Merge branch 'shay/batch_events' of https://github.com/matrix-org/synapse into shay/batch_events

61 files changed, 692 insertions, 602 deletions

diff --git a/CHANGES.md b/CHANGES.md
index 823f4f40b3..0bc8f95855 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+Synapse 1.65.0rc2 (2022-08-11)
+==============================
+
+Internal Changes
+----------------
+
+- Revert 'Remove the unspecced `room_id` field in the `/hierarchy` response. ([\#13365](https://github.com/matrix-org/synapse/issues/13365))' to give more time for clients to update. ([\#13501](https://github.com/matrix-org/synapse/issues/13501))
+
+
 Synapse 1.65.0rc1 (2022-08-09)
 ==============================
 
diff --git a/changelog.d/13453.misc b/changelog.d/13453.misc
new file mode 100644
index 0000000000..d30c5230c8
--- /dev/null
+++ b/changelog.d/13453.misc
@@ -0,0 +1 @@
+Allow use of both `@trace` and `@tag_args` stacked on the same function (tracing).
diff --git a/changelog.d/13459.misc b/changelog.d/13459.misc
new file mode 100644
index 0000000000..e6082210a0
--- /dev/null
+++ b/changelog.d/13459.misc
@@ -0,0 +1 @@
+Faster joins: update the rejected state of events during de-partial-stating.
diff --git a/changelog.d/13472.doc b/changelog.d/13472.doc
new file mode 100644
index 0000000000..2ff6317300
--- /dev/null
+++ b/changelog.d/13472.doc
@@ -0,0 +1 @@
+Add `openssl` example for generating registration HMAC digest.
diff --git a/changelog.d/13474.misc b/changelog.d/13474.misc
new file mode 100644
index 0000000000..d34c661fed
--- /dev/null
+++ b/changelog.d/13474.misc
@@ -0,0 +1 @@
+Add some miscellaneous comments to document sync, especially around `compute_state_delta`.
diff --git a/changelog.d/13488.misc b/changelog.d/13488.misc
new file mode 100644
index 0000000000..315930deab
--- /dev/null
+++ b/changelog.d/13488.misc
@@ -0,0 +1 @@
+Use literals in place of `HTTPStatus` constants in tests.
\ No newline at end of file
diff --git a/changelog.d/13492.doc b/changelog.d/13492.doc
new file mode 100644
index 0000000000..fc4850d556
--- /dev/null
+++ b/changelog.d/13492.doc
@@ -0,0 +1 @@
+Document that event purging related to the `redaction_retention_period` config option is executed only every 5 minutes.
diff --git a/changelog.d/13493.misc b/changelog.d/13493.misc
new file mode 100644
index 0000000000..d7d5c33a89
--- /dev/null
+++ b/changelog.d/13493.misc
@@ -0,0 +1 @@
+Modify HTML template content to better support mobile devices' screen sizes.
\ No newline at end of file
diff --git a/debian/changelog b/debian/changelog
index 6e4bdc3a00..21115d7be2 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.65.0~rc2) stable; urgency=medium
+
+  * New Synapse release 1.65.0rc2.
+
+ -- Synapse Packaging team <packages@matrix.org>  Thu, 11 Aug 2022 11:38:18 +0100
+
 matrix-synapse-py3 (1.65.0~rc1) stable; urgency=medium
 
   * New Synapse release 1.65.0rc1.
diff --git a/docs/admin_api/register_api.md b/docs/admin_api/register_api.md
index c346090bb1..d7b7cf6a76 100644
--- a/docs/admin_api/register_api.md
+++ b/docs/admin_api/register_api.md
@@ -46,7 +46,24 @@ As an example:
 The MAC is the hex digest output of the HMAC-SHA1 algorithm, with the key being
 the shared secret and the content being the nonce, user, password, either the
 string "admin" or "notadmin", and optionally the user_type
-each separated by NULs. For an example of generation in Python:
+each separated by NULs.
+
+Here is an easy way to generate the HMAC digest if you have Bash and OpenSSL:
+
+```bash
+# Update these values and then paste this code block into a bash terminal
+nonce='thisisanonce'
+username='pepper_roni'
+password='pizza'
+admin='admin'
+secret='shared_secret'
+
+printf '%s\0%s\0%s\0%s' "$nonce" "$username" "$password" "$admin" |
+  openssl sha1 -hmac "$secret" |
+  awk '{print $2}'
+```
+
+For an example of generation in Python:
 
 ```python
 import hmac, hashlib
@@ -70,4 +87,4 @@ def generate_mac(nonce, user, password, admin=False, user_type=None):
         mac.update(user_type.encode('utf8'))
 
     return mac.hexdigest()
-```
\ No newline at end of file
+```
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
index 2af32a6155..bc3d2bec6a 100644
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@@ -759,6 +759,10 @@ allowed_avatar_mimetypes: ["image/png", "image/jpeg", "image/gif"]
 How long to keep redacted events in unredacted form in the database. After
 this period redacted events get replaced with their redacted form in the DB.
 
+Synapse will check whether the rentention period has concluded for redacted
+events every 5 minutes. Thus, even if this option is set to `0`, Synapse may
+still take up to 5 minutes to purge redacted events from the database.
+
 Defaults to `7d`. Set to `null` to disable.
 
 Example configuration:
diff --git a/pyproject.toml b/pyproject.toml
index ad2224f564..a9f59a676f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -54,7 +54,7 @@ skip_gitignore = true
 
 [tool.poetry]
 name = "matrix-synapse"
-version = "1.65.0rc1"
+version = "1.65.0rc2"
 description = "Homeserver for the Matrix decentralised comms protocol"
 authors = ["Matrix.org Team and Contributors <packages@matrix.org>"]
 license = "Apache-2.0"
diff --git a/synapse/handlers/room_summary.py b/synapse/handlers/room_summary.py
index ebd445adca..732b0310bc 100644
--- a/synapse/handlers/room_summary.py
+++ b/synapse/handlers/room_summary.py
@@ -453,6 +453,7 @@ class RoomSummaryHandler:
                 "type": e.type,
                 "state_key": e.state_key,
                 "content": e.content,
+                "room_id": e.room_id,
                 "sender": e.sender,
                 "origin_server_ts": e.origin_server_ts,
             }
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index d827c03ad1..3ca01391c9 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -13,7 +13,17 @@
 # limitations under the License.
 import itertools
 import logging
-from typing import TYPE_CHECKING, Any, Dict, FrozenSet, List, Optional, Set, Tuple
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Dict,
+    FrozenSet,
+    List,
+    Optional,
+    Sequence,
+    Set,
+    Tuple,
+)
 
 import attr
 from prometheus_client import Counter
@@ -89,7 +99,7 @@ class SyncConfig:
 @attr.s(slots=True, frozen=True, auto_attribs=True)
 class TimelineBatch:
     prev_batch: StreamToken
-    events: List[EventBase]
+    events: Sequence[EventBase]
     limited: bool
     # A mapping of event ID to the bundled aggregations for the above events.
     # This is only calculated if limited is true.
@@ -852,16 +862,26 @@ class SyncHandler:
         now_token: StreamToken,
         full_state: bool,
     ) -> MutableStateMap[EventBase]:
-        """Works out the difference in state between the start of the timeline
-        and the previous sync.
+        """Works out the difference in state between the end of the previous sync and
+        the start of the timeline.
 
         Args:
             room_id:
             batch: The timeline batch for the room that will be sent to the user.
             sync_config:
-            since_token: Token of the end of the previous batch. May be None.
+            since_token: Token of the end of the previous batch. May be `None`.
             now_token: Token of the end of the current batch.
             full_state: Whether to force returning the full state.
+                `lazy_load_members` still applies when `full_state` is `True`.
+
+        Returns:
+            The state to return in the sync response for the room.
+
+            Clients will overlay this onto the state at the end of the previous sync to
+            arrive at the state at the start of the timeline.
+
+            Clients will then overlay state events in the timeline to arrive at the
+            state at the end of the timeline, in preparation for the next sync.
         """
         # TODO(mjark) Check if the state events were received by the server
         # after the previous sync, since we need to include those state
@@ -869,7 +889,8 @@ class SyncHandler:
         # TODO(mjark) Check for new redactions in the state events.
 
         with Measure(self.clock, "compute_state_delta"):
-
+            # The memberships needed for events in the timeline.
+            # Only calculated when `lazy_load_members` is on.
             members_to_fetch = None
 
             lazy_load_members = sync_config.filter_collection.lazy_load_members()
@@ -897,38 +918,46 @@ class SyncHandler:
             else:
                 state_filter = StateFilter.all()
 
+            # The contribution to the room state from state events in the timeline.
+            # Only contains the last event for any given state key.
             timeline_state = {
                 (event.type, event.state_key): event.event_id
                 for event in batch.events
                 if event.is_state()
             }
 
+            # Now calculate the state to return in the sync response for the room.
+            # This is more or less the change in state between the end of the previous
+            # sync's timeline and the start of the current sync's timeline.
+            # See the docstring above for details.
