I have this action in React:
export function fetchPosts() {
const request = axios.get(`${WORDPRESS_URL}`);
return {
type: FETCH_POSTS,
payload: request
}
}
How do I test Axios in this case?
Jest has this use case on their site for asynchronous code where they use a mock function, but can I do this with Axios?
Reference: An Async Example
I have done this so far to test that it is returning the correct type:
it('should dispatch actions with the correct type', () => {
store.dispatch(fetchPosts());
let action = store.getActions();
expect(action[0].type).toBe(FETCH_POSTS);
});
How can I pass in mock data and test that it returns?
Without using any other libraries:
import * as axios from "axios";
// Mock out all top level functions, such as get, put, delete and post:
jest.mock("axios");
// ...
test("good response", () => {
axios.get.mockImplementation(() => Promise.resolve({ data: {...} }));
// ...
});
test("bad response", () => {
axios.get.mockImplementation(() => Promise.reject({ ... }));
// ...
});
It is possible to specify the response code:
axios.get.mockImplementation(() => Promise.resolve({ status: 200, data: {...} }));
It is possible to change the mock based on the parameters:
axios.get.mockImplementation((url) => {
if (url === 'www.example.com') {
return Promise.resolve({ data: {...} });
} else {
//...
}
});
Jest v23 introduced some syntactic sugar for mocking Promises:
axios.get.mockImplementation(() => Promise.resolve({ data: {...} }));
It can be simplified to
axios.get.mockResolvedValue({ data: {...} });
There is also an equivalent for rejected promises: mockRejectedValue.
Further Reading:
Jest mocking documentation
A GitHub discussion that explains about the scope of the jest.mock("axios") line.
A related question which addresses applying the techniques above to Axios request interceptors.
Using jest functions like mockImplementation in TypeScript: Typescript and Jest: Avoiding type errors on mocked functions
I used axios-mock-adapter.
In this case the service is described in ./chatbot.
In the mock adapter you specify what to return when the API endpoint is consumed.
import axios from 'axios';
import MockAdapter from 'axios-mock-adapter';
import chatbot from './chatbot';
describe('Chatbot', () => {
it('returns data when sendMessage is called', done => {
var mock = new MockAdapter(axios);
const data = { response: true };
mock.onGet('https://us-central1-hutoma-backend.cloudfunctions.net/chat').reply(200, data);
chatbot.sendMessage(0, 'any').then(response => {
expect(response).toEqual(data);
done();
});
});
});
You can see it the whole example here:
Service:
https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.js
Test:
https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.test.js
I could do that following the steps:
Create a folder __mocks__/ (as pointed by #Januartha comment)
Implement an axios.js mock file
Use my implemented module on test
The mock will happen automatically
Example of the mock module:
module.exports = {
get: jest.fn((url) => {
if (url === '/something') {
return Promise.resolve({
data: 'data'
});
}
}),
post: jest.fn((url) => {
if (url === '/something') {
return Promise.resolve({
data: 'data'
});
}
if (url === '/something2') {
return Promise.resolve({
data: 'data2'
});
}
}),
create: jest.fn(function () {
return this;
})
};
Look at this
The function to test album.js
const fetchAlbum = function () {
return axios
.get("https://jsonplaceholder.typicode.com/albums/2")
.then((response) => {
return response.data;
});
};
The test album.test.js
const axios = require("axios");
const { fetchAlbum } = require("../utils.js");
jest.mock("axios");
test("mock axios get function", async () => {
expect.assertions(1);
const album = {
userId: 1,
id: 2,
title: "sunt qui excepturi placeat culpa",
};
const payload = { data: album };
// Now mock axios get method
axios.get = jest.fn().mockResolvedValue(payload);
await expect(fetchAlbum()).resolves.toEqual(album);
});
I've done this with nock, like so:
import nock from 'nock'
import axios from 'axios'
import httpAdapter from 'axios/lib/adapters/http'
axios.defaults.adapter = httpAdapter
describe('foo', () => {
it('bar', () => {
nock('https://example.com:443')
.get('/example')
.reply(200, 'some payload')
// test...
