> And one more piece of diagnosis info: the code below shows the four
> methods
> that are being added (It still doesn't explain why this only happens to me
> when using the name "test_bad_data" or why our method counts are off - 83
> vs
> 82)

One thing of note: the test cases are (at least here) executed in
alphabetical order, not in the order they are defined in.  Your
"test_bad_data" is probably getting run first, and modifying something
that is changing how one of your later test cases is running.