From 32c828d0f760492711a98b11376e229d795fd1b3 Mon Sep 17 00:00:00 2001 From: Dirk Klimpel <5740567+dklimpel@users.noreply.github.com> Date: Fri, 11 Mar 2022 13:42:22 +0100 Subject: [PATCH] Add type hints to `tests/rest`. (#12208) Co-authored-by: Patrick Cloke --- changelog.d/12208.misc | 1 + mypy.ini | 1 - tests/rest/client/test_transactions.py | 19 +++- tests/rest/media/v1/test_media_storage.py | 110 +++++++++++++--------- tests/rest/media/v1/test_url_preview.py | 83 ++++++++-------- 5 files changed, 129 insertions(+), 85 deletions(-) create mode 100644 changelog.d/12208.misc diff --git a/changelog.d/12208.misc b/changelog.d/12208.misc new file mode 100644 index 000000000000..c5b635679931 --- /dev/null +++ b/changelog.d/12208.misc @@ -0,0 +1 @@ +Add type hints to tests files. \ No newline at end of file diff --git a/mypy.ini b/mypy.ini index c8390ddba96d..f9c39fcaaee3 100644 --- a/mypy.ini +++ b/mypy.ini @@ -90,7 +90,6 @@ exclude = (?x) |tests/push/test_push_rule_evaluator.py |tests/rest/client/test_transactions.py |tests/rest/media/v1/test_media_storage.py - |tests/rest/media/v1/test_url_preview.py |tests/scripts/test_new_matrix_user.py |tests/server.py |tests/server_notices/test_resource_limits_server_notices.py diff --git a/tests/rest/client/test_transactions.py b/tests/rest/client/test_transactions.py index 3b5747cb12b8..8d8251b2ac99 100644 --- a/tests/rest/client/test_transactions.py +++ b/tests/rest/client/test_transactions.py @@ -1,3 +1,18 @@ +# Copyright 2018-2021 The Matrix.org Foundation C.I.C. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from http import HTTPStatus from unittest.mock import Mock, call from twisted.internet import defer, reactor @@ -11,14 +26,14 @@ class HttpTransactionCacheTestCase(unittest.TestCase): - def setUp(self): + def setUp(self) -> None: self.clock = MockClock() self.hs = Mock() self.hs.get_clock = Mock(return_value=self.clock) self.hs.get_auth = Mock() self.cache = HttpTransactionCache(self.hs) - self.mock_http_response = (200, "GOOD JOB!") + self.mock_http_response = (HTTPStatus.OK, "GOOD JOB!") self.mock_key = "foo" @defer.inlineCallbacks diff --git a/tests/rest/media/v1/test_media_storage.py b/tests/rest/media/v1/test_media_storage.py index cba9be17c4ca..7204b2dfe075 100644 --- a/tests/rest/media/v1/test_media_storage.py +++ b/tests/rest/media/v1/test_media_storage.py @@ -16,7 +16,7 @@ import tempfile from binascii import unhexlify from io import BytesIO -from typing import Optional +from typing import Any, BinaryIO, Dict, List, Optional, Union from unittest.mock import Mock from urllib import parse @@ -26,18 +26,24 @@ from twisted.internet import defer from twisted.internet.defer import Deferred +from twisted.test.proto_helpers import MemoryReactor +from synapse.events import EventBase from synapse.events.spamcheck import load_legacy_spam_checkers from synapse.logging.context import make_deferred_yieldable +from synapse.module_api import ModuleApi from synapse.rest import admin from synapse.rest.client import login from synapse.rest.media.v1._base import FileInfo from synapse.rest.media.v1.filepath import MediaFilePaths -from synapse.rest.media.v1.media_storage import MediaStorage +from synapse.rest.media.v1.media_storage import MediaStorage, ReadableFileWrapper from synapse.rest.media.v1.storage_provider import FileStorageProviderBackend +from synapse.server import HomeServer +from synapse.types import RoomAlias +from synapse.util import Clock from tests import unittest -from tests.server import FakeSite, make_request +from tests.server import FakeChannel, FakeSite, make_request from tests.test_utils import SMALL_PNG from tests.utils import default_config @@ -46,7 +52,7 @@ class MediaStorageTests(unittest.HomeserverTestCase): needs_threadpool = True - def prepare(self, reactor, clock, hs): + def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None: