Sometimes, we want to change mock implementation on a per single test basis with Jest and JavaScript.
In this article, we’ll look at how to change mock implementation on a per single test basis with Jest and JavaScript.
How to change mock implementation on a per single test basis with Jest and JavaScript?
To change mock implementation on a per single test basis with Jest and JavaScript, we call mockImplementation.
For instance, we write
import { funcToMock } from "./somewhere";
jest.mock("./somewhere");
beforeEach(() => {
funcToMock.mockImplementation(() => {
//...
});
});
test("test", () => {
funcToMock.mockImplementation(() => {
//...
});
});
to call funcToMock.mockImplementation with a function that has the implementation of the funcToMock function we’re mocking.
Conclusion
To change mock implementation on a per single test basis with Jest and JavaScript, we call mockImplmentation.
