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Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

       Test::More - yet another framework for writing test

         use Test::More tests => $Num_Tests;
         # or
         use Test::More qw(no_plan);
         # or
         use Test::More skip_all => $reason;

         BEGIN { use_ok( 'Some::Module' ); }
         require_ok( 'Some::Module' );

         # Various ways to say "ok"
         ok($this eq $that, $test_name);

         is  ($this, $that,    $test_name);
         isnt($this, $that,    $test_name);

         # Rather than print STDERR "# here's what went wrong\n"
         diag("here's what went wrong");

         like  ($this, qr/that/, $test_name);
         unlike($this, qr/that/, $test_name);

         cmp_ok($this, '==', $that, $test_name);

         is_deeply($complex_structure1, $complex_structure2, $test_name);

         SKIP: {
             skip $why, $how_many unless $have_some_feature;

             ok( foo(),       $test_name );
             is( foo(42), 23, $test_name );

         TODO: {
             local $TODO = $why;

             ok( foo(),       $test_name );
             is( foo(42), 23, $test_name );

         can_ok($module, @methods);
         isa_ok($object, $class);


         # Utility comparison functions.
         eq_array(\@this, \@that);
         eq_hash(\%this, \%that);
         eq_set(\@this, \@that);

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Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

         # UNIMPLEMENTED!!!
         my @status = Test::More::status;

         # UNIMPLEMENTED!!!

       STOP! If you're just getting started writing tests, have a
       look at Test::Simple first.  This is a drop in replacement
       for Test::Simple which you can switch to once you get the
       hang of basic testing.

       The purpose of this module is to provide a wide range of
       testing utilities.  Various ways to say "ok" with better
       diagnostics, facilities to skip tests, test future fea-
       tures and compare complicated data structures.  While you
       can do almost anything with a simple "ok()" function, it
       doesn't provide good diagnostic output.

       I love it when a plan comes together

       Before anything else, you need a testing plan.  This basi-
       cally declares how many tests your script is going to run
       to protect against premature failure.

       The preferred way to do this is to declare a plan when you
       "use Test::More".

         use Test::More tests => $Num_Tests;

       There are rare cases when you will not know beforehand how
       many tests your script is going to run.  In this case, you
       can declare that you have no plan.  (Try to avoid using
       this as it weakens your test.)

         use Test::More qw(no_plan);

       In some cases, you'll want to completely skip an entire
       testing script.

         use Test::More skip_all => $skip_reason;

       Your script will declare a skip with the reason why you
       skipped and exit immediately with a zero (success).  See
       Test::Harness for details.

       If you want to control what functions Test::More will
       export, you have to use the 'import' option.  For example,
       to import everything but 'fail', you'd do:

         use Test::More tests => 23, import => ['!fail'];

       Alternatively, you can use the plan() function.  Useful
       for when you have to calculate the number of tests.

perl v5.8.5                 2002-11-06                          2

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

         use Test::More;
         plan tests => keys %Stuff * 3;

       or for deciding between running the tests at all:

         use Test::More;
         if( $^O eq 'MacOS' ) {
             plan skip_all => 'Test irrelevant on MacOS';
         else {
             plan tests => 42;

       Test names

       By convention, each test is assigned a number in order.
       This is largely done automatically for you.  However, it's
       often very useful to assign a name to each test.  Which
       would you rather see:

         ok 4
         not ok 5
         ok 6


         ok 4 - basic multi-variable
         not ok 5 - simple exponential
         ok 6 - force == mass * acceleration

       The later gives you some idea of what failed.  It also
       makes it easier to find the test in your script, simply
       search for "simple exponential".

       All test functions take a name argument.  It's optional,
       but highly suggested that you use it.

       I'm ok, you're not ok.

       The basic purpose of this module is to print out either
       "ok #" or "not ok #" depending on if a given test suc-
       ceeded or failed.  Everything else is just gravy.

