See the current Perl documentation for Test::Harness.
Here is our local, out-dated (pre-5.6) version:
Test::Harness - run perl standard test scripts with statistics
(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
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.
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
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
FAILED tests 1, 3, 6
Failed 3/6 tests, 50.00% okay
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.
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
If the standard output line contains substring
<PRE> # Skip
(with variations in spacing and case) after
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.
&runtests is exported by Test::Harness per default.
- All tests successful.\nFiles=%d, Tests=%d, %s
If all tests are successful some statistics about the performance are
- FAILED tests %s\n\tFailed %d/%d tests, %.2f%% okay.
For any single script that has failing subtests statistics like the above
- Test returned status %d (wstat %d)
Scripts that return a non-zero exit status, both
$? >> 8 and
$? are printed in a message similar to the above.
- Failed 1 test, %.2f%% okay. %s
- Failed %d/%d tests, %.2f%% okay. %s
If not all tests were successful, the script dies with one of the above
HARNESS_IGNORE_EXITCODE makes harness ignore the exit status of child processes.
HARNESS_FILELEAK_IN_DIR is set to the name of a directory, harness will check after each test
whether new files appeared in that directory, and report them as
LEAKED FILES: scr.tmp 0 my.db
If relative, directory name is with respect to the current directory at the moment
runtests() was called. Putting absolute path into
HARNESS_FILELEAK_IN_DIR may give more predicatable results.
Test for writing test scripts and also Benchmark for the underlying timing routines.
Either Tim Bunce or Andreas Koenig, we don't know. What we know for sure is, that it was inspired by Larry Wall's
TEST script that came with perl distributions for ages. Numerous anonymous contributors exist. Current maintainer is Andreas Koenig.
$^X to determine the perl binary to run the tests
with. Test scripts running via the shebang (
#!) line may not be portable because
$^X is not consistent for shebang scripts across platforms. This is no problem when Test::Harness is run with an absolute path to the perl binary or when
$^X can be found in the path.