Test::More is a unit testing module for Perl. Created and maintained by Michael G Schwern with help from Barrie Slaymaker, Tony Bowden, chromatic, Fergal Daly and perl-qa. Introduced in 2001 to replace Test.pm, Test::More simplified and re-energized the culture of testing in Perl leading to an explosion of new testing modules and a strongly test driven community.
Test::More is the most popular Perl testing module, as of this writing about 80% of all CPAN distributions make use of it. Unlike other testing systems, Test::More is not a framework but can be used in concert with other testing libraries via a shared Test::Builder object. As a result, Test::More provides only the baseline testing functions leaving other libraries to implement more specific and sophisticated functionality. This removes what would otherwise be a development bottleneck and allows a rich eco-system of specialized niche testing functions.
Test::More is not a complete testing framework. Rather, test programs written with Test::More output their results as TAP which can then either be interpreted by a human, or more usually run through a TAP parser such as Test::Harness. It is this separation between test program and test result interpreter via a common protocol which allows Perl programmers to develop so many different testing modules and use them in combination. Additionally, the TAP output can be stored and reinterpreted later providing a historical record of test results.