NAME
    Test::Base - A Data Driven Testing Framework

SYNOPSIS
    A new test module:

        # lib/MyProject/Test.pm
        package MyProject::Test;
        use Test::Base -Base;
    
        use MyProject;
    
        package MyProject::Test::Filter;
        use Test::Base::Filter -base;

        sub my_filter {
            return MyProject->do_something(shift);
        }

    A sample test:

        # t/sample.t
        use MyProject::Test;
    
        plan tests => 1 * blocks;
    
        run_is input => 'expected';
    
        __END__
    
        === Test one (the name of the test)
        --- input my_filter
        my
        input
        lines
        --- expected
        expected
        output
    
        === Test two
        This is an optional description
        of this particular test.
        --- input my_filter
        other
        input
        lines
        --- expected
        other expected
        output

DESCRIPTION
    Testing is usually the ugly part of Perl module authoring. Perl gives
    you a standard way to run tests with Test::Harness, and basic testing
    primitives with Test::More. After that you are pretty much on your own
    to develop a testing framework and philosophy. Test::More encourages you
    to make your own framework by subclassing Test::Builder, but that is not
    trivial.

    Test::Base gives you a way to write your own test framework base class
    that *is* trivial. In fact it is as simple as two lines:

        package MyTestFramework;
        use Test::Base -Base;

    A module called "MyTestFramework.pm" containing those two lines, will
    give all the power of Test::More and all the power of Test::Base to
    every test file that uses it. As you build up the capabilities of
    "MyTestFramework", your tests will have all of that power as well.

    "MyTestFramework" becomes a place for you to put all of your reusable
    testing bits. As you write tests, you will see patterns and duplication,
    and you can "upstream" them into "MyTestFramework". Of course, you don't
    have to subclass Test::Base at all. You can use it directly in many
    applications, including everywhere you would use Test::More.

    Test::Base concentrates on offering reusable data driven patterns, so
    that you can write tests with a minimum of code. At the heart of all
    testing you have inputs, processes and expected outputs. Test::Base
    provides some clean ways for you to express your input and expected
    output data, so you can spend your time focusing on that rather than
    your code scaffolding.

EXPORTED FUNCTIONS
    Test::Base extends Test::More and exports all of its functions. So you
    can basically write your tests the same as Test::More. Test::Base also
    exports many functions of its own:

  is(actual, expected, [test-name])
    This is the equivalent of Test::More's "is" function with one
    interesting twist. If your actual and expected results differ and the
    output is multi-line, this function will show you a unified diff format
    of output. Consider the benefit when looking for the one character that
    is different in hundreds of lines of output!

    Diff output requires the optional "Text::Diff" CPAN module. If you don't
    have this module, the "is()" function will simply give you normal
    Test::More output. To disable diffing altogether, set the
    "TEST_SHOW_NO_DIFFS" environment variable (or $ENV{TEST_SHOW_NO_DIFFS})
    to a true value.

  blocks( [data-section-name] )
    The most important function is "blocks". In list context it returns a
    list of "Test::Base::Block" objects that are generated from the test
    specification in the "DATA" section of your test file. In scalar context
    it returns the number of objects. This is useful to calculate your
    Test::More plan.

    Each Test::Base::Block object has methods that correspond to the names
    of that object's data sections. There is also a "name" and a
    "description" method for accessing those parts of the block if they were
    specified.

    The "blocks" function can take an optional single argument, that
    indicates to only return the blocks that contain a particular named data
    section. Otherwise "blocks" returns all blocks.

        my @all_of_my_blocks = blocks;

        my @just_the_foo_blocks = blocks('foo');

  next_block()
    You can use the next_block function to iterate over all the blocks.

        while (my $block = next_block) {
            ...
        }

    It returns undef after all blocks have been iterated over. It can then
    be called again to reiterate.

  first_block()
    Returns the first block or undef if there are none. It resets the
    iterator to the "next_block" function.

  run(&subroutine)
    There are many ways to write your tests. You can reference each block
    individually or you can loop over all the blocks and perform a common
    operation. The "run" function does the looping for you, so all you need
    to do is pass it a code block to execute for each block.

