diff --git a/changelog.d/12146.misc b/changelog.d/12146.misc
new file mode 100644
index 000000000..3ca7c4721
--- /dev/null
+++ b/changelog.d/12146.misc
@@ -0,0 +1 @@
+Add type hints to `tests/rest`.
diff --git a/mypy.ini b/mypy.ini
index 10971b722..481e8a536 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -89,8 +89,6 @@ exclude = (?x)
    |tests/push/test_presentable_names.py
    |tests/push/test_push_rule_evaluator.py
    |tests/rest/client/test_transactions.py
-   |tests/rest/key/v2/test_remote_key_resource.py
-   |tests/rest/media/v1/test_base.py
    |tests/rest/media/v1/test_media_storage.py
    |tests/rest/media/v1/test_url_preview.py
    |tests/scripts/test_new_matrix_user.py
@@ -254,10 +252,7 @@ disallow_untyped_defs = True
 [mypy-tests.storage.test_user_directory]
 disallow_untyped_defs = True
 
-[mypy-tests.rest.admin.*]
-disallow_untyped_defs = True
-
-[mypy-tests.rest.client.*]
+[mypy-tests.rest.*]
 disallow_untyped_defs = True
 
 [mypy-tests.federation.transport.test_client]
diff --git a/tests/rest/key/v2/test_remote_key_resource.py b/tests/rest/key/v2/test_remote_key_resource.py
index 4672a6859..978c252f8 100644
--- a/tests/rest/key/v2/test_remote_key_resource.py
+++ b/tests/rest/key/v2/test_remote_key_resource.py
@@ -13,19 +13,24 @@
 # limitations under the License.
 import urllib.parse
 from io import BytesIO, StringIO
+from typing import Any, Dict, Optional, Union
 from unittest.mock import Mock
 
 import signedjson.key
 from canonicaljson import encode_canonical_json
-from nacl.signing import SigningKey
 from signedjson.sign import sign_json
+from signedjson.types import SigningKey
 
-from twisted.web.resource import NoResource
+from twisted.test.proto_helpers import MemoryReactor
+from twisted.web.resource import NoResource, Resource
 
 from synapse.crypto.keyring import PerspectivesKeyFetcher
 from synapse.http.site import SynapseRequest
 from synapse.rest.key.v2 import KeyApiV2Resource
+from synapse.server import HomeServer
 from synapse.storage.keys import FetchKeyResult
+from synapse.types import JsonDict
+from synapse.util import Clock
 from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.stringutils import random_string
 
@@ -35,11 +40,11 @@ from tests.utils import default_config
 
 
 class BaseRemoteKeyResourceTestCase(unittest.HomeserverTestCase):
-    def make_homeserver(self, reactor, clock):
+    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
         self.http_client = Mock()
         return self.setup_test_homeserver(federation_http_client=self.http_client)
 
-    def create_test_resource(self):
+    def create_test_resource(self) -> Resource:
         return create_resource_tree(
             {"/_matrix/key/v2": KeyApiV2Resource(self.hs)}, root_resource=NoResource()
         )
@@ -51,7 +56,12 @@ class BaseRemoteKeyResourceTestCase(unittest.HomeserverTestCase):
         Tell the mock http client to expect an outgoing GET request for the given key
         """
 
-        async def get_json(destination, path, ignore_backoff=False, **kwargs):
+        async def get_json(
+            destination: str,
+            path: str,
+            ignore_backoff: bool = False,
+            **kwargs: Any,
+        ) -> Union[JsonDict, list]:
             self.assertTrue(ignore_backoff)
             self.assertEqual(destination, server_name)
             key_id = "%s:%s" % (signing_key.alg, signing_key.version)
@@ -84,7 +94,8 @@ class RemoteKeyResourceTestCase(BaseRemoteKeyResourceTestCase):
         Checks that the response is a 200 and returns the decoded json body.
         """
         channel = FakeChannel(self.site, self.reactor)
-        req = SynapseRequest(channel, self.site)
+        # channel is a `FakeChannel` but `HTTPChannel` is expected
+        req = SynapseRequest(channel, self.site)  # type: ignore[arg-type]
         req.content = BytesIO(b"")
         req.requestReceived(
             b"GET",
@@ -97,7 +108,7 @@ class RemoteKeyResourceTestCase(BaseRemoteKeyResourceTestCase):
         resp = channel.json_body
         return resp
 
