diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index 089d906fa..d352ea9be 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -36,7 +36,7 @@ class LoggingConfig(Config):
             help="The verbosity level."
         )
         logging_group.add_argument(
-            '-f', '--log-file', dest="log_file", default=None,
+            '-f', '--log-file', dest="log_file", default="homeserver.log",
             help="File to log to."
         )
         logging_group.add_argument(
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index 984f14fce..34b1b944a 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -30,20 +30,20 @@ class _EventInternalMetadata(object):
 
 
 def _event_dict_property(key):
-        def getter(self):
-            return self._event_dict[key]
+    def getter(self):
+        return self._event_dict[key]
 
-        def setter(self, v):
-            self._event_dict[key] = v
+    def setter(self, v):
+        self._event_dict[key] = v
 
-        def delete(self):
-            del self._event_dict[key]
+    def delete(self):
+        del self._event_dict[key]
 
-        return property(
-            getter,
-            setter,
-            delete,
-        )
+    return property(
+        getter,
+        setter,
+        delete,
+    )
 
 
 class EventBase(object):
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index af8eb5f0f..97ebd9891 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -20,8 +20,6 @@ from synapse.util.async import run_on_reactor
 from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.api.constants import Membership, EventTypes
 
-from synapse.events.snapshot import EventContext
-
 import logging
 
 
@@ -61,8 +59,6 @@ class BaseHandler(object):
     def _create_new_client_event(self, builder):
         yield run_on_reactor()
 
-        context = EventContext()
-
         latest_ret = yield self.store.get_latest_events_in_room(
             builder.room_id,
         )
@@ -78,14 +74,11 @@ class BaseHandler(object):
         builder.depth = depth
 
         state_handler = self.state_handler
-        ret = yield state_handler.annotate_context_with_state(
-            builder,
-            context,
-        )
-        prev_state = ret
+
+        context = yield state_handler.compute_event_context(builder)
 
         if builder.is_state():
-            builder.prev_state = prev_state
+            builder.prev_state = context.prev_state_events
 
         yield self.auth.add_auth_events(builder, context)
 
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 404baea79..66d3b533d 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -156,4 +156,3 @@ class DirectoryHandler(BaseHandler):
             "sender": user_id,
             "content": {"aliases": aliases},
         })
-
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 16a104c0e..4aec3563a 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -17,7 +17,6 @@
 
 from ._base import BaseHandler
 
-from synapse.events.snapshot import EventContext
 from synapse.events.utils import prune_event
 from synapse.api.errors import (
     AuthError, FederationError, SynapseError, StoreError,
@@ -202,7 +201,7 @@ class FederationHandler(BaseHandler):
                 e.msg,
                 affected=event.event_id,
             )
-            
+
         # if we're receiving valid events from an origin,
         # it's probably a good idea to mark it as not in retry-state
         # for sending (although this is a bit of a leap)
@@ -260,12 +259,9 @@ class FederationHandler(BaseHandler):
             event = pdu
 
             # FIXME (erikj): Not sure this actually works :/
-            context = EventContext()
-            yield self.state_handler.annotate_context_with_state(event, context)
+            context = yield self.state_handler.compute_event_context(event)
 
-            events.append(
-                (event, context)
-            )
+            events.append((event, context))
 
             yield self.store.persist_event(
                 event,
@@ -547,8 +543,6 @@ class FederationHandler(BaseHandler):
         """
         event = pdu
 
-        context = EventContext()
-
         event.internal_metadata.outlier = True
 
         event.signatures.update(
@@ -559,7 +553,7 @@ class FederationHandler(BaseHandler):
             )
         )
 
-        yield self.state_handler.annotate_context_with_state(event, context)
+        context = yield self.state_handler.compute_event_context(event)
 
         yield self.store.persist_event(
             event,
@@ -685,17 +679,14 @@ class FederationHandler(BaseHandler):
     @defer.inlineCallbacks
     def _handle_new_event(self, event, state=None, backfilled=False,
                           current_state=None, fetch_missing=True):
-        context = EventContext()
 
         logger.debug(
             "_handle_new_event: Before annotate: %s, sigs: %s",
             event.event_id, event.signatures,
         )
 