    The "run" function takes a subroutine as an argument, and calls the sub
    one time for each block in the specification. It passes the current
    block object to the subroutine.

        run {
            my $block = shift;
            is(process($block->foo), $block->bar, $block->name);
        };

  run_is(data_name1, data_name2)
    Many times you simply want to see if two data sections are equivalent in
    every block, probably after having been run through one or more filters.
    With the "run_is" function, you can just pass the names of any two data
    sections that exist in every block, and it will loop over every block
    comparing the two sections.

        run_is 'foo', 'bar';

    NOTE: Test::Base will silently ignore any blocks that don't contain both
    sections.

  run_is_deeply(data_name1, data_name2)
    Like "run_is" but uses "is_deeply" for complex data structure
    comparison.

  run_like(data_name, regexp | data_name);
    The "run_like" function is similar to "run_is" except the second
    argument is a regular expression. The regexp can either be a "qr{}"
    object or a data section that has been filtered into a regular
    expression.

        run_like 'foo', qr{<html.*};
        run_like 'foo', 'match';

  run_unlike(data_name, regexp | data_name);
    The "run_unlike" function is similar to "run_like", except the opposite.

        run_unlike 'foo', qr{<html.*};
        run_unlike 'foo', 'no_match';

  delimiters($block_delimiter, $data_delimiter)
    Override the default delimiters of "===" and "---".

  spec_file($file_name)
    By default, Test::Base reads its input from the DATA section. This
    function tells it to get the spec from a file instead.

  spec_string($test_data)
    By default, Test::Base reads its input from the DATA section. This
    function tells it to get the spec from a string that has been prepared
    somehow.

  filters( @filters_list or $filters_hashref )
    Specify a list of additional filters to be applied to all blocks. See
    FILTERS below.

    You can also specify a hash ref that maps data section names to an array
    ref of filters for that data type.

        filters {
            xxx => [qw(chomp lines)],
            yyy => ['yaml'],
            zzz => 'eval',
        };

    If a filters list has only one element, the array ref is optional.

  filters_delay( [1 | 0] );
    By default Test::Base::Block objects are have all their filters run
    ahead of time. There are testing situations in which it is advantageous
    to delay the filtering. Calling this function with no arguments or a
    true value, causes the filtering to be delayed.

        use Test::Base;
        filters_delay;
        plan tests => 1 * blocks;
        for my $block (blocks) {
            ...
            $block->run_filters;
            ok($block->is_filtered);
            ...
        }

    In the code above, the filters are called manually, using the
    "run_filters" method of Test::Base::Block. In functions like "run_is",
    where the tests are run automatically, filtering is delayed until right
    before the test.

  filter_arguments()
    Return the arguments after the equals sign on a filter.

        sub my_filter {
            my $args = filter_arguments;
            # is($args, 'whazzup');
            ...
        }

        __DATA__
        === A test
        --- data my_filter=whazzup

  tie_output()
    You can capture STDOUT and STDERR for operations with this function:

        my $out = '';
        tie_output(*STDOUT, $buffer);
        print "Hey!\n";
        print "Che!\n";
        untie *STDOUT;
        is($out, "Hey!\nChe!\n");

  default_object()
    Returns the default Test::Base object. This is useful if you feel the
    need to do an OO operation in otherwise functional test code. See OO
    below.

  WWW() XXX() YYY() ZZZ()
    These debugging functions are exported from the Spiffy.pm module. See
    Spiffy for more info.

  croak() carp() cluck() confess()
    You can use the functions from the Carp module without needing to import
    them. Test::Base does it for you by default.

TEST SPECIFICATION
    Test::Base allows you to specify your test data in an external file, the
    DATA section of your program or from a scalar variable containing all
    the text input.

    A *test specification* is a series of text lines. Each test (or block)
    is separated by a line containing the block delimiter and an optional
    test "name". Each block is further subdivided into named sections with a
    line containing the data delimiter and the data section name. A
    "description" of the test can go on lines after the block delimiter but
    before the first data section.