-    def test_get_key(self):
+    def test_get_key(self) -> None:
         """Fetch a remote key"""
         SERVER_NAME = "remote.server"
         testkey = signedjson.key.generate_signing_key("ver1")
@@ -114,7 +125,7 @@ class RemoteKeyResourceTestCase(BaseRemoteKeyResourceTestCase):
         self.assertIn(SERVER_NAME, keys[0]["signatures"])
         self.assertIn(self.hs.hostname, keys[0]["signatures"])
 
-    def test_get_own_key(self):
+    def test_get_own_key(self) -> None:
         """Fetch our own key"""
         testkey = signedjson.key.generate_signing_key("ver1")
         self.expect_outgoing_key_request(self.hs.hostname, testkey)
@@ -141,7 +152,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
     endpoint, to check that the two implementations are compatible.
     """
 
-    def default_config(self):
+    def default_config(self) -> Dict[str, Any]:
         config = super().default_config()
 
         # replace the signing key with our own
@@ -152,7 +163,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
 
         return config
 
-    def prepare(self, reactor, clock, homeserver):
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
         # make a second homeserver, configured to use the first one as a key notary
         self.http_client2 = Mock()
         config = default_config(name="keyclient")
@@ -175,7 +186,9 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
 
         # wire up outbound POST /key/v2/query requests from hs2 so that they
         # will be forwarded to hs1
-        async def post_json(destination, path, data):
+        async def post_json(
+            destination: str, path: str, data: Optional[JsonDict] = None
+        ) -> Union[JsonDict, list]:
             self.assertEqual(destination, self.hs.hostname)
             self.assertEqual(
                 path,
@@ -183,7 +196,8 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
             )
 
             channel = FakeChannel(self.site, self.reactor)
-            req = SynapseRequest(channel, self.site)
+            # channel is a `FakeChannel` but `HTTPChannel` is expected
+            req = SynapseRequest(channel, self.site)  # type: ignore[arg-type]
             req.content = BytesIO(encode_canonical_json(data))
 
             req.requestReceived(
@@ -198,7 +212,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
 
         self.http_client2.post_json.side_effect = post_json
 
-    def test_get_key(self):
+    def test_get_key(self) -> None:
         """Fetch a key belonging to a random server"""
         # make up a key to be fetched.
         testkey = signedjson.key.generate_signing_key("abc")
@@ -218,7 +232,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
             signedjson.key.encode_verify_key_base64(testkey.verify_key),
         )
 
-    def test_get_notary_key(self):
+    def test_get_notary_key(self) -> None:
         """Fetch a key belonging to the notary server"""
         # make up a key to be fetched. We randomise the keyid to try to get it to
         # appear before the key server signing key sometimes (otherwise we bail out
@@ -240,7 +254,7 @@ class EndToEndPerspectivesTests(BaseRemoteKeyResourceTestCase):
             signedjson.key.encode_verify_key_base64(testkey.verify_key),
         )
 
-    def test_get_notary_keyserver_key(self):
+    def test_get_notary_keyserver_key(self) -> None:
         """Fetch the notary's keyserver key"""
         # we expect hs1 to make a regular key request to itself
         self.expect_outgoing_key_request(self.hs.hostname, self.hs_signing_key)
diff --git a/tests/rest/media/v1/test_base.py b/tests/rest/media/v1/test_base.py
index f761e23f1..c73179151 100644
--- a/tests/rest/media/v1/test_base.py
+++ b/tests/rest/media/v1/test_base.py
@@ -28,11 +28,11 @@ class GetFileNameFromHeadersTests(unittest.TestCase):
         b"inline; filename*=utf-8''foo%C2%A3bar": "foo£bar",
     }
 
-    def tests(self):
+    def tests(self) -> None:
         for hdr, expected in self.TEST_CASES.items():
             res = get_filename_from_headers({b"Content-Disposition": [hdr]})
             self.assertEqual(
                 res,
                 expected,
-                "expected output for %s to be %s but was %s" % (hdr, expected, res),
+                f"expected output for {hdr!r} to be {expected} but was {res}",
             )
diff --git a/tests/rest/media/v1/test_filepath.py b/tests/rest/media/v1/test_filepath.py
index 913bc530a..43e6f0f70 100644
--- a/tests/rest/media/v1/test_filepath.py
+++ b/tests/rest/media/v1/test_filepath.py
@@ -21,12 +21,12 @@ from tests import unittest
 
 
 class MediaFilePathsTestCase(unittest.TestCase):
-    def setUp(self):
+    def setUp(self) -> None:
         super().setUp()
 
         self.filepaths = MediaFilePaths("/media_store")
 
