let image = await object
.firstCall(params)
.promise()
.then(data => {
return data
})
.catch(err => {
console.(err)
});
What's the way to stub the chained promises with sinon ? I've tried the following, but with no luck
promiseStub = sinon.stub().callsArg(0).resolves("something");
firtCallStub = sinon.stub(object, "firstCall").returns(this.promiseStub);
Unit test solution:
index.ts:
import { object } from './obj';
export async function main() {
const params = {};
return object
.firstCall(params)
.promise()
.then((data) => {
return data;
})
.catch((err) => {
console.log(err);
});
}
obj.ts:
export const object = {
firstCall(params) {
return this;
},
async promise() {
return 'real data';
},
};
index.test.ts:
import { main } from './';
import { object } from './obj';
import sinon from 'sinon';
import { expect } from 'chai';
describe('64795845', () => {
afterEach(() => {
sinon.restore();
});
it('should return data', async () => {
const promiseStub = sinon.stub(object, 'promise').resolves('fake data');
const firtCallStub = sinon.stub(object, 'firstCall').returnsThis();
const actual = await main();
expect(actual).to.be.equal('fake data');
sinon.assert.calledWithExactly(firtCallStub, {});
sinon.assert.calledOnce(promiseStub);
});
});
unit test result:
64795845
✓ should return data
1 passing (32ms)
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 66.67 | 100 | 40 | 66.67 |
index.ts | 83.33 | 100 | 66.67 | 83.33 | 12
obj.ts | 33.33 | 100 | 0 | 33.33 | 3-6
----------|---------|----------|---------|---------|-------------------
Related
Here is my Node.js module to test (userdata.js file):
const myService = require('./my-service')
class UserData {
getData(query) {
return new Promise((resolve, reject) => {
myService.getUserData(query)
.then((userdata) => {
myService.getManagerData(userdata)
.then((managerdata) => {
resolve(managerdata)
})
})
})
}
}
module.exports = UserData
and test file:
const UserData = require('/.userdata')
test('UserData.getData', () => {
expect(UserData.getData('John Smith')).toBe('John\' manager');
});
I want to mock myService.getUserData and/or myService.getManagerData functions call that I'm not directly declare in test file.. How do I mock them properly to return some dummy result?
You can use jest.spyOn(object, methodName) to make stub for myService.getUserData and myService. getManagerData methods.
E.g.
userData.js:
const myService = require('./myService');
class UserData {
getData(query) {
return new Promise((resolve, reject) => {
myService.getUserData(query).then((userdata) => {
myService.getManagerData(userdata).then((managerdata) => {
resolve(managerdata);
});
});
});
}
}
module.exports = UserData;
myService.js:
const myService = {
getUserData(query) {
return 'real user data';
},
getManagerData(userdata) {
return 'real manager data';
},
};
module.exports = myService;
userData.test.js:
const UserData = require('./userData');
const myService = require('./myService');
describe('61784452', () => {
afterEach(() => {
jest.restoreAllMocks();
});
it('should pass', async () => {
jest.spyOn(myService, 'getUserData').mockResolvedValueOnce('fake user data');
jest.spyOn(myService, 'getManagerData').mockResolvedValueOnce('fake manager data');
const userData = new UserData();
const actual = await userData.getData('query');
expect(actual).toEqual('fake manager data');
expect(myService.getUserData).toBeCalledWith('query');
expect(myService.getManagerData).toBeCalledWith('fake user data');
});
});
unit test results with coverage report:
PASS stackoverflow/61784452/userData.test.js (12.908s)
61784452
✓ should pass (5ms)
--------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
--------------|---------|----------|---------|---------|-------------------
All files | 84.62 | 100 | 71.43 | 84.62 |
myService.js | 50 | 100 | 0 | 50 | 3-6
userData.js | 100 | 100 | 100 | 100 |
--------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 13.99s
new UrlBuilder(urlString).buildURL(params).getShortenedURL().then(data => {
.....
});
How can I stub the object creation and check whether getShortenedURL() has been called?
I tried
this.urlBuilder = sinon.stub(UrlBuilder.prototype, getShortenedURL).resolves({url: '/someUrl'});
But every time I run a test that has:
assert(this.urlBuilder.getShortenedURL.called);
it'll say
ReferenceError: getShortenedURL is not defined
Here is the unit test solution:
index.js:
const UrlBuilder = require('./urlBuilder');
function main() {
const urlString = 'https://stackoverflow.com/';
const params = {};
return new UrlBuilder(urlString)
.buildURL(params)
.getShortenedURL()
.then((data) => data);
}
module.exports = main;
urlBuilder.js:
class UrlBuilder {
constructor(url) {
this.url = url;
}
buildURL(params) {
return this;
}
getShortenedURL() {
return Promise.resolve('real data');
}
}
module.exports = UrlBuilder;
index.test.js:
const sinon = require('sinon');
const proxyquire = require('proxyquire');
const { expect } = require('chai');
describe('60214679', () => {
it('should pass', async () => {
const urlBuilderInstanceStub = {
buildURL: sinon.stub().returnsThis(),
getShortenedURL: sinon.stub().resolves('fake data'),
};
const urlBuilderStub = sinon.stub().callsFake(() => urlBuilderInstanceStub);
const main = proxyquire('./', {
'./urlBuilder': urlBuilderStub,
});
const actual = await main();
expect(actual).to.be.eq('fake data');
sinon.assert.calledWithExactly(urlBuilderStub, 'https://stackoverflow.com/');
sinon.assert.calledWithExactly(urlBuilderInstanceStub.buildURL, {});
sinon.assert.calledOnce(urlBuilderInstanceStub.getShortenedURL);
});
});
Unit test results with coverage report:
60214679
✓ should pass (2010ms)
1 passing (2s)
---------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
---------------|---------|----------|---------|---------|-------------------
All files | 70 | 100 | 40 | 70 |
index.js | 100 | 100 | 100 | 100 |
urlBuilder.js | 25 | 100 | 0 | 25 | 3,6,9
---------------|---------|----------|---------|---------|-------------------
Source code: https://github.com/mrdulin/expressjs-research/tree/master/src/stackoverflow/60214679
export const get = () => {
return fetch().then((response) => funcA(response));
};
const funcA = (response) => {
if (!response.ok) {
return response.json().then((data) => {
throw Error(...);
});
}
};
How can i mock response.json().then() ? I got the error response.json(...).then is not a function.
