diff --git a/backend/tests/unit/test_memories_create.py b/backend/tests/unit/test_memories_create.py
index b507155c1e..94dc1882e3 100644
--- a/backend/tests/unit/test_memories_create.py
+++ b/backend/tests/unit/test_memories_create.py
@@ -24,14 +24,14 @@
 
 
 def _read_router():
-    with open(ROUTER_PATH) as f:
+    with open(ROUTER_PATH, encoding='utf-8') as f:
         return f.read()
 
 
 def _grep_router(pattern: str) -> list[str]:
     """Return lines matching pattern in the memories router."""
     matches = []
-    with open(ROUTER_PATH) as f:
+    with open(ROUTER_PATH, encoding='utf-8') as f:
         for line in f:
             if re.search(pattern, line):
                 matches.append(line.strip())