})
})
For those looking to use axios-mock-adapter in place of the mockfetch example in the Redux documentation for async testing, I successfully used the following:
File actions.test.js:
describe('SignInUser', () => {
var history = {
push: function(str) {
expect(str).toEqual('/feed');
}
}
it('Dispatches authorization', () => {
let mock = new MockAdapter(axios);
mock.onPost(`${ROOT_URL}/auth/signin`, {
email: 'test#test.com',
password: 'test'
}).reply(200, {token: 'testToken' });
const expectedActions = [ { type: types.AUTH_USER } ];
const store = mockStore({ auth: [] });
return store.dispatch(actions.signInUser({
email: 'test#test.com',
password: 'test',
}, history)).then(() => {
expect(store.getActions()).toEqual(expectedActions);
});
});
In order to test a successful case for signInUser in file actions/index.js:
export const signInUser = ({ email, password }, history) => async dispatch => {
const res = await axios.post(`${ROOT_URL}/auth/signin`, { email, password })
.catch(({ response: { data } }) => {
...
});
if (res) {
dispatch({ type: AUTH_USER }); // Test verified this
localStorage.setItem('token', res.data.token); // Test mocked this
history.push('/feed'); // Test mocked this
}
}
Given that this is being done with jest, the localstorage call had to be mocked. This was in file src/setupTests.js:
const localStorageMock = {
removeItem: jest.fn(),
getItem: jest.fn(),
setItem: jest.fn(),
clear: jest.fn()
};
global.localStorage = localStorageMock;
New tools for testing have been introduced since the question was initially answered.
The problem with mocking is that you often test the mock and not the real context of your code, leaving some areas of this context untested.
An improvement over telling axios what promise to return is intercepting http requests via Service Workers.
Service worker is a client-side programmable proxy between your web app and the outside world. So instead of mocking promise resolution it is a more broader solution to mock the proxy server itself, intercepting requests to be tested. Since the interception happens on the network level, your application knows nothing about the mocking.
You can use msw (Mock Service Worker) library to do just that. Here is a short video explaining how it works.
The most basic setup I can think of is this:
1️⃣ set up handlers, which are similar to express.js routing methods;
2️⃣ set up mock server and pass handlers as it’s arguments;
3️⃣ configure tests to so that mock server will intercept our requests;
4️⃣ perform tests;
5️⃣ close mock server.
Say you want to test the following feature:
import axios from "axios";
export const fetchPosts = async () => {
const request = await axios.get("/some/endpoint/");
return {
payload: request,
};
};
Then test could look like this:
import { rest } from "msw";
import { setupServer } from "msw/node";
import fetchPosts from "./somewhere";
// handlers are usually saved in separate file(s) in one destined place of the app,
// so that you don't have to search for them when the endpoints have changed
const handlers = [ 1️⃣
rest.get("/some/endpoint/", (req, res, ctx) =>
res(ctx.json({ message: "success" }))
),
];
const server = setupServer(...handlers); 2️⃣
beforeAll(() => {
server.listen(); 3️⃣
});
describe("fetchPosts", () => {
it("should return 'success' message", async () => {
const resp = await fetchPosts();
expect(resp.payload?.data?.message).toEqual("success"); 4️⃣
});
});
afterAll(() => {
server.close(); 5️⃣
});
The configuration may be different depending on framework you are using. Some general examples for, among others, React (both REST and GraphQL) and Angular can be found on MSW’ repo. A Vue example is provided by VueMastery.
You can also find examples on MSW' recipes page.
Related
I have a file which I am trying to unit test. I wish to test that the API object is created by calling the feathers and auth library methods as well as testing that the exported login and logout methods call the appropriate library methods.
I would like to mock all calls to the library methods so as to just unit test this file.
