import datetime
import itertools
import os
import re
from importlib import import_module
from unittest import mock
from urllib.parse import quote

from django.apps import apps
from django.conf import settings
from django.contrib.admin.models import LogEntry
from django.contrib.auth import (
    BACKEND_SESSION_KEY, REDIRECT_FIELD_NAME, SESSION_KEY,
)
from django.contrib.auth.forms import (
    AuthenticationForm, PasswordChangeForm, SetPasswordForm,
)
from django.contrib.auth.models import Permission, User
from django.contrib.auth.views import (
    INTERNAL_RESET_SESSION_TOKEN, LoginView, logout_then_login,
    redirect_to_login,
)
from django.contrib.contenttypes.models import ContentType
from django.contrib.sessions.middleware import SessionMiddleware
from django.contrib.sites.requests import RequestSite
from django.core import mail
from django.db import connection
from django.http import HttpRequest, HttpResponse
from django.middleware.csrf import CsrfViewMiddleware, get_token
from django.test import Client, TestCase, override_settings
from django.test.client import RedirectCycleError
from django.urls import NoReverseMatch, reverse, reverse_lazy
from django.utils.http import urlsafe_base64_encode

from .client import PasswordResetConfirmClient
from .models import CustomUser, UUIDUser
from .settings import AUTH_TEMPLATES


@override_settings(
    LANGUAGES=[('en', 'English')],
    LANGUAGE_CODE='en',
    TEMPLATES=AUTH_TEMPLATES,
    ROOT_URLCONF='auth_tests.urls',
)
class AuthViewsTestCase(TestCase):
    """
    Helper base class for all the follow test cases.
    """

    @classmethod
    def setUpTestData(cls):
        cls.u1 = User.objects.create_user(username='testclient', password='password', email='testclient@example.com')
        cls.u3 = User.objects.create_user(username='staff', password='password', email='staffmember@example.com')

    def login(self, username='testclient', password='password'):
        response = self.client.post('/login/', {
            'username': username,
            'password': password,
        })
        self.assertIn(SESSION_KEY, self.client.session)
        return response

    def logout(self):
        response = self.client.get('/admin/logout/')
        self.assertEqual(response.status_code, 200)
        self.assertNotIn(SESSION_KEY, self.client.session)

    def assertFormError(self, response, error):
        """Assert that error is found in response.context['form'] errors"""
        form_errors = list(itertools.chain(*response.context['form'].errors.values()))
        self.assertIn(str(error), form_errors)


@override_settings(ROOT_URLCONF='django.contrib.auth.urls')
class AuthViewNamedURLTests(AuthViewsTestCase):

    def test_named_urls(self):
        "Named URLs should be reversible"
        expected_named_urls = [
            ('login', [], {}),
            ('logout', [], {}),
            ('password_change', [], {}),
            ('password_change_done', [], {}),
            ('password_reset', [], {}),
            ('password_reset_done', [], {}),
            ('password_reset_confirm', [], {
                'uidb64': 'aaaaaaa',
                'token': '1111-aaaaa',
            }),
            ('password_reset_complete', [], {}),
        ]
        for name, args, kwargs in expected_named_urls:
            with self.subTest(name=name):
                try:
                    reverse(name, args=args, kwargs=kwargs)
                except NoReverseMatch:
                    self.fail("Reversal of url named '%s' failed with NoReverseMatch" % name)


class PasswordResetTest(AuthViewsTestCase):

    def setUp(self):
        self.client = PasswordResetConfirmClient()

    def test_email_not_found(self):
        """If the provided email is not registered, don't raise any error but
        also don't send any email."""
        response = self.client.get('/password_reset/')
        self.assertEqual(response.status_code, 200)
        response = self.client.post('/password_reset/', {'email': 'not_a_real_email@email.com'})
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 0)

    def test_email_found(self):
        "Email is sent if a valid email address is provided for password reset"
        response = self.client.post('/password_reset/', {'email': 'staffmember@example.com'})
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 1)
        self.assertIn("http://", mail.outbox[0].body)
        self.assertEqual(settings.DEFAULT_FROM_EMAIL, mail.outbox[0].from_email)
        # optional multipart text/html email has been added.  Make sure original,
        # default functionality is 100% the same
        self.assertFalse(mail.outbox[0].message().is_multipart())

    def test_extra_email_context(self):
        """
        extra_email_context should be available in the email template context.
        """
        response = self.client.post(
            '/password_reset_extra_email_context/',
            {'email': 'staffmember@example.com'},
        )
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 1)
        self.assertIn('Email email context: "Hello!"', mail.outbox[0].body)
        self.assertIn('http://custom.example.com/reset/', mail.outbox[0].body)

    def test_html_mail_template(self):
        """
        A multipart email with text/plain and text/html is sent
        if the html_email_template parameter is passed to the view
        """
        response = self.client.post('/password_reset/html_email_template/', {'email': 'staffmember@example.com'})
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 1)
        message = mail.outbox[0].message()
        self.assertEqual(len(message.get_payload()), 2)
        self.assertTrue(message.is_multipart())
        self.assertEqual(message.get_payload(0).get_content_type(), 'text/plain')
        self.assertEqual(message.get_payload(1).get_content_type(), 'text/html')
        self.assertNotIn('<html>', message.get_payload(0).get_payload())
        self.assertIn('<html>', message.get_payload(1).get_payload())

    def test_email_found_custom_from(self):
        "Email is sent if a valid email address is provided for password reset when a custom from_email is provided."
        response = self.client.post('/password_reset_from_email/', {'email': 'staffmember@example.com'})
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 1)
        self.assertEqual("staffmember@example.com", mail.outbox[0].from_email)

