| |
Test::Class(3pm) - phpMan
Test::Class(3pm) User Contributed Perl Documentation Test::Class(3pm)
NAME
Test::Class - Easily create test classes in an xUnit/JUnit style
SYNOPSIS
package Example::Test;
use base qw(Test::Class);
use Test::More;
# setup methods are run before every test method.
sub make_fixture : Test(setup) {
my $array = [1, 2];
shift->{test_array} = $array;
};
# a test method that runs 1 test
sub test_push : Test {
my $array = shift->{test_array};
push @$array, 3;
is_deeply($array, [1, 2, 3], 'push worked');
};
# a test method that runs 4 tests
sub test_pop : Test(4) {
my $array = shift->{test_array};
is(pop @$array, 2, 'pop = 2');
is(pop @$array, 1, 'pop = 1');
is_deeply($array, [], 'array empty');
is(pop @$array, undef, 'pop = undef');
};
# teardown methods are run after every test method.
sub teardown : Test(teardown) {
my $array = shift->{test_array};
diag("array = (@$array) after test(s)");
};
later in a nearby .t file
#! /usr/bin/perl
use Example::Test;
# run all the test methods in Example::Test
Test::Class->runtests;
Outputs:
1..5
ok 1 - pop = 2
ok 2 - pop = 1
ok 3 - array empty
ok 4 - pop = undef
# array = () after test(s)
ok 5 - push worked
# array = (1 2 3) after test(s)
DESCRIPTION
Test::Class provides a simple way of creating classes and objects to test your code in an
xUnit style.
Built using Test::Builder, it was designed to work with other Test::Builder based modules
(Test::More, Test::Differences, Test::Exception, etc.).
Note: This module will make more sense, if you are already familiar with the "standard"
mechanisms for testing perl code. Those unfamiliar with Test::Harness, Test::Simple,
Test::More and friends should go take a look at them now. Test::Tutorial is a good
starting point.
INTRODUCTION
A brief history lesson
In 1994 Kent Beck wrote a testing framework for Smalltalk called SUnit. It was popular.
You can read a copy of his original paper at <http://www.xprogramming.com/testfram.htm>.
Later Kent Beck and Erich Gamma created JUnit for testing Java <http://www.junit.org/>. It
was popular too.
Now there are xUnit frameworks for every language from Ada to XSLT. You can find a list at
<http://www.xprogramming.com/software.htm>.
While xUnit frameworks are traditionally associated with unit testing they are also useful
in the creation of functional/acceptance tests.
Test::Class is (yet another) implementation of xUnit style testing in Perl.
Why you should use Test::Class
Test::Class attempts to provide simple xUnit testing that integrates simply with the
standard perl *.t style of testing. In particular:
· All the advantages of xUnit testing. You can easily create test fixtures and isolate
tests. It provides a framework that should be familiar to people who have used other
xUnit style test systems.
· It is built with Test::Builder and should co-exist happily with all other
Test::Builder based modules. This makes using test classes in *.t scripts, and
refactoring normal tests into test classes, much simpler because:
· You do not have to learn a new set of new test APIs and can continue using ok(),
like(), etc. from Test::More and friends.
· Skipping tests and todo tests are supported.
· You can have normal tests and Test::Class classes co-existing in the same *.t
script. You don't have to re-write an entire script, but can use test classes as
and when it proves useful.
· You can easily package your tests as classes/modules, rather than *.t scripts. This
simplifies reuse, documentation and distribution, encourages refactoring, and allows
tests to be extended by inheritance.
· You can have multiple setup/teardown methods. For example have one teardown method to
clean up resources and another to check that class invariants still hold.
· It can make running tests faster. Once you have refactored your *.t scripts into
classes they can be easily run from a single script. This gains you the (often
considerable) start up time that each separate *.t script takes.
Why you should not use Test::Class
· If your *.t scripts are working fine then don't bother with Test::Class. For simple
test suites it is almost certainly overkill. Don't start thinking about using
Test::Class until issues like duplicate code in your test scripts start to annoy.
· If you are distributing your code it is yet another module that the user has to have
to run your tests (unless you distribute it with your test suite of course).
· If you are used to the TestCase/Suite/Runner class structure used by JUnit and similar
testing frameworks you may find Test::Unit more familiar (but try reading "HELP FOR
CONFUSED JUNIT USERS" before you give up).
TEST CLASSES
A test class is just a class that inherits from Test::Class. Defining a test class is as
simple as doing:
package Example::Test;
use base qw(Test::Class);
Since Test::Class does not provide its own test functions, but uses those provided by
Test::More and friends, you will nearly always also want to have:
use Test::More;
to import the test functions into your test class.
METHOD TYPES
There are three different types of method you can define using Test::Class.
1) Test methods
You define test methods using the Test attribute. For example:
package Example::Test;
use base qw(Test::Class);
use Test::More;
sub subtraction : Test {
is( 2-1, 1, 'subtraction works' );
};
This declares the "subtraction" method as a test method that runs one test.
