The goal of this test is to automate MDLQA-23, apparently there are no coverage for availability dates and specially the "read only" from/to settings.

Testing instructions

1. Log in as a teacher and set available from and to dates for a database activity.
2. Log in as a student and check that the activity is only available between the available from and to dates. Outside these dates a message explaining when the activity will be available or when it ceased to be available should be displayed.
3. Log in as a teacher again, remove the available from and to dates and set read only from and to dates.
4. Log in as a student and check that between the read only from and to dates the 'Add entry' tab is not displayed.