-        yield self.state_handler.annotate_context_with_state(
-            event,
-            context,
-            old_state=state
+        context = yield self.state_handler.compute_event_context(
+            event, old_state=state
         )
 
         logger.debug(
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 7939d2bff..49c0e9811 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -18,8 +18,6 @@ from twisted.internet import defer
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import RoomError
 from synapse.streams.config import PaginationConfig
-from synapse.util.logcontext import PreserveLoggingContext
-
 from synapse.events.validator import EventValidator
 
 from ._base import BaseHandler
@@ -66,35 +64,6 @@ class MessageHandler(BaseHandler):
 
         defer.returnValue(None)
 
-    @defer.inlineCallbacks
-    def send_message(self, event=None, suppress_auth=False):
-        """ Send a message.
-
-        Args:
-            event : The message event to store.
-            suppress_auth (bool) : True to suppress auth for this message. This
-            is primarily so the home server can inject messages into rooms at
-            will.
-        Raises:
-            SynapseError if something went wrong.
-        """
-
-        self.ratelimit(event.user_id)
-        # TODO(paul): Why does 'event' not have a 'user' object?
-        user = self.hs.parse_userid(event.user_id)
-        assert self.hs.is_mine(user), "User must be our own: %s" % (user,)
-
-        snapshot = yield self.store.snapshot_room(event)
-
-        yield self._on_new_room_event(
-            event, snapshot, suppress_auth=suppress_auth
-        )
-
-        with PreserveLoggingContext():
-            self.hs.get_handlers().presence_handler.bump_presence_active_time(
-                user
-            )
-
     @defer.inlineCallbacks
     def get_messages(self, user_id=None, room_id=None, pagin_config=None,
                      feedback=False):
@@ -217,13 +186,6 @@ class MessageHandler(BaseHandler):
             defer.returnValue(fb)
         defer.returnValue(None)
 
-    @defer.inlineCallbacks
-    def send_feedback(self, event):
-        snapshot = yield self.store.snapshot_room(event)
-
-        # store message in db
-        yield self._on_new_room_event(event, snapshot)
-
     @defer.inlineCallbacks
     def get_state_events(self, user_id, room_id):
         """Retrieve all state events for a given room.
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 77d66f66f..7626b0728 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -45,8 +45,8 @@ class TypingNotificationHandler(BaseHandler):
 
         hs.get_distributor().observe("user_left_room", self.user_left_room)
 
-        self._member_typing_until = {} # clock time we expect to stop
-        self._member_typing_timer = {} # deferreds to manage theabove
+        self._member_typing_until = {}  # clock time we expect to stop
+        self._member_typing_timer = {}  # deferreds to manage theabove
 
         # map room IDs to serial numbers
         self._room_serials = {}
diff --git a/synapse/media/v1/base_resource.py b/synapse/media/v1/base_resource.py
index 14735ff37..2f5440ab6 100644
--- a/synapse/media/v1/base_resource.py
+++ b/synapse/media/v1/base_resource.py
@@ -135,6 +135,7 @@ class BaseMediaResource(Resource):
         if download is None:
             download = self._get_remote_media_impl(server_name, media_id)
             self.downloads[key] = download
+
             @download.addBoth
             def callback(media_info):
                 del self.downloads[key]
diff --git a/synapse/rest/room.py b/synapse/rest/room.py
index 0e2d5fbaa..005a9f6f4 100644
--- a/synapse/rest/room.py
+++ b/synapse/rest/room.py
@@ -310,8 +310,8 @@ class RoomMessageListRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
         user = yield self.auth.get_user_by_req(request)
-        pagination_config = PaginationConfig.from_request(request,
-            default_limit=10,
+        pagination_config = PaginationConfig.from_request(
+            request, default_limit=10,
         )
         with_feedback = "feedback" in request.args
         handler = self.handlers.message_handler
@@ -466,7 +466,9 @@ class RoomRedactEventRestServlet(RestServlet):
 
 
 class RoomTypingRestServlet(RestServlet):
-    PATTERN = client_path_pattern("/rooms/(?P<room_id>[^/]*)/typing/(?P<user_id>[^/]*)$")
+    PATTERN = client_path_pattern(
+        "/rooms/(?P<room_id>[^/]*)/typing/(?P<user_id>[^/]*)$"
+    )
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, user_id):
diff --git a/synapse/rest/transactions.py b/synapse/rest/transactions.py
index 8c41ab4ed..31377bd41 100644
--- a/synapse/rest/transactions.py
+++ b/synapse/rest/transactions.py
@@ -19,6 +19,7 @@ import logging
 
 logger = logging.getLogger(__name__)
 
