diff --git a/tests/unit/test_auth_bind_wechat_sync.py b/tests/unit/test_auth_bind_wechat_sync.py
index 767a59451..e11a41e7f 100755
--- a/tests/unit/test_auth_bind_wechat_sync.py
+++ b/tests/unit/test_auth_bind_wechat_sync.py
@@ -23,7 +23,6 @@ from packages.application.auth.wechat_sync_use_case import (
     WechatSyncUseCase,
 )
 
-
 # ── Test helpers ─────────────────────────────────────────
 
 
@@ -107,11 +106,13 @@ class FakeVerificationCodeService:
         self.generated = []
 
     def verify(self, recipient, code_type, code_value):
-        self.verified.append({
-            "recipient": recipient,
-            "code_type": code_type,
-            "code_value": code_value,
-        })
+        self.verified.append(
+            {
+                "recipient": recipient,
+                "code_type": code_type,
+                "code_value": code_value,
+            }
+        )
         return self._verify_success, self._verify_error
 
     def generate(self, recipient, code_type):
@@ -670,11 +671,13 @@ class TestWechatSyncUseCase:
         repo.find_by_wechat_unionid.return_value = None
         # first find_by_username returns a user (conflict), second time None (unique)
         call_count = {"n": 0}
+
         def mock_find_by_username(username):
             call_count["n"] += 1
             if call_count["n"] == 1:
                 return FakeUser(username=username)  # conflict
             return None  # unique on second try
+
         repo.find_by_username.side_effect = mock_find_by_username
         repo.save = MagicMock(side_effect=lambda u: u)