Steps and entrypoint to yield control from Kapow! handlers

spec/test/features/steps/testinghandler.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+import signal
+import sys
+import os
+
+
+if __name__ == '__main__':
+    test_runner_fifo = sys.argv[1]
+    with open(test_runner_fifo, 'w') as other_side:
+        other_side.write(f"{os.getpid()};{os.environ['KAPOW_HANDLER_ID']}\n")
+
+    signal.pause()