+
 # FIXME: elsewhere we use FooStore to indicate something in the storage layer...
 class HttpTransactionStore(object):
 
diff --git a/synapse/state.py b/synapse/state.py
index 580053d3f..15397e2f3 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -19,10 +19,10 @@ from twisted.internet import defer
 from synapse.util.logutils import log_function
 from synapse.util.async import run_on_reactor
 from synapse.api.constants import EventTypes
+from synapse.events.snapshot import EventContext
 
 from collections import namedtuple
 
-import copy
 import logging
 import hashlib
 
@@ -43,71 +43,6 @@ class StateHandler(object):
     def __init__(self, hs):
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    @log_function
-    def annotate_event_with_state(self, event, old_state=None):
-        """ Annotates the event with the current state events as of that event.
-
-        This method adds three new attributes to the event:
-            * `state_events`: The state up to and including the event. Encoded
-              as a dict mapping tuple (type, state_key) -> event.
-            * `old_state_events`: The state up to, but excluding, the event.
-              Encoded similarly as `state_events`.
-            * `state_group`: If there is an existing state group that can be
-              used, then return that. Otherwise return `None`. See state
-              storage for more information.
-
-        If the argument `old_state` is given (in the form of a list of
-        events), then they are used as a the values for `old_state_events` and
-        the value for `state_events` is generated from it. `state_group` is
-        set to None.
-
-        This needs to be called before persisting the event.
-        """
-        yield run_on_reactor()
-
-        if old_state:
-            event.state_group = None
-            event.old_state_events = {
-                (s.type, s.state_key): s for s in old_state
-            }
-            event.state_events = event.old_state_events
-
-            if hasattr(event, "state_key"):
-                event.state_events[(event.type, event.state_key)] = event
-
-            defer.returnValue(False)
-            return
-
-        if event.is_outlier():
-            event.state_group = None
-            event.old_state_events = None
-            event.state_events = None
-            defer.returnValue(False)
-            return
-
-        ids = [e for e, _ in event.prev_events]
-
-        ret = yield self.resolve_state_groups(ids)
-        state_group, new_state, _ = ret
-
-        event.old_state_events = copy.deepcopy(new_state)
-
-        if hasattr(event, "state_key"):
-            key = (event.type, event.state_key)
-            if key in new_state:
-                event.replaces_state = new_state[key].event_id
-            new_state[key] = event
-        elif state_group:
-            event.state_group = state_group
-            event.state_events = new_state
-            defer.returnValue(False)
-
-        event.state_group = None
-        event.state_events = new_state
-
-        defer.returnValue(hasattr(event, "state_key"))
-
     @defer.inlineCallbacks
     def get_current_state(self, room_id, event_type=None, state_key=""):
         """ Returns the current state for the room as a list. This is done by
@@ -136,7 +71,7 @@ class StateHandler(object):
         defer.returnValue(res[1].values())
 
     @defer.inlineCallbacks
-    def annotate_context_with_state(self, event, context, old_state=None):
+    def compute_event_context(self, event, old_state=None):
         """ Fills out the context with the `current state` of the graph. The
         `current state` here is defined to be the state of the event graph
         just before the event - i.e. it never includes `event`
@@ -146,8 +81,11 @@ class StateHandler(object):
 
         Args:
             event (EventBase)
-            context (EventContext)
+        Returns:
+            an EventContext
         """
+        context = EventContext()
+
         yield run_on_reactor()
 
         if old_state:
@@ -173,7 +111,8 @@ class StateHandler(object):
                     if replaces.event_id != event.event_id:  # Paranoia check
                         event.unsigned["replaces_state"] = replaces.event_id
 
-            defer.returnValue([])
+            context.prev_state_events = []
+            defer.returnValue(context)
 
         if event.is_state():
             ret = yield self.resolve_state_groups(
@@ -211,7 +150,8 @@ class StateHandler(object):
         else:
             context.auth_events = {}
 
-        defer.returnValue(prev_state)
+        context.prev_state_events = prev_state
+        defer.returnValue(context)
 
     @defer.inlineCallbacks
     @log_function
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index e236bf495..e6bb66593 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -417,86 +417,6 @@ class DataStore(RoomMemberStore, RoomStore,
             ],
         )
 
