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Test::Harness::TAP - Documentation for the TAP format
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.
Exit code of the process.
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
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.
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 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 output. 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 mandatory
part of the line.
Note that unlike the Directives below, ok and not ok are
case-sensitive.
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 following 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
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.
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:
Directives are special notes that follow a # on the test line.
Only two are currently defined: TODO and SKIP. Note that
these two keywords are not case-sensitive.
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.
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
As an emergency measure a test script can decide that further tests are useless (e.g. missing dependencies) and testing should stop immediately. 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.
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 harness is
free, however, to display the diagnostics. Typically diagnostics 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
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.
All names, places, and events depicted in any example are wholly fictitious and bear no resemblance to, connection with, or relation to any real entity. Any such similarity is purely coincidental, unintentional, and unintended.
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
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
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.
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
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
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
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
Andy Lester, based on the original Test::Harness documentation by Michael Schwern.
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 further with their modifications to Test::Harness.
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.