Now when I entered all my details (application# & UCI) in the above link which you have sent, its saying that as if I was not invited for the test. But in the online status tracker its showing that I need to appear for the test in a 20 days time period in September. Called helpdesk but no one is picking the phone. Its really strange & surprise to me.Email will come as close as 2 days before the start date. Dont wait for the email.
Start preparing. Give the test within that 3 weeks(even if you dont get email https://www.canada.ca/en/immigration-refugees-citizenship/services/canadian-citizenship/become-canadian-citizen/citizenship-test/access.html).