edx-platform/lms/djangoapps/courseware/tests/test_masquerade.py

"""
Unit tests for masquerade.
"""


import json
import pickle
from datetime import datetime
from importlib import import_module
from unittest.mock import patch
import pytest
import ddt
from django.conf import settings
from django.test import TestCase, RequestFactory
from django.urls import reverse
from edx_toggles.toggles.testutils import override_waffle_flag
from pytz import UTC
from xblock.runtime import DictKeyValueStore

from capa.tests.response_xml_factory import OptionResponseXMLFactory
from lms.djangoapps.courseware.masquerade import (
    MASQUERADE_SETTINGS_KEY,
    CourseMasquerade,
    MasqueradingKeyValueStore,
    get_masquerading_user_group,
    setup_masquerade,
)
from lms.djangoapps.courseware.tests.factories import StaffFactory
from lms.djangoapps.courseware.tests.helpers import LoginEnrollmentTestCase, MasqueradeMixin, masquerade_as_group_member
from lms.djangoapps.courseware.tests.test_submitting_problems import ProblemSubmissionTestMixin
from openedx.core.djangoapps.lang_pref import LANGUAGE_KEY
from openedx.core.djangoapps.self_paced.models import SelfPacedConfiguration
from openedx.core.djangoapps.user_api.preferences.api import get_user_preference, set_user_preference
from openedx.features.course_experience import DISABLE_UNIFIED_COURSE_TAB_FLAG
from common.djangoapps.student.models import CourseEnrollment
from common.djangoapps.student.tests.factories import UserFactory
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
from xmodule.partitions.partitions import Group, UserPartition


class MasqueradeTestCase(SharedModuleStoreTestCase, LoginEnrollmentTestCase, MasqueradeMixin):
    """
    Base class for masquerade tests that sets up a test course and enrolls a user in the course.
    """
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        cls.course = CourseFactory.create(number='masquerade-test', metadata={'start': datetime.now(UTC)})
        cls.info_page = ItemFactory.create(
            category="course_info", parent_location=cls.course.location,
            data="OOGIE BLOOGIE", display_name="updates"
        )
        cls.chapter = ItemFactory.create(
            parent_location=cls.course.location,
            category="chapter",
            display_name="Test Section",
        )
        cls.sequential_display_name = "Test Masquerade Subsection"
        cls.sequential = ItemFactory.create(
            parent_location=cls.chapter.location,
            category="sequential",
            display_name=cls.sequential_display_name,
        )
        cls.vertical = ItemFactory.create(
            parent_location=cls.sequential.location,
            category="vertical",
            display_name="Test Unit",
        )
        problem_xml = OptionResponseXMLFactory().build_xml(
            question_text='The correct answer is Correct',
            num_inputs=2,
            weight=2,
            options=['Correct', 'Incorrect'],
            correct_option='Correct'
        )
        cls.problem_display_name = "TestMasqueradeProblem"
        cls.problem = ItemFactory.create(
            parent_location=cls.vertical.location,
            category='problem',
            data=problem_xml,
            display_name=cls.problem_display_name
        )

    def setUp(self):
        super().setUp()

        self.test_user = self.create_user()
        self.login(self.test_user.email, 'test')
        self.enroll(self.course, True)

    def get_courseware_page(self):
        """
        Returns the server response for the courseware page.
        """
        url = reverse(
            'courseware_section',
            kwargs={
                'course_id': str(self.course.id),
                'chapter': self.chapter.location.block_id,
                'section': self.sequential.location.block_id,
            }
        )
        return self.client.get(url)

    def get_course_info_page(self):
        """
        Returns the server response for course info page.
        """
        url = reverse(
            'info',
            kwargs={
                'course_id': str(self.course.id),
            }
        )
        return self.client.get(url)

    def get_progress_page(self):
        """
        Returns the server response for progress page.
        """
        url = reverse(
            'progress',
            kwargs={
                'course_id': str(self.course.id),
            }
        )
        return self.client.get(url)

    def verify_staff_debug_present(self, staff_debug_expected):
        """
        Verifies that the staff debug control visibility is as expected (for staff only).
        """
        content = self.get_courseware_page().content.decode('utf-8')
        assert self.sequential_display_name in content, 'Subsection should be visible'
        assert staff_debug_expected == ('Staff Debug Info' in content)

    def get_problem(self):
        """
        Returns the JSON content for the problem in the course.
        """
        problem_url = reverse(
            'xblock_handler',
            kwargs={
                'course_id': str(self.course.id),
                'usage_id': str(self.problem.location),
                'handler': 'xmodule_handler',
                'suffix': 'problem_get'
            }
        )
        return self.client.get(problem_url)

    def verify_show_answer_present(self, show_answer_expected):
        """
        Verifies that "Show answer" is only present when expected (for staff only).
        """
        problem_html = json.loads(self.get_problem().content.decode('utf-8'))['html']
        assert self.problem_display_name in problem_html
        assert show_answer_expected == ('Show answer' in problem_html)

    def ensure_masquerade_as_group_member(self, partition_id, group_id):
        """
        Installs a masquerade for the test_user and test course, to enable the
        user to masquerade as belonging to the specific partition/group combination.
        Also verifies that the call to install the masquerade was successful.

