I obtained my Canadian Basic with Honours certificate in the late 90's and haven't done much with it since. Was looking to get back into the hobby.
Has my certificate expired? Do I need to take the test again?
As a friend has just gone through exactly this, I can confirm that yes, your certificate and callsign are still valid. As wkm noted above, the RAC states that “The Amateur Radio Certificates are valid for your lifetime”.
Wile this is great for returning operators, it does mean that the Canadian Amateur Radio Operator Certificates database contains many SKs and inactive hams.
According to RAC:
The Amateur Radio Certificates are valid for your lifetime.