In situations where you have deep trees of classes, there is a common situation in which you test a module 4 or 5 subclasses down, which should follow the correct behaviour of not just the subclass, but of all the parent classes.

This should be done to ensure that the implementation of a subclass has not somehow ``broken'' the object's behaviour in a more general sense.

Test::Object is a testing package designed to allow you to easily test what you believe is a valid object against the expected behaviour of all of the classes in its inheritance tree in one single call.

Test::Version checks to ensure that all modules have a version defined, and that the version is valid.

This module is primarily (but not exclusively) for use in test scripts: A block eval configurable and extensible but by default trapping STDOUT, STDERR, warnings, exceptions, would-be exit codes, and return values from boxed blocks of test code.

This module tests that commands given particular arguments result in particular outputs by way of the exit status word, standard output, and standard error.

This module can test routines that manipulate random numbers by providing a known output from rand. Given a list of seeds with srand, it will return each in turn. After seeded random numbers are exhausted, it will always return 0. Seed numbers must be of a form that meets the expected output from rand as called with no arguments: they must be between 0 (inclusive) and 1 (exclusive). In order to facilitate generating and testing a nearly-one number, this module exports the function oneish, which returns a number just fractionally less than one.

Test::Simple contains basic utilities for writing tests.

This module contains a collection of acceptance tests for implementations of Future::IO.

This module provides a collection of test utilities for directory attributes.

Simple test harness which allows tests to be run and results automatically aggregated and output to STDOUT.

Test::File::ShareDir is some low level plumbing to enable a distribution to perform tests while consuming its own share directories in a manner similar to how they will be once installed.

This Perl module is intended to easily test network connectivity to non-local Internet resources before functional tests begin. If the sockets cannot connect to the specified hosts and ports, the exception is caught and reported, and the tests skipped.

This module causes any warnings during testing to be captured and stored. It automatically adds an extra test that will run when your script ends to check that there were no warnings. If there were any warnings, the test will fail and output diagnostics of where, when and what the warning was, including a stack trace of what was going on when it occurred.

Test::MockModule lets you temporarily redefine subroutines in other packages for the purposes of unit testing. A Test::MockModule object is set up to mock subroutines for a given module. The mocked object remembers the original subroutine so it can be easily restored. This happens automatically when all MockModule objects for the given module go out of scope, or when you unmock() the subroutine.

This module allows you to deliberately hide modules from a program even though they are installed. This is mostly useful for testing modules that have a fallback when a certain dependency module is not installed.

This package provides a rich set of tools, plugins, bundles, etc built upon the Test2 testing library.

This module is a collection of tests useful for dealing with UTF-8 strings in Perl. This module has two types of tests: The validity tests check if a string is valid and not corrupt, whereas the characteristics tests will check that string has a given set of characteristics.

Testing code which forks is problematic because each test has a number associated with it. Coordinating the test number amongst the parent and child processes is complicated. Test::Fork provides a function to smooth over the complications.

Test::NoTabs lets you check the presence of tabs in your perl code.

This library provides functions to enable testing of files and directories. For instance, the file_ok helper can test whether the contents of a file is equal to a particular string.

This module provides routines for testing the exit status, standard output and standard error of external commands.

There are a number of different situations (like testing caching code) where you want to want to do a number of tests, and then verify that some underlying subroutine deep within the code was called a specific number of times.

Test::SubCalls module provides a number of functions for doing testing in this way in association with your normal Test::More (or similar) test scripts.

Test::EOL lets you check for the presence of trailing whitespace and/or windows line endings in your perl code.

Test::Tester allows testing of test modules based on Test::Builder with a minimum of effort.

Test::Memory::Cycle is built on top of Devel::Cycle to give you an easy way to check for these circular references.

use Test::Memory::Cycle;

my $object = new MyObject;
# Do stuff with the object.
memory_cycle_ok( $object );