        Arguments:
            partition_id (int): the integer partition id, referring to partitions already
               configured in the course.
            group_id (int); the integer group id, within the specified partition.
        """
        assert 200 == masquerade_as_group_member(self.test_user, self.course, partition_id, group_id)


class NormalStudentVisibilityTest(MasqueradeTestCase):
    """
    Verify the course displays as expected for a "normal" student (to ensure test setup is correct).
    """
    def create_user(self):
        """
        Creates a normal student user.
        """
        return UserFactory()

    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_staff_debug_not_visible(self):
        """
        Tests that staff debug control is not present for a student.
        """
        self.verify_staff_debug_present(False)

    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_show_answer_not_visible(self):
        """
        Tests that "Show Answer" is not visible for a student.
        """
        self.verify_show_answer_present(False)


class StaffMasqueradeTestCase(MasqueradeTestCase):
    """
    Base class for tests of the masquerade behavior for a staff member.
    """
    def create_user(self):
        """
        Creates a staff user.
        """
        return StaffFactory(course_key=self.course.id)


class TestStaffMasqueradeAsStudent(StaffMasqueradeTestCase):
    """
    Check for staff being able to masquerade as student.
    """
    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_staff_debug_with_masquerade(self):
        """
        Tests that staff debug control is not visible when masquerading as a student.
        """
        # Verify staff initially can see staff debug
        self.verify_staff_debug_present(True)

        # Toggle masquerade to student
        self.update_masquerade(role='student')
        self.verify_staff_debug_present(False)

        # Toggle masquerade back to staff
        self.update_masquerade(role='staff')
        self.verify_staff_debug_present(True)

    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_show_answer_for_staff(self):
        """
        Tests that "Show Answer" is not visible when masquerading as a student.
        """
        # Verify that staff initially can see "Show Answer".
        self.verify_show_answer_present(True)

        # Toggle masquerade to student
        self.update_masquerade(role='student')
        self.verify_show_answer_present(False)

        # Toggle masquerade back to staff
        self.update_masquerade(role='staff')
        self.verify_show_answer_present(True)


@ddt.ddt
class TestStaffMasqueradeAsSpecificStudent(StaffMasqueradeTestCase, ProblemSubmissionTestMixin):
    """
    Check for staff being able to masquerade as a specific student.
    """
    def setUp(self):
        super().setUp()
        self.student_user = self.create_user()
        self.login_student()
        self.enroll(self.course, True)

    def login_staff(self):
        """ Login as a staff user """
        self.logout()
        self.login(self.test_user.email, 'test')

    def login_student(self):
        """ Login as a student """
        self.logout()
        self.login(self.student_user.email, 'test')

    def submit_answer(self, response1, response2):
        """
        Submit an answer to the single problem in our test course.
        """
        return self.submit_question_answer(
            self.problem_display_name,
            {'2_1': response1, '2_2': response2}
        )

    def get_progress_detail(self):
        """
        Return the reported progress detail for the problem in our test course.

        The return value is a string like u'1/2'.
        """
        json_data = json.loads(self.look_at_question(self.problem_display_name).content.decode('utf-8'))
        progress = '{}/{}'.format(str(json_data['current_score']), str(json_data['total_possible']))
        return progress

    def assertExpectedLanguageInPreference(self, user, expected_language_code):
        """
        This method is a custom assertion verifies that a given user has expected
        language code in the preference and in cookies.

        Arguments:
            user: User model instance
            expected_language_code: string indicating a language code
        """
        assert get_user_preference(user, LANGUAGE_KEY) == expected_language_code
        assert self.client.cookies[settings.LANGUAGE_COOKIE].value == expected_language_code

    @override_waffle_flag(DISABLE_UNIFIED_COURSE_TAB_FLAG, active=True)
    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_masquerade_as_specific_user_on_self_paced(self):
        """
        Test masquerading as a specific user for course info page when self paced configuration
        "enable_course_home_improvements" flag is set

        Login as a staff user and visit course info page.
        set masquerade to view same page as a specific student and revisit the course info page.
        """
        # Log in as staff, and check we can see the info page.
        self.login_staff()
        response = self.get_course_info_page()
        self.assertContains(response, "OOGIE BLOOGIE")

        # Masquerade as the student,enable the self paced configuration, and check we can see the info page.
        SelfPacedConfiguration(enable_course_home_improvements=True).save()
        self.update_masquerade(role='student', username=self.student_user.username)
        response = self.get_course_info_page()
        self.assertContains(response, "OOGIE BLOOGIE")

    @ddt.data(
        'john',  # Non-unicode username
        'fôô@bar',  # Unicode username with @, which is what the ENABLE_UNICODE_USERNAME feature allows
    )
    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_masquerade_as_specific_student(self, username):
        """
        Test masquerading as a specific user.