    # Skip any 500 handler action (like sending more mail...)
    @override_settings(DEBUG_PROPAGATE_EXCEPTIONS=True)
    def test_poisoned_http_host(self):
        "Poisoned HTTP_HOST headers can't be used for reset emails"
        # This attack is based on the way browsers handle URLs. The colon
        # should be used to separate the port, but if the URL contains an @,
        # the colon is interpreted as part of a username for login purposes,
        # making 'evil.com' the request domain. Since HTTP_HOST is used to
        # produce a meaningful reset URL, we need to be certain that the
        # HTTP_HOST header isn't poisoned. This is done as a check when get_host()
        # is invoked, but we check here as a practical consequence.
        with self.assertLogs('django.security.DisallowedHost', 'ERROR'):
            response = self.client.post(
                '/password_reset/',
                {'email': 'staffmember@example.com'},
                HTTP_HOST='www.example:dr.frankenstein@evil.tld'
            )
        self.assertEqual(response.status_code, 400)
        self.assertEqual(len(mail.outbox), 0)

    # Skip any 500 handler action (like sending more mail...)
    @override_settings(DEBUG_PROPAGATE_EXCEPTIONS=True)
    def test_poisoned_http_host_admin_site(self):
        "Poisoned HTTP_HOST headers can't be used for reset emails on admin views"
        with self.assertLogs('django.security.DisallowedHost', 'ERROR'):
            response = self.client.post(
                '/admin_password_reset/',
                {'email': 'staffmember@example.com'},
                HTTP_HOST='www.example:dr.frankenstein@evil.tld'
            )
        self.assertEqual(response.status_code, 400)
        self.assertEqual(len(mail.outbox), 0)

    def _test_confirm_start(self):
        # Start by creating the email
        self.client.post('/password_reset/', {'email': 'staffmember@example.com'})
        self.assertEqual(len(mail.outbox), 1)
        return self._read_signup_email(mail.outbox[0])

    def _read_signup_email(self, email):
        urlmatch = re.search(r"https?://[^/]*(/.*reset/\S*)", email.body)
        self.assertIsNotNone(urlmatch, "No URL found in sent email")
        return urlmatch.group(), urlmatch.groups()[0]

    def test_confirm_valid(self):
        url, path = self._test_confirm_start()
        response = self.client.get(path)
        # redirect to a 'complete' page:
        self.assertContains(response, "Please enter your new password")

    def test_confirm_invalid(self):
        url, path = self._test_confirm_start()
        # Let's munge the token in the path, but keep the same length,
        # in case the URLconf will reject a different length.
        path = path[:-5] + ("0" * 4) + path[-1]

        response = self.client.get(path)
        self.assertContains(response, "The password reset link was invalid")

    def test_confirm_invalid_user(self):
        # A nonexistent user returns a 200 response, not a 404.
        response = self.client.get('/reset/123456/1-1/')
        self.assertContains(response, "The password reset link was invalid")

    def test_confirm_overflow_user(self):
        # A base36 user id that overflows int returns a 200 response.
        response = self.client.get('/reset/zzzzzzzzzzzzz/1-1/')
        self.assertContains(response, "The password reset link was invalid")

    def test_confirm_invalid_post(self):
        # Same as test_confirm_invalid, but trying to do a POST instead.
        url, path = self._test_confirm_start()
        path = path[:-5] + ("0" * 4) + path[-1]

        self.client.post(path, {
            'new_password1': 'anewpassword',
            'new_password2': ' anewpassword',
        })
        # Check the password has not been changed
        u = User.objects.get(email='staffmember@example.com')
        self.assertTrue(not u.check_password("anewpassword"))

    def test_confirm_invalid_hash(self):
        """A POST with an invalid token is rejected."""
        u = User.objects.get(email='staffmember@example.com')
        original_password = u.password
        url, path = self._test_confirm_start()
        path_parts = path.split('-')
        path_parts[-1] = ("0") * 20 + '/'
        path = '-'.join(path_parts)

        response = self.client.post(path, {
            'new_password1': 'anewpassword',
            'new_password2': 'anewpassword',
        })
        self.assertIs(response.context['validlink'], False)
        u.refresh_from_db()
        self.assertEqual(original_password, u.password)  # password hasn't changed

    def test_confirm_complete(self):
        url, path = self._test_confirm_start()
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        # Check the password has been changed
        u = User.objects.get(email='staffmember@example.com')
        self.assertTrue(u.check_password("anewpassword"))
        # The reset token is deleted from the session.
        self.assertNotIn(INTERNAL_RESET_SESSION_TOKEN, self.client.session)

        # Check we can't use the link again
        response = self.client.get(path)
        self.assertContains(response, "The password reset link was invalid")

    def test_confirm_different_passwords(self):
        url, path = self._test_confirm_start()
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'x'})
        self.assertFormError(response, SetPasswordForm.error_messages['password_mismatch'])

    def test_reset_redirect_default(self):
        response = self.client.post('/password_reset/', {'email': 'staffmember@example.com'})
        self.assertRedirects(response, '/password_reset/done/', fetch_redirect_response=False)

    def test_reset_custom_redirect(self):
        response = self.client.post('/password_reset/custom_redirect/', {'email': 'staffmember@example.com'})
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)

    def test_reset_custom_redirect_named(self):
        response = self.client.post('/password_reset/custom_redirect/named/', {'email': 'staffmember@example.com'})
        self.assertRedirects(response, '/password_reset/', fetch_redirect_response=False)

    def test_confirm_redirect_default(self):
        url, path = self._test_confirm_start()
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/reset/done/', fetch_redirect_response=False)

    def test_confirm_redirect_custom(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/custom/')
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)

    def test_confirm_redirect_custom_named(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/custom/named/')
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/password_reset/', fetch_redirect_response=False)

    def test_confirm_custom_reset_url_token(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/custom/token/')
        self.client.reset_url_token = 'set-passwordcustom'
        response = self.client.post(
            path,
            {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'},
        )
        self.assertRedirects(response, '/reset/done/', fetch_redirect_response=False)

    def test_confirm_login_post_reset(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/post_reset_login/')
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/reset/done/', fetch_redirect_response=False)
        self.assertIn(SESSION_KEY, self.client.session)