self.test_dir = tempfile.mkdtemp(prefix="synapse-tests-") self.addCleanup(shutil.rmtree, self.test_dir) @@ -62,7 +68,7 @@ def prepare(self, reactor, clock, hs): hs, self.primary_base_path, self.filepaths, storage_providers ) - def test_ensure_media_is_in_local_cache(self): + def test_ensure_media_is_in_local_cache(self) -> None: media_id = "some_media_id" test_body = "Test\n" @@ -105,7 +111,7 @@ def test_ensure_media_is_in_local_cache(self): self.assertEqual(test_body, body) -@attr.s(slots=True, frozen=True) +@attr.s(auto_attribs=True, slots=True, frozen=True) class _TestImage: """An image for testing thumbnailing with the expected results @@ -121,18 +127,18 @@ class _TestImage: a 404 is expected. """ - data = attr.ib(type=bytes) - content_type = attr.ib(type=bytes) - extension = attr.ib(type=bytes) - expected_cropped = attr.ib(type=Optional[bytes], default=None) - expected_scaled = attr.ib(type=Optional[bytes], default=None) - expected_found = attr.ib(default=True, type=bool) + data: bytes + content_type: bytes + extension: bytes + expected_cropped: Optional[bytes] = None + expected_scaled: Optional[bytes] = None + expected_found: bool = True @parameterized_class( ("test_image",), [ - # smoll png + # small png ( _TestImage( SMALL_PNG, @@ -193,11 +199,17 @@ class MediaRepoTests(unittest.HomeserverTestCase): hijack_auth = True user_id = "@test:user" - def make_homeserver(self, reactor, clock): + def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer: self.fetches = [] - def get_file(destination, path, output_stream, args=None, max_size=None): + def get_file( + destination: str, + path: str, + output_stream: BinaryIO, + args: Optional[Dict[str, Union[str, List[str]]]] = None, + max_size: Optional[int] = None, + ) -> Deferred: """ Returns tuple[int,dict,str,int] of file length, response headers, absolute URI, and response code. @@ -238,7 +250,7 @@ def write_to(r): return hs - def prepare(self, reactor, clock, hs): + def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None: media_resource = hs.get_media_repository_resource() self.download_resource = media_resource.children[b"download"] @@ -248,8 +260,9 @@ def prepare(self, reactor, clock, hs): self.media_id = "example.com/12345" - def _req(self, content_disposition, include_content_type=True): - + def _req( + self, content_disposition: Optional[bytes], include_content_type: bool = True + ) -> FakeChannel: channel = make_request( self.reactor, FakeSite(self.download_resource, self.reactor), @@ -288,7 +301,7 @@ def _req(self, content_disposition, include_content_type=True): return channel - def test_handle_missing_content_type(self): + def test_handle_missing_content_type(self) -> None: channel = self._req( b"inline; filename=out" + self.test_image.extension, include_content_type=False, @@ -299,7 +312,7 @@ def test_handle_missing_content_type(self): headers.getRawHeaders(b"Content-Type"), [b"application/octet-stream"] ) - def test_disposition_filename_ascii(self): + def test_disposition_filename_ascii(self) -> None: """ If the filename is filename= then Synapse will decode it as an ASCII string, and use filename= in the response. @@ -315,7 +328,7 @@ def test_disposition_filename_ascii(self): [b"inline; filename=out" + self.test_image.extension], ) - def test_disposition_filenamestar_utf8escaped(self): + def test_disposition_filenamestar_utf8escaped(self) -> None: """ If the filename is filename=*utf8'' then Synapse will correctly decode it as the UTF-8 string, and use filename* in the @@ -335,7 +348,7 @@ def test_disposition_filenamestar_utf8escaped(self): [b"inline; filename*=utf-8''" + filename + self.test_image.extension], ) - def test_disposition_none(self): + def test_disposition_none(self) -> None: """ If there is no filename, one isn't passed on in the Content-Disposition of