Test (Perl in a Nutshell, 2nd Edition)

8.199. Test

Provides a framework for writing test scripts so you don't need to know the particular output that Test::Harness expects to see. Useful if you are writing modules and writing tests for those modules. Provides the following test types:

Normal: Tests that are expected to succeed.
Skip: Tests that need a platform-specific feature. They work like normal tests except that the first argument should evaluate to true if the required feature is not present.
Todo: Tests designed for maintaining an executable todo list; the tests aren't expected to succeed.

Test also provides an onfail hook that can trigger additional diagnostics for failures at the end of the test run. To use onfail, pass it an array reference of hash references in which each hash contains at least the package, repetition, and result fields, as well as any expected value or diagnostic string.

See the Test manpage for details and examples.