diff --git a/api/tests/unit_tests/services/test_billing_service.py b/api/tests/unit_tests/services/test_billing_service.py
index 575ae8427c9..d50dff3cce2 100644
--- a/api/tests/unit_tests/services/test_billing_service.py
+++ b/api/tests/unit_tests/services/test_billing_service.py
@@ -778,9 +778,7 @@ class TestBillingServiceQuotaOperations:
     def test_quota_release_with_bucket(self, mock_send_request):
         mock_send_request.return_value = {"available": 100, "reserved": 0, "released": 1}
 
-        BillingService.quota_release(
-            tenant_id="t1", feature_key="credit_pool", reservation_id="rid-1", bucket="trial"
-        )
+        BillingService.quota_release(tenant_id="t1", feature_key="credit_pool", reservation_id="rid-1", bucket="trial")
 
         call_json = mock_send_request.call_args[1]["json"]
         assert call_json["bucket"] == "trial"
diff --git a/api/tests/unit_tests/services/test_credit_pool_service.py b/api/tests/unit_tests/services/test_credit_pool_service.py
index ffaafb0edea..e9698aa92b8 100644
--- a/api/tests/unit_tests/services/test_credit_pool_service.py
+++ b/api/tests/unit_tests/services/test_credit_pool_service.py
@@ -365,8 +365,9 @@ def test_check_and_deduct_credits_logs_when_billing_release_fails() -> None:
         patch("services.credit_pool_service.dify_config.BILLING_ENABLED", True),
         patch("services.billing_service.BillingService.quota_reserve") as quota_reserve,
         patch("services.billing_service.BillingService.quota_commit", side_effect=RuntimeError("commit failed")),
-        patch("services.billing_service.BillingService.quota_release", side_effect=RuntimeError("release failed"))
-        as quota_release,
+        patch(
+            "services.billing_service.BillingService.quota_release", side_effect=RuntimeError("release failed")
+        ) as quota_release,
         patch("services.credit_pool_service.logger.warning") as logger_warning,
     ):
         quota_reserve.return_value = {"reservation_id": "reservation-1", "available": 7, "reserved": 3}