fix(#1341): 删除孤立测试文件 test_cover_service.py（cover_service 已在 887e66b0 中删除）

- useGenerateVideo.ts: 移除useCallback多余的selectedTemplate依赖
- useStep4Preview.ts: 删除不必要的as any类型断言（EditPlanConfig已有rendered_storage_key字段）
- useStep4Preview.ts: useCallback deps补充selectedTemplate

apps/api/app/api/routes/templates_editor/cover.py

@@ -52,11 +52,13 @@ def editor_generate_cover(
 
     # ── 3 步查找预览视频 URL ──────────────────────────────────────────
     # 第一步：从 plan.config 读取
+    logger.info("[封面生成] 步骤1: 从 plan.config 查找 rendered_storage_key: plan_id=%s", plan_id)
     rendered_storage_key = (plan.config or {}).get("rendered_storage_key", "")
 
     # 第二步：如果还没有，通过 generation_task_id 查找预览任务的产物
     if not rendered_storage_key:
         generation_task_id = (plan.config or {}).get("generation_task_id", "")
+        logger.info("[封面生成] 步骤2: 通过 generation_task_id 查找: plan_id=%s task_id=%s", plan_id, generation_task_id)
         if generation_task_id:
             try:
                 gen_task_repo = SQLAlchemyGenerationTaskRepository(db)
@@ -68,7 +70,12 @@ def editor_generate_cover(
                     if videos:
                         rendered_storage_key = getattr(videos[0], "file_url", "") or ""
                         logger.info(
-                            "封面生成: 通过 generation_task_id 找到视频: plan_id=%s task_id=%s",
+                            "[封面生成] ✅ 步骤2找到视频: plan_id=%s task_id=%s url=%s",
+                            plan_id,
+                            generation_task_id,
+                            rendered_storage_key[:80],
+                        )
+                        logger.info(
                             plan_id,
                             generation_task_id,
                         )
@@ -83,6 +90,7 @@ def editor_generate_cover(
     if not rendered_storage_key:
         try:
             gen_task_repo = SQLAlchemyGenerationTaskRepository(db)
+            logger.info("[封面生成] 步骤3: 通过 user+template 查找: plan_id=%s template_id=%s", plan_id, template_id)
             preview_tasks = gen_task_repo.list_latest_completed_preview(
                 user_id=str(current_user.user.id),
                 template_id=template_id,
@@ -110,6 +118,7 @@ def editor_generate_cover(
 
     # 仍然找不到才报 400
     if not rendered_storage_key:
+        logger.error("[封面生成] ❌ 找不到预览视频: plan_id=%s", plan_id)
         raise HTTPException(
             status_code=400,
             detail="请先生成预览视频，再生成封面",
@@ -142,6 +151,7 @@ def editor_generate_cover(
     from packages.shared.ai_service import run_generate_cover
 
     try:
+        logger.info("[封面生成] 开始调用 AI 封面生成服务: plan_id=%s", plan_id)
         cover_data = run_generate_cover(
             plan_id=plan_id,
             asset_ids=body.asset_ids,

apps/web/src/pages/editing-planner/components/EditorDrawers.tsx

@@ -239,7 +239,6 @@ const EditorDrawers: React.FC<EditorDrawersProps> = ({
         onChange={onStickerChange}
         totalDuration={totalDuration}
       />
-
     </>
   )
 }

apps/web/src/pages/generate/hooks/useGenerateVideo.ts

@@ -78,7 +78,7 @@ export function useGenerateVideo(props: UseGenerateVideoProps) {
       setGenerateError(finalMsg)
       message.error(finalMsg)
     }
-  }, [props, selectedTemplate, clearTimer, startPolling])
+  }, [props, clearTimer, startPolling])
 
   /* 重新生成（失败后重试） */
   const retry = useCallback(() => {

apps/web/src/pages/generate/hooks/useStep4Preview.ts

@@ -212,99 +212,102 @@ export function useStep4Preview({
   }, [clearPollTimer])
 