        We answer the problem in our test course as the student and as staff user, and we use the
        progress as a proxy to determine who's state we currently see.
        """
        student = UserFactory.create(username=username)
        CourseEnrollment.enroll(student, self.course.id)
        self.logout()
        self.login(student.email, 'test')
        # Answer correctly as the student, and check progress.
        self.submit_answer('Correct', 'Correct')
        assert self.get_progress_detail() == '2/2'

        # Log in as staff, and check the problem is unanswered.
        self.login_staff()
        assert self.get_progress_detail() == '0/2'

        # Masquerade as the student, and check we can see the student state.
        self.update_masquerade(role='student', username=student.username)
        assert self.get_progress_detail() == '2/2'

        # Temporarily override the student state.
        self.submit_answer('Correct', 'Incorrect')
        assert self.get_progress_detail() == '1/2'

        # Reload the page and check we see the student state again.
        self.get_courseware_page()
        assert self.get_progress_detail() == '2/2'

        # Become the staff user again, and check the problem is still unanswered.
        self.update_masquerade(role='staff')
        assert self.get_progress_detail() == '0/2'

        # Verify the student state did not change.
        self.logout()
        self.login(student.email, 'test')
        assert self.get_progress_detail() == '2/2'

    def test_masquerading_with_language_preference(self):
        """
        Tests that masquerading as a specific user for the course does not update preference language
        for the staff.

        Login as a staff user and set user's language preference to english and visit the courseware page.
        Set masquerade to view same page as a specific student having different language preference and
        revisit the courseware page.
        """
        english_language_code = 'en'
        set_user_preference(self.test_user, preference_key=LANGUAGE_KEY, preference_value=english_language_code)
        self.login_staff()

        # Reload the page and check we have expected language preference in system and in cookies.
        self.get_courseware_page()
        self.assertExpectedLanguageInPreference(self.test_user, english_language_code)

        # Set student language preference and set masquerade to view same page the student.
        set_user_preference(self.student_user, preference_key=LANGUAGE_KEY, preference_value='es-419')
        self.update_masquerade(role='student', username=self.student_user.username)

        # Reload the page and check we have expected language preference in system and in cookies.
        self.get_courseware_page()
        self.assertExpectedLanguageInPreference(self.test_user, english_language_code)

    @override_waffle_flag(DISABLE_UNIFIED_COURSE_TAB_FLAG, active=True)
    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_masquerade_as_specific_student_course_info(self):
        """
        Test masquerading as a specific user for course info page.

        We login with login_staff and check course info page content if it's working and then we
        set masquerade to view same page as a specific student and test if it's working or not.
        """
        # Log in as staff, and check we can see the info page.
        self.login_staff()
        content = self.get_course_info_page().content.decode('utf-8')
        assert 'OOGIE BLOOGIE' in content

        # Masquerade as the student, and check we can see the info page.
        self.update_masquerade(role='student', username=self.student_user.username)
        content = self.get_course_info_page().content.decode('utf-8')
        assert 'OOGIE BLOOGIE' in content

    def test_masquerade_as_specific_student_progress(self):
        """
        Test masquerading as a specific user for progress page.
        """
        # Give the student some correct answers, check their progress page
        self.login_student()
        self.submit_answer('Correct', 'Correct')
        student_progress = self.get_progress_page().content.decode('utf-8')
        assert '1 of 2 possible points' not in student_progress
        assert '2 of 2 possible points' in student_progress

        # Staff answers are slightly different
        self.login_staff()
        self.submit_answer('Incorrect', 'Correct')
        staff_progress = self.get_progress_page().content.decode('utf-8')
        assert '2 of 2 possible points' not in staff_progress
        assert '1 of 2 possible points' in staff_progress

        # Should now see the student's scores
        self.update_masquerade(role='student', username=self.student_user.username)
        masquerade_progress = self.get_progress_page().content.decode('utf-8')
        assert '1 of 2 possible points' not in masquerade_progress
        assert '2 of 2 possible points' in masquerade_progress


class TestGetMasqueradingGroupId(StaffMasqueradeTestCase):
    """
    Check for staff being able to masquerade as belonging to a group.
    """
    def setUp(self):
        super().setUp()
        self.user_partition = UserPartition(
            0, 'Test User Partition', '',
            [Group(0, 'Group 1'), Group(1, 'Group 2')],
            scheme_id='cohort'
        )
        self.course.user_partitions.append(self.user_partition)
        modulestore().update_item(self.course, self.test_user.id)

