After passing the Canadian Citizenship Test the judge accepts that you met all the neccessaries to became the Canadian Citizen. And the Canadian Citizenship Judge invite you for citizenship ceremony. In the citizenship ceremony you will take the oath of citizenship and Canadian citizenship certificate.
If you failed in the Canadian Citizenship Written Test, you get the notice stating that please appear for an Oral interview (30 90 minutes) with a citizenship judge. In the Oral interview the Canadian Citizenship judge give you one more chance to demonstrate that you meet all the requirements of citizenship (including knowledge and language).