pylightning: Add a small test for async rpcmethods

Signed-off-by: Christian Decker <decker.christian@gmail.com>

tests/plugins/asynctest.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""This plugin is used to check that async method calls are working correctly.
+
+The plugin registers a method `callme` with an argument. All calls are
+stashed away, and are only resolved on the fifth invocation. All calls
+will then return the argument of the fifth call.
+
+"""
+from lightning import Plugin
+
+plugin = Plugin()
+
+
+@plugin.init()
+def init(configuration, options, plugin):
+    plugin.requests = []
+
+
+@plugin.method('asyncqueue', sync=False)
+def async_queue(request, plugin):
+    plugin.requests.append(request)
+
+
+@plugin.method('asyncflush')
+def async_flush(res, plugin):
+    for r in plugin.requests:
+        r.set_result(res)
+
+
+plugin.run()

tests/test_plugin.py

@@ -5,6 +5,7 @@ from utils import only_one
 
 import pytest
 import subprocess
+import time
 
 
 def test_option_passthrough(node_factory):
@@ -146,3 +147,27 @@ def test_plugin_connected_hook(node_factory):
 
     peer = l1.rpc.listpeers(l3.info['id'])['peers']
     assert(peer == [] or not peer[0]['connected'])
+
+
+def test_async_rpcmethod(node_factory, executor):
+    """This tests the async rpcmethods.
+
+    It works in conjunction with the `asynctest` plugin which stashes
+    requests and then resolves all of them on the fifth call.
+    """
+    l1 = node_factory.get_node(options={'plugin': 'tests/plugins/asynctest.py'})
+
+    results = []
+    for i in range(10):
+        results.append(executor.submit(l1.rpc.asyncqueue))
+
+    time.sleep(3)
+
+    # None of these should have returned yet
+    assert len([r for r in results if r.done()]) == 0
+
+    # This last one triggers the release and all results should be 42,
+    # since the last number is returned for all
+    l1.rpc.asyncflush(42)
+
+    assert [r.result() for r in results] == [42] * len(results)