+            state_ids: StateMap[str]
+
             if full_state:
                 if batch:
-                    current_state_ids = (
+                    state_at_timeline_end = (
                         await self._state_storage_controller.get_state_ids_for_event(
                             batch.events[-1].event_id, state_filter=state_filter
                         )
                     )
 
-                    state_ids = (
+                    state_at_timeline_start = (
                         await self._state_storage_controller.get_state_ids_for_event(
                             batch.events[0].event_id, state_filter=state_filter
                         )
                     )
 
                 else:
-                    current_state_ids = await self.get_state_at(
+                    state_at_timeline_end = await self.get_state_at(
                         room_id, stream_position=now_token, state_filter=state_filter
                     )
 
-                    state_ids = current_state_ids
+                    state_at_timeline_start = state_at_timeline_end
 
                 state_ids = _calculate_state(
                     timeline_contains=timeline_state,
-                    timeline_start=state_ids,
-                    previous={},
-                    current=current_state_ids,
+                    timeline_start=state_at_timeline_start,
+                    timeline_end=state_at_timeline_end,
+                    previous_timeline_end={},
                     lazy_load_members=lazy_load_members,
                 )
             elif batch.limited:
@@ -968,24 +997,23 @@ class SyncHandler:
                 )
 
                 if batch:
-                    current_state_ids = (
+                    state_at_timeline_end = (
                         await self._state_storage_controller.get_state_ids_for_event(
                             batch.events[-1].event_id, state_filter=state_filter
                         )
                     )
                 else:
-                    # Its not clear how we get here, but empirically we do
-                    # (#5407). Logging has been added elsewhere to try and
-                    # figure out where this state comes from.
-                    current_state_ids = await self.get_state_at(
+                    # We can get here if the user has ignored the senders of all
+                    # the recent events.
+                    state_at_timeline_end = await self.get_state_at(
                         room_id, stream_position=now_token, state_filter=state_filter
                     )
 
                 state_ids = _calculate_state(
                     timeline_contains=timeline_state,
                     timeline_start=state_at_timeline_start,
-                    previous=state_at_previous_sync,
-                    current=current_state_ids,
+                    timeline_end=state_at_timeline_end,
+                    previous_timeline_end=state_at_previous_sync,
                     # we have to include LL members in case LL initial sync missed them
                     lazy_load_members=lazy_load_members,
                 )
@@ -1010,6 +1038,13 @@ class SyncHandler:
                             ),
                         )
 
+            # At this point, if `lazy_load_members` is enabled, `state_ids` includes
+            # the memberships of all event senders in the timeline. This is because we
+            # may not have sent the memberships in a previous sync.
+
+            # When `include_redundant_members` is on, we send all the lazy-loaded
+            # memberships of event senders. Otherwise we make an effort to limit the set
+            # of memberships we send to those that we have not already sent to this client.
             if lazy_load_members and not include_redundant_members:
                 cache_key = (sync_config.user.to_string(), sync_config.device_id)
                 cache = self.get_lazy_loaded_members_cache(cache_key)
@@ -2216,8 +2251,8 @@ def _action_has_highlight(actions: List[JsonDict]) -> bool:
 def _calculate_state(
     timeline_contains: StateMap[str],
     timeline_start: StateMap[str],
-    previous: StateMap[str],
-    current: StateMap[str],
+    timeline_end: StateMap[str],
+    previous_timeline_end: StateMap[str],
     lazy_load_members: bool,
 ) -> StateMap[str]:
     """Works out what state to include in a sync response.
@@ -2225,45 +2260,50 @@ def _calculate_state(
     Args:
         timeline_contains: state in the timeline
         timeline_start: state at the start of the timeline
-        previous: state at the end of the previous sync (or empty dict
+        timeline_end: state at the end of the timeline
+        previous_timeline_end: state at the end of the previous sync (or empty dict
             if this is an initial sync)
-        current: state at the end of the timeline
         lazy_load_members: whether to return members from timeline_start
             or not.  assumes that timeline_start has already been filtered to
             include only the members the client needs to know about.
     """
-    event_id_to_key = {
-        e: key
-        for key, e in itertools.chain(
+    event_id_to_state_key = {
+        event_id: state_key
+        for state_key, event_id in itertools.chain(
             timeline_contains.items(),
-            previous.items(),
             timeline_start.items(),
-            current.items(),
+            timeline_end.items(),
+            previous_timeline_end.items(),
         )
     }
 
-    c_ids = set(current.values())
-    ts_ids = set(timeline_start.values())
-    p_ids = set(previous.values())
-    tc_ids = set(timeline_contains.values())
+    timeline_end_ids = set(timeline_end.values())
+    timeline_start_ids = set(timeline_start.values())
+    previous_timeline_end_ids = set(previous_timeline_end.values())
+    timeline_contains_ids = set(timeline_contains.values())
 
     # If we are lazyloading room members, we explicitly add the membership events
     # for the senders in the timeline into the state block returned by /sync,
     # as we may not have sent them to the client before.  We find these membership
     # events by filtering them out of timeline_start, which has already been filtered
     # to only include membership events for the senders in the timeline.
-    # In practice, we can do this by removing them from the p_ids list,
-    # which is the list of relevant state we know we have already sent to the client.
+    # In practice, we can do this by removing them from the previous_timeline_end_ids
+    # list, which is the list of relevant state we know we have already sent to the
+    # client.
     # see https://github.com/matrix-org/synapse/pull/2970/files/efcdacad7d1b7f52f879179701c7e0d9b763511f#r204732809
 
     if lazy_load_members:
-        p_ids.difference_update(
+        previous_timeline_end_ids.difference_update(
             e for t, e in timeline_start.items() if t[0] == EventTypes.Member
         )
 
-    state_ids = ((c_ids | ts_ids) - p_ids) - tc_ids
+    state_ids = (
+        (timeline_end_ids | timeline_start_ids)
+        - previous_timeline_end_ids
+        - timeline_contains_ids
+    )
 
-    return {event_id_to_key[e]: e for e in state_ids}
+    return {event_id_to_state_key[e]: e for e in state_ids}
 
 
 @attr.s(slots=True, auto_attribs=True)
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index fa3f76c27f..d1fa2cf8ae 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -173,6 +173,7 @@ from typing import (
     Any,
     Callable,
     Collection,
+    ContextManager,
     Dict,
     Generator,
     Iterable,
@@ -823,75 +824,117 @@ def extract_text_map(carrier: Dict[str, str]) -> Optional["opentracing.SpanConte
 # Tracing decorators
 
 
-def trace_with_opname(opname: str) -> Callable[[Callable[P, R]], Callable[P, R]]:
+def _custom_sync_async_decorator(
+    func: Callable[P, R],
+    wrapping_logic: Callable[[Callable[P, R], Any, Any], ContextManager[None]],
+) -> Callable[P, R]:
     """
-    Decorator to trace a function with a custom opname.
-
-    See the module's doc string for usage examples.
+    Decorates a function that is sync or async (coroutines), or that returns a Twisted
+    `Deferred`. The custom business logic of the decorator goes in `wrapping_logic`.
+
+    Example usage:
+    ```py
+    # Decorator to time the function and log it out
+    def duration(func: Callable[P, R]) -> Callable[P, R]:
+        @contextlib.contextmanager
+        def _wrapping_logic(func: Callable[P, R], *args: P.args, **kwargs: P.kwargs) -> Generator[None, None, None]:
+            start_ts = time.time()
+            try:
+                yield
+            finally:
+                end_ts = time.time()
+                duration = end_ts - start_ts
+                logger.info("%s took %s seconds", func.__name__, duration)
+        return _custom_sync_async_decorator(func, _wrapping_logic)
+    ```
 
+    Args:
+        func: The function to be decorated
+        wrapping_logic: The business logic of your custom decorator.
+            This should be a ContextManager so you are able to run your logic
+            before/after the function as desired.
     """
 
-    def decorator(func: Callable[P, R]) -> Callable[P, R]:
-        if opentracing is None:
-            return func  # type: ignore[unreachable]
+    if inspect.iscoroutinefunction(func):
 
-        if inspect.iscoroutinefunction(func):
+        @wraps(func)
+        async def _wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+            with wrapping_logic(func, *args, **kwargs):
+                return await func(*args, **kwargs)  # type: ignore[misc]
 
-            @wraps(func)
-            async def _trace_inner(*args: P.args, **kwargs: P.kwargs) -> R:
-                with start_active_span(opname):
-                    return await func(*args, **kwargs)  # type: ignore[misc]
+    else:
+        # The other case here handles both sync functions and those
+        # decorated with inlineDeferred.
+        @wraps(func)
+        def _wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+            scope = wrapping_logic(func, *args, **kwargs)
+            scope.__enter__()
 
-        else:
-            # The other case here handles both sync functions and those
-            # decorated with inlineDeferred.