       All of the following print "ok" or "not ok" depending on
       if the test succeeded or failed.  They all also return
       true or false, respectively.

             ok($this eq $that, $test_name);

           This simply evaluates any expression ("$this eq $that"
           is just a simple example) and uses that to determine
           if the test succeeded or failed.  A true expression
           passes, a false one fails.  Very simple.

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Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

           For example:

               ok( $exp{9} == 81,                   'simple exponential' );
               ok( Film->can('db_Main'),            'set_db()' );
               ok( $p->tests == 4,                  'saw tests' );
               ok( !grep !defined $_, @items,       'items populated' );

           (Mnemonic:  "This is ok.")

           $test_name is a very short description of the test
           that will be printed out.  It makes it very easy to
           find a test in your script when it fails and gives
           others an idea of your intentions.  $test_name is
           optional, but we very strongly encourage its use.

           Should an ok() fail, it will produce some diagnostics:

               not ok 18 - sufficient mucus
               #     Failed test 18 (foo.t at line 42)

           This is actually Test::Simple's ok() routine.

             is  ( $this, $that, $test_name );
             isnt( $this, $that, $test_name );

           Similar to ok(), is() and isnt() compare their two
           arguments with "eq" and "ne" respectively and use the
           result of that to determine if the test succeeded or
           failed.  So these:

               # Is the ultimate answer 42?
               is( ultimate_answer(), 42,          "Meaning of Life" );

               # $foo isn't empty
               isnt( $foo, '',     "Got some foo" );

           are similar to these:

               ok( ultimate_answer() eq 42,        "Meaning of Life" );
               ok( $foo ne '',     "Got some foo" );

           (Mnemonic:  "This is that."  "This isn't that.")

           So why use these?  They produce better diagnostics on
           failure.  ok() cannot know what you are testing for
           (beyond the name), but is() and isnt() know what the
           test was and why it failed.  For example this test:

               my $foo = 'waffle';  my $bar = 'yarblokos';
               is( $foo, $bar,   'Is foo the same as bar?' );

           Will produce something like this:

perl v5.8.5                 2002-11-06                          4

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

               not ok 17 - Is foo the same as bar?
               #     Failed test (foo.t at line 139)
               #          got: 'waffle'
               #     expected: 'yarblokos'

           So you can figure out what went wrong without rerun-
           ning the test.

           You are encouraged to use is() and isnt() over ok()
           where possible, however do not be tempted to use them
           to find out if something is true or false!

             # XXX BAD!  $pope->isa('Catholic') eq 1
             is( $pope->isa('Catholic'), 1,        'Is the Pope Catholic?' );

           This does not check if "$pope-"isa('Catholic')> is
           true, it checks if it returns 1.  Very different.
           Similar caveats exist for false and 0.  In these
           cases, use ok().

             ok( $pope->isa('Catholic') ),         'Is the Pope Catholic?' );

           For those grammatical pedants out there, there's an
           "isn't()" function which is an alias of isnt().

             like( $this, qr/that/, $test_name );

           Similar to ok(), like() matches $this against the
           regex "qr/that/".

           So this:

               like($this, qr/that/, 'this is like that');

           is similar to:

               ok( $this =~ /that/, 'this is like that');

           (Mnemonic "This is like that".)

           The second argument is a regular expression.  It may
           be given as a regex reference (i.e. "qr//") or (for
           better compatibility with older perls) as a string
           that looks like a regex (alternative delimiters are
           currently not supported):

               like( $this, '/that/', 'this is like that' );

           Regex options may be placed on the end ('/that/i').

           Its advantages over ok() are similar to that of is()
           and isnt().  Better diagnostics on failure.

perl v5.8.5                 2002-11-06                          5

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

             unlike( $this, qr/that/, $test_name );

           Works exactly as like(), only it checks if $this does
           not match the given pattern.

             cmp_ok( $this, $op, $that, $test_name );

           Halfway between ok() and is() lies cmp_ok().  This
           allows you to compare two arguments using any binary
           perl operator.