If your test method runs more than one test, you should put the number of tests in
brackets like this:
sub addition : Test(2) {
is(10 + 20, 30, 'addition works');
is(20 + 10, 30, ' both ways');
};
If you don't know the number of tests at compile time you can use "no_plan" like this.
sub check_class : Test(no_plan) {
my $objects = shift->{objects};
isa_ok($_, "Object") foreach @$objects;
};
or use the :Tests attribute, which acts just like ":Test" but defaults to "no_plan" if no
number is given:
sub check_class : Tests {
my $objects = shift->{objects};
isa_ok($_, "Object") foreach @$objects;
};
2) Setup and teardown methods
Setup and teardown methods are run before and after every test. For example:
sub before : Test(setup) { diag("running before test") };
sub after : Test(teardown) { diag("running after test") };
You can use setup and teardown methods to create common objects used by all of your test
methods (a test fixture) and store them in your Test::Class object, treating it as a hash.
For example:
sub pig : Test(setup) {
my $self = shift;
$self->{test_pig} = Pig->new;
};
sub born_hungry : Test {
my $pig = shift->{test_pig};
is($pig->hungry, 'pigs are born hungry');
};
sub eats : Test(3) {
my $pig = shift->{test_pig};
ok( $pig->feed, 'pig fed okay');
ok(! $pig->hungry, 'fed pig not hungry');
ok(! $pig->feed, 'cannot feed full pig');
};
You can also declare setup and teardown methods as running tests. For example you could
check that the test pig survives each test method by doing:
sub pig_alive : Test(teardown => 1) {
my $pig = shift->{test_pig};
ok($pig->alive, 'pig survived tests' );
};
3) Startup and shutdown methods
Startup and shutdown methods are like setup and teardown methods for the whole test class.
All the startup methods are run once when you start running a test class. All the shutdown
methods are run once just before a test class stops running.
You can use these to create and destroy expensive objects that you don't want to have to
create and destroy for every test - a database connection for example:
sub db_connect : Test(startup) {
shift->{dbi} = DBI->connect;
};
sub db_disconnect : Test(shutdown) {
shift->{dbi}->disconnect;
};
Just like setup and teardown methods you can pass an optional number of tests to startup
and shutdown methods. For example:
sub example : Test(startup => 1) {
ok(1, 'a startup method with one test');
};
If you want to run an unknown number of tests within your startup method, you need to say
e.g.
sub example : Test(startup => no_plan) {
ok(1, q{The first of many tests that don't want to have to count});
...
}
as the : Tests attribute behaves exactly like : Test in this context.
If a startup method has a failing test or throws an exception then all other tests for the
current test object are ignored.
RUNNING TESTS
You run test methods with runtests(). Doing:
Test::Class->runtests
runs all of the test methods in every loaded test class. This allows you to easily load
multiple test classes in a *.t file and run them all.
#! /usr/bin/perl
# load all the test classes I want to run
use Foo::Test;
use Foo::Bar::Test;
use Foo::Fribble::Test;
use Foo::Ni::Test;
# and run them all
Test::Class->runtests;
You can use Test::Class::Load to automatically load all the test classes in a given set of
directories.
If you need finer control you can create individual test objects with new(). For example
to just run the tests in the test class "Foo::Bar::Test" you can do:
Example::Test->new->runtests
You can also pass runtests() a list of test objects to run. For example:
my $o1 = Example::Test->new;
my $o2 = Another::Test->new;
# runs all the tests in $o1 and $o2
$o1->runtests($o2);
Since, by definition, the base Test::Class has no tests you could also have written:
my $o1 = Example::Test->new;
my $o2 = Another::Test->new;
Test::Class->runtests($o1, $o2);
If you pass runtests() class names it will automatically create test objects for you, so
the above can be written more compactly as:
Test::Class->runtests(qw( Example::Test Another::Test ))
In all of the above examples runtests() will look at the number of tests both test classes
run and output an appropriate test header for Test::Harness automatically.
What happens if you run test classes and normal tests in the same script? For example:
Test::Class->runtests;
ok(Example->new->foo, 'a test not in the test class');
ok(Example->new->bar, 'ditto');
Test::Harness will complain that it saw more tests than it expected since the test header
output by runtests() will not include the two normal tests.
To overcome this problem you can pass an integer value to runtests(). This is added to the
total number of tests in the test header. So the problematic example can be rewritten as
follows:
Test::Class->runtests(+2);
ok(Example->new->foo, 'a test not in the test class');
ok(Example->new->bar, 'ditto');
If you prefer to write your test plan explicitly you can use expected_tests() to find out
the number of tests a class/object is expected to run.
Since runtests() will not output a test plan if one has already been set the previous
example can be written as:
plan tests => Test::Class->expected_tests(+2);
Test::Class->runtests;
ok(Example->new->foo, 'a test not in the test class');
ok(Example->new->bar, 'ditto');
Remember: Test objects are just normal perl objects. Test classes are just normal perl
classes. Setup, test and teardown methods are just normal methods. You are completely free
to have other methods in your class that are called from your test methods, or have object
specific "new" and "DESTROY" methods.
In particular you can override the new() method to pass parameters to your test object, or
re-define the number of tests a method will run. See num_method_tests() for an example.