the request. @@ -348,26 +361,26 @@ def test_disposition_none(self): ) self.assertEqual(headers.getRawHeaders(b"Content-Disposition"), None) - def test_thumbnail_crop(self): + def test_thumbnail_crop(self) -> None: """Test that a cropped remote thumbnail is available.""" self._test_thumbnail( "crop", self.test_image.expected_cropped, self.test_image.expected_found ) - def test_thumbnail_scale(self): + def test_thumbnail_scale(self) -> None: """Test that a scaled remote thumbnail is available.""" self._test_thumbnail( "scale", self.test_image.expected_scaled, self.test_image.expected_found ) - def test_invalid_type(self): + def test_invalid_type(self) -> None: """An invalid thumbnail type is never available.""" self._test_thumbnail("invalid", None, False) @unittest.override_config( {"thumbnail_sizes": [{"width": 32, "height": 32, "method": "scale"}]} ) - def test_no_thumbnail_crop(self): + def test_no_thumbnail_crop(self) -> None: """ Override the config to generate only scaled thumbnails, but request a cropped one. """ @@ -376,13 +389,13 @@ def test_no_thumbnail_crop(self): @unittest.override_config( {"thumbnail_sizes": [{"width": 32, "height": 32, "method": "crop"}]} ) - def test_no_thumbnail_scale(self): + def test_no_thumbnail_scale(self) -> None: """ Override the config to generate only cropped thumbnails, but request a scaled one. """ self._test_thumbnail("scale", None, False) - def test_thumbnail_repeated_thumbnail(self): + def test_thumbnail_repeated_thumbnail(self) -> None: """Test that fetching the same thumbnail works, and deleting the on disk thumbnail regenerates it. """ @@ -443,7 +456,9 @@ def test_thumbnail_repeated_thumbnail(self): channel.result["body"], ) - def _test_thumbnail(self, method, expected_body, expected_found): + def _test_thumbnail( + self, method: str, expected_body: Optional[bytes], expected_found: bool + ) -> None: params = "?width=32&height=32&method=" + method channel = make_request( self.reactor, @@ -485,7 +500,7 @@ def _test_thumbnail(self, method, expected_body, expected_found): ) @parameterized.expand([("crop", 16), ("crop", 64), ("scale", 16), ("scale", 64)]) - def test_same_quality(self, method, desired_size): + def test_same_quality(self, method: str, desired_size: int) -> None: """Test that choosing between thumbnails with the same quality rating succeeds. We are not particular about which thumbnail is chosen.""" @@ -521,7 +536,7 @@ def test_same_quality(self, method, desired_size): ) ) - def test_x_robots_tag_header(self): + def test_x_robots_tag_header(self) -> None: """ Tests that the `X-Robots-Tag` header is present, which informs web crawlers to not index, archive, or follow links in media. @@ -540,29 +555,38 @@ class TestSpamChecker: `evil`. """ - def __init__(self, config, api): + def __init__(self, config: Dict[str, Any], api: ModuleApi) -> None: self.config = config self.api = api - def parse_config(config): + def parse_config(config: Dict[str, Any]) -> Dict[str, Any]: return config - async def check_event_for_spam(self, foo): + async def check_event_for_spam(self, event: EventBase) -> Union[bool, str]: return False # allow all events - async def user_may_invite(self, inviter_userid, invitee_userid, room_id): + async def user_may_invite( + self, + inviter_userid: str, + invitee_userid: str, + room_id: str, + ) -> bool: return True # allow all invites - async def user_may_create_room(self, userid): + async def user_may_create_room(self, userid: str) -> bool: return True # allow all room creations - async def user_may_create_room_alias(self, userid, room_alias): + async def user_may_create_room_alias( + self, userid: str, room_alias: RoomAlias + ) -> bool: return True # allow all room aliases - async def user_may_publish_room(self, userid, room_id): + async def user_may_publish_room(self, userid: str, room_id: str) -> bool: