libp2p end to end test

tests/libp2p/test_libp2p.py

@@ -0,0 +1,30 @@
+from libp2p.libp2p import Libp2p
+
+
+# TODO: are these connections async? how do we wait on responses?
+def test_simple_messages():
+    lib = Libp2p()
+
+    hostA = lib.new_node()
+    hostB = lib.new_node()
+
+    def stream_handler(stream):
+        print("stream received in host B")
+
+        read_string = stream.read().decode()
+        print("host B received: " + read_string)
+
+        response = "ack: " + read_string
+        stream.write(response.encode())
+
+    hostB.set_stream_handler("/echo/1.0.0", stream_handler)
+
+    # associate the peer with local ip address (see default parameters of Libp2p())
+    hostA.get_peerstore().add_addr("hostB", "/ip4/127.0.0.1/tcp/10000")
+
+    stream = hostA.new_stream("hostB", "/echo/1.0.0")
+    message = "hello"
+    stream.write(message.encode())
+
+    response = stream.read().decode()
+    assert response == ("ack: " + message)