pytest: add notifications to tests.

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

tests/plugins/notify2.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+
+from pyln.client import Plugin
+
+plugin = Plugin()
+
+
+@plugin.method("call_make_notify")
+def call_make_notify(plugin, request, **kwargs):
+    plugin.notify_message(request, "Starting notification", level='debug')
+    plugin.notify_progress(request, 0, 2)
+    plugin.notify_progress(request, 1, 2)
+    return plugin.rpc.call('make_notify')
+
+
+plugin.run()