Provided by: perl-doc_5.28.1-6_all bug

NAME

       Test::Builder - Backend for building test libraries

SYNOPSIS

         package My::Test::Module;
         use base 'Test::Builder::Module';

         my $CLASS = __PACKAGE__;

         sub ok {
             my($test, $name) = @_;
             my $tb = $CLASS->builder;

             $tb->ok($test, $name);
         }

DESCRIPTION

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

   Construction
       new
             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 "new" always returns the same Test::Builder
           object.  No matter how many times you call "new()", you're getting the same object.
           This is called a singleton.  This is done so that multiple modules share such global
           information as the test counter and where test output is going.

           If you want a completely new Test::Builder object different from the singleton, use
           "create".

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

           Ok, so there can be more than one Test::Builder object and this is how you get it.
           You might use this instead of "new()" if you're testing a Test::Builder based module,
           but otherwise you probably want "new".

           NOTE: the implementation is not complete.  "level", for example, is still shared by
           all Test::Builder objects, even ones created using this method.  Also, the method name
           may change in the future.

       subtest
               $builder->subtest($name, \&subtests, @args);

           See documentation of "subtest" in Test::More.

           "subtest" also, and optionally, accepts arguments which will be passed to the subtests
           reference.

       name
            diag $builder->name;

           Returns the name of the current builder.  Top level builders default to $0 (the name
           of the executable).  Child builders are named via the "child" method.  If no name is
           supplied, will be named "Child of $parent->name".

       reset
             $Test->reset;

           Reinitializes the Test::Builder singleton to its original state.  Mostly useful for
           tests run in persistent environments where the same test might be run multiple times
           in the same process.

   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.

       plan
             $Test->plan('no_plan');
             $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.

       expected_tests
               my $max = $Test->expected_tests;
               $Test->expected_tests($max);

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

       no_plan
             $Test->no_plan;

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

       done_testing
             $Test->done_testing();
             $Test->done_testing($num_tests);

           Declares that you are done testing, no more tests will be run after this point.

           If a plan has not yet been output, it will do so.

           $num_tests is the number of tests you planned to run.  If a numbered plan was already
           declared, and if this contradicts, a failing test will be run to reflect the planning
           mistake.  If "no_plan" was declared, this will override.

           If "done_testing()" is called twice, the second call will issue a failing test.

           If $num_tests is omitted, the number of tests run will be used, like no_plan.

           "done_testing()" is, in effect, used when you'd want to use "no_plan", but safer.
           You'd use it like so:

               $Test->ok($a == $b);
               $Test->done_testing();

           Or to plan a variable number of tests:

               for my $test (@tests) {
                   $Test->ok($test);
               }
               $Test->done_testing(scalar @tests);

       has_plan
             $plan = $Test->has_plan

           Find out whether a plan has been defined. $plan is either "undef" (no plan has been
           set), "no_plan" (indeterminate # of tests) or an integer (the number of expected
           tests).

       skip_all
             $Test->skip_all;
             $Test->skip_all($reason);

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

       exported_to
             my $pack = $Test->exported_to;
             $Test->exported_to($pack);

           Tells Test::Builder what package you exported your functions to.

           This method isn't terribly useful since modules which share the same Test::Builder
           object might get exported to different packages and only the last one will be honored.

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

       They all return true if the test passed, false if the test failed.

       $name is always optional.

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

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

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

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

           "undef" only ever matches another "undef".

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

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

           "undef" only ever matches another "undef".

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

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

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

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

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

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

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

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

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

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

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

   Other Testing Methods
       These are methods which are used in the course of writing a test but are not themselves
       tests.

       BAIL_OUT
               $Test->BAIL_OUT($reason);

           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.

       skip
               $Test->skip;
               $Test->skip($why);

           Skips the current test, reporting $why.

       todo_skip
             $Test->todo_skip;
             $Test->todo_skip($why);

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

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

   Test building utility methods
       These methods are useful when writing your own test methods.

       maybe_regex
             $Test->maybe_regex(qr/$regex/);
             $Test->maybe_regex('/$regex/');

           This method used to be useful back when Test::Builder worked on Perls before 5.6 which
           didn't have qr//.  Now its pretty useless.

           Convenience method for building testing functions that take regular expressions as
           arguments.

           Takes a quoted regular expression produced by "qr//", or a string representing a
           regular expression.

           Returns a Perl value which may be used instead of the corresponding regular
           expression, or "undef" if its argument is not recognized.

           For example, a version of "like()", sans the useful diagnostic messages, could be
           written as:

             sub laconic_like {
                 my ($self, $thing, $regex, $name) = @_;
                 my $usable_regex = $self->maybe_regex($regex);
                 die "expecting regex, found '$regex'\n"
                     unless $usable_regex;
                 $self->ok($thing =~ m/$usable_regex/, $name);
             }

       is_fh
               my $is_fh = $Test->is_fh($thing);

           Determines if the given $thing can be used as a filehandle.