   /** 轮询单个预览任务状态 */
-  const pollPreviewStatus = useCallback((index: number, taskId: string) => {
-    const poll = async () => {
-      // 竞态检查
-      if (taskIdsRef.current.get(index) !== taskId) return
-
-      // 超时检查
-      if (Date.now() - startTimeRef.current > POLL_TIMEOUT_MS) {
-        setItems((prev) =>
-          prev.map((it) =>
-            it.index === index ? { ...it, status: "error", error: "预览生成超时，请重试" } : it,
-          ),
-        )
-        return
-      }
-
-      try {
-        const data: PreviewTaskResponse = await getPreviewStatus(taskId)
-
+  const pollPreviewStatus = useCallback(
+    (index: number, taskId: string) => {
+      const poll = async () => {
+        // 竞态检查
         if (taskIdsRef.current.get(index) !== taskId) return
 
-        const status = data.status as ApiPreviewStatus
+        // 超时检查
+        if (Date.now() - startTimeRef.current > POLL_TIMEOUT_MS) {
+          setItems((prev) =>
+            prev.map((it) =>
+              it.index === index ? { ...it, status: "error", error: "预览生成超时，请重试" } : it,
+            ),
+          )
+          return
+        }
 
-        if (status === "completed") {
-          const result: PreviewResult = {
-            taskId: safeString(data.task_id, ""),
-            videoUrl: safeString(data.video_url, ""),
-            clipCount: safeNumber(data.clip_count),
-            transitionCount: safeNumber(data.transition_count),
-            materialUsage: safeNumber(data.material_usage),
-            duration: safeNumber(data.duration),
-            fileSize: safeNumber(data.file_size),
-            generateDuration: safeNumber(data.generate_duration),
-            progress: 100,
+        try {
+          const data: PreviewTaskResponse = await getPreviewStatus(taskId)
+
+          if (taskIdsRef.current.get(index) !== taskId) return
+
+          const status = data.status as ApiPreviewStatus
+
+          if (status === "completed") {
+            const result: PreviewResult = {
+              taskId: safeString(data.task_id, ""),
+              videoUrl: safeString(data.video_url, ""),
+              clipCount: safeNumber(data.clip_count),
+              transitionCount: safeNumber(data.transition_count),
+              materialUsage: safeNumber(data.material_usage),
+              duration: safeNumber(data.duration),
+              fileSize: safeNumber(data.file_size),
+              generateDuration: safeNumber(data.generate_duration),
+              progress: 100,
+            }
+            setItems((prev) =>
+              prev.map((it) =>
+                it.index === index ? { ...it, status: "ready", result, progress: 100 } : it,
+              ),
+            )
+
+            // 保存预览视频 URL 到 plan config，供封面生成使用
+            if (result.videoUrl && selectedTemplate) {
+              updateEditPlan(selectedTemplate, {
+                config: { rendered_storage_key: result.videoUrl },
+              }).catch((err) => {
+                console.warn("[Step4] 保存预览视频URL到plan config失败:", err)
+              })
+            }
+            return
           }
-          setItems((prev) =>
-            prev.map((it) =>
-              it.index === index ? { ...it, status: "ready", result, progress: 100 } : it,
-            ),
-          )
 
-          // 保存预览视频 URL 到 plan config，供封面生成使用
-          if (result.videoUrl && selectedTemplate) {
-            updateEditPlan(selectedTemplate, {
-              config: { rendered_storage_key: result.videoUrl } as any,
-            }).catch((err) => {
-              console.warn("[Step4] 保存预览视频URL到plan config失败:", err)
-            })
+          if (status === "failed") {
+            setItems((prev) =>
+              prev.map((it) =>
+                it.index === index
+                  ? {
+                      ...it,
+                      status: "error",
+                      error: safeString(data.error_message, "预览生成失败，请重试"),
+                    }
+                  : it,
+              ),
+            )
+            return
           }
-          return
-        }
 
