[PATCH] pathutil: add doctests for canonpath()

[Yuya Nishihara]

On Fri, 03 Nov 2017 23:26:40 -0400, Matt Harbison wrote:
> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1509762170 14400
> #      Fri Nov 03 22:22:50 2017 -0400
> # Node ID 7d9abeb82f021b4b96162a719f4a44a0175c0828
> # Parent  3649c3f2cd90c8aec395ca8af5adae33defff12c
> pathutil: add doctests for canonpath()
> 
> This is a followup to f445b10dc7fb.  Since there's no way to ensure that more
> drive letters than C: exist, this seems like the only way to test it.  This is
> enough to catch the f445b10dc7fb scenario, as well as CWD outside of the repo
> when the path isn't prefixed with path/to/repo.

Maybe we can add an hghave rule to check if d: drive exists, is different from
the TESTTMP, and can chdir into it?