-    def test_local_media_filepath(self):
+    def test_local_media_filepath(self) -> None:
         """Test local media paths"""
         self.assertEqual(
             self.filepaths.local_media_filepath_rel("GerZNDnDZVjsOtardLuwfIBg"),
@@ -37,7 +37,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/local_content/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_local_media_thumbnail(self):
+    def test_local_media_thumbnail(self) -> None:
         """Test local media thumbnail paths"""
         self.assertEqual(
             self.filepaths.local_media_thumbnail_rel(
@@ -52,14 +52,14 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/local_thumbnails/Ge/rZ/NDnDZVjsOtardLuwfIBg/800-600-image-jpeg-scale",
         )
 
-    def test_local_media_thumbnail_dir(self):
+    def test_local_media_thumbnail_dir(self) -> None:
         """Test local media thumbnail directory paths"""
         self.assertEqual(
             self.filepaths.local_media_thumbnail_dir("GerZNDnDZVjsOtardLuwfIBg"),
             "/media_store/local_thumbnails/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_remote_media_filepath(self):
+    def test_remote_media_filepath(self) -> None:
         """Test remote media paths"""
         self.assertEqual(
             self.filepaths.remote_media_filepath_rel(
@@ -74,7 +74,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/remote_content/example.com/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_remote_media_thumbnail(self):
+    def test_remote_media_thumbnail(self) -> None:
         """Test remote media thumbnail paths"""
         self.assertEqual(
             self.filepaths.remote_media_thumbnail_rel(
@@ -99,7 +99,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/remote_thumbnail/example.com/Ge/rZ/NDnDZVjsOtardLuwfIBg/800-600-image-jpeg-scale",
         )
 
-    def test_remote_media_thumbnail_legacy(self):
+    def test_remote_media_thumbnail_legacy(self) -> None:
         """Test old-style remote media thumbnail paths"""
         self.assertEqual(
             self.filepaths.remote_media_thumbnail_rel_legacy(
@@ -108,7 +108,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "remote_thumbnail/example.com/Ge/rZ/NDnDZVjsOtardLuwfIBg/800-600-image-jpeg",
         )
 
-    def test_remote_media_thumbnail_dir(self):
+    def test_remote_media_thumbnail_dir(self) -> None:
         """Test remote media thumbnail directory paths"""
         self.assertEqual(
             self.filepaths.remote_media_thumbnail_dir(
@@ -117,7 +117,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/remote_thumbnail/example.com/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_url_cache_filepath(self):
+    def test_url_cache_filepath(self) -> None:
         """Test URL cache paths"""
         self.assertEqual(
             self.filepaths.url_cache_filepath_rel("2020-01-02_GerZNDnDZVjsOtar"),
@@ -128,7 +128,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache/2020-01-02/GerZNDnDZVjsOtar",
         )
 
-    def test_url_cache_filepath_legacy(self):
+    def test_url_cache_filepath_legacy(self) -> None:
         """Test old-style URL cache paths"""
         self.assertEqual(
             self.filepaths.url_cache_filepath_rel("GerZNDnDZVjsOtardLuwfIBg"),
@@ -139,7 +139,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_url_cache_filepath_dirs_to_delete(self):
+    def test_url_cache_filepath_dirs_to_delete(self) -> None:
         """Test URL cache cleanup paths"""
         self.assertEqual(
             self.filepaths.url_cache_filepath_dirs_to_delete(
@@ -148,7 +148,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ["/media_store/url_cache/2020-01-02"],
         )
 
-    def test_url_cache_filepath_dirs_to_delete_legacy(self):
+    def test_url_cache_filepath_dirs_to_delete_legacy(self) -> None:
         """Test old-style URL cache cleanup paths"""
         self.assertEqual(
             self.filepaths.url_cache_filepath_dirs_to_delete(
@@ -160,7 +160,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_url_cache_thumbnail(self):
+    def test_url_cache_thumbnail(self) -> None:
         """Test URL cache thumbnail paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_rel(
@@ -175,7 +175,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache_thumbnails/2020-01-02/GerZNDnDZVjsOtar/800-600-image-jpeg-scale",
         )
 