    @override_settings(
        AUTHENTICATION_BACKENDS=[
            'django.contrib.auth.backends.ModelBackend',
            'django.contrib.auth.backends.AllowAllUsersModelBackend',
        ]
    )
    def test_confirm_login_post_reset_custom_backend(self):
        # This backend is specified in the URL pattern.
        backend = 'django.contrib.auth.backends.AllowAllUsersModelBackend'
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/post_reset_login_custom_backend/')
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/reset/done/', fetch_redirect_response=False)
        self.assertIn(SESSION_KEY, self.client.session)
        self.assertEqual(self.client.session[BACKEND_SESSION_KEY], backend)

    def test_confirm_login_post_reset_already_logged_in(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/post_reset_login/')
        self.login()
        response = self.client.post(path, {'new_password1': 'anewpassword', 'new_password2': 'anewpassword'})
        self.assertRedirects(response, '/reset/done/', fetch_redirect_response=False)
        self.assertIn(SESSION_KEY, self.client.session)

    def test_confirm_display_user_from_form(self):
        url, path = self._test_confirm_start()
        response = self.client.get(path)
        # The password_reset_confirm() view passes the user object to the
        # SetPasswordForm``, even on GET requests (#16919). For this test,
        # {{ form.user }}`` is rendered in the template
        # registration/password_reset_confirm.html.
        username = User.objects.get(email='staffmember@example.com').username
        self.assertContains(response, "Hello, %s." % username)
        # However, the view should NOT pass any user object on a form if the
        # password reset link was invalid.
        response = self.client.get('/reset/zzzzzzzzzzzzz/1-1/')
        self.assertContains(response, "Hello, .")

    def test_confirm_link_redirects_to_set_password_page(self):
        url, path = self._test_confirm_start()
        # Don't use PasswordResetConfirmClient (self.client) here which
        # automatically fetches the redirect page.
        client = Client()
        response = client.get(path)
        token = response.resolver_match.kwargs['token']
        uuidb64 = response.resolver_match.kwargs['uidb64']
        self.assertRedirects(response, '/reset/%s/set-password/' % uuidb64)
        self.assertEqual(client.session['_password_reset_token'], token)

    def test_confirm_custom_reset_url_token_link_redirects_to_set_password_page(self):
        url, path = self._test_confirm_start()
        path = path.replace('/reset/', '/reset/custom/token/')
        client = Client()
        response = client.get(path)
        token = response.resolver_match.kwargs['token']
        uuidb64 = response.resolver_match.kwargs['uidb64']
        self.assertRedirects(response, '/reset/custom/token/%s/set-passwordcustom/' % uuidb64)
        self.assertEqual(client.session['_password_reset_token'], token)

    def test_invalid_link_if_going_directly_to_the_final_reset_password_url(self):
        url, path = self._test_confirm_start()
        _, uuidb64, _ = path.strip('/').split('/')
        response = Client().get('/reset/%s/set-password/' % uuidb64)
        self.assertContains(response, 'The password reset link was invalid')


@override_settings(AUTH_USER_MODEL='auth_tests.CustomUser')
class CustomUserPasswordResetTest(AuthViewsTestCase):
    user_email = 'staffmember@example.com'

    @classmethod
    def setUpTestData(cls):
        cls.u1 = CustomUser.custom_objects.create(
            email='staffmember@example.com',
            date_of_birth=datetime.date(1976, 11, 8),
        )
        cls.u1.set_password('password')
        cls.u1.save()

    def setUp(self):
        self.client = PasswordResetConfirmClient()

    def _test_confirm_start(self):
        # Start by creating the email
        response = self.client.post('/password_reset/', {'email': self.user_email})
        self.assertEqual(response.status_code, 302)
        self.assertEqual(len(mail.outbox), 1)
        return self._read_signup_email(mail.outbox[0])

    def _read_signup_email(self, email):
        urlmatch = re.search(r"https?://[^/]*(/.*reset/\S*)", email.body)
        self.assertIsNotNone(urlmatch, "No URL found in sent email")
        return urlmatch.group(), urlmatch.groups()[0]

    def test_confirm_valid_custom_user(self):
        url, path = self._test_confirm_start()
        response = self.client.get(path)
        # redirect to a 'complete' page:
        self.assertContains(response, "Please enter your new password")
        # then submit a new password
        response = self.client.post(path, {
            'new_password1': 'anewpassword',
            'new_password2': 'anewpassword',
        })
        self.assertRedirects(response, '/reset/done/')


@override_settings(AUTH_USER_MODEL='auth_tests.UUIDUser')
class UUIDUserPasswordResetTest(CustomUserPasswordResetTest):

    def _test_confirm_start(self):
        # instead of fixture
        UUIDUser.objects.create_user(
            email=self.user_email,
            username='foo',
            password='foo',
        )
        return super()._test_confirm_start()

    def test_confirm_invalid_uuid(self):
        """A uidb64 that decodes to a non-UUID doesn't crash."""
        _, path = self._test_confirm_start()
        invalid_uidb64 = urlsafe_base64_encode(b'INVALID_UUID')
        first, _uuidb64_, second = path.strip('/').split('/')
        response = self.client.get('/' + '/'.join((first, invalid_uidb64, second)) + '/')
        self.assertContains(response, 'The password reset link was invalid')


class ChangePasswordTest(AuthViewsTestCase):

    def fail_login(self):
        response = self.client.post('/login/', {
            'username': 'testclient',
            'password': 'password',
        })
        self.assertFormError(response, AuthenticationForm.error_messages['invalid_login'] % {
            'username': User._meta.get_field('username').verbose_name
        })

    def logout(self):
        self.client.get('/logout/')

    def test_password_change_fails_with_invalid_old_password(self):
        self.login()
        response = self.client.post('/password_change/', {
            'old_password': 'donuts',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.assertFormError(response, PasswordChangeForm.error_messages['password_incorrect'])

    def test_password_change_fails_with_mismatched_passwords(self):
        self.login()
        response = self.client.post('/password_change/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'donuts',
        })
        self.assertFormError(response, SetPasswordForm.error_messages['password_mismatch'])

    def test_password_change_succeeds(self):
        self.login()
        self.client.post('/password_change/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.fail_login()
        self.login(password='password1')

    def test_password_change_done_succeeds(self):
        self.login()
        response = self.client.post('/password_change/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.assertRedirects(response, '/password_change/done/', fetch_redirect_response=False)

