diff --git a/tests/replication/slave/storage/test_events.py b/tests/replication/slave/storage/test_events.py
index 105e1228bb8f..f430cce9312a 100644
--- a/tests/replication/slave/storage/test_events.py
+++ b/tests/replication/slave/storage/test_events.py
@@ -226,11 +226,9 @@ def persist(
             context = EventContext()
             context.current_state_ids = state_ids
             context.prev_state_ids = state_ids
-        elif not backfill:
+        else:
             state_handler = self.hs.get_state_handler()
             context = yield state_handler.compute_event_context(event)
-        else:
-            context = EventContext()
 
         context.push_actions = push_actions
 
diff --git a/tests/test_state.py b/tests/test_state.py
index feb84f3d48b8..253aa62f2a0d 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -99,6 +99,10 @@ def register_events(self, events):
         for e in events:
             self._event_id_to_event[e.event_id] = e
 
+    def store_state_group(self, *args, **kwargs):
+        self._next_group += 1
+        return self._next_group
+
 
 class DictObj(dict):
     def __init__(self, **kwargs):
@@ -144,6 +148,7 @@ def setUp(self):
                 "get_events",
                 "get_next_state_group",
                 "get_state_group_delta",
+                "store_state_group",
             ]
         )
         hs = Mock(spec_set=[
@@ -316,6 +321,7 @@ def test_branch_have_banned_conflict(self):
         store = StateGroupStore()
         self.store.get_state_groups_ids.side_effect = store.get_state_groups_ids
         self.store.get_events = store.get_events
+        self.store.store_state_group = store.store_state_group
         store.register_events(graph.walk())
 
         context_store = {}
@@ -399,6 +405,7 @@ def test_branch_have_perms_conflict(self):
         store = StateGroupStore()
         self.store.get_state_groups_ids.side_effect = store.get_state_groups_ids
         self.store.get_events = store.get_events
+        self.store.store_state_group = store.store_state_group
         store.register_events(graph.walk())
 
         context_store = {}