               # ok( $this eq $that );
               cmp_ok( $this, 'eq', $that, 'this eq that' );

               # ok( $this == $that );
               cmp_ok( $this, '==', $that, 'this == that' );

               # ok( $this && $that );
               cmp_ok( $this, '&&', $that, 'this || that' );

           Its advantage over ok() is when the test fails you'll
           know what $this and $that were:

               not ok 1
               #     Failed test (foo.t at line 12)
               #     '23'
               #         &&
               #     undef

           It's also useful in those cases where you are compar-
           ing numbers and is()'s use of "eq" will interfere:

               cmp_ok( $big_hairy_number, '==', $another_big_hairy_number );

             can_ok($module, @methods);
             can_ok($object, @methods);

           Checks to make sure the $module or $object can do
           these @methods (works with functions, too).

               can_ok('Foo', qw(this that whatever));

           is almost exactly like saying:

               ok( Foo->can('this') &&
                   Foo->can('that') &&

           only without all the typing and with a better

perl v5.8.5                 2002-11-06                          6

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

           interface.  Handy for quickly testing an interface.

           No matter how many @methods you check, a single
           can_ok() call counts as one test.  If you desire oth-
           erwise, use:

               foreach my $meth (@methods) {
                   can_ok('Foo', $meth);

             isa_ok($object, $class, $object_name);
             isa_ok($ref,    $type,  $ref_name);

           Checks to see if the given $object->isa($class).  Also
           checks to make sure the object was defined in the
           first place.  Handy for this sort of thing:

               my $obj = Some::Module->new;
               isa_ok( $obj, 'Some::Module' );

           where you'd otherwise have to write

               my $obj = Some::Module->new;
               ok( defined $obj && $obj->isa('Some::Module') );

           to safeguard against your test script blowing up.

           It works on references, too:

               isa_ok( $array_ref, 'ARRAY' );

           The diagnostics of this test normally just refer to
           'the object'.  If you'd like them to be more specific,
           you can supply an $object_name (for example 'Test cus-


           Sometimes you just want to say that the tests have
           passed.  Usually the case is you've got some compli-
           cated condition that is difficult to wedge into an
           ok().  In this case, you can simply use pass() (to
           declare the test ok) or fail (for not ok).  They are
           synonyms for ok(1) and ok(0).

           Use these very, very, very sparingly.

perl v5.8.5                 2002-11-06                          7

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)


       If you pick the right test function, you'll usually get a
       good idea of what went wrong when it failed.  But some-
       times it doesn't work out that way.  So here we have ways
       for you to write your own diagnostic messages which are
       safer than just "print STDERR".


           Prints a diagnostic message which is guaranteed not to
           interfere with test output.  Handy for this sort of

               ok( grep(/foo/, @users), "There's a foo user" ) or
                   diag("Since there's no foo, check that /etc/bar is set up right");

           which would produce:

               not ok 42 - There's a foo user
               #     Failed test (foo.t at line 52)
               # Since there's no foo, check that /etc/bar is set up right.

           You might remember "ok() or diag()" with the mnemonic
           "open() or die()".

           NOTE The exact formatting of the diagnostic output is
           still changing, but it is guaranteed that whatever you
           throw at it it won't interfere with the test.

       Module tests

       You usually want to test if the module you're testing
       loads ok, rather than just vomiting if its load fails.
       For such purposes we have "use_ok" and "require_ok".

              BEGIN { use_ok($module); }
              BEGIN { use_ok($module, @imports); }

           These simply use the given $module and test to make
           sure the load happened ok.  It's recommended that you
           run use_ok() inside a BEGIN block so its functions are
           exported at compile-time and prototypes are properly

           If @imports are given, they are passed through to the
           use.  So this:

              BEGIN { use_ok('Some::Module', qw(foo bar)) }

           is like doing this:

perl v5.8.5                 2002-11-06                          8

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

              use Some::Module qw(foo bar);

           don't try to do this:

              BEGIN {

                  ...some code that depends on the use...
                  ...happening at compile time...

           instead, you want:

             BEGIN { use_ok('Some::Module') }
             BEGIN { ...some code that depends on the use... }


           Like use_ok(), except it requires the $module.