TEST DESCRIPTIONS
The test functions you import from Test::More and other Test::Builder based modules
usually take an optional third argument that specifies the test description, for example:
is $something, $something_else, 'a description of my test';
If you do not supply a test description, and the test function does not supply its own
default, then Test::Class will use the name of the currently running test method,
replacing all "_" characters with spaces so:
sub one_plus_one_is_two : Test {
is 1+1, 2;
}
will result in:
ok 1 - one plus one is two
RUNNING ORDER OF METHODS
Methods of each type are run in the following order:
1. All of the startup methods in alphabetical order
2. For each test method, in alphabetical order:
· All of the setup methods in alphabetical order
· The test method.
· All of the teardown methods in alphabetical order
3. All of the shutdown methods in alphabetical order.
Most of the time you should not care what order tests are run in, but it can occasionally
be useful to force some test methods to be run early. For example:
sub _check_new {
my $self = shift;
isa_ok(Object->new, "Object") or $self->BAILOUT('new fails!');
};
The leading "_" will force the above method to run first - allowing the entire suite to be
aborted before any other test methods run.
HANDLING EXCEPTIONS
If a startup, setup, test, teardown or shutdown method dies then runtests() will catch the
exception and fail any remaining test. For example:
sub test_object : Test(2) {
my $object = Object->new;
isa_ok( $object, "Object" ) or die "could not create object\n";
ok( $object->open, "open worked" );
};
will produce the following if the first test failed:
not ok 1 - The object isa Object
# Failed test 'The object isa Object'
# at /Users/adrianh/Desktop/foo.pl line 14.
# (in MyTest->test_object)
# The object isn't defined
not ok 2 - test_object died (could not create object)
# Failed test 'test_object died (could not create object)'
# at /Users/adrianh/Desktop/foo.pl line 19.
# (in MyTest->test_object)
This can considerably simplify testing code that throws exceptions.
Rather than having to explicitly check that the code exited normally (e.g. with "lives_ok"
in Test::Exception) the test will fail automatically - without aborting the other test
methods. For example contrast:
use Test::Exception;
my $file;
lives_ok { $file = read_file('test.txt') } 'file read';
is($file, "content", 'test file read');
with:
sub read_file : Test {
is(read_file('test.txt'), "content", 'test file read');
};
If more than one test remains after an exception then the first one is failed, and the
remaining ones are skipped.
If the setup method of a test method dies, then all of the remaining setup and shutdown
methods are also skipped.
Since startup methods will usually be creating state needed by all the other test methods
an exception within a startup method will prevent all other test methods of that class
running.
RETURNING EARLY
If a test method returns before it has run all of its tests, by default the missing tests
are deemed to have been skipped; see "Skipped Tests" for more information.
However, if the class's "fail_if_returned_early" method returns true, then the missing
tests will be deemed to have failed. For example,
package MyClass;
use base 'Test::Class';
sub fail_if_returned_early { 1 }
sub oops : Tests(8) {
for (my $n=1; $n*$n<50; ++$n) {
ok 1, "$n squared is less than fifty";
}
}
SKIPPED TESTS
You can skip the rest of the tests in a method by returning from the method before all the
test have finished running (but see "Returning Early" for how to change this). The value
returned is used as the reason for the tests being skipped.
This makes managing tests that can be skipped for multiple reasons very simple. For
example:
sub flying_pigs : Test(5) {
my $pig = Pig->new;
isa_ok($pig, 'Pig') or return("cannot breed pigs")
can_ok($pig, 'takeoff') or return("pigs don't fly here");
ok($pig->takeoff, 'takeoff') or return("takeoff failed");
ok( $pig->altitude > 0, 'Pig is airborne' );
ok( $pig->airspeed > 0, ' and moving' );
};
If you run this test in an environment where "Pig->new" worked and the takeoff method
existed, but failed when ran, you would get:
ok 1 - The object isa Pig
ok 2 - can takeoff
not ok 3 - takeoff
ok 4 # skip takeoff failed
ok 5 # skip takeoff failed
You can also skip tests just as you do in Test::More or Test::Builder - see "Conditional
tests" in Test::More for more information.
Note: if you want to skip tests in a method with "no_plan" tests then you have to
explicitly skip the tests in the method - since Test::Class cannot determine how many
tests (if any) should be skipped:
sub test_objects : Tests {
my $self = shift;
my $objects = $self->{objects};
if (@$objects) {
isa_ok($_, "Object") foreach (@$objects);
} else {
$self->builder->skip("no objects to test");
};
};
Another way of overcoming this problem is to explicitly set the number of tests for the
method at run time using num_method_tests() or "num_tests".
You can make a test class skip all of its tests by setting SKIP_CLASS() before runtests()
is called.
TO DO TESTS
You can create todo tests just as you do in Test::More and Test::Builder using the $TODO
variable. For example:
sub live_test : Test {
local $TODO = "live currently unimplemented";
ok(Object->live, "object live");
};
See "Todo tests" in Test::Harness for more information.
