diff --git a/tests/unit/test_generation_cover.py b/tests/unit/test_generation_cover.py
index e7065b34d..ea10796b8 100644
--- a/tests/unit/test_generation_cover.py
+++ b/tests/unit/test_generation_cover.py
@@ -57,19 +57,29 @@ def test_templates_editor_no_cover_router():
             assert "generate-cover" not in getattr(route, "path", ""), "templates_editor 不应再有 generate-cover 路由"
 
 
+def _collect_route_paths(route, acc):
+    """递归收集路由路径（兼容新版 fastapi 的 _IncludedRouter 延迟包装）。"""
+    path = getattr(route, "path", None)
+    if isinstance(path, str):
+        acc.append(path)
+    # 新版 fastapi：_IncludedRouter.original_router；旧版：嵌套 .routes
+    inner = getattr(route, "original_router", None)
+    if inner is not None and hasattr(inner, "routes"):
+        for sub in inner.routes:
+            _collect_route_paths(sub, acc)
+    sub_routes = getattr(route, "routes", None)
+    if sub_routes:
+        for sub in sub_routes:
+            _collect_route_paths(sub, acc)
+
+
 def test_api_router_has_generation_cover():
     """api_router 应该包含 /api/v1/generation/generate-cover 路径"""
     from app.api.router import api_router
 
-    all_paths = []
+    all_paths: list[str] = []
     for route in api_router.routes:
-        if hasattr(route, "path"):
-            all_paths.append(route.path)
-        # 嵌套 router
-        if hasattr(route, "routes"):
-            for sub_route in route.routes:
-                if hasattr(sub_route, "path"):
-                    all_paths.append(sub_route.path)
+        _collect_route_paths(route, all_paths)
 
     # 应该能找到 generate-cover 路径
     cover_paths = [p for p in all_paths if "generate-cover" in p]
diff --git a/tests/unit/test_variant_plan_selector_1743.py b/tests/unit/test_variant_plan_selector_1743.py
index 753b0a80a..1aa2987c4 100644
--- a/tests/unit/test_variant_plan_selector_1743.py
+++ b/tests/unit/test_variant_plan_selector_1743.py
@@ -235,9 +235,15 @@ class TestBatchOverlapAvoidance:
 
         main = [c for c in clips if c["clip_type"] == "main"]
         assert len(main) == 1
-        ratio = _clip_overlap_ratio("a1", main[0]["start_time"], 10.0, {"a1": [(0.0, 100.0)]})
+        start = main[0]["start_time"]
+        ratio = _clip_overlap_ratio("a1", start, 10.0, {"a1": [(0.0, 100.0)]})
         assert ratio <= BATCH_CLIP_OVERLAP_LIMIT, f"避让后重叠应 ≤20%，实际 {ratio:.2%}"
-        assert main[0]["start_time"] == pytest.approx(105.0, abs=0.01)
+        # #1749：选片改 0.25s 窗口扫描找最优错开起点（不再依赖 rng.uniform 单点），
+        # 落点只需满足语义：与已用区间 [0,100) 不完全重叠且重叠 ≤20%
+        assert start > 0.0
+        # start+10 区间与 [0,100) 的重叠段（若有）≤ 2s
+        overlap = max(0.0, min(start + 10.0, 100.0) - max(start, 0.0))
+        assert overlap <= 2.0 + 1e-6, f"重叠时长 {overlap}s 应 ≤2s（10s 段的 20%）" 
 
     def test_first_variant_segments_become_avoidance_target(self):
         """变体 0 选定区间后，变体 1 选同素材时批次区间生效（不与源区间完全重合）。"""