NOTE: The teacher and student on http://qa.moodle.net/ are using the 'Server's local time' which is UTC+8 . If you run this test on http://qa.moodle.net/ you might wish to change this to your own timezone to avoid time confusion issues.
1. As a teacher in a course, create a choice activity.
2. In the 'Availability' section, tick tick the 'Restrict answering to this time period' checkbox.
3. Set the 'Open' date to a time tomorrow and set the 'Until' date to a time the day after tomorrow.
4. Log in as a student and check that the activity is only available between the Open/Until dates. Outside these dates the message 'This activity is not available' should be displayed.