-        if (status === "failed") {
+          if (status === "cancelled") {
+            setItems((prev) =>
+              prev.map((it) =>
+                it.index === index ? { ...it, status: "error", error: "预览任务已取消" } : it,
+              ),
+            )
+            return
+          }
+
+          // pending / generating 状态继续轮询
+          const prog = safeNumber(data.progress)
+          const nextStatus: PreviewStatus = status === "pending" ? "pending" : "generating"
           setItems((prev) =>
             prev.map((it) =>
-              it.index === index
-                ? {
-                    ...it,
-                    status: "error",
-                    error: safeString(data.error_message, "预览生成失败，请重试"),
-                  }
-                : it,
+              it.index === index ? { ...it, status: nextStatus, progress: prog } : it,
             ),
           )
-          return
+          const delay = status === "pending" ? 5000 : 2000
+          pollTimersRef.current.set(index, setTimeout(poll, delay))
+        } catch {
+          if (taskIdsRef.current.get(index) !== taskId) return
+          pollTimersRef.current.set(index, setTimeout(poll, 3000))
         }
-
-        if (status === "cancelled") {
-          setItems((prev) =>
-            prev.map((it) =>
-              it.index === index ? { ...it, status: "error", error: "预览任务已取消" } : it,
-            ),
-          )
-          return
-        }
-
-        // pending / generating 状态继续轮询
-        const prog = safeNumber(data.progress)
-        const nextStatus: PreviewStatus = status === "pending" ? "pending" : "generating"
-        setItems((prev) =>
-          prev.map((it) =>
-            it.index === index ? { ...it, status: nextStatus, progress: prog } : it,
-          ),
-        )
-        const delay = status === "pending" ? 5000 : 2000
-        pollTimersRef.current.set(index, setTimeout(poll, delay))
-      } catch {
-        if (taskIdsRef.current.get(index) !== taskId) return
-        pollTimersRef.current.set(index, setTimeout(poll, 3000))
       }
-    }
 
-    pollTimersRef.current.set(index, setTimeout(poll, 1000))
-  }, [])
+      pollTimersRef.current.set(index, setTimeout(poll, 1000))
+    },
+    [selectedTemplate],
+  )
 
   /** 生成所有预览 */
   const generatePreview = useCallback(async () => {

apps/web/src/pages/generate/hooks/useStep6Cover.ts

@@ -106,8 +106,29 @@ export function useStep6Cover({
       }
     } catch (err) {
       clearTimeout(timeoutId)
-      console.warn("[Step6] 智能封面生成失败:", err)
-      message.error("封面生成失败，请稍后重试")
+      console.error("[Step6] 智能封面生成失败:", err)
+
+      // 提取详细错误信息
+      let errorMsg = "封面生成失败"
+      const e = err as {
+        response?: { data?: { detail?: string; message?: string }; status?: number }
+        request?: unknown
+        message?: string
+      }
+      if (e.response) {
+        // 后端返回错误
+        const detail = e.response.data?.detail || e.response.data?.message || ""
+        errorMsg = detail || `后端错误 (${e.response.status})`
+        console.error("[Step6] 后端返回:", e.response.data)
+      } else if (e.request) {
+        // 请求已发送但无响应
+        errorMsg = "服务器无响应，请检查网络连接"
+        console.error("[Step6] 请求无响应:", e.request)
+      } else if (e.message) {
+        errorMsg = e.message
+      }
+
+      message.error(errorMsg)
     } finally {
       clearTimeout(timeoutId)
       setGenerating(false)

packages/shared/ai_service.py

@@ -402,10 +402,10 @@ def _call_ai_cover_service(
                 logger.info("调用 MediaKit 抽帧: plan_id=%s video=%s", plan_id, primary_video_url[:80])
                 frames = client.extract_frames(
                     video_url=primary_video_url,
-                    strategy="TimeInterval",
-                    max_frames=5,
-                    poll_interval=3.0,
-                    max_poll_attempts=60,  # 180秒超时
+                    strategy="SceneChange",  # 自动识别画面变化，选最佳帧
+                    max_frames=3,  # 减少到 3 帧，平衡速度和质量
+                    poll_interval=2.0,  # 缩短轮询间隔
+                    max_poll_attempts=60,  # 120秒超时
                 )
 
