Test Anything Protocol

The Test Anything Protocol (TAP) is a protocol to allow communication betwen unit tests and a test harness. It allows individual tests (TAP producers) to communicate test results to the testing harness in a language-agnostic way. Originally developed for unit testing of the Perl interpreter in 1987, producers and parsers are now available for many development platforms.

History

TAP was created for the first version of Perl (released in 1987), as part of the Perl's core test harness (t/TEST). The module was written by Tim Bunce and Andreas König to allow Perl module authors to take advantage of TAP.

Development of TAP, including standardization of the protocol, writing of test producers and consumers, and evangelizing the language is coordinated at the TestAnything website.

Specification

Despite being almost 20 years old and widely used, no formal specification exists for this protocol. The behavior of the Test::Harness module is the de-facto TAP standard, along with a writeup of the specification on CPAN.

A project to produce an IETF standard for TAP was initiated in August 2008, at YAPC::Europe 2008.

Usage examples

TAP's general format is:

   1..N

   ok 1 Description # Directive

   # Diagnostic

   ....

   ok 47 Description

   ok 48 Description

   more tests....

For example, a test file's output might look like:

   1..4

   ok 1 - Input file opened

   not ok 2 - First line of the input valid

   ok 3 - Read the rest of the file

   not ok 4 - Summarized correctly # TODO Not written yet

External Links

• http://testanything.org/ is a site dedicated to the discussion, development and promotion of TAP.

List of TAP Parsers

These are libraries which parse TAP and display the results.

• Test::Harness is the oldest and most complete TAP parser. It is limited in how it displays TAP. Though it most often runs tests written in Perl, it can launch any process which generates TAP. Most of the TAP spec is taken from the behavior of Test::Harness.
• The original Test::Harness has now been deprecated, the new Test::Harness provides a minimal compatibility layer with previous behavior, but any new development shouldn't use this module, rather the TAP::Harness module.
• The t/TEST parser contained in the Perl source code.
• TAP::Parser is a new and more flexible parser being written by Curtis "Ovid" Poe, Andy Armstrong and other people. It was formerly called TAPx::Parser. It will shortly become Test::Harness 3.
• Test::Run is a fork of Test::Harness being written by Shlomi Fish.
• test-harness.php A TAP parser for PHP.

List of TAP Producers

These are libraries for writing tests which output TAP.

• Test::More is the most popular testing module for Perl.
• PHPUnit is the xUnit implementation for PHP.
• test-more.php is a testing module for PHP based on Test::More.
• libtap is a TAP producer written in C.
• Test.Simple is a port of the Perl Test::Simple and Test::More modules to JavaScript by David Wheeler.
• PyTAP A beginning TAP implementation for Python.
• MyTAP MySQL unit test library used for writing TAP producers in C or C++
• Bacon A Ruby library that supports a spec-based syntax and that can produce TAP output
• PLUTO PL/SQL Unit Testing for Oracle
• pgTAP PostgreSQL stored procedures that emit TAP
• SnapTest a PHP unit testing framework with TAP v13 compliant output.

References