I paired with my friend Vernon last week. He mentioned it in a blog post afterwards: Watching my colleagues Lisi and James work is like watching wizards cast spells. He's very kind, and I do like a pointy hat, but there was no sorcery involved, simply intentful exploratory testing. What do I mean by that? In this case, I mean that we started with a question and looked for ways that we could find information to help us to answer it. This particular question was very open because we didn't have a very specific oracle: can we find examples where the output of the system under test might be problematic? What did we do? CODS : Control, Observe, Decompose, Simplify. We could use the debugger to trace execution to a few pivotal functions and see what the application was doing (control, observe) but that was tiresome after a while. So we hacked the source code a little (conceptually simplify) so that variables were available to be d...