import-checker: make stdlib path detection work in virtual environments
The previous logic tried to find the directory containing BaseHTTPServer, which
didn’t work as indended because it was only present on Python 2. Instead, the
argparse module is used now.
Test admin::verify
$ hg init admin-verify
$ cd admin-verify
Test normal output
$ hg admin::verify -c dirstate
running 1 checks
running working-copy.dirstate
checking dirstate
Quiet works
$ hg admin::verify -c dirstate --quiet
Test no check no options
$ hg admin::verify
abort: `checks` required
[255]
Test single check without options
$ hg admin::verify -c working-copy.dirstate
running 1 checks
running working-copy.dirstate
checking dirstate
Test single check (alias) without options
$ hg admin::verify -c dirstate
running 1 checks
running working-copy.dirstate
checking dirstate
Test wrong check name without options
$ hg admin::verify -c working-copy.dir
abort: unknown check working-copy.dir
(did you mean working-copy.dirstate?)
[10]
Test wrong alias without options
$ hg admin::verify -c dir
abort: unknown check dir
[10]