Comments on: Avoiding Brittle Tests / Testing Output http://www.thedeveloperday.com/avoiding-brittle-tests-testing-output/ Staying Curious Wed, 01 Feb 2012 07:05:15 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Dave http://www.thedeveloperday.com/avoiding-brittle-tests-testing-output/comment-page-1/#comment-1023 Dave Thu, 07 Apr 2011 23:03:30 +0000 http://www.thedeveloperday.com/?p=517#comment-1023 This is a really good point and I think it's one of the greatest challenges facing the TDD approach. A lot of classes don't work like black boxes that take some input and return some output. They have side effects on other objects and entities in the system. I don't know of way to test a method like the one you wrote above that reasonably exercises the class without requiring tests to have WAY to much implementation knowledge and thus become brittle. It's likely that just checking whether or not send() was called isn't enough to call that class sufficiently unit tested. This seems to be one of those problems that nobody wants to even acknowledge much less try solve. This is a really good point and I think it’s one of the greatest challenges facing the TDD approach. A lot of classes don’t work like black boxes that take some input and return some output. They have side effects on other objects and entities in the system. I don’t know of way to test a method like the one you wrote above that reasonably exercises the class without requiring tests to have WAY to much implementation knowledge and thus become brittle. It’s likely that just checking whether or not send() was called isn’t enough to call that class sufficiently unit tested.

This seems to be one of those problems that nobody wants to even acknowledge much less try solve.

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