This is what I have so far:
api.js
import feathers from '#feathersjs/feathers'
import auth from '#feathersjs/authentication-client'
export const DEFAULT_TIMEOUT = 30
const api = feathers()
api.configure(auth({ storage: window.localStorage, timeout: DEFAULT_TIMEOUT * 1000 }))
const login = async (credentials) => {
return api.authenticate(credentials)
}
const logout = async () => {
return api.logout()
}
export default { login, logout }
api.test.js
import feathers from '#feathersjs/feathers'
import auth from '#feathersjs/authentication-client'
import api, { DEFAULT_TIMEOUT } from './api'
const mockFeathers = {
configure: jest.fn(),
authenticate: jest.fn(),
logout: jest.fn()
}
jest.mock('#feathersjs/feathers', () => jest.fn(() => mockFeathers))
jest.mock('#feathersjs/authentication-client', () => jest.fn(() => 'AUTH'))
describe('helpers/api', () => {
it('creates a Feathers app with authentication', () => {
expect(feathers).toHaveBeenCalled()
expect(auth).toHaveBeenCalledWith({
storage: window.localStorage,
timeout: DEFAULT_TIMEOUT * 1000
})
expect(mockFeathers.configure).toHaveBeenCalledWith('AUTH')
})
describe('login', () => {
it('authenticates with the Feathers app', async () => {
const loginResult = { loggedIn: true }
mockFeathers.authenticate.mockImplementationOnce(() => loginResult)
const credentials = { email: 'user#example.com', password: 'password' }
const result = await api.login(credentials)
expect(mockFeathers.authenticate).toHaveBeenCalledWith(credentials)
expect(result).toEqual(loginResult)
})
})
describe('logout', () => {
it('logs out from the Feathers app', async () => {
await api.logout()
expect(mockFeathers.logout).toHaveBeenCalled()
})
})
})
This fails with ReferenceError: mockFeathers is not defined because it seems that api.js is being loaded (and therefore the feathers method called) before mockFeathers is defined. I have tried moving the import api line below the definition of mockFeathers but that doesn't make a difference.
How can I mock the result of the feathers() call before the api.js file is loaded?
I did manage to achieve this by removing the import entirely and requireing the api.js in a beforeAll block. This works but seems a little messy to me, and wouldn't scale well if you had multiple individual imports from the required file.
api.test.js
// Remove the import line.
//import api, { DEFAULT_TIMEOUT } from './api'
describe('helpers/api', () => {
let api, DEFAULT_TIMEOUT
beforeAll(() => {
// Require the file here so that the mock has time to be defined.
;({ default: api, DEFAULT_TIMEOUT } = require('./api'))
})
// ...
})
I'm trying to mock axios.create() because I'm using its instance across the app and obviously need all of its implementation which is destroyed by the mock, thus cannot get the result of the get, post method properly.
This is how the code looks like in the actual file:
export const axiosInstance = axios.create({
headers: {
...headers
},
transformRequest: [
function (data, headers) {
return data;
},
],
});
const response = await axiosInstance.get(endpoint);
And here is the mock setup for axios inside the test file
jest.mock('axios', () => {
return {
create: jest.fn(),
get: jest.fn(() => Promise.resolve()),
};
}
);
How could I get all of the instance methods in the axiosInstance variable instead of just having a mock function which does nothing?
Documentation for axios.create and instance methods: https://github.com/axios/axios#instance-methods
You can use jest's genMockFromModule. It will generate jest.fn() for each of the modules's methods and you'll be able to use .mockReturnThis() on create to return the same instance.
example:
./src/__mocks__/axios.js
const axios = jest.genMockFromModule('axios');
axios.create.mockReturnThis();
export default axios;
working example
Edit:
from Jest 26.0.0+ it's renamed to jest.createMockFromModule
Ended up sticking with the axios mock and just pointing to that mock by assigning the axiosInstance pointer to created axios mock.
Basically as #jonrsharpe suggested
Briefly:
import * as m from 'route';
jest.mock('axios', () => {
return {
create: jest.fn(),
get: jest.fn(() => Promise.resolve()),
};
}
);
m.axInstance = axios
Would be very nice though if I could have gone without it.