-            @wraps(func)
-            def _trace_inner(*args: P.args, **kwargs: P.kwargs) -> R:
-                scope = start_active_span(opname)
-                scope.__enter__()
-
-                try:
-                    result = func(*args, **kwargs)
-                    if isinstance(result, defer.Deferred):
-
-                        def call_back(result: R) -> R:
-                            scope.__exit__(None, None, None)
-                            return result
-
-                        def err_back(result: R) -> R:
-                            scope.__exit__(None, None, None)
-                            return result
-
-                        result.addCallbacks(call_back, err_back)
-
-                    else:
-                        if inspect.isawaitable(result):
-                            logger.error(
-                                "@trace may not have wrapped %s correctly! "
-                                "The function is not async but returned a %s.",
-                                func.__qualname__,
-                                type(result).__name__,
-                            )
+            try:
+                result = func(*args, **kwargs)
+                if isinstance(result, defer.Deferred):
+
+                    def call_back(result: R) -> R:
+                        scope.__exit__(None, None, None)
+                        return result
 
+                    def err_back(result: R) -> R:
                         scope.__exit__(None, None, None)
+                        return result
+
+                    result.addCallbacks(call_back, err_back)
+
+                else:
+                    if inspect.isawaitable(result):
+                        logger.error(
+                            "@trace may not have wrapped %s correctly! "
+                            "The function is not async but returned a %s.",
+                            func.__qualname__,
+                            type(result).__name__,
+                        )
+
+                    scope.__exit__(None, None, None)
 
-                    return result
+                return result
 
-                except Exception as e:
-                    scope.__exit__(type(e), None, e.__traceback__)
-                    raise
+            except Exception as e:
+                scope.__exit__(type(e), None, e.__traceback__)
+                raise
 
-        return _trace_inner  # type: ignore[return-value]
+    return _wrapper  # type: ignore[return-value]
 
-    return decorator
+
+def trace_with_opname(
+    opname: str,
+    *,
+    tracer: Optional["opentracing.Tracer"] = None,
+) -> Callable[[Callable[P, R]], Callable[P, R]]:
+    """
+    Decorator to trace a function with a custom opname.
+    See the module's doc string for usage examples.
+    """
+
+    # type-ignore: mypy bug, see https://github.com/python/mypy/issues/12909
+    @contextlib.contextmanager  # type: ignore[arg-type]
+    def _wrapping_logic(
+        func: Callable[P, R], *args: P.args, **kwargs: P.kwargs
+    ) -> Generator[None, None, None]:
+        with start_active_span(opname, tracer=tracer):
+            yield
+
+    def _decorator(func: Callable[P, R]) -> Callable[P, R]:
+        if not opentracing:
+            return func
+
+        return _custom_sync_async_decorator(func, _wrapping_logic)
+
+    return _decorator
 
 
 def trace(func: Callable[P, R]) -> Callable[P, R]:
     """
     Decorator to trace a function.
-
     Sets the operation name to that of the function's name.
-
     See the module's doc string for usage examples.
     """
 
@@ -900,7 +943,7 @@ def trace(func: Callable[P, R]) -> Callable[P, R]:
 
 def tag_args(func: Callable[P, R]) -> Callable[P, R]:
     """
-    Tags all of the args to the active span.
+    Decorator to tag all of the args to the active span.
 
     Args:
         func: `func` is assumed to be a method taking a `self` parameter, or a
@@ -911,22 +954,25 @@ def tag_args(func: Callable[P, R]) -> Callable[P, R]:
     if not opentracing:
         return func
 
-    @wraps(func)
-    def _tag_args_inner(*args: P.args, **kwargs: P.kwargs) -> R:
+    # type-ignore: mypy bug, see https://github.com/python/mypy/issues/12909
+    @contextlib.contextmanager  # type: ignore[arg-type]
+    def _wrapping_logic(
+        func: Callable[P, R], *args: P.args, **kwargs: P.kwargs
+    ) -> Generator[None, None, None]:
         argspec = inspect.getfullargspec(func)
         # We use `[1:]` to skip the `self` object reference and `start=1` to
         # make the index line up with `argspec.args`.
         #
-        # FIXME: We could update this handle any type of function by ignoring the
+        # FIXME: We could update this to handle any type of function by ignoring the
         #   first argument only if it's named `self` or `cls`. This isn't fool-proof
         #   but handles the idiomatic cases.
         for i, arg in enumerate(args[1:], start=1):  # type: ignore[index]
             set_tag("ARG_" + argspec.args[i], str(arg))
         set_tag("args", str(args[len(argspec.args) :]))  # type: ignore[index]
         set_tag("kwargs", str(kwargs))
-        return func(*args, **kwargs)
+        yield
 
-    return _tag_args_inner
+    return _custom_sync_async_decorator(func, _wrapping_logic)
 
 
 @contextlib.contextmanager
diff --git a/synapse/res/templates/account_previously_renewed.html b/synapse/res/templates/account_previously_renewed.html
index b751359bdf..bd4f7cea97 100644
--- a/synapse/res/templates/account_previously_renewed.html
+++ b/synapse/res/templates/account_previously_renewed.html
@@ -1 +1,12 @@
-<html><body>Your account is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.</body><html>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Your account is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.</title>
+</head>
+<body>
+    Your account is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.
+</body>
+</html>
\ No newline at end of file
diff --git a/synapse/res/templates/account_renewed.html b/synapse/res/templates/account_renewed.html
index e8c0f52f05..57b319f375 100644
--- a/synapse/res/templates/account_renewed.html
+++ b/synapse/res/templates/account_renewed.html
@@ -1 +1,12 @@
-<html><body>Your account has been successfully renewed and is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.</body><html>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Your account has been successfully renewed and is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.</title>
+</head>
+<body>
+    Your account has been successfully renewed and is valid until {{ expiration_ts|format_ts("%d-%m-%Y") }}.
+</body>
+</html>
\ No newline at end of file
diff --git a/synapse/res/templates/add_threepid.html b/synapse/res/templates/add_threepid.html
index cc4ab07e09..71f2215b7a 100644
--- a/synapse/res/templates/add_threepid.html
+++ b/synapse/res/templates/add_threepid.html
@@ -1,9 +1,14 @@
-<html>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Request to add an email address to your Matrix account</title>
+</head>
 <body>
     <p>A request to add an email address to your Matrix account has been received. If this was you, please click the link below to confirm adding this email:</p>
-
     <a href="{{ link }}">{{ link }}</a>
-
     <p>If this was not you, you can safely ignore this email. Thank you.</p>
 </body>
 </html>
diff --git a/synapse/res/templates/add_threepid_failure.html b/synapse/res/templates/add_threepid_failure.html
index 441d11c846..bd627ee9ce 100644
--- a/synapse/res/templates/add_threepid_failure.html
+++ b/synapse/res/templates/add_threepid_failure.html
@@ -1,8 +1,13 @@
-<html>
-<head></head>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Request failed</title>
+</head>
 <body>
-<p>The request failed for the following reason: {{ failure_reason }}.</p>
-
-<p>No changes have been made to your account.</p>
+    <p>The request failed for the following reason: {{ failure_reason }}.</p>
+    <p>No changes have been made to your account.</p>
 </body>
 </html>
diff --git a/synapse/res/templates/add_threepid_success.html b/synapse/res/templates/add_threepid_success.html
index fbd6e4018f..49170c138e 100644
--- a/synapse/res/templates/add_threepid_success.html
+++ b/synapse/res/templates/add_threepid_success.html
@@ -1,6 +1,12 @@
-<html>
-<head></head>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Your email has now been validated</title>
+</head>
 <body>
-<p>Your email has now been validated, please return to your client. You may now close this window.</p>
+    <p>Your email has now been validated, please return to your client. You may now close this window.</p>
 </body>
-</html>
+</html>
\ No newline at end of file
diff --git a/synapse/res/templates/auth_success.html b/synapse/res/templates/auth_success.html
index baf4633142..2d6ac44a0e 100644
--- a/synapse/res/templates/auth_success.html
+++ b/synapse/res/templates/auth_success.html
@@ -1,8 +1,8 @@
 <html>
 <head>
 <title>Success!</title>
-<meta name='viewport' content='width=device-width, initial-scale=1,
-    user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <link rel="stylesheet" href="/_matrix/static/client/register/style.css">
 <script>
 if (window.onAuthDone) {
diff --git a/synapse/res/templates/invalid_token.html b/synapse/res/templates/invalid_token.html
index 6bd2b98364..2c7c384fe3 100644
--- a/synapse/res/templates/invalid_token.html
+++ b/synapse/res/templates/invalid_token.html
@@ -1 +1,12 @@
-<html><body>Invalid renewal token.</body><html>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Invalid renewal token.</title>
+</head>
+<body>
+    Invalid renewal token.
