Is it possible to mock a function imported from a package in golang?

Question

I have the following method to test, which uses a function imported from a package.

import x.y.z

func abc() {
    ...
    v := z.SomeFunc()
    ... 
}
         


        

Answer 1

One thing you can do is this:

import "x/y/z"

var someFunc = z.SomeFunc

func abc() {
    ...
    v := someFunc()
    ... 
}

And in your test file you would do this.

func Test_abc() {
    someFunc = mockFunc
    abc()
}

But make sure that you do this in a concurrent manner, if you have multiple TestXxx functions calling abc or setting someFunc you may be better of using a struct with a someFunc field.