diff --git a/tests/unit/domain/test_edit_plan_clip.py b/tests/unit/domain/test_edit_plan_clip.py
new file mode 100644
index 000000000..e1361cdd2
--- /dev/null
+++ b/tests/unit/domain/test_edit_plan_clip.py
@@ -0,0 +1,362 @@
+"""edit_plan_clip 单测.
+
+domain 层剪辑计划片段纯逻辑模块，0 外部依赖。
+覆盖：枚举常量、create工厂/校验、素材分配、状态流转、属性计算。
+"""
+
+from __future__ import annotations
+
+from packages.domain.edit_plan_clip import EditPlanClip, EditPlanClipStatus
+
+
+class TestEditPlanClipStatus:
+    """EditPlanClipStatus 枚举测试."""
+
+    def test_four_statuses(self):
+        """四种状态."""
+        assert len(EditPlanClipStatus) == 4
+
+    def test_pending(self):
+        """pending 状态."""
+        assert EditPlanClipStatus.PENDING == "pending"
+
+    def test_ready(self):
+        """ready 状态."""
+        assert EditPlanClipStatus.READY == "ready"
+
+    def test_rendered(self):
+        """rendered 状态."""
+        assert EditPlanClipStatus.RENDERED == "rendered"
+
+    def test_failed(self):
+        """failed 状态."""
+        assert EditPlanClipStatus.FAILED == "failed"
+
+    def test_is_string(self):
+        """枚举值是字符串."""
+        for status in EditPlanClipStatus:
+            assert isinstance(status.value, str)
+            assert len(status.value) > 0
+
+    def test_str_compatible(self):
+        """StrEnum 可与字符串比较."""
+        assert EditPlanClipStatus.PENDING == "pending"
+        assert EditPlanClipStatus.READY + "" == "ready"
+
+
+class TestEditPlanClipCreate:
+    """EditPlanClip.create 工厂方法测试."""
+
+    def test_create_minimal(self):
+        """最简创建."""
+        clip = EditPlanClip.create(plan_id="plan1", clip_type="video", order=0)
+        assert clip.plan_id == "plan1"
+        assert clip.clip_type == "video"
+        assert clip.order == 0
+        assert clip.status == EditPlanClipStatus.PENDING
+        assert clip.template_clip_config_id == ""
+        assert clip.asset_id == ""
+        assert clip.text_content == ""
+        assert clip.start_time == 0.0
+        assert clip.duration == 0.0
+        assert clip.transition_effect == "cut"
+        assert clip.config == {}
+        assert isinstance(clip.id, str)
+        assert len(clip.id) > 0
+
+    def test_create_with_all_fields(self):
+        """带全部字段创建."""
+        clip = EditPlanClip.create(
+            plan_id="plan1",
+            clip_type="video",
+            order=2,
+            template_clip_config_id="tpl1",
+            asset_id="asset1",
+            text_content="  你好世界  ",
+            start_time=10.5,
+            duration=5.0,
+            transition_effect="fade",
+            config={"key": "value"},
+        )
+        assert clip.order == 2
+        assert clip.template_clip_config_id == "tpl1"
+        assert clip.asset_id == "asset1"
+        assert clip.text_content == "你好世界"  # strip了
+        assert clip.start_time == 10.5
+        assert clip.duration == 5.0
+        assert clip.transition_effect == "fade"
+        assert clip.config == {"key": "value"}
+
+    def test_create_strips_ids(self):
+        """plan_id 和 clip_type 会 strip."""
+        clip = EditPlanClip.create(plan_id="  plan1  ", clip_type="  video  ", order=0)
+        assert clip.plan_id == "plan1"
+        assert clip.clip_type == "video"
+
+    def test_create_empty_plan_id(self):
+        """空 plan_id 无效."""
+        try:
+            EditPlanClip.create(plan_id="", clip_type="video", order=0)
+            assert False
+        except ValueError as e:
+            assert "plan_id" in str(e)
+
+    def test_create_whitespace_plan_id(self):
+        """纯空白 plan_id 无效."""