+</body>
+</html>
diff --git a/synapse/res/templates/notice_expiry.html b/synapse/res/templates/notice_expiry.html
index d87311f659..865f9f7ada 100644
--- a/synapse/res/templates/notice_expiry.html
+++ b/synapse/res/templates/notice_expiry.html
@@ -1,6 +1,8 @@
 <!doctype html>
 <html lang="en">
     <head>
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {% include 'mail.css' without context %}
             {% include "mail-%s.css" % app_name ignore missing without context %}
diff --git a/synapse/res/templates/notif_mail.html b/synapse/res/templates/notif_mail.html
index 27d4182790..9dba0c0253 100644
--- a/synapse/res/templates/notif_mail.html
+++ b/synapse/res/templates/notif_mail.html
@@ -1,6 +1,8 @@
 <!doctype html>
 <html lang="en">
     <head>
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {%- include 'mail.css' without context %}
             {%- include "mail-%s.css" % app_name ignore missing without context %}
diff --git a/synapse/res/templates/password_reset.html b/synapse/res/templates/password_reset.html
index a197bf872c..a8bdce357b 100644
--- a/synapse/res/templates/password_reset.html
+++ b/synapse/res/templates/password_reset.html
@@ -1,4 +1,9 @@
-<html>
+<html lang="en">
+    <head>
+        <title>Password reset</title>
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    </head>
 <body>
     <p>A password reset request has been received for your Matrix account. If this was you, please click the link below to confirm resetting your password:</p>
 
diff --git a/synapse/res/templates/password_reset_confirmation.html b/synapse/res/templates/password_reset_confirmation.html
index def4b5162b..2e3fd2ec1e 100644
--- a/synapse/res/templates/password_reset_confirmation.html
+++ b/synapse/res/templates/password_reset_confirmation.html
@@ -1,5 +1,9 @@
-<html>
-<head></head>
+<html lang="en">
+<head>
+    <title>Password reset confirmation</title>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
 <!--Use a hidden form to resubmit the information necessary to reset the password-->
 <form method="post">
diff --git a/synapse/res/templates/password_reset_failure.html b/synapse/res/templates/password_reset_failure.html
index 9e3c4446e3..2d59c463f0 100644
--- a/synapse/res/templates/password_reset_failure.html
+++ b/synapse/res/templates/password_reset_failure.html
@@ -1,5 +1,9 @@
-<html>
-<head></head>
+<html lang="en">
+<head>
+    <title>Password reset failure</title>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
 <p>The request failed for the following reason: {{ failure_reason }}.</p>
 
diff --git a/synapse/res/templates/password_reset_success.html b/synapse/res/templates/password_reset_success.html
index 7324d66d1e..5165bd1fa2 100644
--- a/synapse/res/templates/password_reset_success.html
+++ b/synapse/res/templates/password_reset_success.html
@@ -1,5 +1,8 @@
-<html>
-<head></head>
+<html lang="en">
+<head>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
 <p>Your email has now been validated, please return to your client to reset your password. You may now close this window.</p>
 </body>
diff --git a/synapse/res/templates/recaptcha.html b/synapse/res/templates/recaptcha.html
index b3db06ef97..615d3239c6 100644
--- a/synapse/res/templates/recaptcha.html
+++ b/synapse/res/templates/recaptcha.html
@@ -1,8 +1,8 @@
 <html>
 <head>
 <title>Authentication</title>
-<meta name='viewport' content='width=device-width, initial-scale=1,
-    user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <script src="https://www.recaptcha.net/recaptcha/api.js"
     async defer></script>
 <script src="//code.jquery.com/jquery-1.11.2.min.js"></script>
diff --git a/synapse/res/templates/registration.html b/synapse/res/templates/registration.html
index 16730a527f..20e831ff4a 100644
--- a/synapse/res/templates/registration.html
+++ b/synapse/res/templates/registration.html
@@ -1,4 +1,9 @@
-<html>
+<html lang="en">
+<head>
+    <title>Registration</title>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
     <p>You have asked us to register this email with a new Matrix account. If this was you, please click the link below to confirm your email address:</p>
 
diff --git a/synapse/res/templates/registration_failure.html b/synapse/res/templates/registration_failure.html
index 2833d79c37..a6ed22bc90 100644
--- a/synapse/res/templates/registration_failure.html
+++ b/synapse/res/templates/registration_failure.html
@@ -1,5 +1,8 @@
-<html>
-<head></head>
+<html lang="en">
+<head>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
 <p>Validation failed for the following reason: {{ failure_reason }}.</p>
 </body>
diff --git a/synapse/res/templates/registration_success.html b/synapse/res/templates/registration_success.html
index fbd6e4018f..d51d5549d8 100644
--- a/synapse/res/templates/registration_success.html
+++ b/synapse/res/templates/registration_success.html
@@ -1,5 +1,9 @@
-<html>
-<head></head>
+<html lang="en">
+<head>
+    <title>Your email has now been validated</title>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+</head>
 <body>
 <p>Your email has now been validated, please return to your client. You may now close this window.</p>
 </body>
diff --git a/synapse/res/templates/registration_token.html b/synapse/res/templates/registration_token.html
index 4577ce1702..59a98f564c 100644
--- a/synapse/res/templates/registration_token.html
+++ b/synapse/res/templates/registration_token.html
@@ -1,8 +1,8 @@
-<html>
+<html lang="en">
 <head>
 <title>Authentication</title>
-<meta name='viewport' content='width=device-width, initial-scale=1,
-    user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <link rel="stylesheet" href="/_matrix/static/client/register/style.css">
 </head>
 <body>
diff --git a/synapse/res/templates/sso_account_deactivated.html b/synapse/res/templates/sso_account_deactivated.html
index c3e4deed93..075f801cec 100644
--- a/synapse/res/templates/sso_account_deactivated.html
+++ b/synapse/res/templates/sso_account_deactivated.html
@@ -3,8 +3,8 @@
     <head>
         <meta charset="UTF-8">
         <title>SSO account deactivated</title>
-        <meta name="viewport" content="width=device-width, user-scalable=no">
-        <style type="text/css">
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">        <style type="text/css">
             {% include "sso.css" without context %}
         </style>
     </head>
diff --git a/synapse/res/templates/sso_auth_account_details.html b/synapse/res/templates/sso_auth_account_details.html
index cf72df0a2a..2d1db386e1 100644
--- a/synapse/res/templates/sso_auth_account_details.html
+++ b/synapse/res/templates/sso_auth_account_details.html
@@ -3,7 +3,8 @@
   <head>
     <title>Create your account</title>
     <meta charset="utf-8">
-    <meta name="viewport" content="width=device-width, user-scalable=no">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <script type="text/javascript">
       let wasKeyboard = false;
       document.addEventListener("mousedown", function() { wasKeyboard = false; });
diff --git a/synapse/res/templates/sso_auth_bad_user.html b/synapse/res/templates/sso_auth_bad_user.html
index da579ffe69..94403fc3ce 100644
--- a/synapse/res/templates/sso_auth_bad_user.html
+++ b/synapse/res/templates/sso_auth_bad_user.html
@@ -3,7 +3,8 @@
     <head>
         <meta charset="UTF-8">
         <title>Authentication failed</title>
-        <meta name="viewport" content="width=device-width, user-scalable=no">
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {% include "sso.css" without context %}
         </style>
diff --git a/synapse/res/templates/sso_auth_confirm.html b/synapse/res/templates/sso_auth_confirm.html
index f9d0456f0a..aa1c974a6b 100644
--- a/synapse/res/templates/sso_auth_confirm.html
+++ b/synapse/res/templates/sso_auth_confirm.html
@@ -3,7 +3,8 @@
     <head>
         <meta charset="UTF-8">
         <title>Confirm it's you</title>
-        <meta name="viewport" content="width=device-width, user-scalable=no">
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {% include "sso.css" without context %}
         </style>
diff --git a/synapse/res/templates/sso_auth_success.html b/synapse/res/templates/sso_auth_success.html
index 1ed3967e87..4898af6011 100644
--- a/synapse/res/templates/sso_auth_success.html
+++ b/synapse/res/templates/sso_auth_success.html
@@ -3,7 +3,8 @@
     <head>
         <meta charset="UTF-8">
         <title>Authentication successful</title>
-        <meta name="viewport" content="width=device-width, user-scalable=no">
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {% include "sso.css" without context %}
         </style>
diff --git a/synapse/res/templates/sso_error.html b/synapse/res/templates/sso_error.html
index 472309c350..19992ff2ad 100644
--- a/synapse/res/templates/sso_error.html
+++ b/synapse/res/templates/sso_error.html
@@ -3,7 +3,8 @@
     <head>
         <meta charset="UTF-8">
         <title>Authentication failed</title>
-        <meta name="viewport" content="width=device-width, user-scalable=no">
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <style type="text/css">
             {% include "sso.css" without context %}
 
diff --git a/synapse/res/templates/sso_login_idp_picker.html b/synapse/res/templates/sso_login_idp_picker.html
index 53b82db84e..56fabfa3d2 100644
--- a/synapse/res/templates/sso_login_idp_picker.html
+++ b/synapse/res/templates/sso_login_idp_picker.html
@@ -1,6 +1,8 @@
 <!DOCTYPE html>
 <html lang="en">
     <head>
+        <meta http-equiv="X-UA-Compatible" content="IE=edge">
+        <meta name="viewport" content="width=device-width, initial-scale=1.0">
         <meta charset="UTF-8">
         <title>Choose identity provider</title>
         <style type="text/css">
diff --git a/synapse/res/templates/sso_new_user_consent.html b/synapse/res/templates/sso_new_user_consent.html
index 68c8b9f33a..523f64c4fc 100644
--- a/synapse/res/templates/sso_new_user_consent.html
+++ b/synapse/res/templates/sso_new_user_consent.html
@@ -3,7 +3,8 @@
 <head>
     <meta charset="UTF-8">
     <title>Agree to terms and conditions</title>
-    <meta name="viewport" content="width=device-width, user-scalable=no">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <style type="text/css">
       {% include "sso.css" without context %}
 
diff --git a/synapse/res/templates/sso_redirect_confirm.html b/synapse/res/templates/sso_redirect_confirm.html
index 1b01471ac8..1049a9bd92 100644
--- a/synapse/res/templates/sso_redirect_confirm.html
+++ b/synapse/res/templates/sso_redirect_confirm.html
@@ -3,7 +3,8 @@
 <head>
     <meta charset="UTF-8">
     <title>Continue to your account</title>
-    <meta name="viewport" content="width=device-width, user-scalable=no">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <style type="text/css">
       {% include "sso.css" without context %}
 
diff --git a/synapse/res/templates/terms.html b/synapse/res/templates/terms.html
index 369ff446d2..2081d990ab 100644
--- a/synapse/res/templates/terms.html
+++ b/synapse/res/templates/terms.html
@@ -1,8 +1,8 @@
 <html>
 <head>
 <title>Authentication</title>
-<meta name='viewport' content='width=device-width, initial-scale=1,
-    user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
 <link rel="stylesheet" href="/_matrix/static/client/register/style.css">
 </head>
 <body>
diff --git a/synapse/static/client/login/index.html b/synapse/static/client/login/index.html
index 9e6daf38ac..40510889ac 100644
--- a/synapse/static/client/login/index.html
+++ b/synapse/static/client/login/index.html
@@ -3,7 +3,8 @@
 <head>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
     <title> Login </title>
-    <meta name='viewport' content='width=device-width, initial-scale=1, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <link rel="stylesheet" href="style.css">
     <script src="js/jquery-3.4.1.min.js"></script>
     <script src="js/login.js"></script>
diff --git a/synapse/static/client/register/index.html b/synapse/static/client/register/index.html
index 140653574d..27bbd76f51 100644
--- a/synapse/static/client/register/index.html
+++ b/synapse/static/client/register/index.html
@@ -2,7 +2,8 @@
 <html>
 <head>
 <title> Registration </title>
-<meta name='viewport' content='width=device-width, initial-scale=1, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'> 
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
+<meta name="viewport" content="width=device-width, initial-scale=1.0">
 <link rel="stylesheet" href="style.css">
 <script src="js/jquery-3.4.1.min.js"></script>
 <script src="https://www.recaptcha.net/recaptcha/api/js/recaptcha_ajax.js"></script>
diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py
index e9ff6cfb34..b07d812ae2 100644
--- a/synapse/storage/databases/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -2200,3 +2200,63 @@ class EventsWorkerStore(SQLBaseStore):
             (room_id,),
         )
         return [row[0] for row in txn]
+
+    def mark_event_rejected_txn(
+        self,
+        txn: LoggingTransaction,
+        event_id: str,
+        rejection_reason: Optional[str],
+    ) -> None:
+        """Mark an event that was previously accepted as rejected, or vice versa
+
+        This can happen, for example, when resyncing state during a faster join.
