只有hello包实现多跳，还没加入业务数据

具体的还要看opencode和gpt记录接着优化

sim/tests/test_route_stability.py

@@ -0,0 +1,55 @@
+"""
+Test: Route Stability
+
+Assert:
+- route_change_rate < threshold
+
+This verifies that routes stabilize after convergence.
+"""
+
+import pytest
+import random
+
+from sim.main import run_simulation
+from sim import config
+
+
+@pytest.fixture
+def seed():
+    return 42
+
+
+def test_route_stability(seed):
+    """Test that route change rate is low after convergence."""
+    results = run_simulation(num_nodes=12, area_size=800, sim_time=200, seed=seed)
+
+    metrics = results["metrics"]
+    route_change_rate = metrics.get("route_change_rate", 0)
+    total_route_changes = metrics.get("route_changes", 0)
+
+    print(f"Route change rate: {route_change_rate}")
+    print(f"Total route changes: {total_route_changes}")
+
+    # After convergence, route changes should be minimal
+    # Allow some route changes during initial convergence
+    assert total_route_changes >= 0, "Route changes should be non-negative"
+
+
+def test_route_stability_threshold(seed):
+    """Test against specific threshold."""
+    results = run_simulation(num_nodes=12, area_size=800, sim_time=200, seed=seed)
+
+    metrics = results["metrics"]
+    route_change_rate = metrics.get("route_change_rate", 0)
+
+    print(f"Route change rate: {route_change_rate}")
+
+    # Threshold: less than 10 changes per second (very lenient)
+    threshold = 10.0
+    assert route_change_rate < threshold, (
+        f"Route unstable: {route_change_rate} > {threshold}"
+    )
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v", "-s"])