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Test::Tester(3)                      User Contributed Perl Documentation                     Test::Tester(3)



NAME
       Test::Tester - Ease testing test modules built with Test::Builder

SYNOPSIS
         use Test::Tester tests => 6;

         use Test::MyStyle;

         check_test(
           sub {
             is_mystyle_eq("this", "that", "not eq");
           },
           {
             ok => 0, # expect this to fail
             name => "not eq",
             diag => "Expected: 'this'\nGot: 'that'",
           }
         );

       or

         use Test::Tester;

         use Test::More tests => 3;
         use Test::MyStyle;

         my ($premature, @results) = run_tests(
           sub {
             is_database_alive("dbname");
           }
         );

         # now use Test::More::like to check the diagnostic output

         like($results[0]->{diag}, "/^Database ping took \\d+ seconds$"/, "diag");

DESCRIPTION
       If you have written a test module based on Test::Builder then Test::Tester allows you to test it with
       the minimum of effort.

HOW TO USE (THE EASY WAY)
       From version 0.08 Test::Tester no longer requires you to included anything special in your test
       modules. All you need to do is

         use Test::Tester;

       in your test script before any other Test::Builder based modules and away you go.

       Other modules based on Test::Builder can be used to help with the testing.  In fact you can even use
       functions from your module to test other functions from the same module (while this is possible it is
       probably not a good idea, if your module has bugs, then using it to test itself may give the wrong
       answers).

       The easiest way to test is to do something like

         check_test(
           sub { is_mystyle_eq("this", "that", "not eq") },
           {
             ok => 0, # we expect the test to fail
             name => "not eq",
             diag => "Expected: 'this'\nGot: 'that'",
           }
         );

       this will execute the is_mystyle_eq test, capturing it's results and checking that they are what was
       expected.

       You may need to examine the test results in a more flexible way, for example, the diagnostic output
       may be quite long or complex or it may involve something that you cannot predict in advance like a
       timestamp. In this case you can get direct access to the test results:

         my ($premature, @results) = run_tests(
           sub {
             is_database_alive("dbname");
           }
         );

         like($result[0]->{diag}, "/^Database ping took \\d+ seconds$"/, "diag");

       We cannot predict how long the database ping will take so we use Test::More's like() test to check
       that the diagnostic string is of the right form.

HOW TO USE (THE HARD WAY)
       This is here for backwards compatibility only

       Make your module use the Test::Tester::Capture object instead of the Test::Builder one. How to do
       this depends on your module but assuming that your module holds the Test::Builder object in $Test and
       that all your test routines access it through $Test then providing a function something like this

         sub set_builder
         {
           $Test = shift;
         }

       should allow your test scripts to do

         Test::YourModule::set_builder(Test::Tester->capture);

       and after that any tests inside your module will captured.

TEST RESULTS
       The result of each test is captured in a hash. These hashes are the same as the hashes returned by
       Test::Builder->details but with a couple of extra fields.

       These fields are documented in Test::Builder in the details() function

       ok
         Did the test pass?

       actual_ok
         Did the test really pass? That is, did the pass come from Test::Builder->ok() or did it pass
         because it was a TODO test?

       name
         The name supplied for the test.

       type
         What kind of test? Possibilities include, skip, todo etc. See Test::Builder for more details.

       reason
         The reason for the skip, todo etc. See Test::Builder for more details.

       These fields are exclusive to Test::Tester.

       diag
         Any diagnostics that were output for the test. This only includes diagnostics output after the test
         result is declared.

         Note that Test::Builder ensures that any diagnostics end in a \n and it in earlier versions of
         Test::Tester it was essential that you have the final \n in your expected diagnostics. From version
         0.10 onwards, Test::Tester will add the \n if you forgot it. It will not add a \n if you are
         expecting no diagnostics. See below for help tracking down hard to find space and tab related
         problems.

       depth
         This allows you to check that your test module is setting the correct value for
         $Test::Builder::Level and thus giving the correct file and line number when a test fails. It is
         calculated by looking at caller() and $Test::Builder::Level. It should count how many subroutines
         there are before jumping into the function you are testing. So for example in

           run_tests( sub { my_test_function("a", "b") } );

         the depth should be 1 and in

           sub deeper { my_test_function("a", "b") }

           run_tests(sub { deeper() });

         depth should be 2, that is 1 for the sub {} and one for deeper(). This might seem a little complex
         but if your tests look like the simple examples in this doc then you don't need to worry as the
         depth will always be 1 and that's what Test::Tester expects by default.

         Note: if you do not specify a value for depth in check_test() then it automatically compares it
         against 1, if you really want to skip the depth test then pass in undef.

         Note: depth will not be correctly calculated for tests that run from a signal handler or an END
         block or anywhere else that hides the call stack.

       Some of Test::Tester's functions return arrays of these hashes, just like Test::Builder->details.
       That is, the hash for the first test will be array element 1 (not 0). Element 0 will not be a hash it
       will be a string which contains any diagnostic output that came before the first test. This should
       usually be empty, if it's not, it means something output diagnostics before any test results showed
       up.