Since I need to manage Axios instances, I need a way of retrieving the mocks that are created so I can manipulate the responses. Here's how I did it.
import type { AxiosInstance, AxiosStatic } from 'axios';
const mockAxios = jest.createMockFromModule<AxiosStatic>('axios') as jest.Mocked<AxiosStatic>;
let mockAxiosInstances: jest.Mocked<AxiosInstance>[] = [];
mockAxios.create = jest.fn((defaults) => {
const mockAxiosInstance = jest.createMockFromModule<AxiosInstance>(
'axios'
) as jest.Mocked<AxiosInstance>;
mockAxiosInstance.defaults = { ...mockAxiosInstance.defaults, ...defaults };
mockAxiosInstances.push(mockAxiosInstance);
return mockAxiosInstance;
});
export function getMockAxiosInstances() {
return mockAxiosInstances;
}
export function mostRecentAxiosInstanceSatisfying(fn: (a: AxiosInstance) => boolean) {
return mockAxiosInstances.filter(fn).at(-1);
}
export function clearMockAxios() {
mockAxiosInstances = [];
}
export default mockAxios;
I added three additional methods:
clearMockAxios which clears the instance list
getMockAxiosInstances which gets the list of axios instances that are generated by axios.create
mostRecentAxiosInstanceSatisfying is a function that will do a filter to get the most recent axios instance that satisfies the predicate. This is what I generally use in the test case since React may render more than expected (or as expected) and I generally just need the last instance.
I use it as follows:
import { getMockAxiosInstances, mostRecentAxiosInstanceSatisfying, clearMockAxios } from '../../__mocks__/axios';
it("...", () => {
...
const mockAppClient = mostRecentAxiosInstanceSatisfying(
a => a.defaults.auth?.username === "myusername"
);
mockAppClient.post.mockImplementation(() => {
return Promise.resolve({ data: "AAA" })
})
... do something that calls the client ...
});
The following code works!
jest.mock("axios", () => {
return {
create: jest.fn(() => axios),
post: jest.fn(() => Promise.resolve()),
};
});
I am trying to write a unit test (with jest) that asserts that data is being pushed into job_execs. The two issues I'm running into are mocking the api endpoint and if it's even possible to mock this.$route.params.tool in a unit test.
So the main question is, can I write a test with the component below? I know that it should be possible to mock the api endpoint (still haven't figured out how to), but my concern is that I have too many external dependencies in the component for this to be unit-testable. Do I need to rewrite my component to support unit tests?
Jobs.vue
<script>
export default {
name: "Jobs",
data() {
return {
job_execs: []
}
},
created() {
this.JobExecEndpoint = process.env.VUE_APP_UATU_URL + '/api/v1/job_execution/?tool='+this.$route.params.tool+'&job='+this.$route.params.job+'&id='+this.$route.params.id
fetch(this.JobExecEndpoint)
.then(response => response.json())
.then(body => {
this.job_execs.push({
'code_checkouts': body[0].code_checkouts,
})
})
.catch( err => {
console.log('Error Fetching:', this.JobExecEndpoint, err);
return { 'failure': this.JobExecEndpoint, 'reason': err };
})
},
};
</script>
unit test
import { shallowMount } from "#vue/test-utils";
import fetchMock from 'fetch-mock'
import flushPromises from 'flush-promises'
import Jobs from "../../src/components/execution_details/Jobs.vue";
const job_execs = [
{
'code_checkouts': [{'name': 'test', 'git_hash': 'test', 'git_repo': 'test'}, {'name': 'test', 'git_hash': 'test', 'git_repo': 'test'}]}]
const $route = {
params = {
tool: 'jenkins',
job: 'jobname',
id: '1',
}
}
describe('Jobs.vue', () => {
beforeEach(() => {
fetchMock.get(process.env.VUE_APP_UATU_URL + '/api/v2/job_execution/?product=eBay%20Mobile&tool='+$route.params.tool+'&job='+$route.params.job+'&id='+$route.params.id, job_execs)
})
it('Construct a JSON object of Git Refs from job_execution API', async () => {
const wrapper = shallowMount(GitRefs)
await flushPromises()
expect(wrapper.vm.job_execs).toEqual(job_execs)
})
afterEach(() => {
fetchMock.restore()
})
})
You need to import all the dependencies used in the component and also need to import whatever global values or properties used router, axios etc
I have a node module which exports a few classes, one of which is Client, which I use to create a client (having a few APIs as methods).
