tests/test-dirstate-backup.t

revlog: add some direct testing of the slicing logic

This test check slicing backed by an actual revlog. It will test the C version
of slicing (if the test are run with the C extensions).

Set up

  $ hg init repo
  $ cd repo

Try to import an empty patch

  $ hg import --no-commit - <<EOF
  > EOF
  applying patch from stdin
  abort: stdin: no diffs found
  [255]

No dirstate backups are left behind

  $ ls .hg/dirstate* | sort
  .hg/dirstate