I tried many solution from this task. I want testing axios instance api call without any libralies (jest-axios-mock, moaxios, msw, etc). I hope it's possible, because i succeeded testing simple axios call ( axios.get / axios.post without .create ) The main problem comes i tried testing axios instance call, i collides with three main errors on different attempts.
1 axios_instance_1.axiosInstance is not a function
2 Cannot read property 'then' of undefined
3 Cannot read property 'post' of undefined
I get this when i try bypassing module mock ( jestjs.io/docs/bypassing-module-mocks )
My last attempt looked like this
axios-instance.ts
import axios from "axios";
export const axiosInstance = axios.create({
headers: {'X-Custom-Header': 'foobar'}
})
api.ts
import { axiosInstance } from "../instancec/axios-instance";
export const axiosInstanceCounter = () => {
return axiosInstance({
method: 'post'
}).then((data) => {
console.log(data)
})
}
axios.test.ts
import { axiosInstanceCounter } from '../features/api/axiosTest';
import { axiosInstance } from '../features/instancec/axios-instance';
import axios, { AxiosResponse } from 'axios';
jest.mock('../features/instancec/axios-instance', () => ({
const instance = {
create: jest.fn(),
};
return jest.fn(() => instance);
}));
it('Axios instance standart test', async () => {
(axiosInstance.post as jest.Mock).mockResolvedValueOnce(() =>
Promise.resolve(),
);
await axiosInstanceCounter();
expect(axiosInstance).toBeCalledTimes(1);
});
And last error i receive it is Cannot read 'post' of undefined. Create mocks file in folder mocks and export from there also doesn't help. I don't quite understand why it happens and I'll be very thankful any hint, i also tried option with jest.spyOn but this failed.
Addition to solution
I replace mocked() with ts-jest to avoid warnings
const mockedAxiosInstance = axiosInstance as jest.MockedFunction<
typeof axiosInstance
>;
this works too and is more simple for your purpose
import { axiosInstanceCounter } from "../features/api/axiosTest";
import { axiosInstance } from "../features/instancec/axios-instance";
let apiSpy;
describe("getPokemonOptions", () => {
beforeEach(() => {
jest.clearAllMocks();
});
it("Axios instance standart test", async () => {
apiSpy = jest.spyOn(axiosInstance, "post");
apiSpy.mockResolvedValue({});
await axiosInstanceCounter();
expect(axiosInstance).toBeCalledTimes(1);
});
});
As you can see, return axiosInstance({ means axiosInstance is a function, then if you want to test axiosInstanceCounter function, just mock axiosInstance as a normal function(in your case the api call will not return anything):
api.test.ts // testing for api.ts
import { AxiosPromise } from "axios";
import { mocked } from "ts-jest/utils"; // a helper function from ts-jest
import { axiosInstanceCounter } from '../features/api/axiosTest'; // should be ../features/api ???
import { axiosInstance } from '../features/instancec/axios-instance';
jest.mock("../features/instancec/axios-instance");
describe("api", () => {
describe("axiosInstanceCounter()", () => {
it("should call api with correct parameters", async () => {
// mock to resolve a Promise<void>
mocked(axiosInstance).mockResolvedValue(Promise.resolve() as unknown as AxiosPromise<void>);
await axiosInstanceCounter();
expect(axiosInstance).toHaveBeenCalledWith({ method: "post" });
});
});
});