[ANN] FlexMock 0.4.0 Released

= FlexMock 0.4.0 Released

FlexMock is a flexible mocking library for use in Ruby’s Test::Unit
test framework. Version 0.4.0 enhances FlexMock with the ability to
stub and mock methods in existing objects.

== New Features in 0.4.0

  • You can now use the flexstub(object) method to mock or stub
    individual methods in an existing object. The original definitions
    of the methods are restored at the end of a test.

  • The and_return (and its alias, returns) now accepts a list of
    arguments and will return the values in the list one at a time for
    each successive call to the mocked method.

  • The flexmock() method now accepts an initialization block so that a
    mock can be created and configured in one step without using a local
    variable. This is really handy when mocking factory or creation
    methods that in turn return a mock.

== What is FlexMock?

FlexMock is a flexible Ruby mocking library that works with Ruby’s
Test::Unit framework to create easy to use mocks.

=== Features

  • Easy integration with Test::Unit. Mocks created with the flexmock
    method are automatically verified at the end of the test.

  • A fluent interface that allows mock behavior to be specified very

  • A “record mode” where an existing implementation can record its
    interaction with a mock for later validation against a new

  • Easy mocking of individual methods in existing, non-mock objects.

=== Example

Suppose you had a Dog object that wagged a tail when it was happy.
Something like this:

class Dog
def initialize(a_tail)
@tail = a_tail
def happy

To test the +Dog+ class without a real +Tail+ object (perhaps because
real +Tail+ objects activate servos in some robotic equipment), you
can do something like this:

require ‘test/unit’
require ‘flexmock’

class TestDog < Test::Unit::TestCase
include FlexMock::TestCase

def test_dog_wags_tail_when_happy
  tail = flexmock("tail")
  dog = Dog.new(tail)


FlexMock will automatically verify that the mocked tail object
received the message +wag+ exactly one time. If it doesn’t, the test
will not pass.

See the FlexMock documentation at
http://onestepback.org/software/flexmock for details on specifying
arguments and return values on mocked methods, as well as a simple
technique for mocking tail objects when the Dog class creates the tail
objects directly.

== Availability

FlexMock is distributed with Rails, or you can make sure you have the
latest version with a quick RubyGems command:

gem install flexmock (you may need root/admin privileges)

Otherwise, you can get it from the more traditional places:

Download:: http://rubyforge.org/project/showfiles.php?group_id=170

You will find documentation at:

– Jim W.