= 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
easily. -
A “record mode” where an existing implementation can record its
interaction with a mock for later validation against a new
implementation. -
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
end
def happy
@tail.wag
end
end
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")
tail.should_receive(:wag).once
dog = Dog.new(tail)
dog.happy
end
end
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:
http://onestepback.org/software/flexmock/
– Jim W.