    @override_settings(LOGIN_URL='/login/')
    def test_password_change_done_fails(self):
        response = self.client.get('/password_change/done/')
        self.assertRedirects(response, '/login/?next=/password_change/done/', fetch_redirect_response=False)

    def test_password_change_redirect_default(self):
        self.login()
        response = self.client.post('/password_change/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.assertRedirects(response, '/password_change/done/', fetch_redirect_response=False)

    def test_password_change_redirect_custom(self):
        self.login()
        response = self.client.post('/password_change/custom/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)

    def test_password_change_redirect_custom_named(self):
        self.login()
        response = self.client.post('/password_change/custom/named/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        self.assertRedirects(response, '/password_reset/', fetch_redirect_response=False)


class SessionAuthenticationTests(AuthViewsTestCase):
    def test_user_password_change_updates_session(self):
        """
        #21649 - Ensure contrib.auth.views.password_change updates the user's
        session auth hash after a password change so the session isn't logged out.
        """
        self.login()
        original_session_key = self.client.session.session_key
        response = self.client.post('/password_change/', {
            'old_password': 'password',
            'new_password1': 'password1',
            'new_password2': 'password1',
        })
        # if the hash isn't updated, retrieving the redirection page will fail.
        self.assertRedirects(response, '/password_change/done/')
        # The session key is rotated.
        self.assertNotEqual(original_session_key, self.client.session.session_key)


class LoginTest(AuthViewsTestCase):

    def test_current_site_in_context_after_login(self):
        response = self.client.get(reverse('login'))
        self.assertEqual(response.status_code, 200)
        if apps.is_installed('django.contrib.sites'):
            Site = apps.get_model('sites.Site')
            site = Site.objects.get_current()
            self.assertEqual(response.context['site'], site)
            self.assertEqual(response.context['site_name'], site.name)
        else:
            self.assertIsInstance(response.context['site'], RequestSite)
        self.assertIsInstance(response.context['form'], AuthenticationForm)

    def test_security_check(self):
        login_url = reverse('login')

        # These URLs should not pass the security check.
        bad_urls = (
            'http://example.com',
            'http:///example.com',
            'https://example.com',
            'ftp://example.com',
            '///example.com',
            '//example.com',
            'javascript:alert("XSS")',
        )
        for bad_url in bad_urls:
            with self.subTest(bad_url=bad_url):
                nasty_url = '%(url)s?%(next)s=%(bad_url)s' % {
                    'url': login_url,
                    'next': REDIRECT_FIELD_NAME,
                    'bad_url': quote(bad_url),
                }
                response = self.client.post(nasty_url, {
                    'username': 'testclient',
                    'password': 'password',
                })
                self.assertEqual(response.status_code, 302)
                self.assertNotIn(bad_url, response.url, '%s should be blocked' % bad_url)

        # These URLs should pass the security check.
        good_urls = (
            '/view/?param=http://example.com',
            '/view/?param=https://example.com',
            '/view?param=ftp://example.com',
            'view/?param=//example.com',
            'https://testserver/',
            'HTTPS://testserver/',
            '//testserver/',
            '/url%20with%20spaces/',
        )
        for good_url in good_urls:
            with self.subTest(good_url=good_url):
                safe_url = '%(url)s?%(next)s=%(good_url)s' % {
                    'url': login_url,
                    'next': REDIRECT_FIELD_NAME,
                    'good_url': quote(good_url),
                }
                response = self.client.post(safe_url, {
                    'username': 'testclient',
                    'password': 'password',
                })
                self.assertEqual(response.status_code, 302)
                self.assertIn(good_url, response.url, '%s should be allowed' % good_url)

    def test_security_check_https(self):
        login_url = reverse('login')
        non_https_next_url = 'http://testserver/path'
        not_secured_url = '%(url)s?%(next)s=%(next_url)s' % {
            'url': login_url,
            'next': REDIRECT_FIELD_NAME,
            'next_url': quote(non_https_next_url),
        }
        post_data = {
            'username': 'testclient',
            'password': 'password',
        }
        response = self.client.post(not_secured_url, post_data, secure=True)
        self.assertEqual(response.status_code, 302)
        self.assertNotEqual(response.url, non_https_next_url)
        self.assertEqual(response.url, settings.LOGIN_REDIRECT_URL)

    def test_login_form_contains_request(self):
        # The custom authentication form for this login requires a request to
        # initialize it.
        response = self.client.post('/custom_request_auth_login/', {
            'username': 'testclient',
            'password': 'password',
        })
        # The login was successful.
        self.assertRedirects(response, settings.LOGIN_REDIRECT_URL, fetch_redirect_response=False)

    def test_login_csrf_rotate(self):
        """
        Makes sure that a login rotates the currently-used CSRF token.
        """
        def get_response(request):
            return HttpResponse()

        # Do a GET to establish a CSRF token
        # The test client isn't used here as it's a test for middleware.
        req = HttpRequest()
        CsrfViewMiddleware(get_response).process_view(req, LoginView.as_view(), (), {})
        # get_token() triggers CSRF token inclusion in the response
        get_token(req)
        resp = CsrfViewMiddleware(LoginView.as_view())(req)
        csrf_cookie = resp.cookies.get(settings.CSRF_COOKIE_NAME, None)
        token1 = csrf_cookie.coded_value

        # Prepare the POST request
        req = HttpRequest()
        req.COOKIES[settings.CSRF_COOKIE_NAME] = token1
        req.method = "POST"
        req.POST = {'username': 'testclient', 'password': 'password', 'csrfmiddlewaretoken': token1}

