The test suite framework of choice is Test::Harness, which takes care of controlling a test run, collecting the results, etc.
Various modules exist to provide certain kinds of tests, the most common of which can be found in Test::Simple and Test::More (both are included in the Test-Simple distribution). The entire Test namespace on the CPAN is dedicated to specialized unit-testing modules, the majority of which are designed to be run under Test::Harness.
By convention, tests are stored in the t/ directory of a project, and each test file uses the file extension .t ; tests are commonly run via
prove t/*.t
Module distributions typically include a make target named 'test' that runs the test suite before installation. By default, the CPAN installation process requires that tests pass after the build before a module will be installed.