EXTENDING TEST CLASSES BY INHERITANCE
You can extend test methods by inheritance in the usual way. For example consider the
following test class for a "Pig" object.
package Pig::Test;
use base qw(Test::Class);
use Test::More;
sub testing_class { "Pig" };
sub new_args { (-age => 3) };
sub setup : Test(setup) {
my $self = shift;
my $class = $self->testing_class;
my @args = $self->new_args;
$self->{pig} = $class->new( @args );
};
sub _creation : Test {
my $self = shift;
isa_ok($self->{pig}, $self->testing_class)
or $self->FAIL_ALL('Pig->new failed');
};
sub check_fields : Test {
my $pig = shift->{pig};
is($pig->age, 3, "age accessed");
};
Next consider "NamedPig" a subclass of "Pig" where you can give your pig a name.
We want to make sure that all the tests for the "Pig" object still work for "NamedPig". We
can do this by subclassing "Pig::Test" and overriding the "testing_class" and "new_args"
methods.
package NamedPig::Test;
use base qw(Pig::Test);
use Test::More;
sub testing_class { "NamedPig" };
sub new_args { (shift->SUPER::new_args, -name => 'Porky') };
Now we need to test the name method. We could write another test method, but we also have
the option of extending the existing "check_fields" method.
sub check_fields : Test(2) {
my $self = shift;
$self->SUPER::check_fields;
is($self->{pig}->name, 'Porky', 'name accessed');
};
While the above works, the total number of tests for the method is dependent on the number
of tests in its "SUPER::check_fields". If we add a test to "Pig::Test->check_fields" we
will also have to update the number of tests of "NamedPig::test->check_fields".
Test::Class allows us to state explicitly that we are adding tests to an existing method
by using the "+" prefix. Since we are adding a single test to "check_fields" it can be
rewritten as:
sub check_fields : Test(+1) {
my $self = shift;
$self->SUPER::check_fields;
is($self->{pig}->name, 'Porky', 'name accessed');
};
With the above definition you can add tests to "check_fields" in "Pig::Test" without
affecting "NamedPig::Test".
RUNNING INDIVIDUAL TESTS
NOTE: The exact mechanism for running individual tests is likely to change in the future.
Sometimes you just want to run a single test. Commenting out other tests or writing code
to skip them can be a hassle, so you can specify the "TEST_METHOD" environment variable.
The value is expected to be a valid regular expression and, if present, only runs test
methods whose names match the regular expression. Startup, setup, teardown and shutdown
tests will still be run.
One easy way of doing this is by specifying the environment variable before the "runtests"
method is called.
Running a test named "customer_profile":
#! /usr/bin/perl
use Example::Test;
$ENV{TEST_METHOD} = 'customer_profile';
Test::Class->runtests;
Running all tests with "customer" in their name:
#! /usr/bin/perl
use Example::Test;
$ENV{TEST_METHOD} = '.*customer.*';
Test::Class->runtests;
If you specify an invalid regular expression, your tests will not be run:
#! /usr/bin/perl
use Example::Test;
$ENV{TEST_METHOD} = 'C++';
Test::Class->runtests;
And when you run it:
TEST_METHOD (C++) is not a valid regular expression: Search pattern \
not terminated at (eval 17) line 1.
ORGANISING YOUR TEST CLASSES
You can, of course, organise your test modules as you wish. My personal preferences is:
· Name test classes with a suffix of "::Test" so the test class for the "Foo::Bar"
module would be "Foo::Bar::Test".
· Place all test classes in t/lib.
The Test::Class::Load provides a simple mechanism for easily loading all of the test
classes in a given set of directories.
A NOTE ON LOADING TEST CLASSES
Due to its use of subroutine attributes Test::Class based modules must be loaded at
compile rather than run time. This is because the :Test attribute is applied by a CHECK
block.
This can be problematic if you want to dynamically load Test::Class modules. Basically
while:
require $some_test_class;
will break, doing:
BEGIN { require $some_test_class };
will work just fine. For more information on CHECK blocks see "BEGIN, CHECK, INIT and END"
in perlmod.
If you still can't arrange for your classes to be loaded at runtime, you could use an
alternative mechanism for adding your tests:
# sub test_something : Test(3) {...}
# becomes
sub test_something {...}
__PACKAGE__->add_testinfo('test_something', test => 3);
See the add_testinfo method for more details.
GENERAL FILTERING OF TESTS
The use of $ENV{TEST_METHOD} to run just a subset of tests is useful, but sometimes it
doesn't give the level of granularity that you desire. Another feature of this class is
the ability to do filtering on other static criteria. In order to permit this, a generic
filtering method is supported. This can be used by specifying coderefs to the
'add_filter' method of this class.
In determining which tests should be run, all filters that have previously been specified
via the add_filter method will be run in-turn for each normal test method. If any of
these filters return a false value, the method will not be executed, or included in the
number of tests. Note that filters will only be run for normal test methods, they are
ignored for startup, shutdown, setup, and teardown test methods.
Note that test filters are global, and will affect all tests in all classes, not just the
one that they were defined in.
