FlexMock is a flexible mocking library for use in unit testing and behavior specification in Ruby. This release is a minor release with a few bug fixes and some simple features.
Removed use of assert_block (which is deprecated in MiniTest).
Documentation fixes.
Add 'and' and 'on' modifiers for the RSpec spy matcher.
Add 'and' and 'on' options to the assert_spy_called test method.
General documentation improvement.
Fix bug in should_fail test helper that was not detecting failed failures.
Add auto configure by requiring 'flexmock/rspec/configure'.
Add block support to pass_thru.
Mocks may now have a base class that limits what methods may be mocked. This allows early detection of outdated mock setups when the methods in the class are refactored.
Spy assertions are now allowed. The verification of the calling of mocked methods may now be done in the "then" portion of the test, after the code under test has been run. This allows for much more natural Given/When/Then style testing.
A custom assert method (assert_spy_called) has been added to make spy assertions easy when using Test::Unit or MiniTest.
An RSpec matcher (have_received) has been added to make spy assertions easy when using RSpec.
Now correctly handling the mocking of meta-programmed methods.
Using the documented singleton_methods method.
Accidently trying to partial mock a regular mock is now a no-op.
FlexMock is a flexible framework for creating mock object for testing. When running unit tests, it is often desirable to use isolate the objects being tested from the "real world" by having them interact with simplified test objects. Sometimes these test objects simply return values when called, other times they verify that certain methods were called with particular arguments in a particular order.
FlexMock makes creating these test objects easy.
Easy integration with both Test::Unit and RSpec. Mocks created with the flexmock method are automatically verified at the end of the test or example.
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.
Easy mocking of chains of method calls.
The ability to cause classes to instantiate test instances (instead of real instances) for the duration of a test.
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:
RSpec.configure do |config| config.mock_with :flexmock end describe Dog do it "wags its tail when happy" do 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.
Here's the same thing using the new spy support:
describe Dog do it "wags its tail when happy" do tail = flexmock("tail") dog = Dog.new(tail) dog.happy tail.should have_received(:wag) end end
This style works particularly well with the rspec-given library.
require 'rspec/given' describe Dog do context "when the dog is happy" do Given(:tail) { flexmock(:on, Tail) } Given(:dog) { Dog.new(tail) } When { dog.happy } Then { tail.should have_received(:wag) } end end
See the FlexMock documentation at flexmock.rubyforge.org 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.
You can make sure you have the latest version with a quick RubyGems command:
gem install flexmock (you may need root/admin privileges)
You will find documentation at: flexmock.rubyforge.org.
-- Jim Weirich
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