How would I benchmark the run-time of one of my object's paint events using QBENCHMARK?

From what I understood in the QTestLib documentation, to use QBENCHMARK you have to create a test that is executed using qExec. (Plus, the SEG fault because of uninitialized objects within the QBENCHMARK macro told me the same thing).

However, a test case seems to assume you have some function you can call explicitly, in order to test it. I cannot properly make a call to a paint event, or can I?

Is there a way around this?