Test::Harness::TAP(3) Perl Programmers Reference Guide Test::Harness::TAP(3)NAMETest::Harness::TAP - Documentation for the TAP format
SYNOPSIS
TAP, the Test Anything Protocol, is Perl's simple text-based interface
between testing modules such as Test::More and the test harness
Test::Harness.
TODO
Exit code of the process.
THE TAP FORMAT
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
HARNESS BEHAVIOR
In this document, the "harness" is any program analyzing TAP output.
Typically this will be Perl's prove program, or the underlying
"Test::Harness::runtests" subroutine.
A harness must only read TAP output from standard output and not from
standard error. Lines written to standard output matching "/^(not
)?ok\b/" must be interpreted as test lines. All other lines must not
be considered test output.
TESTS LINES AND THE PLAN
The plan
The plan tells how many tests will be run, or how many tests have run.
It's a check that the test file hasn't stopped prematurely. It must
appear once, whether at the beginning or end of the output.
The plan is usually the first line of TAP output and it specifies how
many test points are to follow. For example,
1..10
means you plan on running 10 tests. This is a safeguard in case your
test file dies silently in the middle of its run. The plan is optional
but if there is a plan before the test points it must be the first non-
diagnostic line output by the test file.
In certain instances a test file may not know how many test points it
will ultimately be running. In this case the plan can be the last non-
diagnostic line in the output.
The plan cannot appear in the middle of the output, nor can it appear
more than once.
The test line
The core of TAP is the test line. A test file prints one test line
test point executed. There must be at least one test line in TAP out‐
put. Each test line comprises the following elements:
* "ok" or "not ok"
This tells whether the test point passed or failed. It must be at
the beginning of the line. "/^not ok/" indicates a failed test
point. "/^ok/" is a successful test point. This is the only manda‐
tory part of the line.
Note that unlike the Directives below, "ok" and "not ok" are
case-sensitive.
* Test number
TAP expects the "ok" or "not ok" to be followed by a test point
number. If there is no number the harness must maintain its own
counter until the script supplies test numbers again. So the fol‐
lowing test output
1..6
not ok
ok
not ok
ok
ok
has five tests. The sixth is missing. Test::Harness will generate
FAILED tests 1, 3, 6
Failed 3/6 tests, 50.00% okay
* Description
Any text after the test number but before a "#" is the description
of the test point.
ok 42 this is the description of the test
Descriptions should not begin with a digit so that they are not
confused with the test point number.
The harness may do whatever it wants with the description.
* Directive
The test point may include a directive, following a hash on the
test line. There are currently two directives allowed: "TODO" and
"SKIP". These are discussed below.
To summarize:
* ok/not ok (required)
* Test number (recommended)
* Description (recommended)
* Directive (only when necessary)
DIRECTIVES
Directives are special notes that follow a "#" on the test line. Only
two are currently defined: "TODO" and "SKIP". Note that these two key‐
words are not case-sensitive.
TODO tests
If the directive starts with "# TODO", the test is counted as a todo
test, and the text after "TODO" is the explanation.
not ok 13 # TODO bend space and time
Note that if the TODO has an explanation it must be separated from
"TODO" by a space.
These tests represent a feature to be implemented or a bug to be fixed
and act as something of an executable "things to do" list. They are
not expected to succeed. Should a todo test point begin succeeding,
the harness should report it as a bonus. This indicates that whatever
you were supposed to do has been done and you should promote this to a
normal test point.
Skipping tests
If the directive starts with "# SKIP", the test is counted as having
been skipped. If the whole test file succeeds, the count of skipped
tests is included in the generated output. The harness should report
the text after " # SKIP\S*\s+" as a reason for skipping.
ok 23 # skip Insufficient flogiston pressure.
Similarly, one can include an explanation in a plan line, emitted if
the test file is skipped completely:
1..0 # Skipped: WWW::Mechanize not installed
OTHER LINES
Bail out!
As an emergency measure a test script can decide that further tests are
useless (e.g. missing dependencies) and testing should stop immedi‐
ately. In that case the test script prints the magic words
Bail out!
to standard output. Any message after these words must be displayed by
the interpreter as the reason why testing must be stopped, as in
Bail out! MySQL is not running.