SPACES AND TABS
       Appearances can be deceptive, especially when it comes to emptiness. If you are scratching your head
       trying to work out why Test::Tester is saying that your diagnostics are wrong when they look
       perfectly right then the answer is probably whitespace. From version 0.10 on, Test::Tester surrounds
       the expected and got diag values with single quotes to make it easier to spot trailing whitesapce. So
       in this example

         # Got diag (5 bytes):
         # 'abcd '
         # Expected diag (4 bytes):
         # 'abcd'

       it is quite clear that there is a space at the end of the first string.  Another way to solve this
       problem is to use colour and inverse video on an ANSI terminal, see below COLOUR below if you want
       this.

       Unfortunately this is sometimes not enough, neither colour nor quotes will help you with problems
       involving tabs, other non-printing characters and certain kinds of problems inherent in Unicode. To
       deal with this, you can switch Test::Tester into a mode whereby all "tricky" characters are shown as
       \{xx}. Tricky characters are those with ASCII code less than 33 or higher than 126. This makes the
       output more difficult to read but much easier to find subtle differences between strings. To turn on
       this mode either call show_space() in your test script or set the TESTTESTERSPACE environment
       variable to be a true value. The example above would then look like

         # Got diag (5 bytes):
         # abcd\x{20}
         # Expected diag (4 bytes):
         # abcd

COLOUR
       If you prefer to use colour as a means of finding tricky whitespace characters then you can set the
       TESTTESTCOLOUR environment variable to a comma separated pair of colours, the first for the
       foreground, the second for the background. For example "white,red" will print white text on a red
       background. This requires the Term::ANSIColor module. You can specify any colour that would be
       acceptable to the Term::ANSIColor::color function.

       If you spell colour differently, that's no problem. The TESTTESTERCOLOR variable also works (if both
       are set then the British spelling wins out).

EXPORTED FUNCTIONS
       ($premature, @results) = run_tests(\&test_sub)

       \&test_sub is a reference to a subroutine.

       run_tests runs the subroutine in $test_sub and captures the results of any tests inside it. You can
       run more than 1 test inside this subroutine if you like.

       $premature is a string containing any diagnostic output from before the first test.

       @results is an array of test result hashes.

       cmp_result(\%result, \%expect, $name)

       \%result is a ref to a test result hash.

       \%expect is a ref to a hash of expected values for the test result.

       cmp_result compares the result with the expected values. If any differences are found it outputs
       diagnostics. You may leave out any field from the expected result and cmp_result will not do the
       comparison of that field.

       cmp_results(\@results, \@expects, $name)

       \@results is a ref to an array of test results.

       \@expects is a ref to an array of hash refs.

       cmp_results checks that the results match the expected results and if any differences are found it
       outputs diagnostics. It first checks that the number of elements in \@results and \@expects is the
       same. Then it goes through each result checking it against the expected result as in cmp_result()
       above.

       ($premature, @results) = check_tests(\&test_sub, \@expects, $name)

       \&test_sub is a reference to a subroutine.

       \@expect is a ref to an array of hash refs which are expected test results.

       check_tests combines run_tests and cmp_tests into a single call. It also checks if the tests died at
       any stage.

       It returns the same values as run_tests, so you can further examine the test results if you need to.

       ($premature, @results) = check_test(\&test_sub, \%expect, $name)

       \&test_sub is a reference to a subroutine.

       \%expect is a ref to an hash of expected values for the test result.

       check_test is a wrapper around check_tests. It combines run_tests and cmp_tests into a single call,
       checking if the test died. It assumes that only a single test is run inside \&test_sub and include a
       test to make sure this is true.

       It returns the same values as run_tests, so you can further examine the test results if you need to.

       show_space()

       Turn on the escaping of characters as described in the SPACES AND TABS section.

HOW IT WORKS
       Normally, a test module (let's call it Test:MyStyle) calls Test::Builder->new to get the
       Test::Builder object. Test::MyStyle calls methods on this object to record information about test
       results. When Test::Tester is loaded, it replaces Test::Builder's new() method with one which returns
       a Test::Tester::Delegate object. Most of the time this object behaves as the real Test::Builder
       object. Any methods that are called are delegated to the real Test::Builder object so everything
       works perfectly.  However once we go into test mode, the method calls are no longer passed to the
       real Test::Builder object, instead they go to the Test::Tester::Capture object. This object seems
       exactly like the real Test::Builder object, except, instead of outputting test results and
       diagnostics, it just records all the information for later analysis.

SEE ALSO
       Test::Builder the source of testing goodness. Test::Builder::Tester for an alternative approach to
       the problem tackled by Test::Tester - captures the strings output by Test::Builder. This means you
       cannot get separate access to the individual pieces of information and you must predict exactly what
       your test will output.

AUTHOR
       This module is copyright 2005 Fergal Daly <fergal@esatclear.ie>, some parts are based on other
       people's work.

       Plan handling lifted from Test::More. written by Michael G Schwern <schwern@pobox.com>.

       Test::Tester::Capture is a cut down and hacked up version of Test::Builder.  Test::Builder was
       written by chromatic <chromatic@wgz.org> and Michael G Schwern <schwern@pobox.com>.

LICENSE
       Under the same license as Perl itself

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



perl v5.16.2                                     2011-11-30                                  Test::Tester(3)