   Test style
       level
               $Test->level($how_high);

           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:

               sub my_ok {
                   my $test = shift;

                   local $Test::Builder::Level = $Test::Builder::Level + 1;
                   $TB->ok($test);
               }

           To be polite to other functions wrapping your own you usually want to increment $Level
           rather than set it to a constant.

       use_numbers
               $Test->use_numbers($on_or_off);

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

             ok 1
             ok 2
             ok 3

           or this if false

             ok
             ok
             ok

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

           Defaults to on.

       no_diag
               $Test->no_diag($no_diag);

           If set true no diagnostics will be printed.  This includes calls to "diag()".

       no_ending
               $Test->no_ending($no_ending);

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

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

       no_header
               $Test->no_header($no_header);

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

   Output
       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.

       diag
               $Test->diag(@msgs);

           Prints out the given @msgs.  Like "print", arguments are simply appended together.

           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.

           Returns false.  Why?  Because "diag()" is often used in conjunction with a failing
           test ("ok() || diag()") it "passes through" the failure.

               return ok(...) || diag(...);

       note
               $Test->note(@msgs);

           Like "diag()", but it prints to the "output()" handle so it will not normally be seen
           by the user except in verbose mode.

       explain
               my @dump = $Test->explain(@msgs);

           Will dump the contents of any references in a human readable format.  Handy for things
           like...

               is_deeply($have, $want) || diag explain $have;

           or

               is_deeply($have, $want) || note explain $have;

       output
       failure_output
       todo_output
               my $filehandle = $Test->output;
               $Test->output($filehandle);
               $Test->output($filename);
               $Test->output(\$scalar);

           These methods control where Test::Builder will print its output.  They take either an
           open $filehandle, a $filename to open and write to or a $scalar reference to append
           to.  It will always return a $filehandle.

           output is where normal "ok/not ok" test output goes.

           Defaults to STDOUT.

           failure_output is where diagnostic output on test failures and "diag()" goes.  It is
           normally not read by Test::Harness and instead is displayed to the user.

           Defaults to STDERR.

           "todo_output" is used instead of "failure_output()" for the diagnostics of a failing
           TODO test.  These will not be seen by the user.

           Defaults to STDOUT.

       reset_outputs
             $tb->reset_outputs;

           Resets all the output filehandles back to their defaults.

       carp
             $tb->carp(@message);

           Warns with @message but the message will appear to come from the point where the
           original test function was called ("$tb->caller").

       croak
             $tb->croak(@message);

           Dies with @message but the message will appear to come from the point where the
           original test function was called ("$tb->caller").

   Test Status and Info
       no_log_results
           This will turn off result long-term storage. Calling this method will make "details"
           and "summary" useless. You may want to use this if you are running enough tests to
           fill up all available memory.

               Test::Builder->new->no_log_results();

           There is no way to turn it back on.

       current_test
               my $curr_test = $Test->current_test;
               $Test->current_test($num);

           Gets/sets the current test number we're on.  You usually shouldn't have to set this.

           If set forward, the details of the missing tests are filled in as 'unknown'.  if set
           backward, the details of the intervening tests are deleted.  You can erase history if
           you really want to.

       is_passing
              my $ok = $builder->is_passing;

           Indicates if the test suite is currently passing.

           More formally, it will be false if anything has happened which makes it impossible for
           the test suite to pass.  True otherwise.

           For example, if no tests have run "is_passing()" will be true because even though a
           suite with no tests is a failure you can add a passing test to it and start passing.

           Don't think about it too much.

       summary
               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...

       details
               my @tests = $Test->details;

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

               $tests[$test_num - 1] =
                       { 'ok'       => is the test considered a pass?
                         actual_ok  => did it literally say 'ok'?
                         name       => name of the test (if any)
                         type       => type of test (if any, see below).
                         reason     => reason for the above (if any)
                       };

           'ok' is true if Test::Harness will consider the test to be a pass.

           'actual_ok' is a reflection of whether or not the test literally printed 'ok' or 'not
           ok'.  This is for examining the result of 'todo' tests.

           'name' is the name of the test.

           'type' indicates if it was a special test.  Normal tests have a type of ''.  Type can
           be one of the following:

               skip        see skip()
               todo        see todo()
               todo_skip   see todo_skip()
               unknown     see below

           Sometimes the Test::Builder test counter is incremented without it printing any test
           output, for example, when "current_test()" is changed.  In these cases, Test::Builder
           doesn't know the result of the test, so its type is 'unknown'.  These details for
           these tests are filled in.  They are considered ok, but the name and actual_ok is left
           "undef".