        # Use POST request to log in
        SessionMiddleware(get_response).process_request(req)
        CsrfViewMiddleware(get_response).process_view(req, LoginView.as_view(), (), {})
        req.META["SERVER_NAME"] = "testserver"  # Required to have redirect work in login view
        req.META["SERVER_PORT"] = 80
        resp = CsrfViewMiddleware(LoginView.as_view())(req)
        csrf_cookie = resp.cookies.get(settings.CSRF_COOKIE_NAME, None)
        token2 = csrf_cookie.coded_value

        # Check the CSRF token switched
        self.assertNotEqual(token1, token2)

    def test_session_key_flushed_on_login(self):
        """
        To avoid reusing another user's session, ensure a new, empty session is
        created if the existing session corresponds to a different authenticated
        user.
        """
        self.login()
        original_session_key = self.client.session.session_key

        self.login(username='staff')
        self.assertNotEqual(original_session_key, self.client.session.session_key)

    def test_session_key_flushed_on_login_after_password_change(self):
        """
        As above, but same user logging in after a password change.
        """
        self.login()
        original_session_key = self.client.session.session_key

        # If no password change, session key should not be flushed.
        self.login()
        self.assertEqual(original_session_key, self.client.session.session_key)

        user = User.objects.get(username='testclient')
        user.set_password('foobar')
        user.save()

        self.login(password='foobar')
        self.assertNotEqual(original_session_key, self.client.session.session_key)

    def test_login_session_without_hash_session_key(self):
        """
        Session without django.contrib.auth.HASH_SESSION_KEY should login
        without an exception.
        """
        user = User.objects.get(username='testclient')
        engine = import_module(settings.SESSION_ENGINE)
        session = engine.SessionStore()
        session[SESSION_KEY] = user.id
        session.save()
        original_session_key = session.session_key
        self.client.cookies[settings.SESSION_COOKIE_NAME] = original_session_key

        self.login()
        self.assertNotEqual(original_session_key, self.client.session.session_key)


class LoginURLSettings(AuthViewsTestCase):
    """Tests for settings.LOGIN_URL."""
    def assertLoginURLEquals(self, url):
        response = self.client.get('/login_required/')
        self.assertRedirects(response, url, fetch_redirect_response=False)

    @override_settings(LOGIN_URL='/login/')
    def test_standard_login_url(self):
        self.assertLoginURLEquals('/login/?next=/login_required/')

    @override_settings(LOGIN_URL='login')
    def test_named_login_url(self):
        self.assertLoginURLEquals('/login/?next=/login_required/')

    @override_settings(LOGIN_URL='http://remote.example.com/login')
    def test_remote_login_url(self):
        quoted_next = quote('http://testserver/login_required/')
        expected = 'http://remote.example.com/login?next=%s' % quoted_next
        self.assertLoginURLEquals(expected)

    @override_settings(LOGIN_URL='https:///login/')
    def test_https_login_url(self):
        quoted_next = quote('http://testserver/login_required/')
        expected = 'https:///login/?next=%s' % quoted_next
        self.assertLoginURLEquals(expected)

    @override_settings(LOGIN_URL='/login/?pretty=1')
    def test_login_url_with_querystring(self):
        self.assertLoginURLEquals('/login/?pretty=1&next=/login_required/')

    @override_settings(LOGIN_URL='http://remote.example.com/login/?next=/default/')
    def test_remote_login_url_with_next_querystring(self):
        quoted_next = quote('http://testserver/login_required/')
        expected = 'http://remote.example.com/login/?next=%s' % quoted_next
        self.assertLoginURLEquals(expected)

    @override_settings(LOGIN_URL=reverse_lazy('login'))
    def test_lazy_login_url(self):
        self.assertLoginURLEquals('/login/?next=/login_required/')


class LoginRedirectUrlTest(AuthViewsTestCase):
    """Tests for settings.LOGIN_REDIRECT_URL."""
    def assertLoginRedirectURLEqual(self, url):
        response = self.login()
        self.assertRedirects(response, url, fetch_redirect_response=False)

    def test_default(self):
        self.assertLoginRedirectURLEqual('/accounts/profile/')

    @override_settings(LOGIN_REDIRECT_URL='/custom/')
    def test_custom(self):
        self.assertLoginRedirectURLEqual('/custom/')

    @override_settings(LOGIN_REDIRECT_URL='password_reset')
    def test_named(self):
        self.assertLoginRedirectURLEqual('/password_reset/')

    @override_settings(LOGIN_REDIRECT_URL='http://remote.example.com/welcome/')
    def test_remote(self):
        self.assertLoginRedirectURLEqual('http://remote.example.com/welcome/')


class RedirectToLoginTests(AuthViewsTestCase):
    """Tests for the redirect_to_login view"""
    @override_settings(LOGIN_URL=reverse_lazy('login'))
    def test_redirect_to_login_with_lazy(self):
        login_redirect_response = redirect_to_login(next='/else/where/')
        expected = '/login/?next=/else/where/'
        self.assertEqual(expected, login_redirect_response.url)

    @override_settings(LOGIN_URL=reverse_lazy('login'))
    def test_redirect_to_login_with_lazy_and_unicode(self):
        login_redirect_response = redirect_to_login(next='/else/where/झ/')
        expected = '/login/?next=/else/where/%E0%A4%9D/'
        self.assertEqual(expected, login_redirect_response.url)


class LogoutThenLoginTests(AuthViewsTestCase):
    """Tests for the logout_then_login view"""

    def confirm_logged_out(self):
        self.assertNotIn(SESSION_KEY, self.client.session)

