Re:Is TDD Dead? (2014)
by theptip on Wednesday August 26, 2020 @07:42PM
(#24288590)
> When people talk about "unit tests", a unit doesn't refer to the common pattern of "a single class". A unit is a piece of the software with a clear boundary. It might be a whole microservice, or a chunk of a monolith that is internally consistent.
This is a really important aspect, and I think is one of the key things that separates "journeyman" level from "master" on the subject of testing.
> The structure of the tests must not reflect the structure of the production code, because that much coupling makes the system fragile and obstructs refactoring. Rather, the structure of the tests must be independently designed so as to minimize the coupling to the production code.
The "one test class per class" or "one test file per file" approach is an extremely common anti-pattern, and it's insidious because a lot of engineers think it's the obviously correct way of writing tests.
This is a really important aspect, and I think is one of the key things that separates "journeyman" level from "master" on the subject of testing.
The most concise piece I've found on this is Bob Martin's "Testing Contra-Variance" (https://blog.cleancoder.com/uncle-bob/2017/10/03/TestContrav...), if you can look past the slightly forced "Socratic dialog" style of the article.
> The structure of the tests must not reflect the structure of the production code, because that much coupling makes the system fragile and obstructs refactoring. Rather, the structure of the tests must be independently designed so as to minimize the coupling to the production code.
The "one test class per class" or "one test file per file" approach is an extremely common anti-pattern, and it's insidious because a lot of engineers think it's the obviously correct way of writing tests.