[ByteJockey]

In languages like JS/Python, you can mock imports. Actually, sometimes you can mock things defined in the same file if you set things up right.

Basically, the logic not being inlined into the function is enough to provide this behavior in certain languages.

This is not true for other languages, which is why DI frameworks tend to be more useful there.

In go specifically, I just always throw the dependencies behind an interface and shove them into a struct. Then you just create a struct of mocks for your testing.