-    def snapshot_room(self, event):
-        """Snapshot the room for an update by a user
-        Args:
-            room_id (synapse.types.RoomId): The room to snapshot.
-            user_id (synapse.types.UserId): The user to snapshot the room for.
-            state_type (str): Optional state type to snapshot.
-            state_key (str): Optional state key to snapshot.
-        Returns:
-            synapse.storage.Snapshot: A snapshot of the state of the room.
-        """
-        def _snapshot(txn):
-            prev_events = self._get_latest_events_in_room(
-                txn,
-                event.room_id
-            )
-
-            prev_state = None
-            state_key = None
-            if hasattr(event, "state_key"):
-                state_key = event.state_key
-                prev_state = self._get_latest_state_in_room(
-                    txn,
-                    event.room_id,
-                    type=event.type,
-                    state_key=state_key,
-                )
-
-            return Snapshot(
-                store=self,
-                room_id=event.room_id,
-                user_id=event.user_id,
-                prev_events=prev_events,
-                prev_state=prev_state,
-                state_type=event.type,
-                state_key=state_key,
-            )
-
-        return self.runInteraction("snapshot_room", _snapshot)
-
-
-class Snapshot(object):
-    """Snapshot of the state of a room
-    Args:
-        store (DataStore): The datastore.
-        room_id (RoomId): The room of the snapshot.
-        user_id (UserId): The user this snapshot is for.
-        prev_events (list): The list of event ids this snapshot is after.
-        membership_state (RoomMemberEvent): The current state of the user in
-            the room.
-        state_type (str, optional): State type captured by the snapshot
-        state_key (str, optional): State key captured by the snapshot
-        prev_state_pdu (PduEntry, optional): pdu id of
-            the previous value of the state type and key in the room.
-    """
-
-    def __init__(self, store, room_id, user_id, prev_events,
-                 prev_state, state_type=None, state_key=None):
-        self.store = store
-        self.room_id = room_id
-        self.user_id = user_id
-        self.prev_events = prev_events
-        self.prev_state = prev_state
-        self.state_type = state_type
-        self.state_key = state_key
-
-    def fill_out_prev_events(self, event):
-        if not hasattr(event, "prev_events"):
-            event.prev_events = [
-                (event_id, hashes)
-                for event_id, hashes, _ in self.prev_events
-            ]
-
-            if self.prev_events:
-                event.depth = max([int(v) for _, _, v in self.prev_events]) + 1
-            else:
-                event.depth = 0
-
-        if not hasattr(event, "prev_state") and self.prev_state is not None:
-            event.prev_state = self.prev_state
-
 
 def schema_path(schema):
     """ Get a filesystem path for the named database schema
diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py
index ed351367c..ed21defd1 100644
--- a/tests/handlers/test_federation.py
+++ b/tests/handlers/test_federation.py
@@ -34,7 +34,7 @@ class FederationTestCase(unittest.TestCase):
         self.mock_config.signing_key = [MockKey()]
 
         self.state_handler = NonCallableMock(spec_set=[
-            "annotate_context_with_state",
+            "compute_event_context",
         ])
 
         self.auth = NonCallableMock(spec_set=[
@@ -91,11 +91,12 @@ class FederationTestCase(unittest.TestCase):
         self.datastore.get_room.return_value = defer.succeed(True)
         self.auth.check_host_in_room.return_value = defer.succeed(True)
 
-        def annotate(ev, context, old_state=None):
+        def annotate(ev, old_state=None):
+            context = Mock()
             context.current_state = {}
             context.auth_events = {}
-            return defer.succeed(False)
-        self.state_handler.annotate_context_with_state.side_effect = annotate
+            return defer.succeed(context)
+        self.state_handler.compute_event_context.side_effect = annotate
 
         yield self.handlers.federation_handler.on_receive_pdu(
             "fo", pdu, False
@@ -109,15 +110,12 @@ class FederationTestCase(unittest.TestCase):
             context=ANY,
         )
 
-        self.state_handler.annotate_context_with_state.assert_called_once_with(
-            ANY,
-            ANY,
-            old_state=None,
+        self.state_handler.compute_event_context.assert_called_once_with(
+            ANY, old_state=None,
         )
 
         self.auth.check.assert_called_once_with(ANY, auth_events={})
 
         self.notifier.on_new_room_event.assert_called_once_with(
-            ANY,
-            extra_users=[]
+            ANY, extra_users=[]
         )
diff --git a/tests/handlers/test_room.py b/tests/handlers/test_room.py
index 83493cae2..0cb8aa4fb 100644
--- a/tests/handlers/test_room.py
+++ b/tests/handlers/test_room.py
@@ -60,7 +60,7 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
                 "check_host_in_room",
             ]),
             state_handler=NonCallableMock(spec_set=[
-                "annotate_context_with_state",
+                "compute_event_context",
                 "get_current_state",
             ]),
             config=self.mock_config,
@@ -110,7 +110,8 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
             defer.succeed([])
         )
 