-    def test_url_cache_thumbnail_legacy(self):
+    def test_url_cache_thumbnail_legacy(self) -> None:
         """Test old-style URL cache thumbnail paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_rel(
@@ -190,7 +190,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache_thumbnails/Ge/rZ/NDnDZVjsOtardLuwfIBg/800-600-image-jpeg-scale",
         )
 
-    def test_url_cache_thumbnail_directory(self):
+    def test_url_cache_thumbnail_directory(self) -> None:
         """Test URL cache thumbnail directory paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_directory_rel(
@@ -203,7 +203,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache_thumbnails/2020-01-02/GerZNDnDZVjsOtar",
         )
 
-    def test_url_cache_thumbnail_directory_legacy(self):
+    def test_url_cache_thumbnail_directory_legacy(self) -> None:
         """Test old-style URL cache thumbnail directory paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_directory_rel(
@@ -216,7 +216,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             "/media_store/url_cache_thumbnails/Ge/rZ/NDnDZVjsOtardLuwfIBg",
         )
 
-    def test_url_cache_thumbnail_dirs_to_delete(self):
+    def test_url_cache_thumbnail_dirs_to_delete(self) -> None:
         """Test URL cache thumbnail cleanup paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_dirs_to_delete(
@@ -228,7 +228,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_url_cache_thumbnail_dirs_to_delete_legacy(self):
+    def test_url_cache_thumbnail_dirs_to_delete_legacy(self) -> None:
         """Test old-style URL cache thumbnail cleanup paths"""
         self.assertEqual(
             self.filepaths.url_cache_thumbnail_dirs_to_delete(
@@ -241,7 +241,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_server_name_validation(self):
+    def test_server_name_validation(self) -> None:
         """Test validation of server names"""
         self._test_path_validation(
             [
@@ -274,7 +274,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_file_id_validation(self):
+    def test_file_id_validation(self) -> None:
         """Test validation of local, remote and legacy URL cache file / media IDs"""
         # File / media IDs get split into three parts to form paths, consisting of the
         # first two characters, next two characters and rest of the ID.
@@ -357,7 +357,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             invalid_values=invalid_file_ids,
         )
 
-    def test_url_cache_media_id_validation(self):
+    def test_url_cache_media_id_validation(self) -> None:
         """Test validation of URL cache media IDs"""
         self._test_path_validation(
             [
@@ -387,7 +387,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_content_type_validation(self):
+    def test_content_type_validation(self) -> None:
         """Test validation of thumbnail content types"""
         self._test_path_validation(
             [
@@ -410,7 +410,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
             ],
         )
 
-    def test_thumbnail_method_validation(self):
+    def test_thumbnail_method_validation(self) -> None:
         """Test validation of thumbnail methods"""
         self._test_path_validation(
             [
@@ -440,7 +440,7 @@ class MediaFilePathsTestCase(unittest.TestCase):
         parameter: str,
         valid_values: Iterable[str],
         invalid_values: Iterable[str],
-    ):
+    ) -> None:
         """Test that the specified methods validate the named parameter as expected
 
         Args:
diff --git a/tests/rest/media/v1/test_html_preview.py b/tests/rest/media/v1/test_html_preview.py
index a4b57e3d1..3fb37a2a5 100644
--- a/tests/rest/media/v1/test_html_preview.py
+++ b/tests/rest/media/v1/test_html_preview.py
@@ -32,7 +32,7 @@ class SummarizeTestCase(unittest.TestCase):
     if not lxml:
         skip = "url preview feature requires lxml"
 
-    def test_long_summarize(self):
+    def test_long_summarize(self) -> None:
         example_paras = [
             """Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:
             Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in
@@ -90,7 +90,7 @@ class SummarizeTestCase(unittest.TestCase):
             " Tromsøya had a population of 36,088. Substantial parts of the urban…",
         )
 
-    def test_short_summarize(self):
+    def test_short_summarize(self) -> None:
         example_paras = [
             "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
             " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
@@ -117,7 +117,7 @@ class SummarizeTestCase(unittest.TestCase):
             " most of the year.",
         )
 
