Sudhanshu,
You’re correct about test availability dates and the time limit.
Before the student starts the test, they see a message like this:
This assessment is due Sunday, 2020-Jan-26 12:00 PM.
Once you click “Begin Assessment,” you will have 10 minutes or until Sunday, 2020-Jan-26 12:00 PM whichever is shorter to complete this assessment. It will be submitted at that time, regardless of whether you have answered all the questions.
You can submit this assessment 1 time(s).
Then, once they start, they see a timer at the top of the page, as documented here.
-Rob
