diff --git a/tests/unit/test_preset_bgm.py b/tests/unit/test_preset_bgm.py
index 2120fcf7d..932f4facc 100755
--- a/tests/unit/test_preset_bgm.py
+++ b/tests/unit/test_preset_bgm.py
@@ -1,6 +1,7 @@
 """Preset BGM 预设背景音乐单元测试。"""
 
 import pytest
+from dataclasses import FrozenInstanceError
 
 from packages.domain.preset_bgm import (
     BGM_STYLES,
@@ -42,7 +43,7 @@ class TestPresetBGMDataclass:
 
     def test_frozen_immutable(self):
         bgm = PresetBGM(id="t1", name="T", style="upbeat", duration=60.0)
-        with pytest.raises(Exception):  # FrozenInstanceError
+        with pytest.raises(FrozenInstanceError):
             bgm.name = "new name"
 
     def test_equality(self):
@@ -96,7 +97,7 @@ class TestBGMStyles:
         assert "cinematic" in BGM_STYLES
 
     def test_styles_have_chinese_names(self):
-        for key, value in BGM_STYLES.items():
+        for _, value in BGM_STYLES.items():
             assert isinstance(value, str)
             assert len(value) > 0