Diagnostics
Additional information may be put into the testing output on separate
lines. Diagnostic lines should begin with a "#", which the harness
must ignore, at least as far as analyzing the test results. The har‐
ness is free, however, to display the diagnostics. Typically diagnos‐
tics are used to provide information about the environment in which
test file is running, or to delineate a group of tests.
...
ok 18 - Closed database connection
# End of database section.
# This starts the network part of the test.
# Daemon started on port 2112
ok 19 - Opened socket
...
ok 47 - Closed socket
# End of network tests
Anything else
Any output line that is not a plan, a test line or a diagnostic is
incorrect. How a harness handles the incorrect line is undefined.
Test::Harness silently ignores incorrect lines, but will become more
stringent in the future.
EXAMPLES
All names, places, and events depicted in any example are wholly ficti‐
tious and bear no resemblance to, connection with, or relation to any
real entity. Any such similarity is purely coincidental, unintentional,
and unintended.
Common with explanation
The following TAP listing declares that six tests follow as well as
provides handy feedback as to what the test is about to do. All six
tests pass.
1..6
#
# Create a new Board and Tile, then place
# the Tile onto the board.
#
ok 1 - The object isa Board
ok 2 - Board size is zero
ok 3 - The object isa Tile
ok 4 - Get possible places to put the Tile
ok 5 - Placing the tile produces no error
ok 6 - Board size is 1
Unknown amount and failures
This hypothetical test program ensures that a handful of servers are
online and network-accessible. Because it retrieves the hypothetical
servers from a database, it doesn't know exactly how many servers it
will need to ping. Thus, the test count is declared at the bottom after
all the test points have run. Also, two of the tests fail.
ok 1 - retrieving servers from the database
# need to ping 6 servers
ok 2 - pinged diamond
ok 3 - pinged ruby
not ok 4 - pinged saphire
ok 5 - pinged onyx
not ok 6 - pinged quartz
ok 7 - pinged gold
1..7
Giving up
This listing reports that a pile of tests are going to be run. However,
the first test fails, reportedly because a connection to the database
could not be established. The program decided that continuing was
pointless and exited.
1..573
not ok 1 - database handle
Bail out! Couldn't connect to database.
Skipping a few
The following listing plans on running 5 tests. However, our program
decided to not run tests 2 thru 5 at all. To properly report this, the
tests are marked as being skipped.
1..5
ok 1 - approved operating system
# $^0 is solaris
ok 2 - # SKIP no /sys directory
ok 3 - # SKIP no /sys directory
ok 4 - # SKIP no /sys directory
ok 5 - # SKIP no /sys directory
Skipping everything
This listing shows that the entire listing is a skip. No tests were
run.
1..0 # skip because English-to-French translator isn't installed
Got spare tuits?
The following example reports that four tests are run and the last two
tests failed. However, because the failing tests are marked as things
to do later, they are considered successes. Thus, a harness should
report this entire listing as a success.
1..4
ok 1 - Creating test program
ok 2 - Test program runs, no error
not ok 3 - infinite loop # TODO halting problem unsolved
not ok 4 - infinite loop 2 # TODO halting problem unsolved
Creative liberties
This listing shows an alternate output where the test numbers aren't
provided. The test also reports the state of a ficticious board game in
diagnostic form. Finally, the test count is reported at the end.
ok - created Board
ok
ok
ok
ok
ok
ok
ok
# +------+------+------+------+
# ⎪ ⎪16G ⎪ ⎪05C ⎪
# ⎪ ⎪G N C ⎪ ⎪C C G ⎪
# ⎪ ⎪ G ⎪ ⎪ C +⎪
# +------+------+------+------+
# ⎪10C ⎪01G ⎪ ⎪03C ⎪
# ⎪R N G ⎪G A G ⎪ ⎪C C C ⎪
# ⎪ R ⎪ G ⎪ ⎪ C +⎪
# +------+------+------+------+
# ⎪ ⎪01G ⎪17C ⎪00C ⎪
# ⎪ ⎪G A G ⎪G N R ⎪R N R ⎪
# ⎪ ⎪ G ⎪ R ⎪ G ⎪
# +------+------+------+------+
ok - board has 7 tiles + starter tile
1..9
Non-Perl TAP
In Perl, we use Test::Simple and Test::More to generate TAP output.
