1use Test::Base tests => 2; 2 3filters { 4 perl => ['eval', 'bang'], 5 value => 'chomp', 6 perl2 => 'eval', 7 dummy => 'uuu', 8}; 9 10run_is perl => 'value'; 11run_is dummy => 'perl2'; 12 13sub bang { 14 return defined($_) ? ':-(' : '!!!'; 15} 16 17sub uuu { 18 undef($_); 19 return undef; 20} 21 22__DATA__ 23 24 25=== No warnings for sending undef to filter 26--- perl 27undef 28--- value 29!!! 30 31=== No warnings returning undef from filter 32--- dummy 33--- perl2 34undef 35