An example of this mechanism that mostly simulates the use of TEST_METHOD above is:
package MyTests;
use Test::More;
use base qw( Test::Class );
my $MYTEST_METHOD = qr/^t_not_filtered$/;
my $filter = sub {
my ( $test_class, $test_method ) = @_;
return $test_method =~ $MYTEST_METHOD;
};
Test::Class->add_filter( $filter );
sub t_filtered : Test( 1 ) {
fail( "filtered test run" );
}
sub t_not_filtered : Test( 1 ) {
pass( "unfiltered test run" );
}
METHODS
Creating and running tests
Test
# test methods
sub method_name : Test { ... };
sub method_name : Test(N) { ... };
# setup methods
sub method_name : Test(setup) { ... };
sub method_name : Test(setup => N) { ... };
# teardown methods
sub method_name : Test(teardown) { ... };
sub method_name : Test(teardown => N) { ... };
# startup methods
sub method_name : Test(startup) { ... };
sub method_name : Test(startup => N) { ... };
# shutdown methods
sub method_name : Test(shutdown) { ... };
sub method_name : Test(shutdown => N) { ... };
Marks a startup, setup, test, teardown or shutdown method. See runtests() for
information on how to run methods declared with the "Test" attribute.
N specifies the number of tests the method runs.
· If N is an integer then the method should run exactly N tests.
· If N is an integer with a "+" prefix then the method is expected to call its
"SUPER::" method and extend it by running N additional tests.
· If N is the string "no_plan" then the method can run an arbitrary number of tests.
If N is not specified it defaults to 1 for test methods, and 0 for startup, setup,
teardown and shutdown methods.
You can change the number of tests that a method runs using num_method_tests() or
num_tests().
Tests
sub method_name : Tests { ... };
sub method_name : Tests(N) { ... };
Acts just like the ":Test" attribute, except that if the number of tests is not
specified it defaults to "no_plan". So the following are equivalent:
sub silly1 :Test( no_plan ) { ok(1) foreach (1 .. rand 5) };
sub silly2 :Tests { ok(1) foreach (1 .. rand 5) };
new
$Tests = CLASS->new(KEY => VAL ...)
$Tests2 = $Tests->new(KEY => VAL ...)
Creates a new test object (blessed hashref) containing the specified key/value pairs.
If called as an object method the existing object's key/value pairs are copied into
the new object. Any key/value pairs passed to "new" override those in the original
object if duplicates occur.
Since the test object is passed to every test method as it runs it is a convenient
place to store test fixtures. For example:
sub make_fixture : Test(setup) {
my $self = shift;
$self->{object} = Object->new();
$self->{dbh} = Mock::DBI->new(-type => normal);
};
sub test_open : Test {
my $self = shift;
my ($o, $dbh) = ($self->{object}, $self->{dbh});
ok($o->open($dbh), "opened ok");
};
See num_method_tests() for an example of overriding "new".
expected_tests
$n = $Tests->expected_tests
$n = CLASS->expected_tests
$n = $Tests->expected_tests(TEST, ...)
$n = CLASS->expected_tests(TEST, ...)
Returns the total number of tests that runtests() will run on the specified
class/object. This includes tests run by any setup and teardown methods.
Will return "no_plan" if the exact number of tests is undetermined (i.e. if any setup,
test or teardown method has an undetermined number of tests).
The "expected_tests" of an object after runtests() has been executed will include any
run time changes to the expected number of tests made by num_tests() or
num_method_tests().
"expected_tests" can also take an optional list of test objects, test classes and
integers. In this case the result is the total number of expected tests for all the
test/object classes (including the one the method was applied to) plus any integer
values.
"expected_tests" is useful when you're integrating one or more test classes into a
more traditional test script, for example:
use Test::More;
use My::Test::Class;
plan tests => My::Test::Class->expected_tests(+2);
ok(whatever, 'a test');
ok(whatever, 'another test');
My::Test::Class->runtests;
runtests
$allok = $Tests->runtests
$allok = CLASS->runtests
$allok = $Tests->runtests(TEST, ...)
$allok = CLASS->runtests(TEST, ...)
"runtests" is used to run test classes. At its most basic doing:
$test->runtests
will run the test methods of the test object $test, unless "$test->SKIP_CLASS" returns
a true value.
Unless you have already specified a test plan using Test::Builder (or Test::More, et
al) "runtests" will set the test plan just before the first method that runs a test is
executed.
If the environment variable "TEST_VERBOSE" is set "runtests" will display the name of
each test method before it runs like this:
# My::Test::Class->my_test
ok 1 - fribble
# My::Test::Class->another_test
ok 2 - bar
Just like expected_tests(), "runtests" can take an optional list of test
object/classes and integers. All of the test object/classes are run. Any integers are
added to the total number of tests shown in the test header output by "runtests".
For example, you can run all the tests in test classes A, B and C, plus one additional
normal test by doing:
Test::Class->runtests(qw(A B C), +1);
ok(1==1, 'non class test');
Finally, if you call "runtests" on a test class without any arguments it will run all
of the test methods of that class, and all subclasses of that class. For example:
#! /usr/bin/perl
# Test all the Foo stuff
use Foo::Test;
use Foo::Bar::Test;
use Foo::Ni::Test;
# run all the Foo*Test modules we just loaded
Test::Class->runtests;
SKIP_CLASS
$reason = CLASS->SKIP_CLASS;
CLASS->SKIP_CLASS( $reason );
Determines whether the test class CLASS should run it's tests. If SKIP_CLASS returns a
true value then runtests() will not run any of the test methods in CLASS.
