diff --git a/tests/unit/test_cover_frame_pre_extract.py b/tests/unit/test_cover_frame_pre_extract.py
index c44efb969..c8c2141bd 100644
--- a/tests/unit/test_cover_frame_pre_extract.py
+++ b/tests/unit/test_cover_frame_pre_extract.py
@@ -114,7 +114,7 @@ class TestExtractFirstFrame(unittest.TestCase):
             self.assertIn("scale=640", vf_filter)
             Path(result).unlink(missing_ok=True)
 
-    @patch("video_processing.ffmpeg_utils.run_ffmpeg", side_effect=Exception("fail"))
+    @patch("video_processing.ffmpeg_utils.run_ffmpeg", side_effect=RuntimeError("fail"))
     @patch("video_processing.ffmpeg_utils.probe_duration", return_value=10.0)
     def test_cleanup_temp_file_on_failure(self, mock_probe, mock_run):
         """失败时清理临时文件."""
@@ -123,7 +123,7 @@ class TestExtractFirstFrame(unittest.TestCase):
         with tempfile.NamedTemporaryFile(suffix=".mp4") as video:
             Path(video.name).write_bytes(b"fake video")
 
-            with self.assertRaises(Exception):
+            with self.assertRaises(RuntimeError):
                 extract_first_frame(video.name)