Check for root under Cygwin

vsespb has asked for the wisdom of the Perl Monks concerning the following question:

I have unit tests, which check that my code properly handle "permission denied" errors and other IO errors.
My application works only under POSIX systems (i.e. not Win32), and I am thinking now about porting it to CygWin.
Tests look like this (simplified version):

use strict;
use warnings;
use Test::More tests => 2;

my $file = 'somefile.tmp';
unlink $file;
open my $f, '>', $file; close $f;
chmod 0000, $file;

SKIP: {
 skip "cannot run under root", 2 unless $<;
 ok ! eval { somefunc($file); 1; };
 ok $@ =~ /cannot open file/;
}

unlink $file;
[download]

and somefunc() looks like this:

sub somefunc { open my $f, "<", shift or die 'cannot open file' };
[download]

(that is a simplified version too - just for proof of concept)
In the test you can see

skip "cannot run under root", 2 unless $<;
[download]

That's because otherwise test will fail under root.
That check, however, is not working under Cygwin as expected.
And I am wondering how that code could be fixed under cygwin?
(note that I am aware of several file-system emulator modules, but I decided to stick with real filesystem, for now)

Comment on Check for root under Cygwin Select or Download Code

Replies are listed 'Best First'.
Re: Check for root under Cygwin by syphilis (Archbishop) on Sep 02, 2013 at 11:59 UTC
That check, however, is not working under Cygwin as expected Root does not exist on Cygwin - so, something like: `skip "cannot run under root", 2 if(!$< \|\| $^O =~ /cygwin/i);` [download] Cheers, Rob	[reply] [d/l]
Re^2: Check for root under Cygwin by vsespb (Chaplain) on Sep 02, 2013 at 12:04 UTC
Yes, skipping those tests would work for sure. But is there an option to run tests, when possible? (i.e. determine if current cygwin user acts like root under *nix)	[reply]
Re^3: Check for root under Cygwin by syphilis (Archbishop) on Sep 02, 2013 at 12:29 UTC
But is there an option to run tests, when possible? You mean that the tests should be run when running as administrator ? Perhaps Win32::IsAdminUser() is useful for determining that. See the Win32 module's documentation. Consider posting to the Cygwin mailing list (if you fail to receive a satisfactory answer here). Cheers, Rob	[reply]
Re^4: Check for root under Cygwin by vsespb (Chaplain) on Sep 02, 2013 at 13:17 UTC
Re^4: Check for root under Cygwin by vsespb (Chaplain) on Sep 02, 2013 at 12:45 UTC
Re: Check for root under Cygwin by Laurent_R (Canon) on Sep 02, 2013 at 11:36 UTC
What is the value of $< when you are logged on Cygwin?	[reply]
Re^2: Check for root under Cygwin by vsespb (Chaplain) on Sep 02, 2013 at 11:53 UTC
When I run cygwin session normal way, $< is 1001 and I am getting permission denied errors. If I start this session with "run as administrator", there are no more "permission denied" errors, but $< is same (1001)	[reply]