tests/test-revlog-v2.t

perf: use the `perf--` prefix for perf command

This is the one command namespace where they should not be any ambiguity about
command that should be in it. The perf extensions is only adding performance
related command.

so this is a good ground to start putting dash folding to the tests.

Differential Revision: https://phab.mercurial-scm.org/D9516

#require reporevlogstore

A repo with unknown revlogv2 requirement string cannot be opened

  $ hg init invalidreq
  $ cd invalidreq
  $ echo exp-revlogv2.unknown >> .hg/requires
  $ hg log
  abort: repository requires features unknown to this Mercurial: exp-revlogv2.unknown
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ cd ..

Can create and open repo with revlog v2 requirement

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > revlogv2 = enable-unstable-format-and-corrupt-my-data
  > EOF

  $ hg init empty-repo
  $ cd empty-repo
  $ cat .hg/requires
  dotencode
  exp-revlogv2.1
  fncache
  sparserevlog
  store

  $ hg log

Unknown flags to revlog are rejected

  >>> with open('.hg/store/00changelog.i', 'wb') as fh:
  ...     fh.write(b'\xff\x00\xde\xad') and None

  $ hg log
  abort: unknown flags (0xff00) in version 57005 revlog 00changelog.i
  [50]

  $ cd ..

Writing a simple revlog v2 works

  $ hg init simple
  $ cd simple
  $ touch foo
  $ hg -q commit -A -m initial

  $ hg log
  changeset:   0:96ee1d7354c4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial
  
Header written as expected

  $ f --hexdump --bytes 4 .hg/store/00changelog.i
  .hg/store/00changelog.i:
  0000: 00 01 de ad                                     |....|

  $ f --hexdump --bytes 4 .hg/store/data/foo.i
  .hg/store/data/foo.i:
  0000: 00 01 de ad                                     |....|