return True # allow publishing of all rooms - async def check_media_file_for_spam(self, file_wrapper, file_info) -> bool: + async def check_media_file_for_spam( + self, file_wrapper: ReadableFileWrapper, file_info: FileInfo + ) -> bool: buf = BytesIO() await file_wrapper.write_chunks_to(buf.write) @@ -575,7 +599,7 @@ class SpamCheckerTestCase(unittest.HomeserverTestCase): admin.register_servlets, ] - def prepare(self, reactor, clock, hs): + def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None: self.user = self.register_user("user", "pass") self.tok = self.login("user", "pass") @@ -586,7 +610,7 @@ def prepare(self, reactor, clock, hs): load_legacy_spam_checkers(hs) - def default_config(self): + def default_config(self) -> Dict[str, Any]: config = default_config("test") config.update( @@ -602,13 +626,13 @@ def default_config(self): return config - def test_upload_innocent(self): + def test_upload_innocent(self) -> None: """Attempt to upload some innocent data that should be allowed.""" self.helper.upload_media( self.upload_resource, SMALL_PNG, tok=self.tok, expect_code=200 ) - def test_upload_ban(self): + def test_upload_ban(self) -> None: """Attempt to upload some data that includes bytes "evil", which should get rejected by the spam checker. """ diff --git a/tests/rest/media/v1/test_url_preview.py b/tests/rest/media/v1/test_url_preview.py index da2c53326019..5148c39874e2 100644 --- a/tests/rest/media/v1/test_url_preview.py +++ b/tests/rest/media/v1/test_url_preview.py @@ -16,16 +16,21 @@ import json import os import re +from typing import Any, Dict, Optional, Sequence, Tuple, Type from urllib.parse import urlencode from twisted.internet._resolver import HostResolution from twisted.internet.address import IPv4Address, IPv6Address from twisted.internet.error import DNSLookupError -from twisted.test.proto_helpers import AccumulatingProtocol +from twisted.internet.interfaces import IAddress, IResolutionReceiver +from twisted.test.proto_helpers import AccumulatingProtocol, MemoryReactor from synapse.config.oembed import OEmbedEndpointConfig +from synapse.rest.media.v1.media_repository import MediaRepositoryResource from synapse.rest.media.v1.preview_url_resource import IMAGE_CACHE_EXPIRY_MS +from synapse.server import HomeServer from synapse.types import JsonDict +from synapse.util import Clock from synapse.util.stringutils import parse_and_validate_mxc_uri from tests import unittest @@ -52,7 +57,7 @@ class URLPreviewTests(unittest.HomeserverTestCase): b"" ) - def make_homeserver(self, reactor, clock): + def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer: config = self.default_config() config["url_preview_enabled"] = True @@ -113,22 +118,22 @@ def make_homeserver(self, reactor, clock): return hs - def prepare(self, reactor, clock, hs): + def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None: self.media_repo = hs.get_media_repository_resource() self.preview_url = self.media_repo.children[b"preview_url"] - self.lookups = {} + self.lookups: Dict[str, Any] = {} class Resolver: def resolveHostName( _self, - resolutionReceiver, - hostName, - portNumber=0, - addressTypes=None, - transportSemantics="TCP", - ): + resolutionReceiver: IResolutionReceiver, + hostName: str, + portNumber: int = 0, + addressTypes: Optional[Sequence[Type[IAddress]]] = None, + transportSemantics: str = "TCP", + ) -> IResolutionReceiver: resolution = HostResolution(hostName) resolutionReceiver.resolutionBegan(resolution) @@ -140,9 +145,9 @@ def resolveHostName( resolutionReceiver.resolutionComplete() return resolutionReceiver - self.reactor.nameResolver = Resolver() + self.reactor.nameResolver = Resolver() # type: ignore[assignment] - def create_test_resource(self): + def create_test_resource(self) -> MediaRepositoryResource: return self.hs.get_media_repository_resource() def _assert_small_png(self, json_body: JsonDict) -> None: @@ -153,7 +158,7 @@ def _assert_small_png(self, json_body: JsonDict) -> None: self.assertEqual(json_body["og:image:type"], "image/png") self.assertEqual(json_body["matrix:image:size"], 67) - def test_cache_returns_correct_type(self): + def test_cache_returns_correct_type(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] channel = self.make_request( @@ -207,7 +212,7 @@ def test_cache_returns_correct_type(self): channel.json_body, {"og:title": "~matrix~", "og:description": "hi"} ) - def test_non_ascii_preview_httpequiv(self): + def test_non_ascii_preview_httpequiv(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] end_content = ( @@ -243,7 +248,7 @@ def test_non_ascii_preview_httpequiv(self): self.assertEqual(channel.code, 200) self.assertEqual(channel.json_body["og:title"], "\u0434\u043a\u0430") - def test_video_rejected(self): + def test_video_rejected(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] end_content = b"anything" @@ -279,7 +284,7 @@ def test_video_rejected(self): }, ) - def test_audio_rejected(self): + def test_audio_rejected(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] end_content = b"anything" @@ -315,7 +320,7 @@ def test_audio_rejected(self): }, ) - def test_non_ascii_preview_content_type(self): + def test_non_ascii_preview_content_type(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] end_content = ( @@ -350,7 +355,7 @@ def test_non_ascii_preview_content_type(self): self.assertEqual(channel.code, 200) self.assertEqual(channel.json_body["og:title"], "\u0434\u043a\u0430") - def test_overlong_title(self): + def test_overlong_title(self) -> None: self.lookups["matrix.org"] = [(IPv4Address, "10.1.2.3")] end_content = ( @@ -387,7 +392,7 @@ def test_overlong_title(self): # We should only see the `og:description` field, as `title` is too long and should be stripped out self.assertCountEqual(["og:description"], res.keys()) - def test_ipaddr(self): + def test_ipaddr(self) -> None: """ IP addresses can be previewed directly. """ @@ -417,7 +422,7 @@ def test_ipaddr(self): channel.json_body, {"og:title": "~matrix~", "og:description": "hi"} ) - def test_blacklisted_ip_specific(self): + def test_blacklisted_ip_specific(self) -> None: """ Blacklisted IP addresses, found via DNS, are not spidered. """ @@ -438,7 +443,7 @@ def test_blacklisted_ip_specific(self): }, ) - def test_blacklisted_ip_range(self): + def test_blacklisted_ip_range(self) -> None: """ Blacklisted IP ranges, IPs found over DNS, are not spidered. """ @@ -457,7 +462,7 @@ def test_blacklisted_ip_range(self): }, ) - def test_blacklisted_ip_specific_direct(self): + def test_blacklisted_ip_specific_direct(self) -> None: """ Blacklisted IP addresses, accessed directly, are not spidered. """ @@ -476,7 +481,7 @@ def test_blacklisted_ip_specific_direct(self): ) self.assertEqual(channel.code, 403) - def test_blacklisted_ip_range_direct(self): + def test_blacklisted_ip_range_direct(self) -> None: """ Blacklisted IP ranges, accessed directly, are not spidered. """ @@ -493,7 +498,7 @@ def test_blacklisted_ip_range_direct(self): }, ) - def test_blacklisted_ip_range_whitelisted_ip(self): + def test_blacklisted_ip_range_whitelisted_ip(self) -> None: """ Blacklisted but then subsequently whitelisted IP addresses can be spidered. @@ -526,7 +531,7 @@ def test_blacklisted_ip_range_whitelisted_ip(self): channel.json_body, {"og:title": "~matrix~", "og:description": "hi"} ) - def test_blacklisted_ip_with_external_ip(self): + def test_blacklisted_ip_with_external_ip(self) -> None: """ If a hostname resolves a blacklisted IP, even if there's a non-blacklisted one, it will be rejected. @@ -549,7 +554,7 @@ def test_blacklisted_ip_with_external_ip(self): }, ) - def test_blacklisted_ipv6_specific(self): + def test_blacklisted_ipv6_specific(self) -> None: """ Blacklisted IP addresses, found via DNS, are not spidered. """ @@ -572,7 +577,7 @@ def test_blacklisted_ipv6_specific(self): }, ) - def test_blacklisted_ipv6_range(self): + def test_blacklisted_ipv6_range(self) -> None: """ Blacklisted IP ranges, IPs found over DNS, are not spidered. """ @@ -591,7 +596,7 @@ def test_blacklisted_ipv6_range(self): }, ) - def test_OPTIONS(self): + def test_OPTIONS(self) -> None: """ OPTIONS returns the OPTIONS. """ @@ -601,7 +606,7 @@ def test_OPTIONS(self): self.assertEqual(channel.code, 200) self.assertEqual(channel.json_body, {}) - def test_accept_language_config_option(self): + def test_accept_language_config_option(self) -> None: """ Accept-Language header is sent to the remote server """ @@ -652,7 +657,7 @@ def test_accept_language_config_option(self): server.data, ) - def test_data_url(self): + def test_data_url(self) -> None: """ Requesting to preview a data URL is not supported. """ @@ -675,7 +680,7 @@ def test_data_url(self): self.assertEqual(channel.code, 500) - def test_inline_data_url(self): + def test_inline_data_url(self) -> None: """ An inline image (as a data URL) should be parsed properly. """ @@ -712,7 +717,7 @@ def test_inline_data_url(self): self.assertEqual(channel.code, 200) self._assert_small_png(channel.json_body) - def test_oembed_photo(self): + def test_oembed_photo(self) -> None: """Test an oEmbed endpoint which returns a 'photo' type which redirects the preview to a new URL.""" self.lookups["publish.twitter.com"] = [(IPv4Address, "10.1.2.3")] self.lookups["cdn.twitter.com"] = [(IPv4Address, "10.1.2.3")] @@ -771,7 +776,7 @@ def test_oembed_photo(self): self.assertEqual(body["og:url"], "http://twitter.com/matrixdotorg/status/12345") self._assert_small_png(body) - def test_oembed_rich(self): + def test_oembed_rich(self) -> None: """Test an oEmbed endpoint which returns HTML content via the 'rich' type.""" self.lookups["publish.twitter.com"] = [(IPv4Address, "10.1.2.3")] @@ -817,7 +822,7 @@ def test_oembed_rich(self): }, ) - def test_oembed_format(self): + def test_oembed_format(self) -> None: """Test an oEmbed endpoint which requires the format in the URL.""" self.lookups["www.hulu.com"] = [(IPv4Address, "10.1.2.3")] @@ -866,7 +871,7 @@ def test_oembed_format(self): }, ) - def test_oembed_autodiscovery(self): + def test_oembed_autodiscovery(self) -> None: """ Autodiscovery works by finding the link in the HTML response and then requesting an oEmbed URL. 1. Request a preview of a URL which is not known to the oEmbed code. @@ -962,7 +967,7 @@ def test_oembed_autodiscovery(self): ) self._assert_small_png(body) - def _download_image(self): + def _download_image(self) -> Tuple[str, str]: """Downloads an image into the URL cache. Returns: A (host, media_id) tuple representing the MXC URI of the image. @@ -995,7 +1000,7 @@ def _download_image(self): self.assertIsNone(_port) return host, media_id - def test_storage_providers_exclude_files(self): + def test_storage_providers_exclude_files(self) -> None: """Test that files are not stored in or fetched from storage providers.""" host, media_id = self._download_image() @@ -1037,7 +1042,7 @@ def test_storage_providers_exclude_files(self): "URL cache file was unexpectedly retrieved from a storage provider", ) - def test_storage_providers_exclude_thumbnails(self): + def test_storage_providers_exclude_thumbnails(self) -> None: """Test that thumbnails are not stored in or fetched from storage providers.""" host, media_id = self._download_image() @@ -1090,7 +1095,7 @@ def test_storage_providers_exclude_thumbnails(self): "URL cache thumbnail was unexpectedly retrieved from a storage provider", ) - def test_cache_expiry(self): + def test_cache_expiry(self) -> None: """Test that URL cache files and thumbnails are cleaned up properly on expiry.""" self.preview_url.clock = MockClock()