    @override_settings(LOGIN_URL='/login/')
    def test_default_logout_then_login(self):
        self.login()
        req = HttpRequest()
        req.method = 'GET'
        req.session = self.client.session
        response = logout_then_login(req)
        self.confirm_logged_out()
        self.assertRedirects(response, '/login/', fetch_redirect_response=False)

    def test_logout_then_login_with_custom_login(self):
        self.login()
        req = HttpRequest()
        req.method = 'GET'
        req.session = self.client.session
        response = logout_then_login(req, login_url='/custom/')
        self.confirm_logged_out()
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)


class LoginRedirectAuthenticatedUser(AuthViewsTestCase):
    dont_redirect_url = '/login/redirect_authenticated_user_default/'
    do_redirect_url = '/login/redirect_authenticated_user/'

    def test_default(self):
        """Stay on the login page by default."""
        self.login()
        response = self.client.get(self.dont_redirect_url)
        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.context['next'], '')

    def test_guest(self):
        """If not logged in, stay on the same page."""
        response = self.client.get(self.do_redirect_url)
        self.assertEqual(response.status_code, 200)

    def test_redirect(self):
        """If logged in, go to default redirected URL."""
        self.login()
        response = self.client.get(self.do_redirect_url)
        self.assertRedirects(response, '/accounts/profile/', fetch_redirect_response=False)

    @override_settings(LOGIN_REDIRECT_URL='/custom/')
    def test_redirect_url(self):
        """If logged in, go to custom redirected URL."""
        self.login()
        response = self.client.get(self.do_redirect_url)
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)

    def test_redirect_param(self):
        """If next is specified as a GET parameter, go there."""
        self.login()
        url = self.do_redirect_url + '?next=/custom_next/'
        response = self.client.get(url)
        self.assertRedirects(response, '/custom_next/', fetch_redirect_response=False)

    def test_redirect_loop(self):
        """
        Detect a redirect loop if LOGIN_REDIRECT_URL is not correctly set,
        with and without custom parameters.
        """
        self.login()
        msg = (
            "Redirection loop for authenticated user detected. Check that "
            "your LOGIN_REDIRECT_URL doesn't point to a login page."
        )
        with self.settings(LOGIN_REDIRECT_URL=self.do_redirect_url):
            with self.assertRaisesMessage(ValueError, msg):
                self.client.get(self.do_redirect_url)

            url = self.do_redirect_url + '?bla=2'
            with self.assertRaisesMessage(ValueError, msg):
                self.client.get(url)

    def test_permission_required_not_logged_in(self):
        # Not logged in ...
        with self.settings(LOGIN_URL=self.do_redirect_url):
            # redirected to login.
            response = self.client.get('/permission_required_redirect/', follow=True)
            self.assertEqual(response.status_code, 200)
            # exception raised.
            response = self.client.get('/permission_required_exception/', follow=True)
            self.assertEqual(response.status_code, 403)
            # redirected to login.
            response = self.client.get('/login_and_permission_required_exception/', follow=True)
            self.assertEqual(response.status_code, 200)

    def test_permission_required_logged_in(self):
        self.login()
        # Already logged in...
        with self.settings(LOGIN_URL=self.do_redirect_url):
            # redirect loop encountered.
            with self.assertRaisesMessage(RedirectCycleError, 'Redirect loop detected.'):
                self.client.get('/permission_required_redirect/', follow=True)
            # exception raised.
            response = self.client.get('/permission_required_exception/', follow=True)
            self.assertEqual(response.status_code, 403)
            # exception raised.
            response = self.client.get('/login_and_permission_required_exception/', follow=True)
            self.assertEqual(response.status_code, 403)


class LoginSuccessURLAllowedHostsTest(AuthViewsTestCase):
    def test_success_url_allowed_hosts_same_host(self):
        response = self.client.post('/login/allowed_hosts/', {
            'username': 'testclient',
            'password': 'password',
            'next': 'https://testserver/home',
        })
        self.assertIn(SESSION_KEY, self.client.session)
        self.assertRedirects(response, 'https://testserver/home', fetch_redirect_response=False)

    def test_success_url_allowed_hosts_safe_host(self):
        response = self.client.post('/login/allowed_hosts/', {
            'username': 'testclient',
            'password': 'password',
            'next': 'https://otherserver/home',
        })
        self.assertIn(SESSION_KEY, self.client.session)
        self.assertRedirects(response, 'https://otherserver/home', fetch_redirect_response=False)

    def test_success_url_allowed_hosts_unsafe_host(self):
        response = self.client.post('/login/allowed_hosts/', {
            'username': 'testclient',
            'password': 'password',
            'next': 'https://evil/home',
        })
        self.assertIn(SESSION_KEY, self.client.session)
        self.assertRedirects(response, '/accounts/profile/', fetch_redirect_response=False)


class LogoutTest(AuthViewsTestCase):

    def confirm_logged_out(self):
        self.assertNotIn(SESSION_KEY, self.client.session)

    def test_logout_default(self):
        "Logout without next_page option renders the default template"
        self.login()
        response = self.client.get('/logout/')
        self.assertContains(response, 'Logged out')
        self.confirm_logged_out()

    def test_logout_with_post(self):
        self.login()
        response = self.client.post('/logout/')
        self.assertContains(response, 'Logged out')
        self.confirm_logged_out()

    def test_14377(self):
        # Bug 14377
        self.login()
        response = self.client.get('/logout/')
        self.assertIn('site', response.context)

    def test_logout_doesnt_cache(self):
        """
        The logout() view should send "no-cache" headers for reasons described
        in #25490.
        """
        response = self.client.get('/logout/')
        self.assertIn('no-store', response['Cache-Control'])

    def test_logout_with_overridden_redirect_url(self):
        # Bug 11223
        self.login()
        response = self.client.get('/logout/next_page/')
        self.assertRedirects(response, '/somewhere/', fetch_redirect_response=False)

        response = self.client.get('/logout/next_page/?next=/login/')
        self.assertRedirects(response, '/login/', fetch_redirect_response=False)

        self.confirm_logged_out()