       Conditional tests

       Sometimes running a test under certain conditions will
       cause the test script to die.  A certain function or
       method isn't implemented (such as fork() on MacOS), some
       resource isn't available (like a net connection) or a mod-
       ule isn't available.  In these cases it's necessary to
       skip tests, or declare that they are supposed to fail but
       will work in the future (a todo test).

       For more details on the mechanics of skip and todo tests
       see Test::Harness.

       The way Test::More handles this is with a named block.
       Basically, a block of tests which can be skipped over or
       made todo.  It's best if I just show you...

       SKIP: BLOCK
             SKIP: {
                 skip $why, $how_many if $condition;

                 ...normal testing code goes here...

           This declares a block of tests that might be skipped,
           $how_many tests there are, $why and under what $condi-
           tion to skip them.  An example is the easiest way to

               SKIP: {
                   eval { require HTML::Lint };

                   skip "HTML::Lint not installed", 2 if $@;

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Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

                   my $lint = new HTML::Lint;
                   isa_ok( $lint, "HTML::Lint" );

                   $lint->parse( $html );
                   is( $lint->errors, 0, "No errors found in HTML" );

           If the user does not have HTML::Lint installed, the
           whole block of code won't be run at all.  Test::More
           will output special ok's which Test::Harness inter-
           prets as skipped, but passing, tests.  It's important
           that $how_many accurately reflects the number of tests
           in the SKIP block so the # of tests run will match up
           with your plan.

           It's perfectly safe to nest SKIP blocks.  Each SKIP
           block must have the label "SKIP", or Test::More can't
           work its magic.

           You don't skip tests which are failing because there's
           a bug in your program, or for which you don't yet have
           code written.  For that you use TODO.  Read on.

       TODO: BLOCK
               TODO: {
                   local $TODO = $why if $condition;

                   ...normal testing code goes here...

           Declares a block of tests you expect to fail and $why.
           Perhaps it's because you haven't fixed a bug or
           haven't finished a new feature:

               TODO: {
                   local $TODO = "URI::Geller not finished";

                   my $card = "Eight of clubs";
                   is( URI::Geller->your_card, $card, 'Is THIS your card?' );

                   my $spoon;
                   is( $spoon, 'bent',    "Spoon bending, that's original" );

           With a todo block, the tests inside are expected to
           fail.  Test::More will run the tests normally, but
           print out special flags indicating they are "todo".
           Test::Harness will interpret failures as being ok.
           Should anything succeed, it will report it as an unex-
           pected success.  You then know the thing you had todo
           is done and can remove the TODO flag.

           The nice part about todo tests, as opposed to simply

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Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

           commenting out a block of tests, is it's like having a
           programmatic todo list.  You know how much work is
           left to be done, you're aware of what bugs there are,
           and you'll know immediately when they're fixed.

           Once a todo test starts succeeding, simply move it
           outside the block.  When the block is empty, delete

               TODO: {
                   todo_skip $why, $how_many if $condition;

                   ...normal testing code...

           With todo tests, it's best to have the tests actually
           run.  That way you'll know when they start passing.
           Sometimes this isn't possible.  Often a failing test
           will cause the whole program to die or hang, even
           inside an "eval BLOCK" with and using "alarm".  In
           these extreme cases you have no choice but to skip
           over the broken tests entirely.

           The syntax and behavior is similar to a "SKIP: BLOCK"
           except the tests will be marked as failing but todo.
           Test::Harness will interpret them as passing.

       When do I use SKIP vs. TODO?
           If it's something the user might not be able to do,
           use SKIP.  This includes optional modules that aren't
           installed, running under an OS that doesn't have some
           feature (like fork() or symlinks), or maybe you need
           an Internet connection and one isn't available.

           If it's something the programmer hasn't done yet, use
           TODO.  This is for any code you haven't written yet,
           or bugs you have yet to fix, but want to put tests in
           your testing script (always a good idea).

