Perl: mocking -d -f and friends. How to put them into CORE::GLOBAL

Question

The CORE documentation has shown me how to merrily mock various built Perl functions. However, I\'m not really sure how to replace \'-d\' &c. with my methods. So this is

Answer 1

Thanks all for your answers.

What I wound up doing is, on a per module/test target basis, I factored out the code with the "-d" into it into it's own function. Like so...

# Because I cannot mock -d directly
sub dirExists {
    return -d shift;
}

Then I can replace this function in the test module with like

my $doesDirExist = 1;
*MyModule::dirExists   = \&main::mock_dirExists;

sub mock_dirExists {
    return $doesDirExist;
}

It's pretty ugly but i didn't want to get hung up on this too long and it works well enuf for my purposes