opensoul.org - How to test dependencies on external services? Comments

Comment on 'How to test dependencies on external services?' by Floehopper

2007-04-25T22:14:15Z

At first I thought it would help you to read the “Don’t mock third-party libraries” section of this article. But then I realised Tinder is actually meant to be the “adapter layer” that Steve Freeman talks about.

So then I thought you might be better off doing something like what’s described in this article

I hope that’s of some help.

Comment on 'How to test dependencies on external services?' by Brandon

2007-04-25T21:24:54Z

Scott: Excellent idea.

Zach, mocking, stubbing, and dependency injection work great when you’re testing code that uses other code that is the external dependency, but when your code IS the dependency, it doesn’t help much. Somehow I need to prove that my code does what it’s supposed to when interacting with the external service.

Comment on 'How to test dependencies on external services?' by Zach Moazeni

2007-04-25T20:59:43Z

Using Mock Objects will helps me tremendously. Some people view it as “peeking into the guts” however, I strongly believe that you are asserting behavior. When you mock out the external dependencies you are allowed to test the object in isolation.

You become more intentional on what you want to test as you can easily simulate behaviors the external dependencies should exhibit. Just as important, you can assert your code’s interaction with the dependencies (asserting the methods / parameters used).

I’m not sure about the underlying code for Tinder, but seeing the snipbit given I’m going to assume that objects are instantiated within Tinder::Campfire. This becomes a thorn in mock testing since it’s not as easy to inject the dependencies. Two solutions that I generally take are a) Use some type of Dependency Injection like Needle or b) use stubbing capabilities to whichever mock library you’re using, for example both Mocha and Flexmock provide these. Just be wary of overuse of stubbing.

Comment on 'How to test dependencies on external services?' by Scott Raymond

2007-04-25T19:52:07Z

My preferred method is to cache the service’s responses locally, and then flush the cache periodically in order to detect breakage on the service’s end. Ideally, I’d run a CI server that would flush the cache and re-run the tests with every checkin. That way, my local tests could always used the cached responses (keeping them speedy, and able to run off-line), but I’d still get quick notification if the remote service changed.