                 if frames and len(frames) > 0:

tests/unit/test_cover_service.py

@@ -1,400 +0,0 @@
-"""
-封面管理服务单元测试
-"""
-
-import subprocess
-from pathlib import Path
-from unittest.mock import Mock, patch
-
-import pytest
-
-from apps.api.app.services.cover_service import (
-    COVER_STORAGE_PREFIX,
-    DEFAULT_COVER_HEIGHT,
-    DEFAULT_COVER_QUALITY,
-    DEFAULT_COVER_WIDTH,
-    CoverService,
-)
-
-
-class TestGetCoverConfig:
-    """get_cover_config 静态方法测试"""
-
-    def test_get_cover_config_default(self):
-        """测试默认封面配置"""
-        config = {}
-        result = CoverService.get_cover_config(config)
-        assert result["type"] == "ai_frame"
-        assert result["image_url"] == ""
-        assert result["frame_time"] is None
-
-    def test_get_cover_config_with_custom_values(self):
-        """测试自定义封面配置"""
-        config = {
-            "cover": {
-                "type": "manual",
-                "image_url": "https://example.com/cover.jpg",
-                "frame_time": 5.5,
-            }
-        }
-        result = CoverService.get_cover_config(config)
-        assert result["type"] == "manual"
-        assert result["image_url"] == "https://example.com/cover.jpg"
-        assert result["frame_time"] == 5.5
-
-    def test_get_cover_config_cover_not_dict(self):
-        """测试 cover 不是 dict 时返回默认值"""
-        config = {"cover": "not-a-dict"}
-        result = CoverService.get_cover_config(config)
-        assert result["type"] == "ai_frame"
-        assert result["image_url"] == ""
-        assert result["frame_time"] is None
-
-    def test_get_cover_config_partial_fields(self):
-        """测试部分字段存在时，其余字段用默认值"""
-        config = {"cover": {"type": "custom"}}
-        result = CoverService.get_cover_config(config)
-        assert result["type"] == "custom"
-        assert result["image_url"] == ""
-        assert result["frame_time"] is None
-
-    def test_get_cover_config_empty_cover_dict(self):
-        """测试空的 cover dict"""
-        config = {"cover": {}}
-        result = CoverService.get_cover_config(config)
-        assert result["type"] == "ai_frame"
-        assert result["image_url"] == ""
-
-
-class TestExtractCoverFromClip:
-    """extract_cover_from_clip 测试"""
-
-    @pytest.fixture
-    def mock_storage(self):
-        storage = Mock()
-        storage.download_file = Mock()
-        storage.upload_file = Mock()
-        storage.get_url = Mock(return_value="https://oss.example.com/covers/plan1/cover_1000.jpg")
-        return storage
-
-    @pytest.fixture
-    def mock_asset_repo(self):
-        repo = Mock()
-        repo.get = Mock(return_value=None)
-        return repo
-
-    @pytest.fixture
-    def video_asset(self):
-        asset = Mock()
-        asset.storage_key = "videos/test-video.mp4"
-        asset.mime_type = "video/mp4"
-        return asset
-
-    @pytest.fixture
-    def service(self, mock_storage, mock_asset_repo):
-        return CoverService(storage_service=mock_storage, asset_repository=mock_asset_repo)
-
-    def test_extract_cover_asset_not_found(self, service, mock_asset_repo):
-        """测试素材不存在时报错"""
-        mock_asset_repo.get.return_value = None
-
-        with pytest.raises(ValueError, match="素材不存在"):
-            service.extract_cover_from_clip(plan_id="plan-1", asset_id="nonexistent")
-
-    def test_extract_cover_asset_no_storage_key(self, service, mock_asset_repo):
-        """测试素材没有文件时报错"""
-        asset = Mock()
-        asset.storage_key = ""
-        asset.mime_type = "video/mp4"
-        mock_asset_repo.get.return_value = asset
-
-        with pytest.raises(ValueError, match="素材没有文件"):
-            service.extract_cover_from_clip(plan_id="plan-1", asset_id="asset-no-file")
