It’s great to see that Kevin Clark has been playing with Mocha. Like many people, he’s found the ability to mock or stub class methods particularly useful – and this is one of the key differentiators between Mocha and other Ruby mocking libraries.
He’s been trying to improve the test coverage for Rails and submitted this patch where there is an interesting discussion1 about why he would prefer to use Mocha. Interestingly, there has also been some recent discussion on the RSpec mailing list about adding Mocha-like functionality.
On a different note, in his article Mocks for Speed, Kevin draws attention to one of the advantages I have previously mentioned of using mocks extensively to write unit tests that test a class in isolation – namely a fast build.
1 We have now released Mocha under the MIT license so it can be used for testing within Rails.