You can override the default on a class-by-class basis by supplying a new value to
SKIP_CLASS. For example if you have an abstract base class that should not run just
add the following to your module:
My::Abstract::Test->SKIP_CLASS( 1 );
This will not affect any sub-classes of "My::Abstract::Test" which will run as normal.
If the true value returned by SKIP_CLASS is anything other than "1" then a skip test
is output using this value as the skip message. For example:
My::Postgres::Test->SKIP_CLASS(
$ENV{POSTGRES_HOME} ? 0 : '$POSTGRES_HOME needs to be set'
);
will output something like this if "POSTGRES_HOME" is not set
... other tests ...
ok 123 # skip My::Postgres::Test - $POSTGRES_HOME needs to be set
... more tests ...
You can also override SKIP_CLASS for a class hierarchy. For example, to prevent any
subclasses of My::Postgres::Test running we could override SKIP_CLASS like this:
sub My::Postgres::Test::SKIP_CLASS {
$ENV{POSTGRES_HOME} ? 0 : '$POSTGRES_HOME needs to be set'
};
Fetching and setting a method's test number
num_method_tests
$n = $Tests->num_method_tests($method_name)
$Tests->num_method_tests($method_name, $n)
$n = CLASS->num_method_tests($method_name)
CLASS->num_method_tests($method_name, $n)
Fetch or set the number of tests that the named method is expected to run.
If the method has an undetermined number of tests then $n should be the string
"no_plan".
If the method is extending the number of tests run by the method in a superclass then
$n should have a "+" prefix.
When called as a class method any change to the expected number of tests applies to
all future test objects. Existing test objects are unaffected.
When called as an object method any change to the expected number of tests applies to
that object alone.
"num_method_tests" is useful when you need to set the expected number of tests at
object creation time, rather than at compile time.
For example, the following test class will run a different number of tests depending
on the number of objects supplied.
package Object::Test;
use base qw(Test::Class);
use Test::More;
sub new {
my $class = shift;
my $self = $class->SUPER::new(@_);
my $num_objects = @{$self->{objects}};
$self->num_method_tests('test_objects', $num_objects);
return($self);
};
sub test_objects : Tests {
my $self = shift;
ok($_->open, "opened $_") foreach @{$self->{objects}};
};
...
# This runs two tests
Object::Test->new(objects => [$o1, $o2]);
The advantage of setting the number of tests at object creation time, rather than
using a test method without a plan, is that the number of expected tests can be
determined before testing begins. This allows better diagnostics from runtests(),
Test::Builder and Test::Harness.
"num_method_tests" is a protected method and can only be called by subclasses of
Test::Class. It fetches or sets the expected number of tests for the methods of the
class it was called in, not the methods of the object/class it was applied to. This
allows test classes that use "num_method_tests" to be subclassed easily.
For example, consider the creation of a subclass of Object::Test that ensures that all
the opened objects are read-only:
package Special::Object::Test;
use base qw(Object::Test);
use Test::More;
sub test_objects : Test(+1) {
my $self = shift;
$self->SUPER::test_objects;
my @bad_objects = grep {! $_->read_only} (@{$self->{objects}});
ok(@bad_objects == 0, "all objects read only");
};
...
# This runs three tests
Special::Object::Test->new(objects => [$o1, $o2]);
Since the call to "num_method_tests" in Object::Test only affects the "test_objects"
of Object::Test, the above works as you would expect.
num_tests
$n = $Tests->num_tests
$Tests->num_tests($n)
$n = CLASS->num_tests
CLASS->num_tests($n)
Set or return the number of expected tests associated with the currently running test
method. This is the same as calling num_method_tests() with a method name of
current_method().
For example:
sub txt_files_readable : Tests {
my $self = shift;
my @files = <*.txt>;
$self->num_tests(scalar(@files));
ok(-r $_, "$_ readable") foreach (@files);
};
Setting the number of expected tests at run time, rather than just having a "no_plan"
test method, allows runtests() to display appropriate diagnostic messages if the
method runs a different number of tests.
Support methods
builder
$Tests->builder
Returns the underlying Test::Builder object that Test::Class uses. For example:
sub test_close : Test {
my $self = shift;
my ($o, $dbh) = ($self->{object}, $self->{dbh});
$self->builder->ok($o->close($dbh), "closed ok");
};
current_method
$method_name = $Tests->current_method
$method_name = CLASS->current_method
Returns the name of the test method currently being executed by runtests(), or "undef"
if runtests() has not been called.
The method name is also available in the setup and teardown methods that run before
and after the test method. This can be useful in producing diagnostic messages, for
example:
sub test_invarient : Test(teardown => 1) {
my $self = shift;
my $m = $self->current_method;
ok($self->invarient_ok, "class okay after $m");
};
BAILOUT
$Tests->BAILOUT($reason)
CLASS->BAILOUT($reason)
Things are going so badly all testing should terminate, including running any
additional test scripts invoked by Test::Harness. This is exactly the same as doing:
$self->builder->BAILOUT
See "BAILOUT" in Test::Builder for details. Any teardown and shutdown methods are not
run.
FAIL_ALL
$Tests->FAIL_ALL($reason)
CLASS->FAIL_ALL($reason)
Things are going so badly all the remaining tests in the current script should fail.
