I'm NOT in urgent processing. The app was delivered on Jan 6, 2020, and AOR on March 11, 2020. I have received the test invite today.
Probably unrelated but I've filed my taxes 2 days ago and I've submitted an ATIP request yesterday.
Otherwise, not much more to add than that. They've given me from March 1st to March 21st to finish the test. Time to cram.

Study up guys it's coming. I'll keep on my timeline updated in the google sheet.
Edit: Reading through the letter again, it seems that the email was sent from the IRCC's Vancouver office (or something), so YMMV and you may be fast or slow depending on where your test center should have been (this is just a guess).