test(viral-video): 补_ resolve_video_model_id/_replace_henjin_everywhere/_mark_failed fallback单测（diff覆盖率≥60%）

#2157 P0/P1: CI Unit Tests失败根因——diff覆盖率42%<60%门槛
补单测覆盖:
- ai_client._resolve_video_model_id: 9个case (None/空/doubao-/ep-/别名/大小写/dot normalize/未识别警告)
- viral_video._replace_henjin_everywhere: str/list/dict递归+nested+非str透传
- viral_video._mark_failed_and_notify: 原session正常/异常fallback新session/已终态job
本地: 16423 passed, diff覆盖率89%

tests/unit/test_ai_client_video.py

@@ -483,3 +483,70 @@ class TestVideoGenerationCancelled:
                 doubao_video_poll_interval=0, doubao_video_timeout=10, doubao_video_model="seedance"
             )
             assert client.video_generation("p", output_dir=str(tmp_path)) is None
+
+
+# ============ #2157 _resolve_video_model_id 模型ID映射单测 ============
+
+
+class TestResolveVideoModelId:
+    """覆盖 _resolve_video_model_id 各分支（#2157 P0 修复）。"""
+
+    def _import_target(self):
+        from packages.shared.ai_client import _resolve_video_model_id
+
+        return _resolve_video_model_id
+
+    def test_none_uses_default(self):
+        fn = self._import_target()
+        with patch("packages.shared.ai_client.get_shared_settings") as ms:
+            ms.return_value = MagicMock(doubao_video_model="doubao-seedance-2-5-260628")
+            assert fn(None) == "doubao-seedance-2-5-260628"
+
+    def test_empty_uses_default(self):
+        fn = self._import_target()
+        with patch("packages.shared.ai_client.get_shared_settings") as ms:
+            ms.return_value = MagicMock(doubao_video_model="doubao-seedance-2-5-260628")
+            assert fn("   ") == "doubao-seedance-2-5-260628"
+
+    def test_doubao_prefix_passthrough(self):
+        fn = self._import_target()
+        assert fn("doubao-seedance-2-5-260628") == "doubao-seedance-2-5-260628"
+
+    def test_ep_prefix_passthrough(self):
+        fn = self._import_target()
+        assert fn("ep-20260721114705-b568m") == "ep-20260721114705-b568m"
+
+    def test_seedance_2_5_alias(self):
+        fn = self._import_target()
+        assert fn("seedance-2.5") == "doubao-seedance-2-5-260628"
+
+    def test_seedance_2_0_alias(self):
+        fn = self._import_target()
+        assert fn("seedance-2.0") == "doubao-seedance-2-0-250628"
+
+    def test_seedance_2_5_uppercase(self):
+        fn = self._import_target()
+        assert fn("Seedance-2.5") == "doubao-seedance-2-5-260628"
+
+    def test_seedance_dot_normalize(self):
+        fn = self._import_target()
+        # 传 "seedance-2.5" 带 dot 走 MAP.get 已命中；
+        # 构造带 seedance 但 key 变体的兜底场景
+        with patch(
+            "packages.shared.ai_client.VIRAL_VIDEO_MODEL_ID_MAP",
+            {
+                "seedance-2-5": "doubao-seedance-2-5-260628",
+            },
+        ):
+            assert fn("seedance-2.5") == "doubao-seedance-2-5-260628"
+
+    def test_unknown_seedance_falls_back_to_default_and_warns(self, caplog):
+        fn = self._import_target()
+        import logging
+
+        with patch("packages.shared.ai_client.get_shared_settings") as ms:
+            ms.return_value = MagicMock(doubao_video_model="doubao-seedance-2-5-260628")
+            with caplog.at_level(logging.WARNING, logger="shared.ai_client"):
+                # 任何不认识的别名
+                assert fn("seedance-9.9") == "doubao-seedance-2-5-260628"
+        assert any("未识别" in r.message for r in caplog.records if "ai_client" in r.name)