Exits immediately with the number of tests failed, or 254 if more than 254 tests were
run. Any teardown methods are not run.
This does not affect the running of any other test scripts invoked by Test::Harness.
For example, if all your tests rely on the ability to create objects then you might
want something like this as an early test:
sub _test_new : Test(3) {
my $self = shift;
isa_ok(Object->new, "Object")
|| $self->FAIL_ALL('cannot create Objects');
...
};
SKIP_ALL
$Tests->SKIP_ALL($reason)
CLASS->SKIP_ALL($reason)
Things are going so badly all the remaining tests in the current script should be
skipped. Exits immediately with 0 - teardown methods are not run.
This does not affect the running of any other test scripts invoked by Test::Harness.
For example, if you had a test script that only applied to the darwin OS you could
write:
sub _darwin_only : Test(setup) {
my $self = shift;
$self->SKIP_ALL("darwin only") unless $^O eq "darwin";
};
add_testinfo
CLASS->add_testinfo($name, $type, $num_tests)
Chiefly for use by libraries like Test::Class::Sugar, which can't use the ":Test(...)"
interfaces make test methods. "add_testinfo" informs the class about a test method
that has been defined without a "Test", "Tests" or other attribute.
$name is the name of the method, $type must be one of "startup", "setup", "test",
"teardown" or "shutdown", and $num_tests has the same meaning as "N" in the
description of the Test attribute.
add_filter
CLASS->add_filter($filter_coderef);
Adds a filtering coderef. Each filter is passed a test class and method name and
returns a boolean. All filters are applied globally in the order they were added. If
any filter returns false the test method is not run or included in the number of
tests.
Note that filters will only be run for normal test methods, they are ignored for
startup, shutdown, setup, and teardown test methods.
See the section on the "GENERAL FILTERING OF TESTS" for more information.
fail_if_returned_early
Controls what happens if a method returns before it has run all of its tests. It is
called with no arguments in boolean context; if it returns true, then the missing
tests fail, otherwise, they skip. See "Returning Early" and "Skipped Tests".
HELP FOR CONFUSED JUNIT USERS
This section is for people who have used JUnit (or similar) and are confused because they
don't see the TestCase/Suite/Runner class framework they were expecting. Here we take each
of the major classes in JUnit and compare them with their equivalent Perl testing modules.
Class Assert
The test assertions provided by Assert correspond to the test functions provided by
the Test::Builder based modules (Test::More, Test::Exception, Test::Differences, etc.)
Unlike JUnit the test functions supplied by Test::More et al do not throw exceptions
on failure. They just report the failure to STDOUT where it is collected by
Test::Harness. This means that where you have
sub foo : Test(2) {
ok($foo->method1);
ok($foo->method2);
};
The second test will run if the first one fails. You can emulate the JUnit way of
doing it by throwing an explicit exception on test failure:
sub foo : Test(2) {
ok($foo->method1) or die "method1 failed";
ok($foo->method2);
};
The exception will be caught by Test::Class and the other test automatically failed.
Class TestCase
Test::Class corresponds to TestCase in JUnit.
In Test::Class setup, test and teardown methods are marked explicitly using the Test
attribute. Since we need to know the total number of tests to provide a test plan for
Test::Harness we also state how many tests each method runs.
Unlike JUnit you can have multiple setup/teardown methods in a class.
Class TestSuite
Test::Class also does the work that would be done by TestSuite in JUnit.
Since the methods are marked with attributes Test::Class knows what is and isn't a
test method. This allows it to run all the test methods without having the developer
create a suite manually, or use reflection to dynamically determine the test methods
by name. See the runtests() method for more details.
The running order of the test methods is fixed in Test::Class. Methods are executed in
alphabetical order.
Unlike JUnit, Test::Class currently does not allow you to run individual test methods.
Class TestRunner
Test::Harness does the work of the TestRunner in JUnit. It collects the test results
(sent to STDOUT) and collates the results.
Unlike JUnit there is no distinction made by Test::Harness between errors and
failures. However, it does support skipped and todo test - which JUnit does not.
If you want to write your own test runners you should look at Test::Harness::Straps.
OTHER MODULES FOR XUNIT TESTING IN PERL
In addition to Test::Class there are two other distributions for xUnit testing in perl.
Both have a longer history than Test::Class and might be more suitable for your needs.
I am biased since I wrote Test::Class - so please read the following with appropriate
levels of scepticism. If you think I have misrepresented the modules please let me know.
Test::SimpleUnit
A very simple unit testing framework. If you are looking for a lightweight single
module solution this might be for you.
The advantage of Test::SimpleUnit is that it is simple! Just one module with a
smallish API to learn.
Of course this is also the disadvantage.
It's not class based so you cannot create testing classes to reuse and extend.
It doesn't use Test::Builder so it's difficult to extend or integrate with other
testing modules. If you are already familiar with Test::Builder, Test::More and
friends you will have to learn a new test assertion API. It does not support todo
tests.
Test::Unit
Test::Unit is a port of JUnit <http://www.junit.org/> into perl. If you have used
JUnit then the Test::Unit framework should be very familiar.
It is class based so you can easily reuse your test classes and extend by subclassing.