-        def annotate(_, ctx):
+        def annotate(_):
+            ctx = Mock()
             ctx.current_state = {
                 (EventTypes.Member, "@alice:green"): self._create_member(
                     user_id="@alice:green",
@@ -121,10 +122,11 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
                     room_id=room_id,
                 ),
             }
+            ctx.prev_state_events = []
 
-            return defer.succeed(True)
+            return defer.succeed(ctx)
 
-        self.state_handler.annotate_context_with_state.side_effect = annotate
+        self.state_handler.compute_event_context.side_effect = annotate
 
         def add_auth(_, ctx):
             ctx.auth_events = ctx.current_state[
@@ -146,8 +148,8 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
 
         yield room_handler.change_membership(event, context)
 
-        self.state_handler.annotate_context_with_state.assert_called_once_with(
-            builder, context
+        self.state_handler.compute_event_context.assert_called_once_with(
+            builder
         )
 
         self.auth.add_auth_events.assert_called_once_with(
@@ -189,7 +191,8 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
             defer.succeed([])
         )
 
-        def annotate(_, ctx):
+        def annotate(_):
+            ctx = Mock()
             ctx.current_state = {
                 (EventTypes.Member, "@bob:red"): self._create_member(
                     user_id="@bob:red",
@@ -197,10 +200,11 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
                     membership=Membership.INVITE
                 ),
             }
+            ctx.prev_state_events = []
 
-            return defer.succeed(True)
+            return defer.succeed(ctx)
 
-        self.state_handler.annotate_context_with_state.side_effect = annotate
+        self.state_handler.compute_event_context.side_effect = annotate
 
         def add_auth(_, ctx):
             ctx.auth_events = ctx.current_state[
@@ -262,7 +266,8 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
             defer.succeed([])
         )
 
-        def annotate(_, ctx):
+        def annotate(_):
+            ctx = Mock()
             ctx.current_state = {
                 (EventTypes.Member, "@bob:red"): self._create_member(
                     user_id="@bob:red",
@@ -270,10 +275,11 @@ class RoomMemberHandlerTestCase(unittest.TestCase):
                     membership=Membership.JOIN
                 ),
             }
+            ctx.prev_state_events = []
 
-            return defer.succeed(True)
+            return defer.succeed(ctx)
 
-        self.state_handler.annotate_context_with_state.side_effect = annotate
+        self.state_handler.compute_event_context.side_effect = annotate
 
         def add_auth(_, ctx):
             ctx.auth_events = ctx.current_state[
diff --git a/tests/test_state.py b/tests/test_state.py
index 7979b54a3..98ad9e54c 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -26,6 +26,7 @@ class StateTestCase(unittest.TestCase):
         self.store = Mock(
             spec_set=[
                 "get_state_groups",
+                "add_event_hashes",
             ]
         )
         hs = Mock(spec=["get_datastore"])
@@ -44,17 +45,20 @@ class StateTestCase(unittest.TestCase):
             self.create_event(type="test2", state_key=""),
         ]
 
-        yield self.state.annotate_event_with_state(event, old_state=old_state)
+        context = yield self.state.compute_event_context(
+            event, old_state=old_state
+        )
 
-        for k, v in event.old_state_events.items():
+        for k, v in context.current_state.items():
             type, state_key = k
             self.assertEqual(type, v.type)
             self.assertEqual(state_key, v.state_key)
 
-        self.assertEqual(set(old_state), set(event.old_state_events.values()))
-        self.assertDictEqual(event.old_state_events, event.state_events)
+        self.assertEqual(
+            set(old_state), set(context.current_state.values())
+        )
 
-        self.assertIsNone(event.state_group)
+        self.assertIsNone(context.state_group)
 
     @defer.inlineCallbacks
     def test_annotate_with_old_state(self):
@@ -66,21 +70,21 @@ class StateTestCase(unittest.TestCase):
             self.create_event(type="test2", state_key=""),
         ]
 
-        yield self.state.annotate_event_with_state(event, old_state=old_state)
+        context = yield self.state.compute_event_context(
+            event, old_state=old_state
+        )
 
-        for k, v in event.old_state_events.items():
+        for k, v in context.current_state.items():
             type, state_key = k
             self.assertEqual(type, v.type)
             self.assertEqual(state_key, v.state_key)
 
         self.assertEqual(
-            set(old_state + [event]),
-            set(event.old_state_events.values())
+            set(old_state),
+            set(context.current_state.values())
         )
 
