1 if max_depth else 100
                    })
                    data["parent_id"] = "not_too_deep"
                else:
                    data["parent_id"] = None
                serializer = CommentSerializer(data=data, context=context)
                self.assertTrue(serializer.is_valid(), serializer.errors)
            if max_depth is not None:
                if max_depth >= 0:
                    self.register_get_comment_response({
                        "id": "too_deep",
                        "thread_id": "test_thread",
                        "depth": max_depth
                    })
                    data["parent_id"] = "too_deep"
                else:
                    data["parent_id"] = None
                serializer = CommentSerializer(data=data, context=context)
                self.assertFalse(serializer.is_valid())
                self.assertEqual(serializer.errors, {"non_field_errors": ["Comment level is too deep."]})

    def test_create_missing_field(self):
        for field in self.minimal_data:
            data = self.minimal_data.copy()
            data.pop(field)
            serializer = CommentSerializer(
                data=data,
                context=get_context(self.course, self.request, make_minimal_cs_thread())
            )
            self.assertFalse(serializer.is_valid())
            self.assertEqual(
                serializer.errors,
                {field: ["This field is required."]}
            )

    def test_create_endorsed(self):
        # TODO: The comments service doesn't populate the endorsement field on
        # comment creation, so this is sadly realistic
        self.register_post_comment_response({"username": self.user.username}, thread_id="test_thread")
        data = self.minimal_data.copy()
        data["endorsed"] = True
        saved = self.save_and_reserialize(data)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "course_id": [unicode(self.course.id)],
                "body": ["Test body"],
                "user_id": [str(self.user.id)],
                "endorsed": ["True"],
            }
        )
        self.assertTrue(saved["endorsed"])
        self.assertIsNone(saved["endorsed_by"])
        self.assertIsNone(saved["endorsed_by_label"])
        self.assertIsNone(saved["endorsed_at"])

    def test_update_empty(self):
        self.register_put_comment_response(self.existing_comment.attributes)
        self.save_and_reserialize({}, instance=self.existing_comment)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "body": ["Original body"],
                "course_id": [unicode(self.course.id)],
                "user_id": [str(self.user.id)],
                "anonymous": ["False"],
                "anonymous_to_peers": ["False"],
                "endorsed": ["False"],
            }
        )

    def test_update_all(self):
        cs_response_data = self.existing_comment.attributes.copy()
        cs_response_data["endorsement"] = {
            "user_id": str(self.user.id),
            "time": "2015-06-05T00:00:00Z",
        }
        self.register_put_comment_response(cs_response_data)
        data = {"raw_body": "Edited body", "endorsed": True}
        saved = self.save_and_reserialize(data, instance=self.existing_comment)
        self.assertEqual(
            httpretty.last_request().parsed_body,
            {
                "body": ["Edited body"],
                "course_id": [unicode(self.course.id)],
                "user_id": [str(self.user.id)],
                "anonymous": ["False"],
                "anonymous_to_peers": ["False"],
                "endorsed": ["True"],
                "endorsement_user_id": [str(self.user.id)],
            }
        )
        for key in data:
            self.assertEqual(saved[key], data[key])
        self.assertEqual(saved["endorsed_by"], self.user.username)
        self.assertEqual(saved["endorsed_at"], "2015-06-05T00:00:00Z")

    @ddt.data("", " ")
    def test_update_empty_raw_body(self, value):
        serializer = CommentSerializer(
            self.existing_comment,
            data={"raw_body": value},
            partial=True,
            context=get_context(self.course, self.request)
        )
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {"raw_body": ["This field may not be blank."]}
        )

    @ddt.data("thread_id", "parent_id")
    def test_update_non_updatable(self, field):
        serializer = CommentSerializer(
            self.existing_comment,
            data={field: "different_value"},
            partial=True,
            context=get_context(self.course, self.request)
        )
        self.assertFalse(serializer.is_valid())
        self.assertEqual(
            serializer.errors,
            {field: ["This field is not allowed in an update."]}
        )