This is Perl module Test::More::Unlike.
Test::More::Unlike installation is straightforward. If your CPAN shell is set up, you should just be able to do
% cpan Test::More::Unlike
Download it, unpack it, then build it as per the usual:
% perl Makefile.PL
% make && make test
Then install it:
% make install
Test::More::Unlike documentation is available as in POD. So you can do:
% perldoc Test::More::Unlike
Test::More::Unlike is hosted on github http://github.com/bayashi/Test-More-Unlike
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
Dai Okabayashi <bayashi@cpan.org>