diff --git a/tests/unit/test_dedup_pure.py b/tests/unit/test_dedup_pure.py
index 9c82021b8..cc58e6d9a 100755
--- a/tests/unit/test_dedup_pure.py
+++ b/tests/unit/test_dedup_pure.py
@@ -10,6 +10,9 @@ import pytest
 
 # 模块级mock cv2（dedup模块import时需要）
 sys.modules["cv2"] = MagicMock()
+# 模块级mock worker_app.db（dedup模块import时会触发数据库初始化，纯算法测试不需要）
+sys.modules["worker_app.db"] = MagicMock()
+sys.modules["worker_app.db"].SessionLocal = MagicMock()
 
 from video_processing.dedup import (  # noqa: E402
     VideoDeduplicator,
diff --git a/tests/unit/test_domain_remaining_small_modules.py b/tests/unit/test_domain_remaining_small_modules.py
index e77f586cb..54faec9e3 100755
--- a/tests/unit/test_domain_remaining_small_modules.py
+++ b/tests/unit/test_domain_remaining_small_modules.py
@@ -1,3 +1,5 @@
+from dataclasses import FrozenInstanceError
+
 """domain 层剩余小模块单测 - bgm_utils/exceptions/editing_mode/recipe/template/template_version/template_clip_config/preset_bgm/preset_voices/title_library/voice_library"""
 
 import pytest
@@ -397,7 +399,7 @@ class TestPresetBGM:
 
     def test_preset_bgm_frozen(self):
         bgm = PresetBGM(id="t1", name="t", style="x", duration=10.0)
-        with pytest.raises(Exception):
+        with pytest.raises(FrozenInstanceError):
             bgm.name = "改名"
 
     def test_library_not_empty(self):
@@ -487,7 +489,7 @@ class TestPresetVoices:
 
     def test_preset_voice_frozen(self):
         v = PresetVoice(voice_id="v1", name="t", description="d", gender="female")
-        with pytest.raises(Exception):
+        with pytest.raises(FrozenInstanceError):
             v.name = "改名"
 
     def test_preset_voices_list_not_empty(self):
diff --git a/tests/unit/test_email_service_smtp.py b/tests/unit/test_email_service_smtp.py
index 8f32d1dde..36c340d81 100755
--- a/tests/unit/test_email_service_smtp.py
+++ b/tests/unit/test_email_service_smtp.py
@@ -267,4 +267,4 @@ class TestGetEmailService:
         svc1 = get_email_service()
         svc2 = get_email_service()
         # 两个都可能是 Noop 或 EmailService，取决于环境
-        assert type(svc1) == type(svc2)
+        assert type(svc1) is type(svc2)
diff --git a/tests/unit/test_filter_presets.py b/tests/unit/test_filter_presets.py
index 903bc0ac2..98efba87e 100755
--- a/tests/unit/test_filter_presets.py
+++ b/tests/unit/test_filter_presets.py
@@ -1,3 +1,5 @@
+from dataclasses import FrozenInstanceError
+
 """filter_presets 领域层单元测试 - 滤镜预设库"""
 
 import pytest
@@ -58,7 +60,7 @@ class TestFilterPreset:
     def test_frozen_immutable(self):
         """frozen dataclass 不可修改"""
         preset = FilterPreset(id="test", name="测试", category="basic")
-        with pytest.raises(Exception):  # FrozenInstanceError
+        with pytest.raises(FrozenInstanceError):
             preset.name = "改名"
 
     def test_tags_default_empty_list(self):
diff --git a/tests/unit/test_jwt_handler.py b/tests/unit/test_jwt_handler.py
index 1c8859539..116062c32 100755
--- a/tests/unit/test_jwt_handler.py
+++ b/tests/unit/test_jwt_handler.py
@@ -5,6 +5,7 @@ from __future__ import annotations
 import time
 
 import pytest
+from jwt.exceptions import ExpiredSignatureError, InvalidTokenError
 
 from packages.application.auth.jwt_handler import (
     JWTHandler,
@@ -86,17 +87,17 @@ class TestJWTHandler:
         # 等待一小段时间确保过期
         time.sleep(0.1)
 
-        with pytest.raises(Exception):
+        with pytest.raises(ExpiredSignatureError):
             handler.verify_access_token(token)
 
     def test_invalid_token_raises_error(self, jwt_handler):
         """无效 token 验证失败"""
-        with pytest.raises(Exception):
+        with pytest.raises(InvalidTokenError):
             jwt_handler.verify_access_token("invalid.token.here")
 
     def test_empty_token_raises_error(self, jwt_handler):
         """空字符串 token 验证失败"""
-        with pytest.raises(Exception):
+        with pytest.raises(InvalidTokenError):
             jwt_handler.verify_access_token("")
 
     def test_different_secret_fails_verification(self):
@@ -106,7 +107,7 @@ class TestJWTHandler:
 
         token = handler1.create_access_token(user_id="user_001")
 
-        with pytest.raises(Exception):
+        with pytest.raises(InvalidTokenError):
             handler2.verify_access_token(token)
 
     def test_custom_algorithm(self):
diff --git a/tests/unit/test_transition_presets.py b/tests/unit/test_transition_presets.py
index d2c2d2d9a..ce2db1f0a 100755
--- a/tests/unit/test_transition_presets.py
+++ b/tests/unit/test_transition_presets.py
@@ -1,3 +1,5 @@
+from dataclasses import FrozenInstanceError
+
 """transition_presets 领域层单元测试 - 转场预设库"""
 
 import pytest
@@ -50,7 +52,7 @@ class TestTransitionPreset:
     def test_frozen_immutable(self):
         """frozen dataclass 不可修改"""
         preset = TransitionPreset(id="test", name="测试", category="basic")
-        with pytest.raises(Exception):
+        with pytest.raises(FrozenInstanceError):
             preset.name = "改名"
 
     def test_tags_default_empty_list(self):
@@ -78,7 +80,7 @@ class TestTransitionPresetLibrary:
     def test_all_presets_have_required_fields(self):
         """所有预设都有必填字段"""
         for preset in TRANSITION_PRESET_LIBRARY:
-            assert preset.id, f"missing id"
+            assert preset.id, "missing id"
             assert preset.name, f"{preset.id} missing name"
             assert preset.category, f"{preset.id} missing category"
             assert preset.transition, f"{preset.id} missing transition"