README.md
# SimpleMock
[](http://travis-ci.org/tatey/simple_mock)
[](https://codeclimate.com/github/tatey/simple_mock)
A fast, tiny (82 lines) hybrid mocking library that supports classical and partial mocking. Partial mocking mixes classical mocking with real objects. There's no monkey patching `Object` or copying. Mock objects are isolated leaving real objects completely untainted. Plays nicely with MiniTest and [RSpec](http://rspec.info/). The interface is 100% compatible with [MiniTest::Mock](https://github.com/seattlerb/minitest) so there is nothing new to learn. SimpleMock's one and only dependancy is Ruby (1.9.2, 1.9.3, 2.0.0).
## Installation
Add this to your project's Gemfile and run `$ bundle`.
``` ruby
gem 'simple_mock', :group => :test
```
SimpleMock is isolated so there is no need to set require to false.
## Usage
### Classical Mocking
A new SimpleMock object behaves identically to MiniTest::Mock.
``` ruby
mock_model = SimpleMock.new
mock_model.expect :valid?, true
mock_model.valid? # => true
mock_model.verify # => true
```
### Partial Mocking
Pass an object to mix expectations with the real object's original behaviour.
``` ruby
class Post < ActiveRecord::Base
validates :title, :presence => true
end
real_model = Post.new
mock_model = SimpleMock.new real_model
mock_model.class # => Post
mock_model.expect :valid?, true
mock_model.valid? # => true
mock_model.create # => true
mock_model.verify # => true
```
This is done with delegation, avoiding monkey patching and copying. The real object is completely untainted.
``` ruby
mock_model.valid # => true
real_model.valid? # => false
real_model.object_id == mock_model.__getobj__.object_id # => true
real_model.object_id != mock_model.object_id # => true
```
More documentation is available at [rubydoc.info](http://rubydoc.info/gems/simple_mock/frames).
## Performance
SimpleMock is fast. In [this benchmark](https://gist.github.com/1871840) we create an array, set an expectation and call that method 10,000 times.
``` plain
user system total real
mocha: 0.000000 0.000000 0.000000 (0.000279)
simple_mock: 0.000000 0.000000 0.000000 (0.000057)
```
## Caveats
Like MiniTest::Mock, `#expect` and `#verify` are reserved methods. Expectations should not be defined on real objects which implement these methods. As an alternative, consider creating an anonymous class which inherits from SimpleDelegator.
``` ruby
mock_class = Class.new SimpleDelegator do
def verify *args
true
end
end
mock_instance = mock_class.new MyRealClass.new
mock_instance.verify # => true
```
SimpleMock does something similar to this under the hood.
## Copyright
Copyright © 2012 Tate Johnson. SimpleMock is released under the MIT license. See LICENSE for details.