           For example "not ok 23 - hole count # TODO insufficient donuts" would result in this
           structure:

               $tests[22] =    # 23 - 1, since arrays start from 0.
                 { ok        => 1,   # logically, the test passed since its todo
                   actual_ok => 0,   # in absolute terms, it failed
                   name      => 'hole count',
                   type      => 'todo',
                   reason    => 'insufficient donuts'
                 };

       todo
               my $todo_reason = $Test->todo;
               my $todo_reason = $Test->todo($pack);

           If the current tests are considered "TODO" it will return the reason, if any.  This
           reason can come from a $TODO variable or the last call to "todo_start()".

           Since a TODO test does not need a reason, this function can return an empty string
           even when inside a TODO block.  Use "$Test->in_todo" to determine if you are currently
           inside a TODO block.

           "todo()" is about finding the right package to look for $TODO in.  It's pretty good at
           guessing the right package to look at.  It first looks for the caller based on "$Level
           + 1", since "todo()" is usually called inside a test function.  As a last resort it
           will use "exported_to()".

           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.

       find_TODO
               my $todo_reason = $Test->find_TODO();
               my $todo_reason = $Test->find_TODO($pack);

           Like "todo()" but only returns the value of $TODO ignoring "todo_start()".

           Can also be used to set $TODO to a new value while returning the old value:

               my $old_reason = $Test->find_TODO($pack, 1, $new_reason);

       in_todo
               my $in_todo = $Test->in_todo;

           Returns true if the test is currently inside a TODO block.

       todo_start
               $Test->todo_start();
               $Test->todo_start($message);

           This method allows you declare all subsequent tests as TODO tests, up until the
           "todo_end" method has been called.

           The "TODO:" and $TODO syntax is generally pretty good about figuring out whether or
           not we're in a TODO test.  However, often we find that this is not possible to
           determine (such as when we want to use $TODO but the tests are being executed in other
           packages which can't be inferred beforehand).

           Note that you can use this to nest "todo" tests

            $Test->todo_start('working on this');
            # lots of code
            $Test->todo_start('working on that');
            # more code
            $Test->todo_end;
            $Test->todo_end;

           This is generally not recommended, but large testing systems often have weird internal
           needs.

           We've tried to make this also work with the TODO: syntax, but it's not guaranteed and
           its use is also discouraged:

            TODO: {
                local $TODO = 'We have work to do!';
                $Test->todo_start('working on this');
                # lots of code
                $Test->todo_start('working on that');
                # more code
                $Test->todo_end;
                $Test->todo_end;
            }

           Pick one style or another of "TODO" to be on the safe side.

       "todo_end"
            $Test->todo_end;

           Stops running tests as "TODO" tests.  This method is fatal if called without a
           preceding "todo_start" method call.

       caller
               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()".

           $height will be added to the "level()".

           If "caller()" winds up off the top of the stack it report the highest context.

EXIT CODES

       If all your tests passed, Test::Builder will exit with zero (which is normal).  If
       anything failed it will exit with how many failed.  If you run less (or more) tests than
       you planned, the missing (or extras) will be considered failures.  If no tests were ever
       run Test::Builder will throw a warning and exit with 255.  If the test died, even after
       having successfully completed all its tests, it will still be considered a failure and
       will exit with 255.

       So the exit codes are...

           0                   all tests successful
           255                 test died or all passed but wrong # of tests run
           any other number    how many failed (including missing or extras)

       If you fail more than 254 tests, it will be reported as 254.

THREADS

       In perl 5.8.1 and later, Test::Builder is thread-safe.  The test number is shared by all
       threads.  This means if one thread sets the test number using "current_test()" they will
       all be effected.

       While versions earlier than 5.8.1 had threads they contain too many bugs to support.

       Test::Builder is only thread-aware if threads.pm is loaded before Test::Builder.

       You can directly disable thread support with one of the following:

           $ENV{T2_NO_IPC} = 1

       or

           no Test2::IPC;

       or

           Test2::API::test2_ipc_disable()

MEMORY

       An informative hash, accessible via "details()", is stored for each test you perform.  So
       memory usage will scale linearly with each test run. Although this is not a problem for
       most test suites, it can become an issue if you do large (hundred thousands to million)
       combinatorics tests in the same run.

       In such cases, you are advised to either split the test file into smaller ones, or use a
       reverse approach, doing "normal" (code) compares and triggering "fail()" should anything
       go unexpected.

       Future versions of Test::Builder will have a way to turn history off.

EXAMPLES

       CPAN can provide the best examples.  Test::Simple, Test::More, Test::Exception and
       Test::Differences all use Test::Builder.

SEE ALSO

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

AUTHORS

       Original code by chromatic, maintained by Michael G Schwern <schwern@pobox.com>

MAINTAINERS

       Chad Granum <exodist@cpan.org>

COPYRIGHT

       Copyright 2002-2008 by chromatic <chromatic@wgz.org> and
                              Michael G Schwern <schwern@pobox.com>.

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

       See http://www.perl.com/perl/misc/Artistic.html