-    def test_small_then_large_summarize(self):
+    def test_small_then_large_summarize(self) -> None:
         example_paras = [
             "Tromsø (Norwegian pronunciation: [ˈtrʊmsœ] ( listen); Northern Sami:"
             " Romsa; Finnish: Tromssa[2] Kven: Tromssa) is a city and municipality in"
@@ -150,7 +150,7 @@ class CalcOgTestCase(unittest.TestCase):
     if not lxml:
         skip = "url preview feature requires lxml"
 
-    def test_simple(self):
+    def test_simple(self) -> None:
         html = b"""
         <html>
         <head><title>Foo</title></head>
@@ -165,7 +165,7 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": "Foo", "og:description": "Some text."})
 
-    def test_comment(self):
+    def test_comment(self) -> None:
         html = b"""
         <html>
         <head><title>Foo</title></head>
@@ -181,7 +181,7 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": "Foo", "og:description": "Some text."})
 
-    def test_comment2(self):
+    def test_comment2(self) -> None:
         html = b"""
         <html>
         <head><title>Foo</title></head>
@@ -206,7 +206,7 @@ class CalcOgTestCase(unittest.TestCase):
             },
         )
 
-    def test_script(self):
+    def test_script(self) -> None:
         html = b"""
         <html>
         <head><title>Foo</title></head>
@@ -222,7 +222,7 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": "Foo", "og:description": "Some text."})
 
-    def test_missing_title(self):
+    def test_missing_title(self) -> None:
         html = b"""
         <html>
         <body>
@@ -236,7 +236,7 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": None, "og:description": "Some text."})
 
-    def test_h1_as_title(self):
+    def test_h1_as_title(self) -> None:
         html = b"""
         <html>
         <meta property="og:description" content="Some text."/>
@@ -251,7 +251,7 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": "Title", "og:description": "Some text."})
 
-    def test_missing_title_and_broken_h1(self):
+    def test_missing_title_and_broken_h1(self) -> None:
         html = b"""
         <html>
         <body>
@@ -266,19 +266,19 @@ class CalcOgTestCase(unittest.TestCase):
 
         self.assertEqual(og, {"og:title": None, "og:description": "Some text."})
 
-    def test_empty(self):
+    def test_empty(self) -> None:
         """Test a body with no data in it."""
         html = b""
         tree = decode_body(html, "http://example.com/test.html")
         self.assertIsNone(tree)
 
-    def test_no_tree(self):
+    def test_no_tree(self) -> None:
         """A valid body with no tree in it."""
         html = b"\x00"
         tree = decode_body(html, "http://example.com/test.html")
         self.assertIsNone(tree)
 
-    def test_xml(self):
+    def test_xml(self) -> None:
         """Test decoding XML and ensure it works properly."""
         # Note that the strip() call is important to ensure the xml tag starts
         # at the initial byte.
@@ -293,7 +293,7 @@ class CalcOgTestCase(unittest.TestCase):
         og = parse_html_to_open_graph(tree, "http://example.com/test.html")
         self.assertEqual(og, {"og:title": "Foo", "og:description": "Some text."})
 
-    def test_invalid_encoding(self):
+    def test_invalid_encoding(self) -> None:
         """An invalid character encoding should be ignored and treated as UTF-8, if possible."""
         html = b"""
         <html>
@@ -307,7 +307,7 @@ class CalcOgTestCase(unittest.TestCase):
         og = parse_html_to_open_graph(tree, "http://example.com/test.html")
         self.assertEqual(og, {"og:title": "Foo", "og:description": "Some text."})
 
-    def test_invalid_encoding2(self):
+    def test_invalid_encoding2(self) -> None:
         """A body which doesn't match the sent character encoding."""
         # Note that this contains an invalid UTF-8 sequence in the title.
         html = b"""
@@ -322,7 +322,7 @@ class CalcOgTestCase(unittest.TestCase):
         og = parse_html_to_open_graph(tree, "http://example.com/test.html")
         self.assertEqual(og, {"og:title": "ÿÿ Foo", "og:description": "Some text."})
 