-        self.assertDictEqual(event.old_state_events, event.state_events)
-
-        self.assertIsNone(event.state_group)
+        self.assertIsNone(context.state_group)
 
     @defer.inlineCallbacks
     def test_trivial_annotate_message(self):
@@ -99,30 +103,19 @@ class StateTestCase(unittest.TestCase):
             group_name: old_state,
         }
 
-        yield self.state.annotate_event_with_state(event)
+        context = yield self.state.compute_event_context(event)
 
-        for k, v in event.old_state_events.items():
+        for k, v in context.current_state.items():
             type, state_key = k
             self.assertEqual(type, v.type)
             self.assertEqual(state_key, v.state_key)
 
         self.assertEqual(
             set([e.event_id for e in old_state]),
-            set([e.event_id for e in event.old_state_events.values()])
+            set([e.event_id for e in context.current_state.values()])
         )
 
-        self.assertDictEqual(
-            {
-                k: v.event_id
-                for k, v in event.old_state_events.items()
-            },
-            {
-                k: v.event_id
-                for k, v in event.state_events.items()
-            }
-        )
-
-        self.assertEqual(group_name, event.state_group)
+        self.assertEqual(group_name, context.state_group)
 
     @defer.inlineCallbacks
     def test_trivial_annotate_state(self):
@@ -141,38 +134,19 @@ class StateTestCase(unittest.TestCase):
             group_name: old_state,
         }
 
-        yield self.state.annotate_event_with_state(event)
+        context = yield self.state.compute_event_context(event)
 
-        for k, v in event.old_state_events.items():
+        for k, v in context.current_state.items():
             type, state_key = k
             self.assertEqual(type, v.type)
             self.assertEqual(state_key, v.state_key)
 
         self.assertEqual(
             set([e.event_id for e in old_state]),
-            set([e.event_id for e in event.old_state_events.values()])
+            set([e.event_id for e in context.current_state.values()])
         )
 
-        self.assertEqual(
-            set([e.event_id for e in old_state] + [event.event_id]),
-            set([e.event_id for e in event.state_events.values()])
-        )
-
-        new_state = {
-            k: v.event_id
-            for k, v in event.state_events.items()
-        }
-        old_state = {
-            k: v.event_id
-            for k, v in event.old_state_events.items()
-        }
-        old_state[(event.type, event.state_key)] = event.event_id
-        self.assertDictEqual(
-            old_state,
-            new_state
-        )
-
-        self.assertIsNone(event.state_group)
+        self.assertIsNone(context.state_group)
 
     @defer.inlineCallbacks
     def test_resolve_message_conflict(self):
@@ -199,16 +173,11 @@ class StateTestCase(unittest.TestCase):
             group_name_2: old_state_2,
         }
 
-        yield self.state.annotate_event_with_state(event)
+        context = yield self.state.compute_event_context(event)
 
-        self.assertEqual(len(event.old_state_events), 5)
+        self.assertEqual(len(context.current_state), 5)
 
-        self.assertEqual(
-            set([e.event_id for e in event.state_events.values()]),
-            set([e.event_id for e in event.old_state_events.values()])
-        )
-
-        self.assertIsNone(event.state_group)
+        self.assertIsNone(context.state_group)
 
     @defer.inlineCallbacks
     def test_resolve_state_conflict(self):
@@ -235,19 +204,11 @@ class StateTestCase(unittest.TestCase):
             group_name_2: old_state_2,
         }
 
-        yield self.state.annotate_event_with_state(event)
+        context = yield self.state.compute_event_context(event)
 
-        self.assertEqual(len(event.old_state_events), 5)
+        self.assertEqual(len(context.current_state), 5)
 
-        expected_new = event.old_state_events
-        expected_new[(event.type, event.state_key)] = event
-
-        self.assertEqual(
-            set([e.event_id for e in expected_new.values()]),
-            set([e.event_id for e in event.state_events.values()]),
-        )
-
-        self.assertIsNone(event.state_group)
+        self.assertIsNone(context.state_group)
 
     def create_event(self, name=None, type=None, state_key=None):
         self.event_id += 1
@@ -266,6 +227,9 @@ class StateTestCase(unittest.TestCase):
             event.state_key = state_key
         event.event_id = event_id
 
+        event.is_state = lambda: (state_key is not None)
+        event.unsigned = {}
+
         event.user_id = "@user_id:example.com"
         event.room_id = "!room_id:example.com"