Fix test_calc_countdown

tests/test_discord_reminder_bot.py

@@ -55,6 +55,8 @@ class TestClass:
     def test_calc_countdown(self):
         """Check if calc_countdown returns days, hours and minutes."""
         # FIXME: This will break when there is 0 seconds/hours/days left
-        pattern = re.compile(r"\d* days, \d* hours, \d* minutes")
+        pattern = re.compile(
+            r"\d* (day|days), \d* (hour|hours). \d* (minute|minutes)",
+        )
         countdown = calc_countdown(self.job)
         assert pattern.match(countdown)