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by formerly_proven 1805 days ago
> You can generally see whether a unit test was a good unit test based on the fact that you were able to refactor the implementation of the method _without_ having to change the unit test. Yes, those definitely do exist, even in larger systems.

"Test the interface, not the implementation."
1 comments
h0l0cube 1803 days ago
Even better, test the specification
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tharkun__ 1802 days ago
The speci-what?

We might be in different types of software development. There's seldom an actual "specification" to a level of detail that you could test to in the sense you're probably thinking of (but I'm having to guess here for lack of detail and context from your end).

In the field I work in for example, a detailed specification in the way I'm guessing you mean would be prohibitively expensive and just not cost effective at all vs. the benefit you can get from throwing something together from imperfect information and improving upon it iteratively.

There was a (WP?) article on HN recently about "Releaseing software the right way" (or similar title), which basically said to use whatever approach actually makes sense in your circumstances. The example IIRC was hardware development (detailed specs) vs. a SaaS company.

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h0l0cube 1801 days ago
In terms of something like embedded systems, aerotech, etc., the specification extends all the way to the unit. In terms of an SaaS, the specifications extend all the way to business logic such as (cartoon examples):

- don't charge the customer twice

- or when I click submit on the front-end the following possibilities happen according to the back-end response

- or when the back-end receives x, the inventory should be updated according to this business logic, as well as y

Say if you're doing this capital-A Agile style, all of these should be present on the acceptance criteria for any user story. As someone who's worked in rapid applications development for mobile, I can say reaching this level of specification increases speed, and reduces redundant communication. It often doesn't take half an hour for someone to write, and then it's iterated on by the team before implementation, and during.

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