tests: add a substitution for ENOENT/ERROR_FILE_NOT_FOUND messages Automatic replacement seems better than trying to figure out a check-code rule. I didn't bother looking to see why the error message and file name is reversed in the annotate and histedit tests, based on Windows or not. I originally had this as a list of tuples, conditional on the platform. But there are a couple of 'No such file or directory' messages emitted by Mercurial itself, so unconditional is required for stability. There are also several variants of what I assume is 'connection refused' and 'unknown host' in test-clone.t and test-clonebundles.t for Docker, FreeBSD jails, etc. Yes, these are handled by (re) tags, but maybe it would be better to capture those strings in order to avoid whack-a-mole in future tests. All of this points to using a dictionary containing one or more strings-to-be-replaced values.

  $ hg init

  $ $PYTHON -c 'open("a", "wb").write(b"confuse str.splitlines\nembedded\rnewline\n")'
  $ hg ci -Ama -d '1 0'
  adding a

  $ echo clean diff >> a
  $ hg ci -mb -d '2 0'

  $ hg diff -r0 -r1
  diff -r 107ba6f817b5 -r 310ce7989cdc a
  --- a/a	Thu Jan 01 00:00:01 1970 +0000
  +++ b/a	Thu Jan 01 00:00:02 1970 +0000
  @@ -1,2 +1,3 @@
   confuse str.splitlines
   embedded\r (no-eol) (esc)
  newline
  +clean diff