I have the following custom Axios instance:
import axios from 'axios'
export const BASE_URL = 'http://jsonplaceholder.typicode.com'
export default axios.create({
baseURL: BASE_URL
})
With the corresponding service:
import http from './http'
export async function fetchUserPosts(id) {
const reponse = await http.get(`/users/${id}/posts`)
return reponse.data
}
And this is the test for said service:
import moxios from 'moxios'
import sinon from 'sinon'
import http from '@/api/http'
import { fetchUserPosts } from '@/api/usersService'
describe('users service', () => {
beforeEach(() => {
moxios.install(http)
})
afterEach(() => {
moxios.uninstall(http)
})
it('fetches the posts of a given user', (done) => {
const id = 1
const expectedPosts = ['Post1', 'Post2']
moxios.stubRequest(`/users/${id}/posts`, {
status: 200,
response: expectedPosts
})
const onFulfilled = sinon.spy()
fetchUserPosts(1).then(onFulfilled)
moxios.wait(() => {
expect(onFulfilled.getCall(0).args[0].data).toBe(expectedPosts)
done()
})
})
})
Which when executed using Karma + Jasmine raises the following error:
Uncaught TypeError: Cannot read property 'args' of null thrown
What I would like to test is that when the endpoint /users/{id}/posts
is hit a mocked response is sent back. All this while using my custom axios instance http
.
I've tried stubbing as the first example of the documentation of moxios shows. However I don't think that fits my use case, as I would like to check that the request is formed correctly in my service.
I've also tried with the following code, which works as expected, however I would like to test my service (which the following code does not do):
import axios from 'axios'
import moxios from 'moxios'
import sinon from 'sinon'
describe('users service', () => {
beforeEach(() => {
moxios.install()
})
afterEach(() => {
moxios.uninstall()
})
it('fetches the posts of a given user', (done) => {
const id = 1
const expectedPosts = ['Post1', 'Post2']
moxios.stubRequest(`/users/${id}/posts`, {
status: 200,
response: expectedPosts
})
const onFulfilled = sinon.spy()
axios.get(`/users/${id}/posts`).then(onFulfilled)
moxios.wait(() => {
expect(onFulfilled.getCall(0).args[0].data).toBe(expectedPosts)
done()
})
})
})
Any ideas on how could I fix the error?
I know that is an old question but as I came across with it with the same problem, I'll post my approach:
You don't need to use sinon
in this case, as you have an instance of axios
, use it to configure moxios
(as you already have done)
beforeEach(() => {
moxios.install(http)
})
afterEach(() => {
moxios.uninstall(http)
})
then you test your method like this:
it('test get', async () => {
const expectedPosts = ['Post1', 'Post2']
moxios.wait(() => {
const request = moxios.requests.mostRecent()
request.respondWith({ status: 200, response: expectedPosts }) //mocked response
})
const result = await fetchUserPosts(1)
console.log(result) // ['Post1','Post2']
expect(result).toEqual(expectedPosts)
})
That's it.
Regards