diff --git a/tests/integration/test_diagnosis_tree_link.py b/tests/integration/test_diagnosis_tree_link.py
new file mode 100644
index 0000000..0b9d1a9
--- /dev/null
+++ b/tests/integration/test_diagnosis_tree_link.py
@@ -0,0 +1,31 @@
+"""集成验证：真实树注入后 _get_ground_truth_for_trace 收到非空 ground_truth；core 不依赖 app。
+
+这两个测试守护"诊断 tree_data 断链"修复：
+- 真实树 → load_tree_nodes → _get_ground_truth_for_trace，证明 bug 之前恒空的环已接通。
+- core/evolution/diagnose.py 不 import app，守护依赖方向（core 不依赖 app）与算法保真。
+"""
+
+from pathlib import Path
+
+from app.harness.tree_nodes import load_tree_nodes
+from core.evolution.diagnose import _get_ground_truth_for_trace
+
+# store 根锚定到仓库根，避免测试运行目录漂移导致相对路径失效（与 Task 1 测试一致）。
+_STORE_DIR = Path(__file__).resolve().parents[2] / "store"
+
+
+def test_ground_truth_nonempty_with_real_tree():
+    """对真实 T2 样本 604-2（video 0RxMZBLeqRI）的 view_node 调用，ground_truth 非空。"""
+    tree_data = load_tree_nodes(_STORE_DIR, "0RxMZBLeqRI")
+    node_id = "0RxMZBLeqRI_L1_000"  # 该视频真实存在的节点
+    ground_truth = _get_ground_truth_for_trace(tree_data, "view_node", {"node_id": node_id})
+    assert ground_truth and ground_truth != "{}"  # 拿到该节点 card 的 JSON，非空
+
+
+def test_core_diagnose_does_not_import_app():
+    """算法保真 + 依赖方向：core/evolution/diagnose.py 不 import app。"""
+    src = (Path(__file__).resolve().parents[2] / "core" / "evolution" / "diagnose.py").read_text(
+        encoding="utf-8"
+    )
+    assert "import app." not in src
+    assert "from app." not in src