+
+        Args:
+            txn:
+            event_id: ID of event to update
+            rejection_reason: reason it has been rejected, or None if it is now accepted
+        """
+        if rejection_reason is None:
+            logger.info(
+                "Marking previously-processed event %s as accepted",
+                event_id,
+            )
+            self.db_pool.simple_delete_txn(
+                txn,
+                "rejections",
+                keyvalues={"event_id": event_id},
+            )
+        else:
+            logger.info(
+                "Marking previously-processed event %s as rejected(%s)",
+                event_id,
+                rejection_reason,
+            )
+            self.db_pool.simple_upsert_txn(
+                txn,
+                table="rejections",
+                keyvalues={"event_id": event_id},
+                values={
+                    "reason": rejection_reason,
+                    "last_check": self._clock.time_msec(),
+                },
+            )
+        self.db_pool.simple_update_txn(
+            txn,
+            table="events",
+            keyvalues={"event_id": event_id},
+            updatevalues={"rejection_reason": rejection_reason},
+        )
+
+        self.invalidate_get_event_cache_after_txn(txn, event_id)
+
+        # TODO(faster_joins): invalidate the cache on workers. Ideally we'd just
+        #   call '_send_invalidation_to_replication', but we actually need the other
+        #   end to call _invalidate_local_get_event_cache() rather than (just)
+        #   _get_event_cache.invalidate().
+        #
+        #   One solution might be to (somehow) get the workers to call
+        #   _invalidate_caches_for_event() (though that will invalidate more than
+        #   strictly necessary).
+        #
+        #   https://github.com/matrix-org/synapse/issues/12994
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index f70705a0af..0b10af0e58 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -430,6 +430,11 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             updatevalues={"state_group": state_group},
         )
 
+        # the event may now be rejected where it was not before, or vice versa,
+        # in which case we need to update the rejected flags.
+        if bool(context.rejected) != (event.rejected_reason is not None):
+            self.mark_event_rejected_txn(txn, event.event_id, context.rejected)
+
         self.db_pool.simple_delete_one_txn(
             txn,
             table="partial_state_events",
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index af3bab2c15..0004d955b4 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -539,15 +539,6 @@ class StateFilter:
             is_mine_id: a callable which confirms if a given state_key matches a mxid
                of a local user
         """
-
-        # TODO(faster_joins): it's not entirely clear that this is safe. In particular,
-        #  there may be circumstances in which we return a piece of state that, once we
-        #  resync the state, we discover is invalid. For example: if it turns out that
-        #  the sender of a piece of state wasn't actually in the room, then clearly that
-        #  state shouldn't have been returned.
-        #  We should at least add some tests around this to see what happens.
-        #  https://github.com/matrix-org/synapse/issues/13006
-
         # if we haven't requested membership events, then it depends on the value of
         # 'include_others'
         if EventTypes.Member not in self.types:
diff --git a/synapse/visibility.py b/synapse/visibility.py
index d947edde66..c810a05907 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -73,8 +73,8 @@ async def filter_events_for_client(
           * the user is not currently a member of the room, and:
           * the user has not been a member of the room since the given
             events
-        always_include_ids: set of event ids to specifically
-            include (unless sender is ignored)
+        always_include_ids: set of event ids to specifically include, if present
+            in events (unless sender is ignored)
         filter_send_to_client: Whether we're checking an event that's going to be
             sent to a client. This might not always be the case since this function can
             also be called to check whether a user can see the state at a given point.
diff --git a/tests/logging/test_opentracing.py b/tests/logging/test_opentracing.py
index 3b14c76d7e..0917e478a5 100644
--- a/tests/logging/test_opentracing.py
+++ b/tests/logging/test_opentracing.py
@@ -25,6 +25,8 @@ from synapse.logging.context import (
 from synapse.logging.opentracing import (
     start_active_span,
     start_active_span_follows_from,
+    tag_args,
+    trace_with_opname,
 )
 from synapse.util import Clock
 
@@ -38,8 +40,12 @@ try:
 except ImportError:
     jaeger_client = None  # type: ignore
 
+import logging
+
 from tests.unittest import TestCase
 
+logger = logging.getLogger(__name__)
+
 
 class LogContextScopeManagerTestCase(TestCase):
     """
@@ -194,3 +200,80 @@ class LogContextScopeManagerTestCase(TestCase):
             self._reporter.get_spans(),
             [scopes[1].span, scopes[2].span, scopes[0].span],
         )
+
+    def test_trace_decorator_sync(self) -> None:
+        """
+        Test whether we can use `@trace_with_opname` (`@trace`) and `@tag_args`
+        with sync functions
+        """
+        with LoggingContext("root context"):
+
+            @trace_with_opname("fixture_sync_func", tracer=self._tracer)
+            @tag_args
+            def fixture_sync_func() -> str:
+                return "foo"
+
+            result = fixture_sync_func()
+            self.assertEqual(result, "foo")
+
+        # the span should have been reported
+        self.assertEqual(
+            [span.operation_name for span in self._reporter.get_spans()],
+            ["fixture_sync_func"],
+        )
+
+    def test_trace_decorator_deferred(self) -> None:
+        """
+        Test whether we can use `@trace_with_opname` (`@trace`) and `@tag_args`
+        with functions that return deferreds
+        """
+        reactor = MemoryReactorClock()
+
+        with LoggingContext("root context"):
+
+            @trace_with_opname("fixture_deferred_func", tracer=self._tracer)
+            @tag_args
+            def fixture_deferred_func() -> "defer.Deferred[str]":
+                d1: defer.Deferred[str] = defer.Deferred()
+                d1.callback("foo")
+                return d1
+
+            result_d1 = fixture_deferred_func()
+
+            # let the tasks complete
+            reactor.pump((2,) * 8)
+
+            self.assertEqual(self.successResultOf(result_d1), "foo")
+
+        # the span should have been reported
+        self.assertEqual(
+            [span.operation_name for span in self._reporter.get_spans()],
+            ["fixture_deferred_func"],
+        )
+
+    def test_trace_decorator_async(self) -> None:
+        """
+        Test whether we can use `@trace_with_opname` (`@trace`) and `@tag_args`
+        with async functions
+        """
+        reactor = MemoryReactorClock()
+
+        with LoggingContext("root context"):
+
+            @trace_with_opname("fixture_async_func", tracer=self._tracer)
+            @tag_args
+            async def fixture_async_func() -> str:
+                return "foo"
+
+            d1 = defer.ensureDeferred(fixture_async_func())
+
+            # let the tasks complete
+            reactor.pump((2,) * 8)
+
+            self.assertEqual(self.successResultOf(d1), "foo")
+
+        # the span should have been reported
+        self.assertEqual(
+            [span.operation_name for span in self._reporter.get_spans()],
+            ["fixture_async_func"],
+        )
diff --git a/tests/rest/admin/test_background_updates.py b/tests/rest/admin/test_background_updates.py
index 7cd8b52f02..d507a3af8d 100644
--- a/tests/rest/admin/test_background_updates.py
+++ b/tests/rest/admin/test_background_updates.py
@@ -11,7 +11,6 @@
 # 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 typing import Collection
 
 from parameterized import parameterized
@@ -81,7 +80,7 @@ class BackgroundUpdatesTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         # job_name invalid
@@ -92,7 +91,7 @@ class BackgroundUpdatesTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
 
     def _register_bg_update(self) -> None:
@@ -365,4 +364,4 @@ class BackgroundUpdatesTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
diff --git a/tests/rest/admin/test_device.py b/tests/rest/admin/test_device.py
index 6a6e8ad7d8..d52aee8f92 100644
--- a/tests/rest/admin/test_device.py
+++ b/tests/rest/admin/test_device.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import urllib.parse
-from http import HTTPStatus
 
 from parameterized import parameterized
 
@@ -104,7 +103,7 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
     @parameterized.expand(["GET", "PUT", "DELETE"])
     def test_user_is_not_local(self, method: str) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = (
             "/_synapse/admin/v2/users/@unknown_person:unknown_domain/devices/%s"
@@ -117,7 +116,7 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
 
     def test_unknown_device(self) -> None:
@@ -179,7 +178,7 @@ class DeviceRestTestCase(unittest.HomeserverTestCase):
             content=update,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.TOO_LARGE, channel.json_body["errcode"])
 
