improve WebRTC NAT reliability diagnostics

test.js

@@ -91,3 +91,13 @@ test('TURN credentials generation with TURN_SECRET', () => {
     delete process.env.TURN_SECRET;
   }
 });
+
+test('ICE transport policy is passed through to browser configuration', () => {
+  const { iceConfig } = require('./server');
+  process.env.ICE_TRANSPORT_POLICY = 'relay';
+  try {
+    assert.strictEqual(iceConfig().iceTransportPolicy, 'relay');
+  } finally {
+    delete process.env.ICE_TRANSPORT_POLICY;
+  }
+});