Here is my timeline:
We received your application for Canadian citizenship (grant of citizenship) on December 15, 2011.
We sent you a letter acknowledging receipt of your application(s), and a study book called Discover Canada on December 15, 2011. Please consider delays in mail delivery before contacting us.
We started processing your application on October 4, 2012.
We sent you a notice on March 25, 2013 to appear and write the citizenship test on April 25, 2013 at 8:30 AM. The notice you will receive by mail will be your official confirmation of your appointment. If you have not received this notice prior to the date of your scheduled appointment, please contact us.
Received notice to appear for Oath today, 9th May
Letter dated 7th May
Oath on 27th May 2013