diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 00000000..d77207a8
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,4 @@
+[run]
+omit =
+    */tests/*
+    */test_*.py
diff --git a/backend/tests/services/test_rooms.py b/backend/tests/services/test_rooms.py
index ac18453c..0f5eea6f 100644
--- a/backend/tests/services/test_rooms.py
+++ b/backend/tests/services/test_rooms.py
@@ -139,8 +139,8 @@ async def test_get_room_and_delete_room_database_error(
         AsyncMock(side_effect=SQLAlchemyError(ROOM_DB_ERROR_MSG)),
     )
     if service_func is delete_room:
-        async_session.rollback = AsyncMock()
-        async_session.commit = AsyncMock()
+        async_session.rollback = AsyncMock()  # type: ignore [method-assign]
+        async_session.commit = AsyncMock()  # type: ignore [method-assign]
     with pytest.raises(SQLAlchemyError):
         await service_func(async_session, room_id)
     session_method = getattr(async_session, session_attr)
@@ -176,9 +176,11 @@ async def test_new_room_database_error(
         - async_session.commit called once
         - async_session.rollback called once
     """
-    async_session.add = MagicMock()
-    async_session.commit = AsyncMock(side_effect=SQLAlchemyError(ROOM_DB_ERROR_MSG))
-    async_session.rollback = AsyncMock()
+    async_session.add = MagicMock()  # type: ignore [method-assign]
+    async_session.commit = AsyncMock(  # type: ignore [method-assign]
+        side_effect=SQLAlchemyError(ROOM_DB_ERROR_MSG)
+    )
+    async_session.rollback = AsyncMock()  # type: ignore [method-assign]
     with pytest.raises(SQLAlchemyError):
         await new_room(async_session, sample_room)
     async_session.add.assert_called_once_with(sample_room)
@@ -208,8 +210,10 @@ async def test_update_room_database_error_param(
         - async_session.execute called once
         - async_session.rollback called once
     """
-    async_session.execute = AsyncMock(side_effect=SQLAlchemyError(ROOM_DB_ERROR_MSG))
-    async_session.rollback = AsyncMock()
+    async_session.execute = AsyncMock(  # type: ignore [method-assign]
+        side_effect=SQLAlchemyError(ROOM_DB_ERROR_MSG)
+    )
+    async_session.rollback = AsyncMock()  # type: ignore [method-assign]
     with pytest.raises(SQLAlchemyError):
         await update_room(async_session, sample_room.id, **room_update_data)
     async_session.execute.assert_called_once()
@@ -255,7 +259,9 @@ async def test_get_room_returns_room(
         - async_session.scalar called once with
             ``select(Room).where(Room.id == sample_room.id)``
     """
-    async_session.scalar = AsyncMock(return_value=sample_room)
+    async_session.scalar = AsyncMock(  # type: ignore [method-assign]
+        return_value=sample_room
+    )
     result: Room = await get_room(async_session, sample_room.id)
     assert result == sample_room
     async_session.scalar.assert_called_once()