You get a nice flexible framework you can tweak to your heart's content. If you can
run Tk you also get a graphical test runner.
However, Test::Unit is not based on Test::Builder. You cannot easily move
Test::Builder based test functions into Test::Unit based classes. You have to learn
another test assertion API.
Test::Unit implements it's own testing framework separate from Test::Harness. You can
retrofit *.t scripts as unit tests, and output test results in the format that
Test::Harness expects, but things like todo tests and skipping tests are not
supported.
BUGS
None known at the time of writing.
If you find any bugs please let me know by e-mail at <adrianh AT quietstars.com>, or report
the problem with <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Test-Class>.
COMMUNITY
perl-qa
If you are interested in testing using Perl I recommend you visit <http://qa.perl.org/>
and join the excellent perl-qa mailing list. See
<http://lists.perl.org/showlist.cgi?name=perl-qa> for details on how to subscribe.
perlmonks
You can find users of Test::Class, including the module author, on
<http://www.perlmonks.org/>. Feel free to ask questions on Test::Class there.
CPAN::Forum
The CPAN Forum is a web forum for discussing Perl's CPAN modules. The Test::Class forum
can be found at <http://www.cpanforum.com/dist/Test-Class>.
TO DO
If you think this module should do something that it doesn't (or does something that it
shouldn't) please let me know.
You can see my current to do list at <http://adrianh.tadalist.com/lists/public/4798>, with
an RSS feed of changes at <http://adrianh.tadalist.com/lists/feed_public/4798>.
ACKNOWLEDGMENTS
This is yet another implementation of the ideas from Kent Beck's Testing Framework paper
<http://www.xprogramming.com/testfram.htm>.
Thanks to Adam Kennedy, agianni, Alexander D'Archangel, Andrew Grangaard, Apocalypse, Ask
Bjorn Hansen, Chris Dolan, Chris Williams, Corion, Cosimo Streppone, Daniel Berger, Dave
Evans, Dave O'Neill, David Cantrell, David Wheeler, Diab Jerius, Emil Jansson, Gunnar
Wolf, Hai Pham, Hynek, imacat, Jeff Deifik, Jim Brandt, Jochen Stenzel, Johan Lindstrom,
John West, Jonathan R. Warden, Joshua ben Jore, Jost Krieger, Ken Fox, Kenichi Ishigaki
Lee Goddard, Mark Morgan, Mark Reynolds, Mark Stosberg, Martin Ferrari, Mathieu Sauve-
Frankel, Matt Trout, Matt Williamson, Michael G Schwern, Murat Uenalan, Naveed Massjouni,
Nicholas Clark, Ovid, Piers Cawley, Rob Kinyon, Sam Raymer, Scott Lanning, Sebastien
Aperghis-Tramoni, Steve Kirkup, Stray Toaster, Ted Carnahan, Terrence Brannon, Todd W, Tom
Metro, Tony Bowden, Tony Edwardson, William McKee, various anonymous folk and all the fine
people on perl-qa for their feedback, patches, suggestions and nagging.
This module wouldn't be possible without the excellent Test::Builder. Thanks to chromatic
and Michael G Schwern for creating such a useful module.
AUTHORS
Adrian Howard <adrianh AT quietstars.com>, Curtis "Ovid" Poe, <ovid at cpan.org>, Mark Morgan
<makk384 AT gmail.com>.
If you use this module, and can spare the time please let us know or rate it at
<http://cpanratings.perl.org/rate/?distribution=Test-Class>.
SEE ALSO
Test::Class::Load
Simple way to load "Test::Class" classes automatically.
<http://del.icio.us/tag/Test::Class>
Delicious links on Test::Class.
Perl Testing: A Developer's Notebook by Ian Langworth and chromatic
Chapter 8 covers using Test::Class.
Advanced Perl Programming, second edition by Simon Cozens
Chapter 8 has a few pages on using Test::Class.
The Perl Journal, April 2003
Includes the article "Test-Driven Development in Perl" by Piers Cawley that uses
Test::Class.
Test::Builder
Support module for building test libraries.
Test::Simple & Test::More
Basic utilities for writing tests.
<http://qa.perl.org/test-modules.html>
Overview of some of the many testing modules available on CPAN.
<http://del.icio.us/tag/perl+testing>
Delicious links on perl testing.
Test::Object
Another approach to object oriented testing.
Test::Group and Test::Block
Alternatives to grouping sets of tests together.
The following modules use Test::Class as part of their test suite. You might want to look
at them for usage examples:
Aspect, Bricolage (<http://www.bricolage.cc/>), Class::StorageFactory,
CGI::Application::Search, DBIx::Romani, Xmldoom, Object::Relational, File::Random,
Geography::JapanesePrefectures, Google::Adwords, Merge::HashRef, PerlBuildSystem,
Pixie, Yahoo::Marketing, and XUL-Node
The following modules are not based on Test::Builder, but may be of interest as
alternatives to Test::Class.
Test::Unit
Perl unit testing framework closely modeled on JUnit.
Test::SimpleUnit
A very simple unit testing framework.
LICENCE
Copyright 2002-2010 Adrian Howard, All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
perl v5.20.1 2014-09-27 Test::Class(3pm)
|