         # Ensure the display name was not updated.
@@ -353,7 +352,7 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
 
     def test_user_is_not_local(self) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = "/_synapse/admin/v2/users/@unknown_person:unknown_domain/devices"
 
@@ -363,7 +362,7 @@ class DevicesRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
 
     def test_user_has_no_devices(self) -> None:
@@ -479,7 +478,7 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
 
     def test_user_is_not_local(self) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = "/_synapse/admin/v2/users/@unknown_person:unknown_domain/delete_devices"
 
@@ -489,7 +488,7 @@ class DeleteDevicesRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only lookup local users", channel.json_body["error"])
 
     def test_unknown_devices(self) -> None:
diff --git a/tests/rest/admin/test_event_reports.py b/tests/rest/admin/test_event_reports.py
index c63a86d5b3..fbc490f46d 100644
--- a/tests/rest/admin/test_event_reports.py
+++ b/tests/rest/admin/test_event_reports.py
@@ -11,7 +11,6 @@
 # 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 typing import List
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -81,11 +80,7 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
         """
         channel = self.make_request("GET", self.url, b"{}")
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_requester_is_no_admin(self) -> None:
@@ -99,11 +94,7 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_tok,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_default_success(self) -> None:
@@ -278,7 +269,7 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
 
     def test_invalid_search_order(self) -> None:
         """
-        Testing that a invalid search order returns a HTTPStatus.BAD_REQUEST
+        Testing that a invalid search order returns a 400
         """
 
         channel = self.make_request(
@@ -287,17 +278,13 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual("Unknown direction: bar", channel.json_body["error"])
 
     def test_limit_is_negative(self) -> None:
         """
-        Testing that a negative limit parameter returns a HTTPStatus.BAD_REQUEST
+        Testing that a negative limit parameter returns a 400
         """
 
         channel = self.make_request(
@@ -306,16 +293,12 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_from_is_negative(self) -> None:
         """
-        Testing that a negative from parameter returns a HTTPStatus.BAD_REQUEST
+        Testing that a negative from parameter returns a 400
         """
 
         channel = self.make_request(
@@ -324,11 +307,7 @@ class EventReportsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_next_token(self) -> None:
@@ -466,11 +445,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
         """
         channel = self.make_request("GET", self.url, b"{}")
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_requester_is_no_admin(self) -> None:
@@ -484,11 +459,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_tok,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_default_success(self) -> None:
@@ -507,7 +478,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
 
     def test_invalid_report_id(self) -> None:
         """
-        Testing that an invalid `report_id` returns a HTTPStatus.BAD_REQUEST.
+        Testing that an invalid `report_id` returns a 400.
         """
 
         # `report_id` is negative
@@ -517,11 +488,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "The report_id parameter must be a string representing a positive integer.",
@@ -535,11 +502,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "The report_id parameter must be a string representing a positive integer.",
@@ -553,11 +516,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "The report_id parameter must be a string representing a positive integer.",
@@ -575,11 +534,7 @@ class EventReportDetailTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            404,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_FOUND, channel.json_body["errcode"])
         self.assertEqual("Event report not found", channel.json_body["error"])
 
diff --git a/tests/rest/admin/test_federation.py b/tests/rest/admin/test_federation.py
index 8affd830d1..4c7864c629 100644
--- a/tests/rest/admin/test_federation.py
+++ b/tests/rest/admin/test_federation.py
@@ -11,7 +11,6 @@
 # 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 typing import List, Optional
 
 from parameterized import parameterized
@@ -77,7 +76,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from
@@ -87,7 +86,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # unkown order_by
@@ -97,7 +96,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid search order
@@ -107,7 +106,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid destination
@@ -469,7 +468,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "The retry timing does not need to be reset for this destination.",
             channel.json_body["error"],
@@ -574,7 +573,7 @@ class DestinationMembershipTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from
@@ -584,7 +583,7 @@ class DestinationMembershipTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid search order
@@ -594,7 +593,7 @@ class DestinationMembershipTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid destination
diff --git a/tests/rest/admin/test_media.py b/tests/rest/admin/test_media.py
index d51c10a515..aadb31ca83 100644
--- a/tests/rest/admin/test_media.py
+++ b/tests/rest/admin/test_media.py
@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import os
-from http import HTTPStatus
 
 from parameterized import parameterized
 
@@ -81,11 +80,7 @@ class DeleteMediaByIDTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_token,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_media_does_not_exist(self) -> None:
@@ -105,7 +100,7 @@ class DeleteMediaByIDTestCase(unittest.HomeserverTestCase):
 
     def test_media_is_not_local(self) -> None:
         """
-        Tests that a lookup for a media that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a media that is not a local returns a 400
         """
         url = "/_synapse/admin/v1/media/%s/%s" % ("unknown_domain", "12345")
 
@@ -115,7 +110,7 @@ class DeleteMediaByIDTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only delete local media", channel.json_body["error"])
 
     def test_delete_media(self) -> None:
@@ -230,11 +225,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
 
         channel = self.make_request("POST", self.url, b"{}")
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_requester_is_no_admin(self) -> None:
@@ -250,16 +241,12 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_token,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_media_is_not_local(self) -> None:
         """
-        Tests that a lookup for media that is not local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for media that is not local returns a 400
         """
         url = "/_synapse/admin/v1/media/%s/delete" % "unknown_domain"
 
@@ -269,7 +256,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only delete local media", channel.json_body["error"])
 
     def test_missing_parameter(self) -> None:
@@ -282,11 +269,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Missing integer query parameter 'before_ts'", channel.json_body["error"]
@@ -302,11 +285,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Query parameter before_ts must be a positive integer.",
@@ -319,11 +298,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Query parameter before_ts you provided is from the year 1970. "
@@ -337,11 +312,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Query parameter size_gt must be a string representing a positive integer.",
@@ -354,11 +325,7 @@ class DeleteMediaByDateSizeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Boolean query parameter 'keep_profiles' must be one of ['true', 'false']",
@@ -667,11 +634,7 @@ class QuarantineMediaByIDTestCase(unittest.HomeserverTestCase):
             b"{}",
         )
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     @parameterized.expand(["quarantine", "unquarantine"])
@@ -688,11 +651,7 @@ class QuarantineMediaByIDTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_token,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_quarantine_media(self) -> None:
@@ -800,11 +759,7 @@ class ProtectMediaByIDTestCase(unittest.HomeserverTestCase):
 
         channel = self.make_request("POST", self.url % (action, self.media_id), b"{}")
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     @parameterized.expand(["protect", "unprotect"])
@@ -821,11 +776,7 @@ class ProtectMediaByIDTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_token,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_protect_media(self) -> None:
@@ -913,11 +864,7 @@ class PurgeMediaCacheTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_token,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_invalid_parameter(self) -> None:
@@ -930,11 +877,7 @@ class PurgeMediaCacheTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Query parameter before_ts must be a positive integer.",
@@ -947,11 +890,7 @@ class PurgeMediaCacheTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
         self.assertEqual(
             "Query parameter before_ts you provided is from the year 1970. "
diff --git a/tests/rest/admin/test_registration_tokens.py b/tests/rest/admin/test_registration_tokens.py
index bcb602382c..8f8abc21c7 100644
--- a/tests/rest/admin/test_registration_tokens.py
+++ b/tests/rest/admin/test_registration_tokens.py
@@ -13,7 +13,6 @@
 # limitations under the License.
 import random
 import string
-from http import HTTPStatus
 from typing import Optional
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -74,11 +73,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
     def test_create_no_auth(self) -> None:
         """Try to create a token without authentication."""