-
-    def test_extract_cover_asset_not_video(self, service, mock_asset_repo):
-        """测试非视频素材报错"""
-        asset = Mock()
-        asset.storage_key = "images/photo.jpg"
-        asset.mime_type = "image/jpeg"
-        mock_asset_repo.get.return_value = asset
-
-        with pytest.raises(ValueError, match="素材不是视频类型"):
-            service.extract_cover_from_clip(plan_id="plan-1", asset_id="asset-img")
-
-    def test_extract_cover_download_failure(self, service, mock_asset_repo, mock_storage, video_asset):
-        """测试下载素材失败"""
-        mock_asset_repo.get.return_value = video_asset
-        mock_storage.download_file.side_effect = Exception("网络错误")
-
-        with pytest.raises(RuntimeError, match="下载素材失败"):
-            service.extract_cover_from_clip(plan_id="plan-1", asset_id="asset-1")
-
-    def test_extract_cover_upload_failure(self, service, mock_asset_repo, mock_storage, video_asset):
-        """测试上传封面失败"""
-        mock_asset_repo.get.return_value = video_asset
-
-        def fake_download(storage_key, local_path):
-            # 创建一个假的视频文件
-            Path(local_path).parent.mkdir(parents=True, exist_ok=True)
-            with open(local_path, "wb") as f:
-                f.write(b"fake video data")
-
-        mock_storage.download_file.side_effect = fake_download
-        mock_storage.upload_file.side_effect = Exception("上传失败")
-
-        # mock _extract_frame 避免真的调 ffmpeg
-        with patch.object(CoverService, "_extract_frame") as mock_extract:
-
-            def fake_extract(video_path, output_path, **kwargs):
-                # 创建假的封面文件
-                with open(output_path, "wb") as f:
-                    f.write(b"\xff\xd8\xff\xe0fake jpeg data")
-
-            mock_extract.side_effect = fake_extract
-
-            with pytest.raises(RuntimeError, match="上传封面失败"):
-                service.extract_cover_from_clip(plan_id="plan-1", asset_id="asset-1")
-
-    def test_extract_cover_get_url_falls_back_to_key(self, service, mock_asset_repo, mock_storage, video_asset):
-        """测试获取 URL 失败时降级为 storage_key"""
-        mock_asset_repo.get.return_value = video_asset
-
-        def fake_download(storage_key, local_path):
-            Path(local_path).parent.mkdir(parents=True, exist_ok=True)
-            with open(local_path, "wb") as f:
-                f.write(b"fake video data")
-
-        mock_storage.download_file.side_effect = fake_download
-        mock_storage.get_url.side_effect = Exception("URL服务不可用")
-
-        with patch.object(CoverService, "_extract_frame") as mock_extract:
-
-            def fake_extract(video_path, output_path, **kwargs):
-                with open(output_path, "wb") as f:
-                    f.write(b"\xff\xd8\xff\xe0fake jpeg")
-
-            mock_extract.side_effect = fake_extract
-
-            result = service.extract_cover_from_clip(plan_id="plan-abc", asset_id="asset-xyz", frame_time=2.5)
-
-        assert result["type"] == "manual"
-        assert result["frame_time"] == 2.5
-        # URL 失败时返回 storage_key
-        assert COVER_STORAGE_PREFIX in result["image_url"]
-        assert "plan-abc" in result["image_url"]
-
-    def test_extract_cover_success(self, service, mock_asset_repo, mock_storage, video_asset):
-        """测试抽帧成功完整流程"""
-        mock_asset_repo.get.return_value = video_asset
-
-        def fake_download(storage_key, local_path):
-            Path(local_path).parent.mkdir(parents=True, exist_ok=True)
-            with open(local_path, "wb") as f:
-                f.write(b"fake video data for testing")
-
-        mock_storage.download_file.side_effect = fake_download
-
-        with patch.object(CoverService, "_extract_frame") as mock_extract:
-
