Based on people who did take the interview and their threads the officer will effectively try to ascertain you can converse in either English or French so might start with small talk and ask you to talk a bit about your life here, your work etc and then ask you more specific questions based on your personal file, check passports and original copies of submitted documents.
You can read this thread :
http://www.canadavisa.com/canada-immigration-discussion-board/scarborough-office-timeline-after-test-t266529.45.html
Specifically the post by desigirltoronto84 which describes in detail the person's experience after the test in Scarborough office.