         channel = self.make_request("POST", self.url + "/new", {})
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_create_requester_not_admin(self) -> None:
@@ -89,11 +84,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {},
             access_token=self.other_user_tok,
         )
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_create_using_defaults(self) -> None:
@@ -168,11 +159,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_create_token_invalid_chars(self) -> None:
@@ -188,11 +175,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_create_token_already_exists(self) -> None:
@@ -215,7 +198,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             data,
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel2.code, msg=channel2.json_body)
+        self.assertEqual(400, channel2.code, msg=channel2.json_body)
         self.assertEqual(channel2.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_create_unable_to_generate_token(self) -> None:
@@ -262,7 +245,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
         self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
+            400,
             channel.code,
             msg=channel.json_body,
         )
@@ -275,11 +258,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"uses_allowed": 1.5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_create_expiry_time(self) -> None:
@@ -291,11 +270,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"expiry_time": self.clock.time_msec() - 10000},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail with float
@@ -305,11 +280,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"expiry_time": self.clock.time_msec() + 1000000.5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_create_length(self) -> None:
@@ -331,11 +302,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"length": 0},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail with a negative integer
@@ -345,11 +312,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"length": -5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail with a float
@@ -359,11 +322,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"length": 8.5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail with 65
@@ -373,11 +332,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"length": 65},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     # UPDATING
@@ -389,11 +344,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             self.url + "/1234",  # Token doesn't exist but that doesn't matter
             {},
         )
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_update_requester_not_admin(self) -> None:
@@ -404,11 +355,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {},
             access_token=self.other_user_tok,
         )
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_update_non_existent(self) -> None:
@@ -420,11 +367,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            404,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
     def test_update_uses_allowed(self) -> None:
@@ -472,11 +415,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"uses_allowed": 1.5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail with a negative integer
@@ -486,11 +425,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"uses_allowed": -5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_update_expiry_time(self) -> None:
@@ -529,11 +464,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"expiry_time": past_time},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
         # Should fail a float
@@ -543,11 +474,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {"expiry_time": new_expiry_time + 0.5},
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     def test_update_both(self) -> None:
@@ -589,11 +516,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.INVALID_PARAM)
 
     # DELETING
@@ -605,11 +528,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             self.url + "/1234",  # Token doesn't exist but that doesn't matter
             {},
         )
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_delete_requester_not_admin(self) -> None:
@@ -620,11 +539,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {},
             access_token=self.other_user_tok,
         )
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_delete_non_existent(self) -> None:
@@ -636,11 +551,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            404,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
     def test_delete(self) -> None:
@@ -666,11 +577,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             self.url + "/1234",  # Token doesn't exist but that doesn't matter
             {},
         )
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_get_requester_not_admin(self) -> None:
@@ -697,11 +604,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            404,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(404, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], Codes.NOT_FOUND)
 
     def test_get(self) -> None:
@@ -728,11 +631,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
     def test_list_no_auth(self) -> None:
         """Try to list tokens without authentication."""
         channel = self.make_request("GET", self.url, {})
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_list_requester_not_admin(self) -> None:
@@ -743,11 +642,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             {},
             access_token=self.other_user_tok,
         )
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_list_all(self) -> None:
@@ -780,11 +675,7 @@ class ManageRegistrationTokensTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
 
     def _test_list_query_parameter(self, valid: str) -> None:
         """Helper used to test both valid=true and valid=false."""
diff --git a/tests/rest/admin/test_room.py b/tests/rest/admin/test_room.py
index 8350f9025a..dd5000679a 100644
--- a/tests/rest/admin/test_room.py
+++ b/tests/rest/admin/test_room.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import urllib.parse
-from http import HTTPStatus
 from typing import List, Optional
 from unittest.mock import Mock
 
@@ -98,7 +97,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
 
     def test_room_is_not_valid(self) -> None:
         """
-        Check that invalid room names, return an error HTTPStatus.BAD_REQUEST.
+        Check that invalid room names, return an error 400.
         """
         url = "/_synapse/admin/v1/rooms/%s" % "invalidroom"
 
@@ -109,7 +108,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "invalidroom is not a legal room ID",
             channel.json_body["error"],
@@ -145,7 +144,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "User must be our own: @not:exist.bla",
             channel.json_body["error"],
@@ -163,7 +162,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
     def test_purge_is_not_bool(self) -> None:
@@ -178,7 +177,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
     def test_purge_room_and_block(self) -> None:
@@ -546,7 +545,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
     )
     def test_room_is_not_valid(self, method: str, url: str) -> None:
         """
-        Check that invalid room names, return an error HTTPStatus.BAD_REQUEST.
+        Check that invalid room names, return an error 400.
         """
 
         channel = self.make_request(
@@ -556,7 +555,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "invalidroom is not a legal room ID",
             channel.json_body["error"],
@@ -592,7 +591,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "User must be our own: @not:exist.bla",
             channel.json_body["error"],
@@ -610,7 +609,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
     def test_purge_is_not_bool(self) -> None:
@@ -625,7 +624,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
     def test_delete_expired_status(self) -> None:
@@ -722,9 +721,7 @@ class DeleteRoomV2TestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST, second_channel.code, msg=second_channel.json_body
-        )
+        self.assertEqual(400, second_channel.code, msg=second_channel.json_body)
         self.assertEqual(Codes.UNKNOWN, second_channel.json_body["errcode"])
         self.assertEqual(
             f"History purge already in progress for {self.room_id}",
@@ -1546,7 +1543,7 @@ class RoomTestCase(unittest.HomeserverTestCase):
 
         _search_test(None, "foo")
         _search_test(None, "bar")
-        _search_test(None, "", expected_http_code=HTTPStatus.BAD_REQUEST)
+        _search_test(None, "", expected_http_code=400)
 
         # Test that the whole room id returns the room
         _search_test(room_id_1, room_id_1)
@@ -1836,7 +1833,7 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
     def test_local_user_does_not_exist(self) -> None:
@@ -1866,7 +1863,7 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "This endpoint can only be used with local users",
             channel.json_body["error"],
@@ -1893,7 +1890,7 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
 
     def test_room_is_not_valid(self) -> None:
         """
-        Check that invalid room names, return an error HTTPStatus.BAD_REQUEST.
+        Check that invalid room names, return an error 400.
         """
         url = "/_synapse/admin/v1/join/invalidroom"
 
@@ -1904,7 +1901,7 @@ class JoinAliasRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "invalidroom was not legal room ID or room alias",
             channel.json_body["error"],
@@ -2243,11 +2240,11 @@ class MakeRoomAdminTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        # We expect this to fail with a HTTPStatus.BAD_REQUEST as there are no room admins.
+        # We expect this to fail with a 400 as there are no room admins.
         #
         # (Note we assert the error message to ensure that it's not denied for
         # some other reason)
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             channel.json_body["error"],
             "No local admin user in room with power to update power levels.",
@@ -2291,7 +2288,7 @@ class BlockRoomTestCase(unittest.HomeserverTestCase):
 
     @parameterized.expand([("PUT",), ("GET",)])
     def test_room_is_not_valid(self, method: str) -> None:
-        """Check that invalid room names, return an error HTTPStatus.BAD_REQUEST."""
+        """Check that invalid room names, return an error 400."""
 
         channel = self.make_request(
             method,
@@ -2300,7 +2297,7 @@ class BlockRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "invalidroom is not a legal room ID",
             channel.json_body["error"],
@@ -2317,7 +2314,7 @@ class BlockRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
         # `block` is not set
@@ -2328,7 +2325,7 @@ class BlockRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         # no content is send
@@ -2338,7 +2335,7 @@ class BlockRoomTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_JSON, channel.json_body["errcode"])
 
     def test_block_room(self) -> None:
diff --git a/tests/rest/admin/test_server_notice.py b/tests/rest/admin/test_server_notice.py
index 3a6b98fbb5..81e125e27d 100644
--- a/tests/rest/admin/test_server_notice.py
+++ b/tests/rest/admin/test_server_notice.py
@@ -11,7 +11,6 @@
 # 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 typing import List
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -94,7 +93,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
     @override_config({"server_notices": {"system_mxid_localpart": "notices"}})
     def test_user_is_not_local(self) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         channel = self.make_request(
             "POST",
@@ -106,7 +105,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             },
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "Server notices can only be sent to local users", channel.json_body["error"]
         )
@@ -122,7 +121,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.NOT_JSON, channel.json_body["errcode"])
 
         # no content
@@ -133,7 +132,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             content={"user_id": self.other_user},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         # no body
@@ -144,7 +143,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             content={"user_id": self.other_user, "content": ""},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
         self.assertEqual("'body' not in content", channel.json_body["error"])
 
@@ -156,7 +155,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             content={"user_id": self.other_user, "content": {"body": ""}},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
         self.assertEqual("'msgtype' not in content", channel.json_body["error"])
 
@@ -172,7 +171,7 @@ class ServerNoticeTestCase(unittest.HomeserverTestCase):
             },
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
         self.assertEqual(
             "Server notices are not enabled on this server", channel.json_body["error"]
diff --git a/tests/rest/admin/test_statistics.py b/tests/rest/admin/test_statistics.py
index 3a8982afea..b60f16b914 100644
--- a/tests/rest/admin/test_statistics.py
+++ b/tests/rest/admin/test_statistics.py
@@ -12,7 +12,6 @@
 # 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 typing import List, Optional
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -51,11 +50,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
         """
         channel = self.make_request("GET", self.url, b"{}")
 
-        self.assertEqual(
-            401,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(401, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_TOKEN, channel.json_body["errcode"])
 
     def test_requester_is_no_admin(self) -> None:
@@ -69,11 +64,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.other_user_tok,
         )
 