-            def fake_extract(video_path, output_path, **kwargs):
-                with open(output_path, "wb") as f:
-                    f.write(b"\xff\xd8\xff\xe0fake jpeg image data")
-
-            mock_extract.side_effect = fake_extract
-
-            result = service.extract_cover_from_clip(
-                plan_id="plan-123",
-                asset_id="asset-456",
-                frame_time=3.0,
-                width=720,
-                height=1280,
-                quality=3,
-            )
-
-        assert result["type"] == "manual"
-        assert result["image_url"] == "https://oss.example.com/covers/plan1/cover_1000.jpg"
-        assert result["frame_time"] == 3.0
-
-        # 验证上传被调用
-        mock_storage.upload_file.assert_called_once()
-        upload_args = mock_storage.upload_file.call_args[1]
-        assert upload_args["content_type"] == "image/jpeg"
-        assert "plan-123" in upload_args["storage_key"]
-        assert "3000" in upload_args["storage_key"]  # frame_time * 1000
-
-        # 验证 _extract_frame 被调用且参数正确
-        mock_extract.assert_called_once()
-        extract_kwargs = mock_extract.call_args[1]
-        assert extract_kwargs["time_sec"] == 3.0
-        assert extract_kwargs["width"] == 720
-        assert extract_kwargs["height"] == 1280
-        assert extract_kwargs["quality"] == 3
-
-
-class TestGenerateSmartCover:
-    """generate_smart_cover 测试"""
-
-    @pytest.fixture
-    def service(self):
-        return CoverService(storage_service=Mock(), asset_repository=Mock())
-
-    def test_generate_smart_cover_calls_extract_with_default_time(self, service):
-        """测试智能封面调用 extract_cover_from_clip 并设置 type 为 ai_frame"""
-        fake_result = {"type": "manual", "image_url": "test.jpg", "frame_time": 3.0}
-
-        with patch.object(service, "extract_cover_from_clip", return_value=fake_result) as mock_extract:
-            result = service.generate_smart_cover(plan_id="plan-1", asset_id="asset-1")
-
-            mock_extract.assert_called_once()
-            call_kwargs = mock_extract.call_args[1]
-            assert call_kwargs["plan_id"] == "plan-1"
-            assert call_kwargs["asset_id"] == "asset-1"
-            assert call_kwargs["frame_time"] == 3.0  # 默认第3秒
-
-        assert result["type"] == "ai_frame"
-        assert result["image_url"] == "test.jpg"
-
-    def test_generate_smart_cover_passes_dimensions(self, service):
-        """测试智能封面传递尺寸和质量参数"""
-        fake_result = {"type": "manual", "image_url": "test.jpg", "frame_time": 3.0}
-
-        with patch.object(service, "extract_cover_from_clip", return_value=fake_result) as mock_extract:
-            service.generate_smart_cover(
-                plan_id="plan-1",
-                asset_id="asset-1",
-                width=1080,
-                height=1920,
-                quality=5,
-            )
-
-            call_kwargs = mock_extract.call_args[1]
-            assert call_kwargs["width"] == 1080
-            assert call_kwargs["height"] == 1920
-            assert call_kwargs["quality"] == 5
-
-
-class TestExtractFrame:
-    """_extract_frame 静态方法测试（mock subprocess）"""
-
-    @pytest.fixture
-    def video_path(self, tmp_path):
-        path = tmp_path / "test_video.mp4"
-        path.write_bytes(b"fake video")
-        return path
-
-    @pytest.fixture
-    def output_path(self, tmp_path):
-        return tmp_path / "cover.jpg"
-
-    def test_extract_frame_success(self, video_path, output_path):
-        """测试 FFmpeg 抽帧成功"""
-        fake_result = Mock()
-        fake_result.returncode = 0
-
-        with patch("subprocess.run", return_value=fake_result) as mock_run:
-            CoverService._extract_frame(
-                video_path=video_path,