-    def test_windows_1252(self):
+    def test_windows_1252(self) -> None:
         """A body which uses cp1252, but doesn't declare that."""
         html = b"""
         <html>
@@ -338,7 +338,7 @@ class CalcOgTestCase(unittest.TestCase):
 
 
 class MediaEncodingTestCase(unittest.TestCase):
-    def test_meta_charset(self):
+    def test_meta_charset(self) -> None:
         """A character encoding is found via the meta tag."""
         encodings = _get_html_media_encodings(
             b"""
@@ -363,7 +363,7 @@ class MediaEncodingTestCase(unittest.TestCase):
         )
         self.assertEqual(list(encodings), ["ascii", "utf-8", "cp1252"])
 
-    def test_meta_charset_underscores(self):
+    def test_meta_charset_underscores(self) -> None:
         """A character encoding contains underscore."""
         encodings = _get_html_media_encodings(
             b"""
@@ -376,7 +376,7 @@ class MediaEncodingTestCase(unittest.TestCase):
         )
         self.assertEqual(list(encodings), ["shift_jis", "utf-8", "cp1252"])
 
-    def test_xml_encoding(self):
+    def test_xml_encoding(self) -> None:
         """A character encoding is found via the meta tag."""
         encodings = _get_html_media_encodings(
             b"""
@@ -388,7 +388,7 @@ class MediaEncodingTestCase(unittest.TestCase):
         )
         self.assertEqual(list(encodings), ["ascii", "utf-8", "cp1252"])
 
-    def test_meta_xml_encoding(self):
+    def test_meta_xml_encoding(self) -> None:
         """Meta tags take precedence over XML encoding."""
         encodings = _get_html_media_encodings(
             b"""
@@ -402,7 +402,7 @@ class MediaEncodingTestCase(unittest.TestCase):
         )
         self.assertEqual(list(encodings), ["utf-16", "ascii", "utf-8", "cp1252"])
 
-    def test_content_type(self):
+    def test_content_type(self) -> None:
         """A character encoding is found via the Content-Type header."""
         # Test a few variations of the header.
         headers = (
@@ -417,12 +417,12 @@ class MediaEncodingTestCase(unittest.TestCase):
             encodings = _get_html_media_encodings(b"", header)
             self.assertEqual(list(encodings), ["ascii", "utf-8", "cp1252"])
 
-    def test_fallback(self):
+    def test_fallback(self) -> None:
         """A character encoding cannot be found in the body or header."""
         encodings = _get_html_media_encodings(b"", "text/html")
         self.assertEqual(list(encodings), ["utf-8", "cp1252"])
 
-    def test_duplicates(self):
+    def test_duplicates(self) -> None:
         """Ensure each encoding is only attempted once."""
         encodings = _get_html_media_encodings(
             b"""
@@ -436,7 +436,7 @@ class MediaEncodingTestCase(unittest.TestCase):
         )
         self.assertEqual(list(encodings), ["utf-8", "cp1252"])
 
-    def test_unknown_invalid(self):
+    def test_unknown_invalid(self) -> None:
         """A character encoding should be ignored if it is unknown or invalid."""
         encodings = _get_html_media_encodings(
             b"""
@@ -451,7 +451,7 @@ class MediaEncodingTestCase(unittest.TestCase):
 
 
 class RebaseUrlTestCase(unittest.TestCase):
-    def test_relative(self):
+    def test_relative(self) -> None:
         """Relative URLs should be resolved based on the context of the base URL."""
         self.assertEqual(
             rebase_url("subpage", "https://example.com/foo/"),
@@ -466,14 +466,14 @@ class RebaseUrlTestCase(unittest.TestCase):
             "https://example.com/bar",
         )
 
-    def test_absolute(self):
+    def test_absolute(self) -> None:
         """Absolute URLs should not be modified."""
         self.assertEqual(
             rebase_url("https://alice.com/a/", "https://example.com/foo/"),
             "https://alice.com/a/",
         )
 
-    def test_data(self):
+    def test_data(self) -> None:
         """Data URLs should not be modified."""
         self.assertEqual(
             rebase_url("data:,Hello%2C%20World%21", "https://example.com/foo/"),
diff --git a/tests/rest/media/v1/test_oembed.py b/tests/rest/media/v1/test_oembed.py
index 048d0ca44..f38d7225f 100644
--- a/tests/rest/media/v1/test_oembed.py
+++ b/tests/rest/media/v1/test_oembed.py
@@ -16,7 +16,7 @@ import json
 
 from twisted.test.proto_helpers import MemoryReactor
 
-from synapse.rest.media.v1.oembed import OEmbedProvider
+from synapse.rest.media.v1.oembed import OEmbedProvider, OEmbedResult
 from synapse.server import HomeServer
 from synapse.types import JsonDict
 from synapse.util import Clock
@@ -25,15 +25,15 @@ from tests.unittest import HomeserverTestCase
 
 
 class OEmbedTests(HomeserverTestCase):
-    def prepare(self, reactor: MemoryReactor, clock: Clock, homeserver: HomeServer):
-        self.oembed = OEmbedProvider(homeserver)
+    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
+        self.oembed = OEmbedProvider(hs)
 