    def test_logout_with_next_page_specified(self):
        "Logout with next_page option given redirects to specified resource"
        self.login()
        response = self.client.get('/logout/next_page/')
        self.assertRedirects(response, '/somewhere/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_logout_with_redirect_argument(self):
        "Logout with query string redirects to specified resource"
        self.login()
        response = self.client.get('/logout/?next=/login/')
        self.assertRedirects(response, '/login/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_logout_with_custom_redirect_argument(self):
        "Logout with custom query string redirects to specified resource"
        self.login()
        response = self.client.get('/logout/custom_query/?follow=/somewhere/')
        self.assertRedirects(response, '/somewhere/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_logout_with_named_redirect(self):
        "Logout resolves names or URLs passed as next_page."
        self.login()
        response = self.client.get('/logout/next_page/named/')
        self.assertRedirects(response, '/password_reset/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_success_url_allowed_hosts_same_host(self):
        self.login()
        response = self.client.get('/logout/allowed_hosts/?next=https://testserver/')
        self.assertRedirects(response, 'https://testserver/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_success_url_allowed_hosts_safe_host(self):
        self.login()
        response = self.client.get('/logout/allowed_hosts/?next=https://otherserver/')
        self.assertRedirects(response, 'https://otherserver/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_success_url_allowed_hosts_unsafe_host(self):
        self.login()
        response = self.client.get('/logout/allowed_hosts/?next=https://evil/')
        self.assertRedirects(response, '/logout/allowed_hosts/', fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_security_check(self):
        logout_url = reverse('logout')

        # These URLs should not pass the security check.
        bad_urls = (
            'http://example.com',
            'http:///example.com',
            'https://example.com',
            'ftp://example.com',
            '///example.com',
            '//example.com',
            'javascript:alert("XSS")',
        )
        for bad_url in bad_urls:
            with self.subTest(bad_url=bad_url):
                nasty_url = '%(url)s?%(next)s=%(bad_url)s' % {
                    'url': logout_url,
                    'next': REDIRECT_FIELD_NAME,
                    'bad_url': quote(bad_url),
                }
                self.login()
                response = self.client.get(nasty_url)
                self.assertEqual(response.status_code, 302)
                self.assertNotIn(bad_url, response.url, '%s should be blocked' % bad_url)
                self.confirm_logged_out()

        # These URLs should pass the security check.
        good_urls = (
            '/view/?param=http://example.com',
            '/view/?param=https://example.com',
            '/view?param=ftp://example.com',
            'view/?param=//example.com',
            'https://testserver/',
            'HTTPS://testserver/',
            '//testserver/',
            '/url%20with%20spaces/',
        )
        for good_url in good_urls:
            with self.subTest(good_url=good_url):
                safe_url = '%(url)s?%(next)s=%(good_url)s' % {
                    'url': logout_url,
                    'next': REDIRECT_FIELD_NAME,
                    'good_url': quote(good_url),
                }
                self.login()
                response = self.client.get(safe_url)
                self.assertEqual(response.status_code, 302)
                self.assertIn(good_url, response.url, '%s should be allowed' % good_url)
                self.confirm_logged_out()

    def test_security_check_https(self):
        logout_url = reverse('logout')
        non_https_next_url = 'http://testserver/'
        url = '%(url)s?%(next)s=%(next_url)s' % {
            'url': logout_url,
            'next': REDIRECT_FIELD_NAME,
            'next_url': quote(non_https_next_url),
        }
        self.login()
        response = self.client.get(url, secure=True)
        self.assertRedirects(response, logout_url, fetch_redirect_response=False)
        self.confirm_logged_out()

    def test_logout_preserve_language(self):
        """Language is preserved after logout."""
        self.login()
        self.client.post('/setlang/', {'language': 'pl'})
        self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, 'pl')
        self.client.get('/logout/')
        self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, 'pl')

    @override_settings(LOGOUT_REDIRECT_URL='/custom/')
    def test_logout_redirect_url_setting(self):
        self.login()
        response = self.client.get('/logout/')
        self.assertRedirects(response, '/custom/', fetch_redirect_response=False)

    @override_settings(LOGOUT_REDIRECT_URL='logout')
    def test_logout_redirect_url_named_setting(self):
        self.login()
        response = self.client.get('/logout/')
        self.assertRedirects(response, '/logout/', fetch_redirect_response=False)


def get_perm(Model, perm):
    ct = ContentType.objects.get_for_model(Model)
    return Permission.objects.get(content_type=ct, codename=perm)


# Redirect in test_user_change_password will fail if session auth hash
# isn't updated after password change (#21649)
@override_settings(ROOT_URLCONF='auth_tests.urls_admin')
class ChangelistTests(AuthViewsTestCase):

    @classmethod
    def setUpTestData(cls):
        super().setUpTestData()
        # Make me a superuser before logging in.
        User.objects.filter(username='testclient').update(is_staff=True, is_superuser=True)

    def setUp(self):
        self.login()
        # Get the latest last_login value.
        self.admin = User.objects.get(pk=self.u1.pk)

    def get_user_data(self, user):
        return {
            'username': user.username,
            'password': user.password,
            'email': user.email,
            'is_active': user.is_active,
            'is_staff': user.is_staff,
            'is_superuser': user.is_superuser,
            'last_login_0': user.last_login.strftime('%Y-%m-%d'),
            'last_login_1': user.last_login.strftime('%H:%M:%S'),
            'initial-last_login_0': user.last_login.strftime('%Y-%m-%d'),
            'initial-last_login_1': user.last_login.strftime('%H:%M:%S'),
            'date_joined_0': user.date_joined.strftime('%Y-%m-%d'),
            'date_joined_1': user.date_joined.strftime('%H:%M:%S'),
            'initial-date_joined_0': user.date_joined.strftime('%Y-%m-%d'),
            'initial-date_joined_1': user.date_joined.strftime('%H:%M:%S'),
            'first_name': user.first_name,
            'last_name': user.last_name,
        }

