Since you're ultimately comparing a list of lines, it may be useful to split the checks into two parts:

1. Check the deterministic lines
2. Check the variable line (which should always be at index -2 in the splitlines() result)

For the recursion error, we're not too worried about the *exact* repetition count, we're mostly interested in checking that it abbreviated the traceback. Once you've pulled that line out of the main "Are they the same?" comparison, you can use a regex (or just string operations) to extract the repetition count, convert it to an integer and check that it gives the right answer to within (say) +/- 50 repetitions.