NAME

Test::Harness - run perl standard test scripts with statistics

SYNOPSIS

  use Test::Harness;

  runtests(@test_files);

DESCRIPTION

(By using the Test module, you can write test scripts without knowing the exact output this module expects. However, if you need to know the specifics, read on!)

Perl test scripts print to standard output "ok N" for each single test, where N is an increasing sequence of integers. The first line output by a standard test script is "1..M" with M being the number of tests that should be run within the test script. Test::Harness::runtests(@tests) runs all the testscripts named as arguments and checks standard output for the expected "ok N" strings.

After all tests have been performed, runtests() prints some performance statistics that are computed by the Benchmark module.

The test script output

The following explains how Test::Harness interprets the output of your test program.

1..M

This header tells how many tests there will be. It should be the first line output by your test program (but its okay if its preceded by comments).

In certain instanced, you may not know how many tests you will ultimately be running. In this case, it is permitted (but not encouraged) for the 1..M header to appear as the last line output by your test (again, it can be followed by further comments). But we strongly encourage you to put it first.

Under no circumstances should 1..M appear in the middle of your output or more than once.

'ok', 'not ok'. Ok?

Any output from the testscript to standard error is ignored and bypassed, thus will be seen by the user. Lines written to standard output containing /^(not\s+)?ok\b/ are interpreted as feedback for runtests(). All other lines are discarded.

/^not ok/ indicates a failed test. /^ok/ is a successful test.

test numbers

Perl normally expects the 'ok' or 'not ok' to be followed by a test number. It is tolerated if the test numbers after 'ok' are omitted. In this case Test::Harness maintains temporarily its own counter until the script supplies test numbers again. So the following test script

    print <<END;
    1..6
    not ok
    ok
    not ok
    ok
    ok
    END

will generate

    FAILED tests 1, 3, 6
    Failed 3/6 tests, 50.00% okay

$Test::Harness::verbose

The global variable $Test::Harness::verbose is exportable and can be used to let runtests() display the standard output of the script without altering the behavior otherwise.

$Test::Harness::switches

The global variable $Test::Harness::switches is exportable and can be used to set perl command line options used for running the test script(s). The default value is -w.

Skipping tests

If the standard output line contains the substring # Skip (with variations in spacing and case) after ok or ok NUMBER, it is counted as a skipped test. If the whole testscript succeeds, the count of skipped tests is included in the generated output. Test::Harness reports the text after # Skip\S*\s+ as a reason for skipping.

  ok 23 # skip Insufficient flogiston pressure.

Similarly, one can include a similar explanation in a 1..0 line emitted if the test script is skipped completely:

  1..0 # Skipped: no leverage found

Todo tests

If the standard output line contains the substring # TODO after not ok or not ok NUMBER, it is counted as a todo test. The text afterwards is the thing that has to be done before this test will succeed.

  not ok 13 # TODO harness the power of the atom

These tests represent a feature to be implemented or a bug to be fixed and act as something of an executable "thing to do" list. They are not expected to succeed. Should a todo test begin succeeding, Test::Harness will 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.

Bail out!

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 will be displayed by Test::Harness as the reason why testing is stopped.

Comments

Additional comments may be put into the testing output on their own lines. Comment lines should begin with a '#', Test::Harness will ignore them.

  ok 1
  # Life is good, the sun is shining, RAM is cheap.
  not ok 2
  # got 'Bush' expected 'Gore'

Functions

Test::Harness currently only has one function, here it is.

runtests

  my $allok = runtests(@test_files);

This runs all the given @test_files and divines whether they passed or failed based on their output to STDOUT (details above). It prints out each individual test which failed along with a summary report and a how long it all took.

It returns true if everything was ok, false otherwise.