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_channel_not_saturated.py

@@ -0,0 +1,59 @@
+"""
+Test: Channel Not Saturated
+
+Assert:
+- utilization < 0.7
+
+This verifies that the channel is not congested.
+"""
+
+import pytest
+import random
+
+from sim.main import run_simulation
+from sim import config
+
+
+@pytest.fixture
+def seed():
+    return 42
+
+
+def test_channel_not_saturated(seed):
+    """Test that channel utilization is below saturation threshold."""
+    results = run_simulation(num_nodes=12, area_size=800, sim_time=200, seed=seed)
+
+    metrics = results["metrics"]
+    utilization = metrics.get("channel_utilization", 0)
+
+    print(f"Channel utilization: {utilization}%")
+
+    # Channel should not be saturated (< 70%)
+    assert utilization < 70, f"Channel saturated: {utilization}%"
+
+
+def test_channel_utilization_healthy_range(seed):
+    """Test that channel utilization is in healthy range."""
+    results = run_simulation(num_nodes=12, area_size=800, sim_time=200, seed=seed)
+
+    metrics = results["metrics"]
+    utilization = metrics.get("channel_utilization", 0)
+
+    print(f"Channel utilization: {utilization}%")
+
+    # Get network state
+    if utilization < 30:
+        state = "HEALTHY"
+    elif utilization < 60:
+        state = "ACCEPTABLE"
+    else:
+        state = "CONGESTED"
+
+    print(f"Network state: {state}")
+
+    # Just verify we can calculate it
+    assert utilization >= 0
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v", "-s"])