pytest: Test a plugin crash while handling a hook call

tests/plugins/hook-crash.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+
+from pyln.client import Plugin
+import sys
+
+
+plugin = Plugin()
+
+
+@plugin.hook('htlc_accepted')
+def on_htlc_accepted(plugin, htlc, onion, **kwargs):
+    """We die silently, i.e., without returning a response
+
+    `lightningd` should detect that and recover.
+    """
+    plugin.log("Plugin is about to crash...")
+    sys.exit(1)
+
+
+plugin.run()