(1) GAT - general aptitude test, you have to pass this test. Its not easy and not hard(memory, math with out using calculator). But, lots of people won't pass this test. ration of pass is 10:4. (2) If you pass GAT, then interview won't be so difficult. (3) Road test - make sure you practice on big van or truck, especially backing park. (4) health test - BP, heart rate, work focus.
Then there will be 3 weeks training where you have to sort 120 letters in 10 min. practice, practice, practice !!
After that they will assign a Depo where you have to give a route, you need to deliver all mail with in your time limit. This part would be hardest one even you got all training. If you make it, you will continue in Canada Post otherwise no!!