Test::Base(3) User Contributed Perl Documentation Test::Base(3)NAMETest::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';
sub local_filter {
s/my/your/;
}
__END__
=== Test one (the name of the test)
--- input my_filter local_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 FUNCTIONSTest::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. You can also call the "no_diff" function as a
shortcut.
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, $block->name);
};
run_is([data_name1, data_name2])
Many times you simply want to see if two data sections are equivalent
in every block, probably after having been run through one or more
filters. With the "run_is" function, you can just pass the names of
any two data sections that exist in every block, and it will loop over
every block comparing the two sections.
run_is 'foo', 'bar';
If no data sections are given "run_is" will try to detect them
automatically.
NOTE: Test::Base will silently ignore any blocks that don't contain
both sections.
is_deep($data1, $data2, $test_name)
Like Test::More's "is_deeply" but uses the more correct Test::Deep
module.
run_is_deeply([data_name1, data_name2])
Like "run_is_deeply" but uses "is_deep" which uses the more correct
Test::Deep.
run_is_deeply([data_name1, data_name2])
Like "run_is" but uses "is_deeply" for complex data structure
comparison.
run_is_deeply([data_name1, data_name2])
Like "run_is_deeply" but uses "is_deep" which uses the more correct
Test::Deep.
run_like([data_name, regexp | data_name]);
The "run_like" function is similar to "run_is" except the second
argument is a regular expression. The regexp can either be a "qr{}"
object or a data section that has been filtered into a regular
expression.
run_like 'foo', qr{<html.*};
run_like 'foo', 'match';
run_unlike([data_name, regexp | data_name]);
The "run_unlike" function is similar to "run_like", except the
opposite.
run_unlike 'foo', qr{<html.*};
run_unlike 'foo', 'no_match';
run_compare(data_name1, data_name2)
The "run_compare" function is like the "run_is", "run_is_deeply" and
the "run_like" functions all rolled into one. It loops over each
relevant block and determines what type of comparison to do.
NOTE: If you do not specify either a plan, or run any tests, the
"run_compare" function will automatically be run.
delimiters($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");
no_diff()
Turn off diff support for is() in a test file.
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 SPECIFICATIONTest::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.
Because ONLY is very useful for debugging and sometimes you forgot to
remove the ONLY flag before commiting to the VCS or uploading to CPAN,
Test::Base by default gives you a diag message saying I found ONLY ...
maybe you're debugging?. If you don't like it, use "no_diag_on_only".
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.
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->current_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.
Note that filters defined in the "main" namespace can look like:
sub filter9 {
s/foo/bar/;
}
since Test::Base automatically munges the input string into $_ variable
and checks the return value of the function to see if it looks like a
number. If you must define a filter that returns just a single number,
do it in a different namespace as a method. These filters don't allow
the simplistic $_ munging.
OOTest::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.
DISTRIBUTION SUPPORT
You might be thinking that you do not want to use Test::Base in you
modules, because it adds an installation dependency. Fear not.
Module::Install takes care of that.
Just write a Makefile.PL that looks something like this:
use inc::Module::Install;
name 'Foo';
all_from 'lib/Foo.pm';
use_test_base;
WriteAll;
The line with "use_test_base" will automatically bundle all the code
the user needs to run Test::Base based tests.
OTHER COOL FEATURESTest::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 inducing
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
Ingy doet Net <ingy@cpan.org>
COPYRIGHT
Copyright (c) 2006, 2008, 2009, 2011. Ingy doet Net. Copyright (c)
2005. Brian Ingerson.
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
perl v5.14.1 2011-04-04 Test::Base(3)
