Something like Haskell, or even Rust, requires similar vigilance in order to get the program even into a working state. With thorough, strong, static type checkers, novel borrow checkers, and more, a lot of development time is spent up front, dealing with compiler/type errors. Thus you can go to prod with high confidence that everything will work without any defect.
Now, back to Clojure. Clojure assumes that you weren't as vigilant as I just described, and that you don't have static type checking for each function, or that you don't have a fixed domain for all of your enums. Thus it is assumed because of that, probably when you go running toward testing (unit, functional, or otherwise), you want to assert the validity of all of this data.
My point in re-painting your words is that we all trade certain guarantees in correctness for ease of development, maintainability, or whatever other reasons. Developers may choose Clojure over Haskell, for example, because maintaining all of that extra vigilance is undesirable overhead. Similarly, developers may reasonably choose not to unit test every single function in the code base, but instead functionally test the public endpoints and unit test only certain systems (such as the one which validates input for the public endpoints), because maintaining all of that extra vigilance is undesirable overhead.
Now, back to Clojure. Clojure assumes that you weren't as vigilant as I just described, and that you don't have static type checking for each function, or that you don't have a fixed domain for all of your enums. Thus it is assumed because of that, probably when you go running toward testing (unit, functional, or otherwise), you want to assert the validity of all of this data.
My point in re-painting your words is that we all trade certain guarantees in correctness for ease of development, maintainability, or whatever other reasons. Developers may choose Clojure over Haskell, for example, because maintaining all of that extra vigilance is undesirable overhead. Similarly, developers may reasonably choose not to unit test every single function in the code base, but instead functionally test the public endpoints and unit test only certain systems (such as the one which validates input for the public endpoints), because maintaining all of that extra vigilance is undesirable overhead.