Instead, he's discovered a pile of bugs (just by his random "ooking" around in the tool--poking at buttons, ignoring intended user processes and knocking on things) and usability issues. This means that he has done a very good job, but it also means that we've had a bit of a tense weekend.
It looked mostly like this, with him coming into the room slowly, apologizing, and then telling me that something else in my implementation sucked.
The hardest part is, he's been right. :)
At our lab meeting on Monday, I gave my report and he said that he found a bunch of issues. Our advisor's next words were, "And you're still talking to each other?"