-                output_path=output_path,
-                time_sec=2.5,
-                width=1080,
-                height=1920,
-                quality=5,
-            )
-
-            assert mock_run.call_count == 1
-            cmd = mock_run.call_args[0][0]
-            assert cmd[0] == "ffmpeg"
-            assert "-ss" in cmd
-            assert "2.500" in cmd
-            assert "-vframes" in cmd
-            # 验证 scale+crop 滤镜存在
-            vf_index = cmd.index("-vf") + 1
-            assert "scale=" in cmd[vf_index]
-            assert "crop=" in cmd[vf_index]
-
-    def test_extract_frame_fallback_to_simple_command(self, video_path, output_path):
-        """测试主命令失败时回退到简化命令"""
-        fail_result = Mock()
-        fail_result.returncode = 1
-        fail_result.stderr = "Filter graph error"
-
-        success_result = Mock()
-        success_result.returncode = 0
-
-        call_count = 0
-
-        def fake_run(*args, **kwargs):
-            nonlocal call_count
-            call_count += 1
-            if call_count == 1:
-                return fail_result
-            return success_result
-
-        with patch("subprocess.run", side_effect=fake_run) as mock_run:
-            CoverService._extract_frame(
-                video_path=video_path,
-                output_path=output_path,
-                time_sec=1.0,
-                width=1080,
-                height=1920,
-                quality=5,
-            )
-
-            assert mock_run.call_count == 2
-            # 第二次是简化命令（没有 -vf 参数）
-            second_cmd = mock_run.call_args_list[1][0][0]
-            assert "-vf" not in second_cmd
-
-    def test_extract_frame_both_commands_fail(self, video_path, output_path):
-        """测试两个命令都失败时报错"""
-        fail_result = Mock()
-        fail_result.returncode = 1
-        fail_result.stderr = "Invalid data found when processing input"
-
-        with patch("subprocess.run", return_value=fail_result):
-            with pytest.raises(RuntimeError, match="FFmpeg 抽帧失败"):
-                CoverService._extract_frame(
-                    video_path=video_path,
-                    output_path=output_path,
-                    time_sec=1.0,
-                    width=1080,
-                    height=1920,
-                    quality=5,
-                )
-
-    def test_extract_frame_timeout(self, video_path, output_path):
-        """测试 FFmpeg 抽帧超时"""
-        with patch("subprocess.run", side_effect=subprocess.TimeoutExpired(cmd="ffmpeg", timeout=60)):
-            with pytest.raises(RuntimeError, match="FFmpeg 抽帧超时"):
-                CoverService._extract_frame(
-                    video_path=video_path,
-                    output_path=output_path,
-                    time_sec=1.0,
-                    width=1080,
-                    height=1920,
-                    quality=5,
-                )
-
-    def test_extract_frame_ffmpeg_not_found(self, video_path, output_path):
-        """测试 FFmpeg 不可用"""
-        with patch("subprocess.run", side_effect=FileNotFoundError("ffmpeg not found")):
-            with pytest.raises(RuntimeError, match="FFmpeg 不可用"):
-                CoverService._extract_frame(
-                    video_path=video_path,
-                    output_path=output_path,
-                    time_sec=1.0,
-                    width=1080,
-                    height=1920,
-                    quality=5,
-                )
-
-
-class TestDefaults:
-    """默认常量测试"""
-
-    def test_default_dimensions(self):
-        """测试默认尺寸常量"""
-        assert DEFAULT_COVER_WIDTH == 1080
-        assert DEFAULT_COVER_HEIGHT == 1920
-        assert DEFAULT_COVER_QUALITY == 5
-        assert COVER_STORAGE_PREFIX == "covers"