pytest: Test the new peer_connected hook with a reject plugin

This plugin just rejects `node_id`s it gets told about.

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

tests/plugins/reject.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+"""Simple plugin to test the connected_hook.
+
+It can mark some node_ids as rejects and it'll check for each
+connection if it should be disconnected immediately or if it can
+continue.
+
+"""
+
+from lightning import Plugin
+
+plugin = Plugin()
+
+
+@plugin.hook('peer_connected')
+def on_connected(peer, plugin):
+    if peer['id'] in plugin.reject_ids:
+        print("{} is in reject list, disconnecting".format(peer['id']))
+        return {'result': 'disconnect'}
+
+    print("{} is allowed".format(peer['id']))
+    return {'result': 'continue'}
+
+
+@plugin.init()
+def init(configuration, options, plugin):
+    plugin.reject_ids = []
+
+
+@plugin.method('reject')
+def reject(node_id, plugin):
+    """Mark a given node_id as reject for future connections.
+    """
+    print("Rejecting connections from {}".format(node_id))
+    plugin.reject_ids.append(node_id)
+
+
+plugin.run()

tests/test_plugin.py

@@ -126,3 +126,23 @@ def test_pay_plugin(node_factory):
     # Make sure usage messages are present.
     assert only_one(l1.rpc.help('pay')['help'])['command'] == 'pay bolt11 [msatoshi] [description] [riskfactor] [maxfeepercent] [retry_for] [maxdelay] [exemptfee]'
     assert only_one(l1.rpc.help('paystatus')['help'])['command'] == 'paystatus [bolt11]'
+
+
+def test_plugin_connected_hook(node_factory):
+    """ l1 uses the reject plugin to reject connections.
+
+    l1 is configured to accept connections from l2, but not from l3.
+    """
+    opts = [{'plugin': 'tests/plugins/reject.py'}, {}, {}]
+    l1, l2, l3 = node_factory.get_nodes(3, opts=opts)
+    l1.rpc.reject(l3.info['id'])
+
+    l2.connect(l1)
+    l1.daemon.wait_for_log(r"{} is allowed".format(l2.info['id']))
+    assert len(l1.rpc.listpeers(l2.info['id'])['peers']) == 1
+
+    l3.connect(l1)
+    l1.daemon.wait_for_log(r"{} is in reject list".format(l3.info['id']))
+
+    peer = l1.rpc.listpeers(l3.info['id'])['peers']
+    assert(peer == [] or not peer[0]['connected'])