+        try:
+            EditPlanClip.create(plan_id="   ", clip_type="video", order=0)
+            assert False
+        except ValueError as e:
+            assert "plan_id" in str(e)
+
+    def test_create_empty_clip_type(self):
+        """空 clip_type 无效."""
+        try:
+            EditPlanClip.create(plan_id="p1", clip_type="", order=0)
+            assert False
+        except ValueError as e:
+            assert "clip_type" in str(e)
+
+    def test_create_whitespace_clip_type(self):
+        """纯空白 clip_type 无效."""
+        try:
+            EditPlanClip.create(plan_id="p1", clip_type="   ", order=0)
+            assert False
+        except ValueError as e:
+            assert "clip_type" in str(e)
+
+    def test_create_negative_start_time(self):
+        """start_time 为负无效."""
+        try:
+            EditPlanClip.create(plan_id="p1", clip_type="v", order=0, start_time=-1.0)
+            assert False
+        except ValueError as e:
+            assert "start_time" in str(e)
+
+    def test_create_negative_duration(self):
+        """duration 为负无效."""
+        try:
+            EditPlanClip.create(plan_id="p1", clip_type="v", order=0, duration=-1.0)
+            assert False
+        except ValueError as e:
+            assert "duration" in str(e)
+
+    def test_create_zero_duration_valid(self):
+        """duration 为 0 合法."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, duration=0.0)
+        assert clip.duration == 0.0
+
+    def test_create_empty_transition_defaults_to_cut(self):
+        """空 transition_effect 默认 cut."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, transition_effect="")
+        assert clip.transition_effect == "cut"
+
+    def test_create_whitespace_transition_defaults_to_cut(self):
+        """空白 transition_effect 默认 cut."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, transition_effect="   ")
+        assert clip.transition_effect == "cut"
+
+    def test_create_config_none_defaults_empty_dict(self):
+        """config=None 默认为空 dict."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, config=None)
+        assert clip.config == {}
+
+    def test_create_unique_id(self):
+        """不同 clip id 不同."""
+        c1 = EditPlanClip.create("p1", "v", 0)
+        c2 = EditPlanClip.create("p1", "v", 0)
+        assert c1.id != c2.id
+
+    def test_create_has_timestamps(self):
+        """有创建和更新时间."""
+        clip = EditPlanClip.create("p1", "v", 0)
+        assert clip.created_at is not None
+        assert clip.updated_at is not None
+
+    def test_create_negative_order_valid(self):
+        """order 可以为负（表示排序位置）."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=-1)
+        assert clip.order == -1
+
+
+class TestEditPlanClipAssignAsset:
+    """素材分配测试."""
+
+    def _make_clip(self):
+        return EditPlanClip.create(plan_id="p1", clip_type="video", order=0)
+
+    def test_assign_asset(self):
+        """正常分配素材."""
+        clip = self._make_clip()
+        old_updated = clip.updated_at
+        clip.assign_asset("asset123")
+        assert clip.asset_id == "asset123"
+        assert clip.updated_at >= old_updated
+
+    def test_assign_asset_strips(self):
+        """asset_id 会 strip."""
+        clip = self._make_clip()
+        clip.assign_asset("  asset123  ")
+        assert clip.asset_id == "asset123"
+
+    def test_assign_asset_empty(self):
+        """空 asset_id 无效."""
+        clip = self._make_clip()
+        try:
+            clip.assign_asset("")
+            assert False
+        except ValueError as e:
+            assert "asset_id" in str(e)
+
+    def test_assign_asset_whitespace(self):
+        """纯空白 asset_id 无效."""
+        clip = self._make_clip()
+        try:
+            clip.assign_asset("   ")
+            assert False
+        except ValueError as e:
+            assert "asset_id" in str(e)
+
+    def test_has_asset_false_initially(self):
+        """初始无素材."""
+        clip = self._make_clip()
+        assert clip.has_asset is False
+
+    def test_has_asset_true_after_assign(self):
+        """分配后有素材."""
+        clip = self._make_clip()
+        clip.assign_asset("a1")
+        assert clip.has_asset is True
+
+
+class TestEditPlanClipStatusFlow:
+    """状态流转测试."""
