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> My opinion is, _my unit tests_ are to protect my code against unwanted changes. This is just about the most bizarre take on unit testing I've seen in my 25-y

> My opinion is, _my unit tests_ are to protect my code against unwanted changes. This is just about the most bizarre take on unit testing I've seen in my 25-year career. > If I have to rewrite a method, usually I rewrite all of its unit tests. If you have to rewrite your tests every time you rewrite a method, you are entirely defeating the point of testing. What value you get from tests that only assert that the current implementation is equal to the current implementation?

hotpocket777 1y ago
> This is just about the most bizarre take on unit testing I've seen in my 25-year career. Lol ok > you are entirely defeating the point of testing We will disagree here > only assert that the current implementation is equal to the current implementation I didn’t state that I do this
1123581321 1y ago
You seem confused about what he was saying. I’m sure you are familiar with unit testing philosophy with your experience. Calling a function and expecting a response does test the behavior of the application, just at a lower level than a request- or multi-request level spec. When he says rewriting a method he is referring to changing the logic of it; a refactor leaves the tests unchanged. That shouldn’t have needed to be spelled out to such a senior developer.
- stouset 1y ago
  Tests should not generally need to be rewritten unless you’re changing the externally-visible behavior API of a function or library (either the literal API, its effects, or its semantics). If you’re changing the tests because you’ve changed the internal, non-externally-visible logic of your code, your tests are almost certainly providing you negative value. Being able to refactor and re-run your existing test suite to ensure consistent behavior is possibly the important property of a good test suite.
  - 1123581321 1y ago
    Yes, exactly so.

hotpocket777 1y ago

> This is just about the most bizarre take on unit testing I've seen in my 25-year career. Lol ok > you are entirely defeating the point of testing We will disagree here > only assert that the current implementation is equal to the current implementation I didn’t state that I do this

1123581321 1y ago

You seem confused about what he was saying. I’m sure you are familiar with unit testing philosophy with your experience. Calling a function and expecting a response does test the behavior of the application, just at a lower level than a request- or multi-request level spec. When he says rewriting a method he is referring to changing the logic of it; a refactor leaves the tests unchanged. That shouldn’t have needed to be spelled out to such a senior developer.

stouset 1y ago
Tests should not generally need to be rewritten unless you’re changing the externally-visible behavior API of a function or library (either the literal API, its effects, or its semantics). If you’re changing the tests because you’ve changed the internal, non-externally-visible logic of your code, your tests are almost certainly providing you negative value. Being able to refactor and re-run your existing test suite to ensure consistent behavior is possibly the important property of a good test suite.
- 1123581321 1y ago
  Yes, exactly so.