make the chat example a runnable test

fixes #71

examples/chat/chat.py

@@ -1,18 +1,18 @@
 #!/usr/bin/env python3
-import sys
-from os.path import dirname, abspath
-sys.path.append(dirname(dirname(dirname(abspath(__file__)))))
-
 import asyncio
+import sys
+from os.path import abspath, dirname
 
 import click
+
 from libp2p.libp2p import *
 from network.multiaddr import MultiAddr
 from peer.peerinfo import info_from_p2p_addr
 
+sys.path.append(dirname(dirname(dirname(abspath(__file__)))))
 
-# TODO: change once muxed_connection supports extracting protocol id from messages
-PROTOCOL_ID = '/echo/1.0.0'
+
+PROTOCOL_ID = '/chat/1.0.0'
 
 
 async def read_data(stream):

tests/examples/test_chat.py

@@ -0,0 +1,110 @@
+#!/bin/env python3
+import asyncio
+import sys
+
+import click
+import multiaddr
+import pytest
+
+from libp2p.libp2p import *
+from peer.peerinfo import info_from_p2p_addr
+from protocol_muxer.multiselect_client import MultiselectClientError
+
+PROTOCOL_ID = '/chat/1.0.0'
+
+
+async def hello_world(host_a, host_b):
+    async def stream_handler(stream):
+        read = await stream.read()
+        assert read == b'hello world from host b'
+        await stream.write(b'hello world from host a')
+        await stream.close()
+
+    host_a.set_stream_handler(PROTOCOL_ID, stream_handler)
+
+    # Start a stream with the destination.
+    # Multiaddress of the destination peer is fetched from the peerstore using 'peerId'.
+    stream = await host_b.new_stream(host_a.get_id(), [PROTOCOL_ID])
+    await stream.write(b'hello world from host b')
+    read = await stream.read()
+    assert read == b'hello world from host a'
+    await stream.close()
+
+
+async def connect_write(host_a, host_b):
+    messages = [b'data %d' % i for i in range(5)]
+
+    async def stream_handler(stream):
+        received = []
+        while True:
+            try:
+                received.append((await stream.read()).decode())
+            except Exception:  # exception is raised when other side close the stream ?
+                break
+        await stream.close()
+        assert received == messages
+    host_a.set_stream_handler(PROTOCOL_ID, stream_handler)
+
+    # Start a stream with the destination.
+    # Multiaddress of the destination peer is fetched from the peerstore using 'peerId'.
+    stream = await host_b.new_stream(host_a.get_id(), [PROTOCOL_ID])
+    for message in messages:
+        await stream.write(message)
+    await stream.close()
+
+
+async def connect_read(host_a, host_b):
+    messages = [b'data %d' % i for i in range(5)]
+
+    async def stream_handler(stream):
+        for message in messages:
+            await stream.write(message)
+        await stream.close()
+
+    host_a.set_stream_handler(PROTOCOL_ID, stream_handler)
+
+    # Start a stream with the destination.
+    # Multiaddress of the destination peer is fetched from the peerstore using 'peerId'.
+    stream = await host_b.new_stream(host_a.get_id(), [PROTOCOL_ID])
+    received = []
+    # while True: Seems the close stream event from the other host is not received
+    for _ in range(5):
+        try:
+            received.append(await stream.read())
+        except Exception:  # exception is raised when other side close the stream ?
+            break
+    await stream.close()
+    assert received == messages
+
+
+async def no_common_protocol(host_a, host_b):
+    messages = [b'data %d' % i for i in range(5)]
+
+    async def stream_handler(stream):
+        for message in messages:
+            await stream.write(message)
+        await stream.close()
+
+    host_a.set_stream_handler(PROTOCOL_ID, stream_handler)
+
+    # try to creates a new new with a procotol not known by the other host
+    with pytest.raises(MultiselectClientError):
+        _ = await host_b.new_stream(host_a.get_id(), ['/fakeproto/0.0.1'])
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("test", [
+    (hello_world),
+    (connect_write),
+    (connect_read),
+    (no_common_protocol),
+])
+async def test_chat(test):
+    host_a = await new_node(transport_opt=["/ip4/127.0.0.1/tcp/0"])
+    host_b = await new_node(transport_opt=["/ip4/127.0.0.1/tcp/0"])
+
+    addr = host_a.get_addrs()[0]
+    info = info_from_p2p_addr(addr)
+    await host_b.connect(info)
+
+    await test(host_a, host_b)