+
+    def _make_clip(self):
+        return EditPlanClip.create(plan_id="p1", clip_type="video", order=0)
+
+    def test_initial_status_pending(self):
+        """初始状态 pending."""
+        clip = self._make_clip()
+        assert clip.status == EditPlanClipStatus.PENDING
+
+    def test_pending_to_ready(self):
+        """pending -> ready."""
+        clip = self._make_clip()
+        clip.mark_ready()
+        assert clip.status == EditPlanClipStatus.READY
+
+    def test_ready_to_rendered(self):
+        """ready -> rendered."""
+        clip = self._make_clip()
+        clip.mark_ready()
+        clip.mark_rendered()
+        assert clip.status == EditPlanClipStatus.RENDERED
+
+    def test_ready_to_failed(self):
+        """ready -> failed."""
+        clip = self._make_clip()
+        clip.mark_ready()
+        clip.mark_failed()
+        assert clip.status == EditPlanClipStatus.FAILED
+
+    def test_cannot_ready_from_rendered(self):
+        """rendered 状态不能再 mark_ready."""
+        clip = self._make_clip()
+        clip.mark_ready()
+        clip.mark_rendered()
+        try:
+            clip.mark_ready()
+            assert False
+        except ValueError as e:
+            assert "pending" in str(e).lower()
+
+    def test_cannot_ready_from_failed(self):
+        """failed 状态不能 mark_ready."""
+        clip = self._make_clip()
+        clip.mark_ready()
+        clip.mark_failed()
+        try:
+            clip.mark_ready()
+            assert False
+        except ValueError as e:
+            assert "pending" in str(e).lower()
+
+    def test_cannot_render_from_pending(self):
+        """pending 不能直接 mark_rendered."""
+        clip = self._make_clip()
+        try:
+            clip.mark_rendered()
+            assert False
+        except ValueError as e:
+            assert "ready" in str(e).lower()
+
+    def test_cannot_failed_from_pending(self):
+        """pending 不能直接 mark_failed."""
+        clip = self._make_clip()
+        try:
+            clip.mark_failed()
+            assert False
+        except ValueError as e:
+            assert "ready" in str(e).lower()
+
+    def test_status_change_updates_timestamp(self):
+        """状态变更更新 updated_at."""
+        clip = self._make_clip()
+        old_updated = clip.updated_at
+        clip.mark_ready()
+        assert clip.updated_at >= old_updated
+
+
+class TestEditPlanClipProperties:
+    """属性计算测试."""
+
+    def test_end_time(self):
+        """end_time = start_time + duration."""
+        clip = EditPlanClip.create(
+            plan_id="p1",
+            clip_type="v",
+            order=0,
+            start_time=10.0,
+            duration=5.5,
+        )
+        assert clip.end_time == 15.5
+
+    def test_end_time_zero_duration(self):
+        """零时长 end_time = start_time."""
+        clip = EditPlanClip.create(
+            plan_id="p1",
+            clip_type="v",
+            order=0,
+            start_time=10.0,
+            duration=0.0,
+        )
+        assert clip.end_time == 10.0
+
+    def test_end_time_zero_start(self):
+        """零起点 end_time = duration."""
+        clip = EditPlanClip.create(
+            plan_id="p1",
+            clip_type="v",
+            order=0,
+            start_time=0.0,
+            duration=7.0,
+        )
+        assert clip.end_time == 7.0
+
+    def test_has_asset_empty_string(self):
+        """空字符串无素材."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, asset_id="")
+        assert clip.has_asset is False
+
+    def test_has_asset_with_value(self):
+        """有值则有素材."""
+        clip = EditPlanClip.create(plan_id="p1", clip_type="v", order=0, asset_id="a1")
+        assert clip.has_asset is True
+
+    def test_config_independent_between_clips(self):
+        """不同 clip 的 config 独立."""
+        c1 = EditPlanClip.create(plan_id="p1", clip_type="v", order=0)
+        c2 = EditPlanClip.create(plan_id="p1", clip_type="v", order=1)
+        c1.config["key"] = "value"
+        assert "key" not in c2.config