I'm trying to test my module which uses this node module as a dependency using Jest. However, I've been unable to successfully mock the one method (say search()) in the Client class.
Here is my spec for myModule:
//index.spec.ts
import * as nock from 'nock';
import * as externalModule from 'node-module-name';
import { createClient } from './../../src/myModule';
describe(() => {
beforeAll(() => {
nock.disableNetConnect();
});
it('test search method in my module', () => {
jest.mock('node-module-name');
const mockedClient = <jest.Mock<externalModule.Client>>externalModule.Client;
const myClient = createClient({/*params*/}); //returns instance of Client class present in node module by executing Client() constructor
myClient.searchByName('abc'); //calls search API - I need to track calls to this API
expect(mockedClient).toHaveBeenCalled();
expect(mockedClient.prototype.search).toHaveBeenCalledWith('abc');
});
});
This, however, doesn't create a mock at all and triggers a nock error since the search API tries to connect to the url (given through params).
I've also tried mocking the Client class like the following. While successfully creating a mock for the Client class and also the search API (verified that search() is also mocked through console logs), it gives me an error while I try to check if search() has been called.
externalModule.Client = jest.fn(() => { return { search: jest.fn(() => Promise.resolve('some response')) } });
//creates the mock successfully, but not sure how to track calls to 'search' property
const client = myModule.createClient(/*params*/);
client.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled(); //Successful
expect(externalModule.Client.prototype.search).toHaveBeenCalled(); //returns error saying "jest.fn() value must be a mock function or spy, Received: undefined"
I'm not sure what I'm doing wrong. Thank you in advance.
Mocking whole module
Try moving jest.mock to the top of file
//index.spec.ts
const search = jest.fn();
jest.mock('node-module-name', () => ({
Client: jest.fn(() => ({ search }))
}));
import * as nock from 'nock';
import * as externalModule from 'node-module-name';
import { createClient } from './../../src/myModule';
describe(() => {
beforeAll(() => {
nock.disableNetConnect();
});
it('test search method in my module', () => {
const myClient = createClient({/*params*/});
myClient.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled();
expect(search).toHaveBeenCalledWith('abc');
externalModule.Client.mockClear();
search.mockClear();
});
});
Mocking only Client
Create search constant and track it.
const search = jest.fn();
externalModule.Client = jest.fn(() => ({ search }));
const client = myModule.createClient(/*params*/);
client.searchByName('abc');
expect(externalModule.Client).toHaveBeenCalled();
expect(search).toHaveBeenCalled();
Here is how I mocked it. I had to change naming and removing some code to avoid exposing original source.
jest.mock('../foo-client', () => {
return { FooClient: () => ({ post: mockPost }) }
})
Full code.
// foo-client.ts
export class FooClient {
constructor(private config: any)
post() {}
}
// foo-service.ts
import { FooClient } from './foo-client'
export class FooLabelService {
private client: FooClient
constructor() {
this.client = new FooClient()
}
createPost() {
return this.client.post()
}
}
// foo-service-test.ts
import { FooService } from '../foo-service'
const mockPost = jest.fn()
jest.mock('../foo-client', () => {
return { FooClient: () => ({ post: mockPost }) }
})
describe('FooService', () => {
let fooService: FooService
beforeEach(() => {
jest.resetAllMocks()
fooService = new FooService()
})
it('something should happened', () => {
mockPost.mockResolvedValue()
fooService.createPost()
})
})
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