Re: [PATCH 1/2] tests: use shell negation instead of test_must_fail for test_cmp

Jeff King [off-list ref] writes:

Hmph. "test_must_fail test_cmp" is a weird thing for somebody to write.
And your patch is obviously an improvement, but I have to wonder if some
of these make any sense.

If we're expecting some outcome, then it's reasonable to say:

  1. The output should look exactly like this. (test_cmp)

  2. The output should look something like this. (grep)

  3. The output should _not_ mention this (! grep)

But "the output should not look exactly like this" doesn't seem very
robust. It's likely to give a false success due to small changes (or
translations), or even bugs in the script.

Yeah, thanks for stepping back and looking at it from higher level.

$ git grep -e 'test_must_fail test_cmp' -e '! test_cmp' t/

gives 21 hits, in addition to the 5 Stefan identified, and it would
be a promising hunt to go through each one of them to see if they
make sense.