Merge pull request 'fix: #1765 generate_pixel_perturbation 支持 int seed 可复现' (#1778) from fix/pixel-perturbation-seed into develop

新增 5 个测试覆盖 int seed 入参分支（reproducible/与 Random 对象
等价/None 默认），满足 diff coverage ≥60% 要求。

packages/domain/variant_plan_selector.py

@@ -129,7 +129,10 @@ def reselect_clips_for_variant(
     Raises:
         ValueError: 源片段为空 / 素材池为空 / 素材时长全为 0（无法差异化选片）。
     """
-    rng = rng or random.Random()
+    if rng is None:
+        rng = random.Random()
+    elif isinstance(rng, int):
+        rng = random.Random(rng)
     if not source_clips:
         raise ValueError("源 plan 无片段，无法为变体重新选片")
     if not candidate_asset_ids:
@@ -312,7 +315,10 @@ def generate_visual_perturbation(rng: random.Random | None = None) -> dict:
     - speed_factor: 0.95~1.05 速度微调（±5%，肉眼不太敏感但时间轴不同）
     - brightness_shift: -10~+10 亮度偏移（eq=brightness，画面明暗差异）
     """
-    rng = rng or random.Random()
+    if rng is None:
+        rng = random.Random()
+    elif isinstance(rng, int):
+        rng = random.Random(rng)
     return {
         "hflip": rng.random() < 0.3,
         "zoom_ratio": round(1.0 + rng.uniform(0, 0.08), 4),
@@ -321,7 +327,7 @@ def generate_visual_perturbation(rng: random.Random | None = None) -> dict:
     }
 
 
-def generate_pixel_perturbation(rng: random.Random | None = None) -> dict:
+def generate_pixel_perturbation(rng: random.Random | int | None = None) -> dict:
     """为一个变体生成像素级扰动滤镜参数（Issue #1765）。
 
     在现有视觉扰动（hflip/zoom/brightness）基础上，额外叠加 2-3 种
@@ -336,7 +342,10 @@ def generate_pixel_perturbation(rng: random.Random | None = None) -> dict:
     返回 dict，可直接存入 plan.config["pixel_perturbation"]。
     渲染侧读取后追加到 ffmpeg filter chain。
     """
-    rng = rng or random.Random()
+    if rng is None:
+        rng = random.Random()
+    elif isinstance(rng, int):
+        rng = random.Random(rng)
 
     # 可用滤镜池
     filter_options = ["noise", "unsharp", "curves", "color_balance"]

tests/unit/test_pixel_perturbation.py

@@ -110,3 +110,32 @@ class TestPixelPerturbationAcceptance:
         # 至少 2 种不同组合
         unique = len(set(results))
         assert unique >= 2, f"Expected >= 2 unique filter combos, got {unique}: {results}"
+
+
+class TestIntSeedSupport:
+    """int seed 入参支持（与 get_rhythm_template(seed) 接口一致）。"""
+
+    def test_int_seed_returns_dict(self):
+        """int seed 正常返回 dict。"""
+        result = generate_pixel_perturbation(42)
+        assert isinstance(result, dict)
+        assert "filters" in result
+
+    def test_int_seed_reproducible(self):
+        """相同 int seed 结果一致。"""
+        assert generate_pixel_perturbation(42) == generate_pixel_perturbation(42)
+
+    def test_int_seed_differs_across_seeds(self):
+        """不同 int seed 大概率不同（遍历确认至少 2 种组合）。"""
+        results = {tuple(generate_pixel_perturbation(s)["filters"]) for s in range(30)}
+        assert len(results) >= 2
+
+    def test_int_seed_matches_random_obj(self):
+        """int seed 与等价 random.Random(seed) 结果一致。"""
+        assert generate_pixel_perturbation(7) == generate_pixel_perturbation(random.Random(7))
+
+    def test_none_seed_works(self):
+        """None 入参（默认随机）正常返回。"""
+        result = generate_pixel_perturbation(None)
+        assert isinstance(result, dict)
+        assert len(result["filters"]) in [2, 3]