test-lfs: add tests covering local exchanges
The root issue here is that requirements are not exchanged and preserved on
push/pull. This can be handled with a changegroup hook. Testing for remote
exchanges is much more extensive (it's possible for one process or the other to
not have the extension loaded at all), so it is added separately.
#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