feat: add unit and integration tests for mDNS.

tests/discovery/mdns/test_mdns.py

@@ -0,0 +1,152 @@
+"""
+Integration test for mDNS discovery where one host finds another.
+"""
+import time
+import socket
+import pytest
+from zeroconf import Zeroconf
+
+from libp2p.discovery.mdns.broadcaster import PeerBroadcaster
+from libp2p.discovery.mdns.listener import PeerListener
+from libp2p.peer.id import ID
+from libp2p.peer.peerstore import PeerStore
+
+
+class TestMDNSDiscovery:
+    """Integration test for mDNS peer discovery."""
+
+    def test_one_host_finds_another(self):
+        """Test that one host can find another host using mDNS."""
+        # Create two separate Zeroconf instances to simulate different hosts
+        host1_zeroconf = Zeroconf()
+        host2_zeroconf = Zeroconf()
+        
+        try:
+            # Host 1: Set up as broadcaster (the host to be discovered)
+            host1_peer_id_obj = ID.from_base58("QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN")
+            host1_peer_id = str(host1_peer_id_obj)  # Convert to string
+            host1_broadcaster = PeerBroadcaster(
+                zeroconf=host1_zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="host1._p2p._udp.local.",
+                peer_id=host1_peer_id,
+                port=8000
+            )
+            
+            # Host 2: Set up as listener (the host that discovers others)
+            host2_peerstore = PeerStore()
+            host2_listener = PeerListener(
+                peerstore=host2_peerstore,
+                zeroconf=host2_zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="host2._p2p._udp.local.",
+            )
+            
+            # Host 1 registers its service for discovery
+            host1_broadcaster.register()
+            
+            
+            # Manually trigger discovery by calling add_service
+            # This simulates what happens when mDNS discovers a service
+            host2_listener.add_service(
+                host1_zeroconf,  # Use host1's zeroconf so it can find the service
+                "_p2p._udp.local.",
+                "host1._p2p._udp.local."
+            )
+            
+            # Verify that host2 discovered host1
+            assert len(host2_listener.discovered_services) > 0
+            assert "host1._p2p._udp.local." in host2_listener.discovered_services
+            
+            # Verify that host1's peer info was added to host2's peerstore
+            discovered_peer_id = host2_listener.discovered_services["host1._p2p._udp.local."]
+            assert str(discovered_peer_id) == host1_peer_id
+            
+            # Verify addresses were added to peerstore
+            try:
+                addrs = host2_peerstore.addrs(discovered_peer_id)
+                assert len(addrs) > 0
+                # Should be TCP since we always use TCP protocol
+                assert "/tcp/8000" in str(addrs[0])
+            except Exception:
+                # If no addresses found, the discovery didn't work properly
+                assert False, "Host1 addresses should be in Host2's peerstore"
+            
+            print(f"✅ Host2 successfully discovered Host1!")
+            print(f"   Discovered peer ID: {discovered_peer_id}")
+            print(f"   Discovered addresses: {[str(addr) for addr in addrs]}")
+            
+            # Clean up
+            host1_broadcaster.unregister()
+            host2_listener.stop()
+            
+        finally:
+            host1_zeroconf.close()
+            host2_zeroconf.close()
+
+    def test_peer_discovery_with_multiple_addresses(self):
+        """Test discovery works with peers having multiple IP addresses."""
+        host1_zeroconf = Zeroconf()
+        host2_zeroconf = Zeroconf()
+        
+        try:
+            # Create a peer with multiple addresses
+            host1_peer_id_obj = ID.from_base58("QmYyQSo1c1Ym7orWxLYvCrM2EmxFTANf8wXmmE7DWjhx5N")
+            host1_peer_id = str(host1_peer_id_obj)  # Convert to string
+            
+            # Manually create service info with multiple addresses
+            from zeroconf import ServiceInfo
+            hostname = socket.gethostname()
+            
+            service_info = ServiceInfo(
+                type_="_p2p._udp.local.",
+                name="multi-addr-host._p2p._udp.local.",
+                port=8001,
+                properties={b"id": host1_peer_id.encode()},
+                server=f"{hostname}.local.",
+                addresses=[
+                    socket.inet_aton("192.168.1.100"),
+                    socket.inet_aton("10.0.0.50"),
+                ],
+            )
+            
+            # Register the service
+            host1_zeroconf.register_service(service_info)
+            
+            # Set up listener
+            host2_peerstore = PeerStore()
+            host2_listener = PeerListener(
+                peerstore=host2_peerstore,
+                zeroconf=host2_zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="host2._p2p._udp.local.",
+            )
+            
+            # Trigger discovery
+            host2_listener.add_service(
+                host1_zeroconf,
+                "_p2p._udp.local.",
+                "multi-addr-host._p2p._udp.local."
+            )
+            
+            # Verify discovery
+            assert "multi-addr-host._p2p._udp.local." in host2_listener.discovered_services
+            discovered_peer_id = host2_listener.discovered_services["multi-addr-host._p2p._udp.local."]
+            
+            # Check multiple addresses were discovered
+            addrs = host2_peerstore.addrs(discovered_peer_id)
+            assert len(addrs) == 2
+            
+            addr_strings = [str(addr) for addr in addrs]
+            assert "/ip4/192.168.1.100/tcp/8001" in addr_strings
+            assert "/ip4/10.0.0.50/tcp/8001" in addr_strings
+            
+            print(f"✅ Successfully discovered peer with multiple addresses!")
+            print(f"   Addresses: {addr_strings}")
+            
+            # Clean up
+            host2_listener.stop()
+            
+        finally:
+            host1_zeroconf.close()
+            host2_zeroconf.close()