tests/test-xdg.t

bundlerepo: enforce the requirements declared by the underlying repository

Previously, `hg log -r 'bundle()' -R bundle.hg` was failing for me when run from
source, complaining about an unknown parent, when the system installed `hg`
didn't.  Some debugging showed the index was 0 length.  It turned out that I
didn't have the C extensions compiled, which a simple `hg log -r .` was able to
indicate.  The problem being that the RequirementError got handled by RepoError,
which uses an empty directory as a fallback to process the bundle.

#if no-windows no-osx

  $ mkdir -p xdgconf/hg
  $ echo '[ui]' > xdgconf/hg/hgrc
  $ echo 'username = foobar' >> xdgconf/hg/hgrc
  $ XDG_CONFIG_HOME="`pwd`/xdgconf" ; export XDG_CONFIG_HOME
  $ unset HGRCPATH
  $ hg config ui.username 2>/dev/null
  foobar

#endif