diff --git a/tests/unit/test_generation_preview.py b/tests/unit/test_generation_preview.py
index 33e174aab..11b584146 100755
--- a/tests/unit/test_generation_preview.py
+++ b/tests/unit/test_generation_preview.py
@@ -1173,9 +1173,7 @@ class TestInferVideoRatioFromTemplate:
         mock_template.mode = "pip"
         mock_db = MagicMock()
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.return_value.get_by_id.return_value = mock_template
             result = _infer_video_ratio_from_template("tpl_001", mock_db)
         assert result == "9:16"
@@ -1188,9 +1186,7 @@ class TestInferVideoRatioFromTemplate:
         mock_template.mode = "standard"
         mock_db = MagicMock()
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.return_value.get_by_id.return_value = mock_template
             result = _infer_video_ratio_from_template("tpl_001", mock_db)
         assert result == "16:9"
@@ -1203,9 +1199,7 @@ class TestInferVideoRatioFromTemplate:
         mock_template.mode = "unknown_mode"
         mock_db = MagicMock()
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.return_value.get_by_id.return_value = mock_template
             result = _infer_video_ratio_from_template("tpl_001", mock_db)
         assert result == ""
@@ -1216,9 +1210,7 @@ class TestInferVideoRatioFromTemplate:
 
         mock_db = MagicMock()
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.return_value.get_by_id.return_value = None
             result = _infer_video_ratio_from_template("nonexistent", mock_db)
         assert result == ""
@@ -1237,9 +1229,7 @@ class TestInferVideoRatioFromTemplate:
 
         mock_db = MagicMock()
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.side_effect = Exception("db connection error")
             result = _infer_video_ratio_from_template("tpl_001", mock_db)
         assert result == ""
@@ -1274,13 +1264,9 @@ class TestPreviewRouteAutoInfersVideoRatio:
             bgm_config={},
         )
 
-        with patch(
-            "app.api.routes.generation_preview.SQLAlchemyTemplateRepository"
-        ) as MockRepo:
+        with patch("app.api.routes.generation_preview.SQLAlchemyTemplateRepository") as MockRepo:
             MockRepo.return_value.get_by_id.return_value = mock_template
-            with patch(
-                "app.api.routes.generation_preview.CreateGenerationTaskUseCase"
-            ) as MockUC:
+            with patch("app.api.routes.generation_preview.CreateGenerationTaskUseCase") as MockUC:
                 MockUC.return_value.execute.return_value = task
                 with patch(
                     "app.api.routes.generation_preview.safe_enqueue_generation_task",