A cleaner and DRYer alternative to mocking and stubbing with RSpec.
When you're setting up for a spec, you can ask that method calls on an object be recorded:
Once your code has run, you can make assertions about what methods were called, what arguments they took, their results, etc.
object.should have_received(:length).without_args.and_returned(42) object.should have_received(:name).twice
See NotAMock::Matchers for an explanation of the available assertions, plus Object#track_methods and Object#untrack_methods.
You can replace a method on an object with a stub version like this:
object.stub_method(:method => return_value)
Any call to
method after this will return
return_value without invoking the method's usual code.
Calls to stub methods are recorded as if you had called
track_methods on them, so you can make assertions about them as shown above.
See Object#stub_methods, Object#unstub_methods.
You can also replace an entire object with a stub version like this:
my_object = MyClass.stub_instance(:method_a => return_value, :method_b => return_value, ...)
my_object is a stub instance of MyClass with the given methods defined to provide the corresponding return values.
When you call
stub_instance on an ActiveRecord::Base subclass, Not A Mock automatically provides an
id method and generates an id for the object.
(The following describes using NotAMock with Rails. It should also be possible to use it outside of Rails, but I haven't tried it.)
First, install the rspec and rspec_on_rails plugins:
ruby script/plugin install http://rspec.rubyforge.org/svn/tags/CURRENT/rspec ruby script/plugin install http://rspec.rubyforge.org/svn/tags/CURRENT/rspec_on_rails ruby script/generate rspec
(See rspec.info/documentation/rails/install.html for more details.)
Second, install the not_a_mock plugin:
ruby script/plugin install git://github.com/notahat/not_a_mock.git
Finally, add the following to your project's spec/spec_helper.rb:
Send bugs, patches, and suggestions to Pete Yandell (firstname.lastname@example.org)
Thanks to Pat Allan and Steve Hayes for contributing patches.