-        self.assertEqual(
-            403,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(403, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.FORBIDDEN, channel.json_body["errcode"])
 
     def test_invalid_parameter(self) -> None:
@@ -87,11 +78,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from
@@ -101,11 +88,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative limit
@@ -115,11 +98,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from_ts
@@ -129,11 +108,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative until_ts
@@ -143,11 +118,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # until_ts smaller from_ts
@@ -157,11 +128,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # empty search term
@@ -171,11 +138,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid search order
@@ -185,11 +148,7 @@ class UserMediaStatisticsTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_limit(self) -> None:
diff --git a/tests/rest/admin/test_user.py b/tests/rest/admin/test_user.py
index beb1b1c120..411e4ec005 100644
--- a/tests/rest/admin/test_user.py
+++ b/tests/rest/admin/test_user.py
@@ -17,7 +17,6 @@ import hmac
 import os
 import urllib.parse
 from binascii import unhexlify
-from http import HTTPStatus
 from typing import List, Optional
 from unittest.mock import Mock, patch
 
@@ -79,7 +78,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
 
         channel = self.make_request("POST", self.url, b"{}")
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(
             "Shared secret registration is not enabled", channel.json_body["error"]
         )
@@ -111,7 +110,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         body = {"nonce": nonce}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("username must be specified", channel.json_body["error"])
 
         # 61 seconds
@@ -119,7 +118,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
 
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("unrecognised nonce", channel.json_body["error"])
 
     def test_register_incorrect_nonce(self) -> None:
@@ -198,7 +197,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Now, try and reuse it
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("unrecognised nonce", channel.json_body["error"])
 
     def test_missing_parts(self) -> None:
@@ -219,7 +218,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be an empty body present
         channel = self.make_request("POST", self.url, {})
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("nonce must be specified", channel.json_body["error"])
 
         #
@@ -229,28 +228,28 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         # Must be present
         channel = self.make_request("POST", self.url, {"nonce": nonce()})
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("username must be specified", channel.json_body["error"])
 
         # Must be a string
         body = {"nonce": nonce(), "username": 1234}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid username", channel.json_body["error"])
 
         # Must not have null bytes
         body = {"nonce": nonce(), "username": "abcd\u0000"}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid username", channel.json_body["error"])
 
         # Must not have null bytes
         body = {"nonce": nonce(), "username": "a" * 1000}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid username", channel.json_body["error"])
 
         #
@@ -261,28 +260,28 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         body = {"nonce": nonce(), "username": "a"}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("password must be specified", channel.json_body["error"])
 
         # Must be a string
         body = {"nonce": nonce(), "username": "a", "password": 1234}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid password", channel.json_body["error"])
 
         # Must not have null bytes
         body = {"nonce": nonce(), "username": "a", "password": "abcd\u0000"}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid password", channel.json_body["error"])
 
         # Super long
         body = {"nonce": nonce(), "username": "a", "password": "A" * 1000}
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid password", channel.json_body["error"])
 
         #
@@ -298,7 +297,7 @@ class UserRegisterTestCase(unittest.HomeserverTestCase):
         }
         channel = self.make_request("POST", self.url, body)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Invalid user type", channel.json_body["error"])
 
     def test_displayname(self) -> None:
@@ -591,7 +590,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from
@@ -601,7 +600,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid guests
@@ -611,7 +610,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid deactivated
@@ -621,7 +620,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # unkown order_by
@@ -631,7 +630,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid search order
@@ -641,7 +640,7 @@ class UsersListTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_limit(self) -> None:
@@ -991,18 +990,18 @@ class DeactivateAccountTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
     def test_user_is_not_local(self) -> None:
         """
-        Tests that deactivation for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that deactivation for a user that is not a local returns a 400
         """
         url = "/_synapse/admin/v1/deactivate/@unknown_person:unknown_domain"
 
         channel = self.make_request("POST", url, access_token=self.admin_user_tok)
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only deactivate local users", channel.json_body["error"])
 
     def test_deactivate_user_erase_true(self) -> None:
@@ -1259,7 +1258,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"admin": "not_bool"},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.BAD_JSON, channel.json_body["errcode"])
 
         # deactivated not bool
@@ -1269,7 +1268,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"deactivated": "not_bool"},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
 
         # password not str
@@ -1279,7 +1278,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"password": True},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
 
         # password not length
@@ -1289,7 +1288,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"password": "x" * 513},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
 
         # user_type not valid
@@ -1299,7 +1298,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"user_type": "new type"},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.UNKNOWN, channel.json_body["errcode"])
 
         # external_ids not valid
@@ -1311,7 +1310,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
                 "external_ids": {"auth_provider": "prov", "wrong_external_id": "id"}
             },
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         channel = self.make_request(
@@ -1320,7 +1319,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"external_ids": {"external_id": "id"}},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         # threepids not valid
@@ -1330,7 +1329,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"threepids": {"medium": "email", "wrong_address": "id"}},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
         channel = self.make_request(
@@ -1339,7 +1338,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"threepids": {"address": "value"}},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.MISSING_PARAM, channel.json_body["errcode"])
 
     def test_get_user(self) -> None:
@@ -2228,7 +2227,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
             content={"deactivated": False},
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
 
         # Reactivate the user.
         channel = self.make_request(
@@ -2431,7 +2430,7 @@ class UserRestTestCase(unittest.HomeserverTestCase):
             content={"password": "abc123", "deactivated": "false"},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
 
         # Check user is not deactivated
         channel = self.make_request(
@@ -2712,7 +2711,7 @@ class PushersRestTestCase(unittest.HomeserverTestCase):
 
     def test_user_is_not_local(self) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = "/_synapse/admin/v1/users/@unknown_person:unknown_domain/pushers"
 
@@ -2722,7 +2721,7 @@ class PushersRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only look up local users", channel.json_body["error"])
 
     def test_get_pushers(self) -> None:
@@ -2840,7 +2839,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
 
     @parameterized.expand(["GET", "DELETE"])
     def test_user_is_not_local(self, method: str) -> None:
-        """Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST"""
+        """Tests that a lookup for a user that is not a local returns a 400"""
         url = "/_synapse/admin/v1/users/@unknown_person:unknown_domain/media"
 
         channel = self.make_request(
@@ -2849,7 +2848,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only look up local users", channel.json_body["error"])
 
     def test_limit_GET(self) -> None:
@@ -2970,7 +2969,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # invalid search order
@@ -2980,7 +2979,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative limit
@@ -2990,7 +2989,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # negative from
@@ -3000,7 +2999,7 @@ class UserMediaRestTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_next_token(self) -> None:
@@ -3614,7 +3613,7 @@ class WhoisRestTestCase(unittest.HomeserverTestCase):
 
     def test_user_is_not_local(self) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = self.url_prefix % "@unknown_person:unknown_domain"  # type: ignore[attr-defined]
 
@@ -3623,7 +3622,7 @@ class WhoisRestTestCase(unittest.HomeserverTestCase):
             url,
             access_token=self.admin_user_tok,
         )
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only whois a local user", channel.json_body["error"])
 
     def test_get_whois_admin(self) -> None:
@@ -3697,12 +3696,12 @@ class ShadowBanRestTestCase(unittest.HomeserverTestCase):
     @parameterized.expand(["POST", "DELETE"])
     def test_user_is_not_local(self, method: str) -> None:
         """
-        Tests that shadow-banning for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that shadow-banning for a user that is not a local returns a 400
         """
         url = "/_synapse/admin/v1/whois/@unknown_person:unknown_domain"
 
         channel = self.make_request(method, url, access_token=self.admin_user_tok)
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
 
     def test_success(self) -> None:
         """
@@ -3806,7 +3805,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
     )
     def test_user_is_not_local(self, method: str, error_msg: str) -> None:
         """
-        Tests that a lookup for a user that is not a local returns a HTTPStatus.BAD_REQUEST
+        Tests that a lookup for a user that is not a local returns a 400
         """
         url = (
             "/_synapse/admin/v1/users/@unknown_person:unknown_domain/override_ratelimit"
@@ -3818,7 +3817,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(error_msg, channel.json_body["error"])
 
     def test_invalid_parameter(self) -> None:
@@ -3833,7 +3832,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
             content={"messages_per_second": "string"},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # messages_per_second is negative
@@ -3844,7 +3843,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
             content={"messages_per_second": -1},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # burst_count is a string
@@ -3855,7 +3854,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
             content={"burst_count": "string"},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
         # burst_count is negative
@@ -3866,7 +3865,7 @@ class RateLimitTestCase(unittest.HomeserverTestCase):
             content={"burst_count": -1},
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(Codes.INVALID_PARAM, channel.json_body["errcode"])
 
     def test_return_zero_when_null(self) -> None:
@@ -4021,7 +4020,7 @@ class AccountDataTestCase(unittest.HomeserverTestCase):
             access_token=self.admin_user_tok,
         )
 
-        self.assertEqual(HTTPStatus.BAD_REQUEST, channel.code, msg=channel.json_body)
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual("Can only look up local users", channel.json_body["error"])
 
     def test_success(self) -> None:
diff --git a/tests/rest/admin/test_username_available.py b/tests/rest/admin/test_username_available.py
index b5e7eecf87..30f12f1bff 100644
--- a/tests/rest/admin/test_username_available.py
+++ b/tests/rest/admin/test_username_available.py
@@ -11,9 +11,6 @@
 # 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.test.proto_helpers import MemoryReactor
 
 import synapse.rest.admin
@@ -40,7 +37,7 @@ class UsernameAvailableTestCase(unittest.HomeserverTestCase):
             if username == "allowed":
                 return True
             raise SynapseError(
-                HTTPStatus.BAD_REQUEST,
+                400,
                 "User ID already taken.",
                 errcode=Codes.USER_IN_USE,
             )
@@ -67,10 +64,6 @@ class UsernameAvailableTestCase(unittest.HomeserverTestCase):
         url = "%s?username=%s" % (self.url, "disallowed")
         channel = self.make_request("GET", url, access_token=self.admin_user_tok)
 
-        self.assertEqual(
-            HTTPStatus.BAD_REQUEST,
-            channel.code,
-            msg=channel.json_body,
-        )
+        self.assertEqual(400, channel.code, msg=channel.json_body)
         self.assertEqual(channel.json_body["errcode"], "M_USER_IN_USE")
         self.assertEqual(channel.json_body["error"], "User ID already taken.")