#!perl

use 5.012; # strict, //
use warnings;
use Test::More;

for (qw/
    test@gmail.com
    test.test@gmail.com
    test.test.test@gmail.com
    test.test.test.test@gmail.com
    test@subdomain.domain.com
    test.test@subdomain.domain.com
    test.test.test@subdomain.domain.com
    test@test@domain.example
    test,test@domain.example
    test@first.example,test@domain.example
/, "contains\nnewline\@fake.address")
{
    unlike $_, qr/\@.*\@|,|\..*\..*\.|\n/i, "test '$_'";
}
done_testing;
__END__
Possible attempt to separate words with commas at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 18.
ok 1 - test 'test@gmail.com'
ok 2 - test 'test.test@gmail.com'
not ok 3 - test 'test.test.test@gmail.com'
#   Failed test 'test 'test.test.test@gmail.com''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test.test.test@gmail.com'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 4 - test 'test.test.test.test@gmail.com'
#   Failed test 'test 'test.test.test.test@gmail.com''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test.test.test.test@gmail.com'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
ok 5 - test 'test@subdomain.domain.com'
not ok 6 - test 'test.test@subdomain.domain.com'
#   Failed test 'test 'test.test@subdomain.domain.com''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test.test@subdomain.domain.com'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 7 - test 'test.test.test@subdomain.domain.com'
#   Failed test 'test 'test.test.test@subdomain.domain.com''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test.test.test@subdomain.domain.com'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 8 - test 'test@test@domain.example'
#   Failed test 'test 'test@test@domain.example''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test@test@domain.example'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 9 - test 'test,test@domain.example'
#   Failed test 'test 'test,test@domain.example''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test,test@domain.example'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 10 - test 'test@first.example,test@domain.example'
#   Failed test 'test 'test@first.example,test@domain.example''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'test@first.example,test@domain.example'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
not ok 11 - test 'contains
# newline@fake.address'
#   Failed test 'test 'contains
# newline@fake.address''
#   at C:\Users\peter.jones\Downloads\TempData\perl\pm.pl line 20.
#                   'contains
# newline@fake.address'
#           matches '(?^ui:\@.*\@|,|\..*\..*\.|\n)'
1..11
# Looks like you failed 8 tests of 11.