-    def parse_response(self, response: JsonDict):
+    def parse_response(self, response: JsonDict) -> OEmbedResult:
         return self.oembed.parse_oembed_response(
             "https://test", json.dumps(response).encode("utf-8")
         )
 
-    def test_version(self):
+    def test_version(self) -> None:
         """Accept versions that are similar to 1.0 as a string or int (or missing)."""
         for version in ("1.0", 1.0, 1):
             result = self.parse_response({"version": version, "type": "link"})
diff --git a/tests/rest/test_health.py b/tests/rest/test_health.py
index 01d48c386..da325955f 100644
--- a/tests/rest/test_health.py
+++ b/tests/rest/test_health.py
@@ -11,7 +11,7 @@
 # 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 synapse.rest.health import HealthResource
 
@@ -19,12 +19,12 @@ from tests import unittest
 
 
 class HealthCheckTests(unittest.HomeserverTestCase):
-    def create_test_resource(self):
+    def create_test_resource(self) -> HealthResource:
         # replace the JsonResource with a HealthResource.
         return HealthResource()
 
-    def test_health(self):
+    def test_health(self) -> None:
         channel = self.make_request("GET", "/health", shorthand=False)
 
-        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.code, HTTPStatus.OK)
         self.assertEqual(channel.result["body"], b"OK")
diff --git a/tests/rest/test_well_known.py b/tests/rest/test_well_known.py
index 118aa93a3..11f78f52b 100644
--- a/tests/rest/test_well_known.py
+++ b/tests/rest/test_well_known.py
@@ -11,6 +11,8 @@
 # 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 twisted.web.resource import Resource
 
 from synapse.rest.well_known import well_known_resource
@@ -19,7 +21,7 @@ from tests import unittest
 
 
 class WellKnownTests(unittest.HomeserverTestCase):
-    def create_test_resource(self):
+    def create_test_resource(self) -> Resource:
         # replace the JsonResource with a Resource wrapping the WellKnownResource
         res = Resource()
         res.putChild(b".well-known", well_known_resource(self.hs))
@@ -31,12 +33,12 @@ class WellKnownTests(unittest.HomeserverTestCase):
             "default_identity_server": "https://testis",
         }
     )
-    def test_client_well_known(self):
+    def test_client_well_known(self) -> None:
         channel = self.make_request(
             "GET", "/.well-known/matrix/client", shorthand=False
         )
 
-        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.code, HTTPStatus.OK)
         self.assertEqual(
             channel.json_body,
             {
@@ -50,27 +52,27 @@ class WellKnownTests(unittest.HomeserverTestCase):
             "public_baseurl": None,
         }
     )
-    def test_client_well_known_no_public_baseurl(self):
+    def test_client_well_known_no_public_baseurl(self) -> None:
         channel = self.make_request(
             "GET", "/.well-known/matrix/client", shorthand=False
         )
 
-        self.assertEqual(channel.code, 404)
+        self.assertEqual(channel.code, HTTPStatus.NOT_FOUND)
 
     @unittest.override_config({"serve_server_wellknown": True})
-    def test_server_well_known(self):
+    def test_server_well_known(self) -> None:
         channel = self.make_request(
             "GET", "/.well-known/matrix/server", shorthand=False
         )
 
-        self.assertEqual(channel.code, 200)
+        self.assertEqual(channel.code, HTTPStatus.OK)
         self.assertEqual(
             channel.json_body,
             {"m.server": "test:443"},
         )
 
-    def test_server_well_known_disabled(self):
+    def test_server_well_known_disabled(self) -> None:
         channel = self.make_request(
             "GET", "/.well-known/matrix/server", shorthand=False
         )
-        self.assertEqual(channel.code, 404)
+        self.assertEqual(channel.code, HTTPStatus.NOT_FOUND)