pytest: test that we kick out pending transient connections too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

tests/test_connection.py

@@ -4617,3 +4617,35 @@ def test_connect_transient(node_factory):
     l1.rpc.connect(l4.info['id'], 'localhost', l4.port)
     assert l1.rpc.listpeers(l3.info['id'])['peers'] == []
     assert l1.daemon.is_in_log(fr"due to stress, randomly closing peer {l3.info['id']} \(score 0\)")
+
+
+def test_connect_transient_pending(node_factory, bitcoind, executor):
+    """Test that we kick out in-connection transient connections"""
+    l1, l2, l3, l4 = node_factory.get_nodes(4, opts=[{},
+                                                     {'dev-handshake-no-reply': None},
+                                                     {'dev-handshake-no-reply': None},
+                                                     {}])
+
+    # This will block...
+    fut1 = executor.submit(l1.rpc.connect, l2.info['id'], 'localhost', l2.port)
+    fut2 = executor.submit(l1.rpc.connect, l3.info['id'], 'localhost', l3.port)
+
+    assert not l1.daemon.is_in_log("due to stress, closing transient connect attempt")
+
+    # Wait until those connects in progress.
+    l2.daemon.wait_for_log("Connect IN")
+    l3.daemon.wait_for_log("Connect IN")
+
+    # Now force exhaustion.
+    l1.rpc.dev_connectd_exhaust_fds()
+
+    # This one will kick out one of the others.
+    l1.rpc.connect(l4.info['id'], 'localhost', l4.port)
+    line = l1.daemon.wait_for_log("due to stress, closing transient connect attempt")
+    peerid = re.search(r'due to stress, closing transient connect attempt to (.*)', line).groups()[0]
+
+    with pytest.raises(RpcError, match="Terminated due to too many connections"):
+        if peerid == l2.info['id']:
+            fut1.result(TIMEOUT)
+        else:
+            fut2.result(TIMEOUT)