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Jarkko Hietaniemi > perl-5.7.3 > Test::Builder



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Module Version: 0.11   Source   Latest Release: perl-5.6.2


Test::Builder - Backend for building test libraries


  package My::Test::Module;
  use Test::Builder;
  require Exporter;
  @ISA = qw(Exporter);
  @EXPORT = qw(ok);

  my $Test = Test::Builder->new;

  sub import {
      my($self) = shift;
      my $pack = caller;


      $self->export_to_level(1, $self, 'ok');

  sub ok {
      my($test, $name) = @_;

      $Test->ok($test, $name);


THIS IS ALPHA GRADE SOFTWARE Meaning the underlying code is well tested, yet the interface is subject to change.

Test::Simple and Test::More have proven to be popular testing modules, but they're not always flexible enough. Test::Builder provides the a building block upon which to write your own test libraries which can work together.


  my $Test = Test::Builder->new;

Returns a Test::Builder object representing the current state of the test.

Since you only run one test per program, there is one and only one Test::Builder object. No matter how many times you call new(), you're getting the same object. (This is called a singleton).

Setting up tests

These methods are for setting up tests and declaring how many there are. You usually only want to call one of these methods.

  my $pack = $Test->exported_to;

Tells Test::Builder what package you exported your functions to. This is important for getting TODO tests right.

  $Test->plan( skip_all => $reason );
  $Test->plan( tests => $num_tests );

A convenient way to set up your tests. Call this and Test::Builder will print the appropriate headers and take the appropriate actions.

If you call plan(), don't call any of the other methods below.

    my $max = $Test->expected_tests;

Gets/sets the # of tests we expect this test to run and prints out the appropriate headers.


Declares that this test will run an indeterminate # of tests.


Skips all the tests, using the given $reason. Exits immediately with 0.

Running tests

These actually run the tests, analogous to the functions in Test::More.

$name is always optional.

  $Test->ok($test, $name);

Your basic test. Pass if $test is true, fail if $test is false. Just like Test::Simple's ok().

  $Test->is_eq($got, $expected, $name);

Like Test::More's is(). Checks if $got eq $expected. This is the string version.

  $Test->is_num($got, $expected, $name);

Like Test::More's is(). Checks if $got == $expected. This is the numeric version.

  $Test->isnt_eq($got, $dont_expect, $name);

Like Test::More's isnt(). Checks if $got ne $dont_expect. This is the string version.

  $Test->is_num($got, $dont_expect, $name);

Like Test::More's isnt(). Checks if $got ne $dont_expect. This is the numeric version.

  $Test->like($this, qr/$regex/, $name);
  $Test->like($this, '/$regex/', $name);

Like Test::More's like(). Checks if $this matches the given $regex.

You'll want to avoid qr// if you want your tests to work before 5.005.

  $Test->unlike($this, qr/$regex/, $name);
  $Test->unlike($this, '/$regex/', $name);

Like Test::More's unlike(). Checks if $this does not match the given $regex.

  $Test->cmp_ok($this, $type, $that, $name);

Works just like Test::More's cmp_ok().

    $Test->cmp_ok($big_num, '!=', $other_big_num);

Indicates to the Test::Harness that things are going so badly all testing should terminate. This includes running any additional test scripts.

It will exit with 255.


Skips the current test, reporting $why.


Like skip(), only it will declare the test as failing and TODO. Similar to

    print "not ok $tnum # TODO $why\n";

Test style


How far up the call stack should $Test look when reporting where the test failed.

Defaults to 1.

Setting $Test::Builder::Level overrides. This is typically useful localized:

        local $Test::Builder::Level = 2;

Whether or not the test should output numbers. That is, this if true:

  ok 1
  ok 2
  ok 3

or this if false


Most useful when you can't depend on the test output order, such as when threads or forking is involved.

Test::Harness will accept either, but avoid mixing the two styles.

Defaults to on.


If set to true, no "1..N" header will be printed.


Normally, Test::Builder does some extra diagnostics when the test ends. It also changes the exit code as described in Test::Simple.

If this is true, none of that will be done.


Controlling where the test output goes.

It's ok for your test to change where STDOUT and STDERR point to, Test::Builder's default output settings will not be affected.


Prints out the given $message. Normally, it uses the failure_output() handle, but if this is for a TODO test, the todo_output() handle is used.

Output will be indented and marked with a # so as not to interfere with test output. A newline will be put on the end if there isn't one already.

We encourage using this rather than calling print directly.


Where normal "ok/not ok" test output should go.

Defaults to STDOUT.


Where diagnostic output on test failures and diag() should go.

Defaults to STDERR.


Where diagnostics about todo test failures and diag() should go.

Defaults to STDOUT.

Test Status and Info

    my $curr_test = $Test->current_test;

Gets/sets the current test # we're on.

You usually shouldn't have to set this.

    my @tests = $Test->summary;

A simple summary of the tests so far. True for pass, false for fail. This is a logical pass/fail, so todos are passes.

Of course, test #1 is $tests[0], etc...

    my @tests = $Test->details;

Like summary(), but with a lot more detail.

    $tests[$test_num - 1] = 
            { ok         => is the test considered ok?
              actual_ok  => did it literally say 'ok'?
              name       => name of the test (if any)
              type       => 'skip' or 'todo' (if any)
              reason     => reason for the above (if any)
    my $todo_reason = $Test->todo;
    my $todo_reason = $Test->todo($pack);

todo() looks for a $TODO variable in your tests. If set, all tests will be considered 'todo' (see Test::More and Test::Harness for details). Returns the reason (ie. the value of $TODO) if running as todo tests, false otherwise.

todo() is pretty part about finding the right package to look for $TODO in. It uses the exported_to() package to find it. If that's not set, it's pretty good at guessing the right package to look at.

Sometimes there is some confusion about where todo() should be looking for the $TODO variable. If you want to be sure, tell it explicitly what $pack to use.

    my $package = $Test->caller;
    my($pack, $file, $line) = $Test->caller;
    my($pack, $file, $line) = $Test->caller($height);

Like the normal caller(), except it reports according to your level().


At this point, Test::Simple and Test::More are your best examples.


Test::Simple, Test::More, Test::Harness


Original code by chromatic, maintained by Michael G Schwern <>


Copyright 2001 by chromatic <>, Michael G Schwern <>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


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