my %tests = ( case1 => { input => …, output => … },
	          case2 => { … } );

subtest "Something" => sub {
    plan skip_all => "Moon is not full" unless …;
    ok 1;
    ok 2;
    done_testing(2);
};

for my $test ( values %tests )
{
    ok $test->{input}, "Have input…";
    is process($test->{input}), $test->{output}, "Process works";
}

done_testing( 1 + 2 * keys %tests );