tests/test-requires.t

convert/bzr: correctly handle divergent nested renames (issue3089)

With renames like:

  a   -> b
  a/c -> a/c

We were ignoring or duplicating the second one instead of leaving files
unchanged or moving them to their proper destination only.

To avoid this, we process the files in reverse lexicographic order, from most
to least specific change, and ignore files already processed.

v2:
- Add a test
- Change "reverse=1" into "reverse=True"

  $ hg init t
  $ cd t
  $ echo a > a
  $ hg add a
  $ hg commit -m test
  $ rm .hg/requires
  $ hg tip
  abort: index 00changelog.i unknown format 2!
  [255]
  $ echo indoor-pool > .hg/requires
  $ hg tip
  abort: unknown repository format: requires features 'indoor-pool' (upgrade Mercurial)!
  [255]
  $ echo outdoor-pool >> .hg/requires
  $ hg tip
  abort: unknown repository format: requires features 'indoor-pool', 'outdoor-pool' (upgrade Mercurial)!
  [255]