Other languages have solutions that generate TAP, so that they can take
advantage of Test::Harness.
The following sections are provided by their maintainers, and may not
be up-to-date.
C/C++
libtap makes it easy to write test programs in C that produce TAP-com‐
patible output. Modeled on the Test::More API, libtap contains all the
functions you need to:
* Specify a test plan
* Run tests
* Skip tests in certain situations
* Have TODO tests
* Produce TAP compatible diagnostics
More information about libtap, including download links, checksums,
anonymous access to the Subersion repository, and a bug tracking sys‐
tem, can be found at:
http://jc.ngo.org.uk/trac-bin/trac.cgi/wiki/LibTap
(Nik Clayton, April 17, 2006)
Python
PyTap will, when it's done, provide a simple, assertive
(Test::More-like) interface for writing tests in Python. It will out‐
put TAP and will include the functionality found in Test::Builder and
Test::More. It will try to make it easy to add more test code (so you
can write your own "TAP.StringDiff", for example.
Right now, it's got a fair bit of the basics needed to emulate
Test::More, and I think it's easy to add more stuff -- just like
Test::Builder, there's a singleton that you can get at easily.
I need to better identify and finish implementing the most basic tests.
I am not a Python guru, I just use it from time to time, so my aim may
not be true. I need to write tests for it, which means either relying
on Perl for the tester tester, or writing one in Python.
Here's a sample test, as found in my Subversion:
from TAP.Simple import *
plan(15)ok(1)
ok(1, "everything is OK!")
ok(0, "always fails")
is_ok(10, 10, "is ten ten?")
is_ok(ok, ok, "even ok is ok!")
ok(id(ok), "ok is not the null pointer")
ok(True, "the Truth will set you ok")
ok(not False, "and nothing but the truth")
ok(False, "and we'll know if you lie to us")
isa_ok(10, int, "10")
isa_ok('ok', str, "some string")
ok(0, "zero is true", todo="be more like Ruby!")
ok(None, "none is true", skip="not possible in this universe")
eq_ok("not", "equal", "two strings are not equal");
(Ricardo Signes, April 17, 2006)
JavaScript
Test.Simple looks and acts just like TAP, although in reality it's
tracking test results in an object rather than scraping them from a
print buffer.
http://openjsan.org/doc/t/th/theory/Test/Simple/
(David Wheeler, April 17, 2006)
PHP
All the big PHP players now produce TAP
* phpt
Outputs TAP by default as of the yet-to-be-released PEAR 1.5.0
http://pear.php.net/PEAR
* PHPUnit
Has a TAP logger (since 2.3.4)
http://www.phpunit.de/wiki/Main_Page
* SimpleTest
There's a third-party TAP reporting extension for SimpleTest
http://www.digitalsandwich.com/archives/51-Updated-Simpletest+Apache-Test.html
* Apache-Test
Apache-Test's PHP writes TAP by default and includes the standalone
test-more.php
http://search.cpan.org/dist/Apache-Test/
(Geoffrey Young, April 17, 2006)
AUTHORS
Andy Lester, based on the original Test::Harness documentation by
Michael Schwern.
ACKNOWLEDGEMENTS
Thanks to Pete Krawczyk, Paul Johnson, Ian Langworth and Nik Clayton
for help and contributions on this document.
The basis for the TAP format was created by Larry Wall in the original
test script for Perl 1. Tim Bunce and Andreas Koenig developed it fur‐
ther with their modifications to Test::Harness.
COPYRIGHT
Copyright 2003-2005 by Michael G Schwern "<schwern@pobox.com>", Andy
Lester "<andy@petdance.com>".
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See <http://www.perl.com/perl/misc/Artistic.html>.
perl v5.8.8 2008-09-19 Test::Harness::TAP(3)
