What everyone said already. Testing in Perl is really quite easy.

# some-test.t
use strict;
use Test::More;

ok(1, "1 is okay");
is("A", "A", "A is A");
cmp_ok("B", "gt", "A", "B is greater than puny A");
isnt("A", "B", "A didn't magically become B");
like("this", qr/that/, "This is like that");

done_testing(5);
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moo@cow[326]~>prove some-test.t -v
some-test.t ..
ok 1 - 1 is okay
ok 2 - A is A
ok 3 - B is greater than puny A
ok 4 - A didn't magically become B
not ok 5 - This is like that
1..5
#   Failed test 'This is like that'
#   at ab.t line 7.
#                   'this'
#     doesn't match '(?-xism:that)'
# Looks like you failed 1 test of 5.
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/5 subtests

Test Summary Report
-------------------
ab.t (Wstat: 256 Tests: 5 Failed: 1)
  Failed test:  5
  Non-zero exit status: 1
Files=1, Tests=5,  0 wallclock secs ( 0.02 usr  0.00 sys +  0.01 cusr 
+ 0.00 csys =  0.03 CPU)
Result: FAIL
[download]

More reading: prove (App::Prove), Test::Simple, Test::More, Test::Fatal, and many, many more for specific applications like Test::WWW::Selenium.