tests/unit/test_viral_video_p0.py

@@ -313,3 +313,130 @@ class TestResumeReadsImageAnalysis:
         # resume 本身应该调用 _run_render_pipeline
         resume_src = inspect.getsource(vv.resume_viral_video_pipeline)
         assert "_run_render_pipeline" in resume_src
+
+
+# ============ #2157 _replace_henjin_everywhere 递归替换单测 ============
+
+
+class TestReplaceHenjinEverywhere:
+    """覆盖 #2157 P1：递归替换 copy_result 中所有层级的'很近'→'最近'。"""
+
+    def _import(self):
+        from apps.worker.worker_app.tasks.viral_video import _replace_henjin_everywhere
+
+        return _replace_henjin_everywhere
+
+    def test_plain_string_no_henjin(self):
+        fn = self._import()
+        assert fn("最近好物推荐") == "最近好物推荐"
+        assert fn("") == ""
+        assert fn(None) is None
+        assert fn(123) == 123
+
+    def test_string_with_henjin(self):
+        fn = self._import()
+        assert fn("很近是不是总觉得颈肩发僵") == "最近是不是总觉得颈肩发僵"
+        # 多次出现
+        assert fn("很近很近都很近") == "最近最近都最近"
+
+    def test_list_recursive(self):
+        fn = self._import()
+        out = fn(["很近a", "b", ["很近c", "d"]])
+        assert out == ["最近a", "b", ["最近c", "d"]]
+
+    def test_dict_recursive_nested(self):
+        fn = self._import()
+        obj = {
+            "overview": {"theme": "很近颈肩", "title": "x"},
+            "scene_and_lighting": "很近才好用",
+            "voiceover_script": "很近是不是",
+            "final_copy": "很近好物",
+            "shots": [
+                {"scene_and_dialogue": "很近第一镜", "action_details": "很近动作", "audio_bgm": "很近音乐"},
+                {"nested": {"deep": "很近深层"}},
+            ],
+            "int_field": 42,
+        }
+        import json
+
+        out = fn(obj)
+        assert "很近" not in json.dumps(out, ensure_ascii=False)
+        assert out["overview"]["theme"] == "最近颈肩"
+        assert out["shots"][0]["scene_and_dialogue"] == "最近第一镜"
+        assert out["shots"][1]["nested"]["deep"] == "最近深层"
+        assert out["int_field"] == 42
+
+
+class TestMarkFailedAndNotifySessionFallback:
+    """#2157 P1：_mark_failed_and_notify 在原session失效时fallback到新SessionLocal。"""
+
+    def test_fallback_to_new_session_when_original_save_raises(self, tmp_path):
+        from unittest.mock import MagicMock, patch
+        from apps.worker.worker_app.tasks import viral_video as vv
+
+        job = MagicMock()
+        job.is_terminal = False
+        job.mark_failed = MagicMock()
+
+        # 原 session 保存抛异常
+        orig_session = MagicMock()
+        orig_repo = MagicMock()
+
+        def _raise(*a, **kw):
+            raise RuntimeError("session in rollback")
+
+        # 第一次调用_save_job抛异常，触发fallback
+        with patch.object(vv, "_save_job", side_effect=_raise):
+            fake_ssn = MagicMock()
+            fake_repo = MagicMock()
+            fake_job_in_db = MagicMock()
+            fake_job_in_db.is_terminal = False
+            fake_repo.get.return_value = fake_job_in_db
+            with patch.object(vv, "SessionLocal", return_value=fake_ssn):
+                with patch.object(vv, "SQLAlchemyViralVideoJobRepository", return_value=fake_repo):
+                    with patch.object(vv, "_emit_progress") as mock_emit:
+                        vv._mark_failed_and_notify("job-1", orig_session, orig_repo, job, "boom", stage="render")
+        # 原session上mark_failed被调用过
+        job.mark_failed.assert_called()
+        # fallback路径：新session上repo.get(job-1)被调用，且新job被mark_failed并commit
+        fake_repo.get.assert_called_with("job-1")
+        fake_job_in_db.mark_failed.assert_called_with("boom")
+        fake_repo.update.assert_called_with(fake_job_in_db)
+        fake_ssn.commit.assert_called()
+        fake_ssn.close.assert_called()
+        mock_emit.assert_called_once()
+
+    def test_original_session_happy_path_no_fallback(self):
+        from unittest.mock import MagicMock, patch
+        from apps.worker.worker_app.tasks import viral_video as vv
+
+        job = MagicMock()
+        job.is_terminal = False
+        session = MagicMock()
+        repo = MagicMock()
+        with patch.object(vv, "_save_job") as mock_save:
+            with patch.object(vv, "_emit_progress") as mock_emit:
+                # 不mock SessionLocal，如果fallback被错误触发会抛AttributeError
+                vv._mark_failed_and_notify("job-2", session, repo, job, "err", stage="copy")
+        job.mark_failed.assert_called_with("err")
+        mock_save.assert_called()
+        mock_emit.assert_called_once()
+
+    def test_terminal_job_not_marked(self):
+        from unittest.mock import MagicMock, patch
+        from apps.worker.worker_app.tasks import viral_video as vv
+
+        job = MagicMock()
+        job.is_terminal = True  # 已终态
+        session = MagicMock()
+        repo = MagicMock()
+        with patch.object(vv, "_save_job") as mock_save:
+            with patch.object(vv, "_emit_progress"):
+                fake_ssn = MagicMock()
+                with patch.object(vv, "SessionLocal", return_value=fake_ssn):
+                    with patch.object(vv, "SQLAlchemyViralVideoJobRepository") as mock_repo_cls:
+                        vv._mark_failed_and_notify("job-3", session, repo, job, "x")
+        # 终态job不调用mark_failed
+        job.mark_failed.assert_not_called()
+        # 且因 job 已终态，_save_job 也不应被调用（marked=False 才fallback；但此处 job 非 None 且 is_terminal=True，marked 保持 False 进入 fallback）
+        # fallback路径会重新打开session，get到的job也是终态，不会update