    # #20078 - users shouldn't be allowed to guess password hashes via
    # repeated password__startswith queries.
    def test_changelist_disallows_password_lookups(self):
        # A lookup that tries to filter on password isn't OK
        with self.assertLogs('django.security.DisallowedModelAdminLookup', 'ERROR'):
            response = self.client.get(reverse('auth_test_admin:auth_user_changelist') + '?password__startswith=sha1$')
        self.assertEqual(response.status_code, 400)

    def test_user_change_email(self):
        data = self.get_user_data(self.admin)
        data['email'] = 'new_' + data['email']
        response = self.client.post(
            reverse('auth_test_admin:auth_user_change', args=(self.admin.pk,)),
            data
        )
        self.assertRedirects(response, reverse('auth_test_admin:auth_user_changelist'))
        row = LogEntry.objects.latest('id')
        self.assertEqual(row.get_change_message(), 'Changed Email address.')

    def test_user_not_change(self):
        response = self.client.post(
            reverse('auth_test_admin:auth_user_change', args=(self.admin.pk,)),
            self.get_user_data(self.admin)
        )
        self.assertRedirects(response, reverse('auth_test_admin:auth_user_changelist'))
        row = LogEntry.objects.latest('id')
        self.assertEqual(row.get_change_message(), 'No fields changed.')

    def test_user_change_password(self):
        user_change_url = reverse('auth_test_admin:auth_user_change', args=(self.admin.pk,))
        password_change_url = reverse('auth_test_admin:auth_user_password_change', args=(self.admin.pk,))

        response = self.client.get(user_change_url)
        # Test the link inside password field help_text.
        rel_link = re.search(
            r'you can change the password using <a href="([^"]*)">this form</a>',
            response.content.decode()
        ).groups()[0]
        self.assertEqual(
            os.path.normpath(user_change_url + rel_link),
            os.path.normpath(password_change_url)
        )

        response = self.client.post(
            password_change_url,
            {
                'password1': 'password1',
                'password2': 'password1',
            }
        )
        self.assertRedirects(response, user_change_url)
        row = LogEntry.objects.latest('id')
        self.assertEqual(row.get_change_message(), 'Changed password.')
        self.logout()
        self.login(password='password1')

    def test_user_change_different_user_password(self):
        u = User.objects.get(email='staffmember@example.com')
        response = self.client.post(
            reverse('auth_test_admin:auth_user_password_change', args=(u.pk,)),
            {
                'password1': 'password1',
                'password2': 'password1',
            }
        )
        self.assertRedirects(response, reverse('auth_test_admin:auth_user_change', args=(u.pk,)))
        row = LogEntry.objects.latest('id')
        self.assertEqual(row.user_id, self.admin.pk)
        self.assertEqual(row.object_id, str(u.pk))
        self.assertEqual(row.get_change_message(), 'Changed password.')

    def test_password_change_bad_url(self):
        response = self.client.get(reverse('auth_test_admin:auth_user_password_change', args=('foobar',)))
        self.assertEqual(response.status_code, 404)

    @mock.patch('django.contrib.auth.admin.UserAdmin.has_change_permission')
    def test_user_change_password_passes_user_to_has_change_permission(self, has_change_permission):
        url = reverse('auth_test_admin:auth_user_password_change', args=(self.admin.pk,))
        self.client.post(url, {'password1': 'password1', 'password2': 'password1'})
        (_request, user), _kwargs = has_change_permission.call_args
        self.assertEqual(user.pk, self.admin.pk)

    def test_view_user_password_is_readonly(self):
        u = User.objects.get(username='testclient')
        u.is_superuser = False
        u.save()
        original_password = u.password
        u.user_permissions.add(get_perm(User, 'view_user'))
        response = self.client.get(reverse('auth_test_admin:auth_user_change', args=(u.pk,)),)
        algo, salt, hash_string = (u.password.split('$'))
        self.assertContains(response, '<div class="readonly">testclient</div>')
        # ReadOnlyPasswordHashWidget is used to render the field.
        self.assertContains(
            response,
            '<strong>algorithm</strong>: %s\n\n'
            '<strong>salt</strong>: %s**********\n\n'
            '<strong>hash</strong>: %s**************************\n\n' % (
                algo, salt[:2], hash_string[:6],
            ),
            html=True,
        )
        # Value in POST data is ignored.
        data = self.get_user_data(u)
        data['password'] = 'shouldnotchange'
        change_url = reverse('auth_test_admin:auth_user_change', args=(u.pk,))
        response = self.client.post(change_url, data)
        self.assertEqual(response.status_code, 403)
        u.refresh_from_db()
        self.assertEqual(u.password, original_password)


@override_settings(
    AUTH_USER_MODEL='auth_tests.UUIDUser',
    ROOT_URLCONF='auth_tests.urls_custom_user_admin',
)
class UUIDUserTests(TestCase):

    def test_admin_password_change(self):
        u = UUIDUser.objects.create_superuser(username='uuid', email='foo@bar.com', password='test')
        self.assertTrue(self.client.login(username='uuid', password='test'))

        user_change_url = reverse('custom_user_admin:auth_tests_uuiduser_change', args=(u.pk,))
        response = self.client.get(user_change_url)
        self.assertEqual(response.status_code, 200)

        password_change_url = reverse('custom_user_admin:auth_user_password_change', args=(u.pk,))
        response = self.client.get(password_change_url)
        self.assertEqual(response.status_code, 200)

        # A LogEntry is created with pk=1 which breaks a FK constraint on MySQL
        with connection.constraint_checks_disabled():
            response = self.client.post(password_change_url, {
                'password1': 'password1',
                'password2': 'password1',
            })
        self.assertRedirects(response, user_change_url)
        row = LogEntry.objects.latest('id')
        self.assertEqual(row.user_id, 1)  # hardcoded in CustomUserAdmin.log_change()
        self.assertEqual(row.object_id, str(u.pk))
        self.assertEqual(row.get_change_message(), 'Changed password.')

        # The LogEntry.user column isn't altered to a UUID type so it's set to
        # an integer manually in CustomUserAdmin to avoid an error. To avoid a
        # constraint error, delete the entry before constraints are checked
        # after the test.
        row.delete()