       Comparison functions

       Not everything is a simple eq check or regex.  There are
       times you need to see if two arrays are equivalent, for
       instance.  For these instances, Test::More provides a
       handful of useful functions.

       NOTE These are NOT well-tested on circular references.
       Nor am I quite sure what will happen with filehandles.

             is_deeply( $this, $that, $test_name );

           Similar to is(), except that if $this and $that are

perl v5.8.5                 2002-11-06                         11

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

           hash or array references, it does a deep comparison
           walking each data structure to see if they are equiva-
           lent.  If the two structures are different, it will
           display the place where they start differing.

           Barrie Slaymaker's Test::Differences module provides
           more in-depth functionality along these lines, and it
           plays well with Test::More.

           NOTE Display of scalar refs is not quite 100%

             eq_array(\@this, \@that);

           Checks if two arrays are equivalent.  This is a deep
           check, so multi-level structures are handled cor-

             eq_hash(\%this, \%that);

           Determines if the two hashes contain the same keys and
           values.  This is a deep check.

             eq_set(\@this, \@that);

           Similar to eq_array(), except the order of the ele-
           ments is not important.  This is a deep check, but the
           irrelevancy of order only applies to the top level.

           NOTE By historical accident, this is not a true set
           comparision.  While the order of elements does not
           matter, duplicate elements do.

       Extending and Embedding Test::More

       Sometimes the Test::More interface isn't quite enough.
       Fortunately, Test::More is built on top of Test::Builder
       which provides a single, unified backend for any test
       library to use.  This means two test libraries which both
       use Test::Builder can be used together in the same pro-

       If you simply want to do a little tweaking of how the
       tests behave, you can access the underlying Test::Builder
       object like so:

               my $test_builder = Test::More->builder;

           Returns the Test::Builder object underlying Test::More
           for you to play with.

perl v5.8.5                 2002-11-06                         12

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

       Test::More is explicitly tested all the way back to perl

       Test::More is thread-safe for perl 5.8.0 and up.

       Making your own ok()
           If you are trying to extend Test::More, don't.  Use
           Test::Builder instead.

       The eq_* family has some caveats.
       Test::Harness upgrades
           no_plan and todo depend on new Test::Harness features
           and fixes.  If you're going to distribute tests that
           use no_plan or todo your end-users will have to
           upgrade Test::Harness to the latest one on CPAN.  If
           you avoid no_plan and TODO tests, the stock Test::Har-
           ness will work fine.

           If you simply depend on Test::More, it's own dependen-
           cies will cause a Test::Harness upgrade.

       This is a case of convergent evolution with Joshua Pri-
       tikin's Test module.  I was largely unaware of its exis-
       tence when I'd first written my own ok() routines.  This
       module exists because I can't figure out how to easily
       wedge test names into Test's interface (along with a few
       other problems).

       The goal here is to have a testing utility that's simple
       to learn, quick to use and difficult to trip yourself up
       with while still providing more flexibility than the
       existing Test.pm.  As such, the names of the most common
       routines are kept tiny, special cases and magic side-
       effects are kept to a minimum.  WYSIWYG.

       Test::Simple if all this confuses you and you just want to
       write some tests.  You can upgrade to Test::More later
       (it's forward compatible).

       Test::Differences for more ways to test complex data
       structures.  And it plays well with Test::More.

       Test is the old testing module.  Its main benefit is that
       it has been distributed with Perl since 5.004_05.

       Test::Harness for details on how your test results are
       interpreted by Perl.

       Test::Unit describes a very featureful unit testing inter-

perl v5.8.5                 2002-11-06                         13

Test::More(3p)   Perl Programmers Reference Guide  Test::More(3p)

       Test::Inline shows the idea of embedded testing.

       SelfTest is another approach to embedded testing.

       Michael G Schwern <schwernATpobox.com> with much inspira-
       tion from Joshua Pritikin's Test module and lots of help
       from Barrie Slaymaker, Tony Bowden, chromatic and the
       perl-qa gang.

       Copyright 2001 by Michael G Schwern <schwernATpobox.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

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