Sorry for answering late; if you're still having issues with the kata, false positives and false negatives are numbers that are not multiple of 3 but reported as such (false positives), or, numbers that are indeed multiples of 3 but not reported as such (false negatives).

Either way, if you're having issues with those, consider making a loop within a range i.e. 1 to 1000, and for each one of them (let's call them i), convert it to binary, and make sure that is recognized by the regex only if it's multiple of 3 (i % 3 == 0), nothing more, nothing less.
You might discover that maybe some numbers are falsely reported, or are missed when they should have been reported - a.k.a false positives and false negatives.

Hi,
I think that I solved the kata, but the last test always fails and I'm not quite sure why.
Neither the test name "testFalsePositivesAndNegatives" nor the error message "Failed asserting that true is false." makes sense to me.
Could someone tell me what does the last test check?