    Here is the basic layout of a specification:

        === <block name 1>
        <optional block description lines>
        --- <data section name 1> <filter-1> <filter-2> <filter-n>
        <test data lines>
        --- <data section name 2> <filter-1> <filter-2> <filter-n>
        <test data lines>
        --- <data section name n> <filter-1> <filter-2> <filter-n>
        <test data lines>

        === <block name 2>
        <optional block description lines>
        --- <data section name 1> <filter-1> <filter-2> <filter-n>
        <test data lines>
        --- <data section name 2> <filter-1> <filter-2> <filter-n>
        <test data lines>
        --- <data section name n> <filter-1> <filter-2> <filter-n>
        <test data lines>

    Here is a code example:

        use Test::Base;
    
        delimiters qw(### :::);

        # test code here

        __END__
    
        ### Test One
        We want to see if foo and bar
        are really the same... 
        ::: foo
        a foo line
        another foo line

        ::: bar
        a bar line
        another bar line

        ### Test Two
    
        ::: foo
        some foo line
        some other foo line
    
        ::: bar
        some bar line
        some other bar line

        ::: baz
        some baz line
        some other baz line

    This example specifies two blocks. They both have foo and bar data
    sections. The second block has a baz component. The block delimiter is
    "###" and the data delimiter is ":::".

    The default block delimiter is "===" and the default data delimiter is
    "---".

    There are some special data section names used for control purposes:

        --- SKIP
        --- ONLY
        --- LAST

    A block with a SKIP section causes that test to be ignored. This is
    useful to disable a test temporarily.

    A block with an ONLY section causes only that block to be used. This is
    useful when you are concentrating on getting a single test to pass. If
    there is more than one block with ONLY, the first one will be chosen.

    A block with a LAST section makes that block the last one in the
    specification. All following blocks will be ignored.

FILTERS
    The real power in writing tests with Test::Base comes from its filtering
    capabilities. Test::Base comes with an ever growing set of useful
    generic filters than you can sequence and apply to various test blocks.
    That means you can specify the block serialization in the most readable
    format you can find, and let the filters translate it into what you
    really need for a test. It is easy to write your own filters as well.

    Test::Base allows you to specify a list of filters to each data section
    of each block. The default filters are "norm" and "trim". These filters
    will be applied (in order) to the data after it has been parsed from the
    specification and before it is set into its Test::Base::Block object.

    You can add to the default filter list with the "filters" function. You
    can specify additional filters to a specific block by listing them after
    the section name on a data section delimiter line.

    Example:

        use Test::Base;

        filters qw(foo bar);
        filters { perl => 'strict' };

        sub upper { uc(shift) }

        __END__

        === Test one
        --- foo trim chomp upper
        ...

        --- bar -norm
        ...

        --- perl eval dumper
        my @foo = map {
            - $_;
        } 1..10;
        \ @foo;

    Putting a "-" before a filter on a delimiter line, disables that filter.

  Scalar vs List
    Each filter can take either a scalar or a list as input, and will return
    either a scalar or a list. Since filters are chained together, it is
    important to learn which filters expect which kind of input and return
    which kind of output.

    For example, consider the following filter list:

        norm trim lines chomp array dumper eval

    The data always starts out as a single scalar string. "norm" takes a
    scalar and returns a scalar. "trim" takes a list and returns a list, but
    a scalar is a valid list. "lines" takes a scalar and returns a list.
    "chomp" takes a list and returns a list. "array" takes a list and
    returns a scalar (an anonymous array reference containing the list
    elements). "dumper" takes a list and returns a scalar. "eval" takes a
    scalar and creates a list.

    A list of exactly one element works fine as input to a filter requiring
    a scalar, but any other list will cause an exception. A scalar in list
    context is considered a list of one element.

    Data accessor methods for blocks will return a list of values when used
    in list context, and the first element of the list in scalar context.
    This is usually "the right thing", but be aware.

    head2 The Stock Filters

    Test::Base comes with large set of stock filters. They are in the
    "Test::Base::Filter" module. See Test::Base::Filter for a listing and
    description of these filters.