    @patch.dict('django.conf.settings.FEATURES', {'DISABLE_START_DATES': False})
    def test_get_masquerade_group(self):
        """
        Tests that a staff member can masquerade as being in a group in a user partition
        """
        # Verify there is no masquerading group initially
        group = get_masquerading_user_group(self.course.id, self.test_user, self.user_partition)
        assert group is None

        # Install a masquerading group
        self.ensure_masquerade_as_group_member(0, 1)

        # Verify that the masquerading group is returned
        group = get_masquerading_user_group(self.course.id, self.test_user, self.user_partition)
        assert group.id == 1


class ReadOnlyKeyValueStore(DictKeyValueStore):
    """
    A KeyValueStore that raises an exception on attempts to modify it.

    Used to make sure MasqueradingKeyValueStore does not try to modify the underlying KeyValueStore.
    """
    def set(self, key, value):
        assert False, "ReadOnlyKeyValueStore may not be modified."

    def delete(self, key):
        assert False, "ReadOnlyKeyValueStore may not be modified."

    def set_many(self, update_dict):  # lint-amnesty, pylint: disable=arguments-differ, unused-argument
        assert False, "ReadOnlyKeyValueStore may not be modified."


class FakeSession(dict):
    """ Mock for Django session object. """
    modified = False  # We need dict semantics with a writable 'modified' property


class MasqueradingKeyValueStoreTest(TestCase):
    """
    Unit tests for the MasqueradingKeyValueStore class.
    """
    def setUp(self):
        super().setUp()
        self.ro_kvs = ReadOnlyKeyValueStore({'a': 42, 'b': None, 'c': 'OpenCraft'})
        self.session = FakeSession()
        self.kvs = MasqueradingKeyValueStore(self.ro_kvs, self.session)

    def test_all(self):
        assert self.kvs.get('a') == 42
        assert self.kvs.get('b') is None
        assert self.kvs.get('c') == 'OpenCraft'
        with pytest.raises(KeyError):
            self.kvs.get('d')

        assert self.kvs.has('a')
        assert self.kvs.has('b')
        assert self.kvs.has('c')
        assert not self.kvs.has('d')

        self.kvs.set_many({'a': 'Norwegian Blue', 'd': 'Giraffe'})
        self.kvs.set('b', 7)

        assert self.kvs.get('a') == 'Norwegian Blue'
        assert self.kvs.get('b') == 7
        assert self.kvs.get('c') == 'OpenCraft'
        assert self.kvs.get('d') == 'Giraffe'

        for key in 'abd':
            assert self.kvs.has(key)
            self.kvs.delete(key)
            with pytest.raises(KeyError):
                self.kvs.get(key)

        assert self.kvs.get('c') == 'OpenCraft'


class CourseMasqueradeTest(TestCase):
    """
    Unit tests for the CourseMasquerade class.
    """
    def test_unpickling_sets_all_attributes(self):
        """
        Make sure that old CourseMasquerade objects receive missing attributes when unpickled from
        the session.
        """
        cmasq = CourseMasquerade(7)
        del cmasq.user_name
        pickled_cmasq = pickle.dumps(cmasq)
        unpickled_cmasq = pickle.loads(pickled_cmasq)
        assert unpickled_cmasq.user_name is None


class SetupMasqueradeTests(SharedModuleStoreTestCase,):
    """
    Tests for the setup_masquerade function.
    """
    def setUp(self):
        super().setUp()
        self.course = CourseFactory.create(number='setup-masquerade-test', metadata={'start': datetime.now(UTC)})
        self.request = RequestFactory().request()
        self.staff = StaffFactory(course_key=self.course.id)
        self.student = UserFactory()

        CourseEnrollment.enroll(self.student, self.course.id)

        session_key = "abcdef"
        self.request.user = self.staff
        self.request.session = import_module(settings.SESSION_ENGINE).SessionStore(session_key)

    def test_setup_masquerade(self):
        masquerade_settings = {
            self.course.id: CourseMasquerade(
                course_key=self.course.id,
                role='student',
                user_name=self.student.username
            )
        }
        self.request.session[MASQUERADE_SETTINGS_KEY] = masquerade_settings

        course_masquerade, masquerade_user = setup_masquerade(
            self.request,
            self.course.id,
            staff_access=True
        )

        # Warning: the SafeSessions middleware relies on the `real_user` attribute to see if a
        # user is masquerading as another user.  If the name of this attribute is changing, please update
        # the check in SafeSessionMiddleware._verify_user as well.
        assert masquerade_user.real_user == self.staff
        assert masquerade_user == self.student
        assert self.request.user.masquerade_settings == masquerade_settings
        assert course_masquerade == masquerade_settings[self.course.id]