TAP, the Test Anything Protocol, is a simple text-based interface between testing modules in a test harness. TAP started life as part of the test harness for Perl but now has implementations in C/C++, Python, PHP, Perl and probably others by the time you read this. Here's what a TAP test transcript looks like (using the development version): TAP version 13 1..4 ok 1 - Input file opened not ok 2 -