测试是否使用 Jest 调用了实际的 function

Question

I am simply trying to test if a function was called using jest 26.6.3. I do not want to mock the implementation of the function. I want to test if my actual function was called.

const add = (a,b) => a + b;

test("add() was called", () => {
    add(1,2);
    expect(add).toHaveBeenCalled();
})

If I create a mock function, I don't understand how that would be testing to see if my REAL function has been invoked. Obviously, the mock function will be executed if I create it using jest.fn() and then invoke it. Would I have to spy on my add function? Still missing the fundamental understanding to do this simple task.

Answer 1

You will need to spy the function add to get some infos about her like when its called... Then you are to be able to do the expect.

You can do this with jest.spyOn.