diff --git a/tests/fpcmoc/custom.py b/tests/fpcmoc/custom.py
index c99dbd03..709ba93b 100755
--- a/tests/fpcmoc/custom.py
+++ b/tests/fpcmoc/custom.py
@@ -1,9 +1,15 @@
 #!/usr/bin/python3
 
+import traceback
+import sys
 import gi
+
 gi.require_version('FPrint', '2.0')
 from gi.repository import FPrint, GLib
 
+# Exit with error on any exception, included those happening in async callbacks
+sys.excepthook = lambda *args: (traceback.print_exception(*args), sys.exit(1))
+
 ctx = GLib.main_context_default()
 
 c = FPrint.Context()