add test script for manipulating datetime

test/run_time_machine.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import datetime
+import os
+import sys
+from zoneinfo import ZoneInfo
+
+import time_machine
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from ffplayout.output import desktop
+
+_tz = ZoneInfo("Europe/Berlin")
+source_time = [2021, 2, 8, 23, 59, 50]
+
+
+@time_machine.travel(datetime.datetime(*source_time, tzinfo=_tz))
+def run_in_time_machine():
+    try:
+        assert datetime.datetime.now() == datetime.datetime(*source_time)
+    except AssertionError:
+        print('Assertion not possible')
+        exit()
+
+    desktop.output()
+
+
+if __name__ == '__main__':
+    run_in_time_machine()