ExtUtils::MakeMaker::Coverage adds a Makefile target to determine
test coverage using Devel::Cover:

    # In Makefile.PL
    use ExtUtils::MakeMaker;
    use ExtUtils::MakeMaker::Coverage;
    ...
    # if you already have a MY::postamble...
    sub MY::postamble {
        testcover();
        ...
    }

WWW: https://metacpan.org/release/SMPETERS/ExtUtils-MakeMaker-Coverage-0.05