Test::TableDriven(3) write tests, not scripts that run them


use A::Module qw/or two!/;
use Test::TableDriven (
foo => { input => 'expected output',
another => 'test',
bar => [[some => 'more tests'],
[that => 'run in order'],
[refs => [qw/also work/]],
[[qw/this is also possible/] => { and => 'it works' }],

sub foo {
my $in = shift;
my $out = ...;
return $out;
sub bar { same as foo }


Writing table-driven tests is usually a good idea. Adding a test case doesn't require adding code, so it's easy to avoid fucking up the other tests. However, actually going from a table of tests to a test that runs is non-trivial.

"Test::TableDriven" makes writing the test drivers trivial. You simply define your test cases and write a function that turns the input data into output data to compare against. "Test::TableDriven" will compute how many tests need to be run, and then run the tests.

Concentrate on your data and what you're testing, not "plan tests =" scalar keys %test_cases> and a big foreach loop.


Start by using the modules that you need for your tests:

   use strict;
   use warnings;
   use String::Length; # the module you're testing

Then write some code to test the module:

   sub strlen {
       my $in  = shift;
       my $out = String::Length->strlen($in);
       return $out;

This "strlen" function will accept a test case (as $in) and turns it into something to compare against your test cases:

Oh yeah, you need some test cases:

   use Test::TableDriven (
       strlen => { foo => 3,
                   bar => 3,

And you'll want those test to run somehow:


Now execute the test file. The output will look like:

   ok 1 - strlen: bar => 3
   ok 2 - strlen: foo => 3

Add another test case:

       strlen => { foo  => 3,
                   bar  => 3,
                   quux => 4,

And your test still works:

   ok 1 - strlen: bar => 3
   ok 2 - strlen: quux => 4
   ok 3 - strlen: foo => 3



I'm not in a prose-generation mood right now, so here's a list of things to keep in mind:
  • Don't forget to "runtests". Just loading the module doesn't do a whole lot.
  • If a subtest is not a subroutine name in the current package, runtests will die.
  • If a subtest definition is a hashref, the tests won't be run in order. If it's an arrayref of arrayrefs, then the tests are run in order.
  • If a test case ``expects'' a reference, "is_deeply" is used to compare the expected result and what your test returned. If it's just a string, "is" is used.
  • Feel free to use "Test::More::diag" and friends, if you like.
  • Don't print to STDOUT.
  • Especially don't print TAP to STDOUT :)



Run the tests. Only call this once.


Report them to RT, or patch them against the git repository at:

   git clone git://git.jrock.us/Test-TableDriven

(or <http://git.jrock.us/>).


Jonathan Rockway "<jrockway AT cpan.org>".


This module is copyright (c) 2007 Jonathan Rockway. You may use, modify, and redistribute it under the same terms as Perl itself.