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.
Coming fast on the heels of 0.4.0, version 0.4.1 fixes a problem with mocking methods that have the same name as methods defined in Kernel.
FlexMock is a flexible Ruby mocking library that works with Ruby's Test::Unit framework to create easy to use mocks.
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.
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 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.
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:
You will find documentation at: onestepback.org/software/flexmock/
– Jim Weirich