In the case of non-invigilated tests, if u have say booked the slot for 4pm, then the test link will be available on ur SHP from 3:30pm to 4:30pm ie a half hour prior to and after the allotted time(4pm).
In the case of invigilated tests, the test link may be available the whole day, but u need an access code(provided at the test centre) to take the test.
aisa zaroori nahi hai bhai. the test link generally appears at 12 midnight on the day for which you have filled the slot for both invigilated and non invigilated.
In my experience, it stays till the end of the testing window (no matter how many days they might be)
However, the only exception is when you have filled first day, first slot in which case the link will appear only at the time of slot starting but will remain till the end of the window.
For eg, for 1315, i filled the 6am slot for today i.e. first day, first slot. however, the link appeared at 6am only. however, had i filled a slot for tomorrow, the link would have appeared at midnight today. both these links stay for the entire duration of the testing window.
This is what i have seen in my experience and this is the third time i am giving AIMCAT's.;);)
I'll make him an offer he can't refuse..... UDT'12 || Captain, BDT'12