  Rolling Your Own Filters
    Creating filter extensions is very simple. You can either write a
    *function* in the "main" namespace, or a *method* in the
    "Test::Base::Filter" namespace or a subclass of it. In either case the
    text and any extra arguments are passed in and you return whatever you
    want the new value to be.

    Here is a self explanatory example:

        use Test::Base;

        filters 'foo', 'bar=xyz';

        sub foo {
            transform(shift);
        }
        
        sub Test::Base::Filter::bar {
            my $self = shift;       # The Test::Base::Filter object
            my $data = shift;
            my $args = $self->arguments;
            my $current_block_object = $self->block;
            # transform $data in a barish manner
            return $data;
        }

    If you use the method interface for a filter, you can access the block
    internals by calling the "block" method on the filter object.

    Normally you'll probably just use the functional interface, although all
    the builtin filters are methods.

OO
    Test::Base has a nice functional interface for simple usage. Under the
    hood everything is object oriented. A default Test::Base object is
    created and all the functions are really just method calls on it.

    This means if you need to get fancy, you can use all the object oriented
    stuff too. Just create new Test::Base objects and use the functions as
    methods.

        use Test::Base;
        my $blocks1 = Test::Base->new;
        my $blocks2 = Test::Base->new;

        $blocks1->delimiters(qw(!!! @@@))->spec_file('test1.txt');
        $blocks2->delimiters(qw(### $$$))->spec_string($test_data);

        plan tests => $blocks1->blocks + $blocks2->blocks;

        # ... etc

THE "Test::Base::Block" CLASS
    In Test::Base, blocks are exposed as Test::Base::Block objects. This
    section lists the methods that can be called on a Test::Base::Block
    object. Of course, each data section name is also available as a method.

  name()
    This is the optional short description of a block, that is specified on
    the block separator line.

  description()
    This is an optional long description of the block. It is the text taken
    from between the block separator and the first data section.

  seq_num()
    Returns a sequence number for this block. Sequence numbers begin with 1.

  blocks_object()
    Returns the Test::Base object that owns this block.

  run_filters()
    Run the filters on the data sections of the blocks. You don't need to
    use this method unless you also used the "filters_delay" function.

  is_filtered()
    Returns true if filters have already been run for this block.

  original_values()
    Returns a hash of the original, unfiltered values of each data section.

SUBCLASSING
    One of the nicest things about Test::Base is that it is easy to
    subclass. This is very important, because in your personal project, you
    will likely want to extend Test::Base with your own filters and other
    reusable pieces of your test framework.

    Here is an example of a subclass:

        package MyTestStuff;
        use Test::Base -Base;

        our @EXPORT = qw(some_func);

        sub some_func {
            (my ($self), @_) = find_my_self(@_);
            ...
        }

        package MyTestStuff::Block;
        use base 'Test::Base::Block';

        sub desc {
            $self->description(@_);
        }

        package MyTestStuff::Filter;
        use base 'Test::Base::Filter';

        sub upper {
            $self->assert_scalar(@_);
            uc(shift);
        }

    Note that you don't have to re-Export all the functions from Test::Base.
    That happens automatically, due to the powers of Spiffy.

    The first line in "some_func" allows it to be called as either a
    function or a method in the test code.

OTHER COOL FEATURES
    Test::Base automatically adds

        use strict;
        use warnings;

    to all of your test scripts and Test::Base subclasses. A Spiffy feature
    indeed.

HISTORY
    This module started its life with the horrible and ridicule invoking
    name "Test::Chunks". It was renamed to "Test::Base" with the hope that
    it would be seen for the very useful module that it has become. If you
    are switching from "Test::Chunks" to "Test::Base", simply substitute the
    concept and usage of "chunks" to "blocks".

AUTHOR
    Brian Ingerson <ingy@cpan.org>

COPYRIGHT
    Copyright (c) 2005. Brian Ingerson. All rights reserved.

    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