I put the json() in the response i mocked
response = { ok: false, json: () => err };
response.json method should return a promise. E.g.
index.ts:
export const funcA = (response) => {
if (!response.ok) {
return response.json().then((data) => {
throw Error(data);
});
}
};
index.test.ts:
import { funcA } from './';
describe('48916842', () => {
it('should pass', () => {
const mResponse = { ok: false, json: jest.fn().mockRejectedValueOnce('custom error') };
expect(funcA(mResponse)).rejects.toThrowError('custom error');
});
});
unit test result with coverage report:
PASS stackoverflow/48916842/index.test.ts (10.276s)
48916842
✓ should pass (5ms)
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 75 | 50 | 50 | 75 |
index.ts | 75 | 50 | 50 | 75 | 4
----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 11.929s, estimated 12s
I have the following simplified method and test, where I want to test that handleResponse() has been called.
The test fails with handleResponse() not beeing called at all. If I modify the code to run handleResponse outside the promise, the test completes successfully.
Is this because the promise is async, and the assertion is being run before the promise? If so, how can I wait for the promise to the completed before running the assertion?
Code:
export function fetchList(id) {
// handleResponse(response); // Works here
return (dispatch) => {
service.getList(id).then((response) => {
handleResponse(response); // Doesnt work here
}, (error) => {
addNotification(error);
});
};
}
Test:
describe('fetchList', () => {
let getListStub;
let handleResponseStub;
beforeEach(() => {
getListStub = sinon.stub(service, 'getList');
handleResponseStub = sinon.stub(appActions, 'handleResponse');
});
afterEach(() => {
getListStub.restore();
handleResponseStub.restore();
});
it('should dispatch handleResponse on success', () => {
const dispatchStub = sinon.stub();
const id = 1;
const returnValue = 'return value';
getListStub.withArgs(id).resolves(returnValue);
listActions.fetchList(id)(dispatchStub);
sinon.assert.calledOnce(getListStub);
sinon.assert.calledOnce(handleResponseStub); // Fails
});
});
You forget add async/await to your unit test and change to return service.getList(...). Otherwise, the assertion will execute before resolving the promise of service.getList(...).
listActions.ts:
import * as service from "./service";
import { handleResponse, addNotification } from "./appActions";
export function fetchList(id) {
return dispatch => {
return service.getList(id).then(
response => {
handleResponse(response);
},
error => {
addNotification(error);
}
);
};
}
appActions.ts:
export function handleResponse(res) {
console.log("handleResponse");
}
export function addNotification(error) {
console.log("addNotification");
}
service.ts:
export function getList(id) {
return new Promise(resolve => {
setTimeout(() => {
resolve([]);
}, 5000);
});
}
listActions.spec.ts:
import * as service from "./service";
import * as appActions from "./appActions";
import * as listActions from "./listActions";
import sinon from "sinon";
describe("fetchList", () => {
let getListStub;
let handleResponseStub;
beforeEach(() => {
getListStub = sinon.stub(service, "getList");
handleResponseStub = sinon.stub(appActions, "handleResponse");
});
afterEach(() => {
getListStub.restore();
handleResponseStub.restore();
});
it("should dispatch handleResponse on success", async () => {
const dispatchStub = sinon.stub();
const id = 1;
const returnValue = "return value";
getListStub.withArgs(id).resolves(returnValue);
await listActions.fetchList(id)(dispatchStub);
sinon.assert.calledOnce(getListStub);
sinon.assert.notCalled(dispatchStub);
sinon.assert.calledOnce(handleResponseStub); // Fails
});
});
Unit test result with coverage report:
fetchList
✓ should dispatch handleResponse on success
1 passing (95ms)
---------------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------|----------|----------|----------|----------|-------------------|
All files | 83.33 | 100 | 53.85 | 82.86 | |
appActions.ts | 50 | 100 | 0 | 50 | 2,6 |
listActions.spec.ts | 100 | 100 | 100 | 100 | |
listActions.ts | 85.71 | 100 | 75 | 85.71 | 11 |
service.ts | 25 | 100 | 0 | 25 | 2,3,4 |
---------------------|----------|----------|----------|----------|-------------------|
Source code: https://github.com/mrdulin/mocha-chai-sinon-codelab/tree/master/src/stackoverflow/43186634
I have been trying to stub and mock my function to be able to test my function
SetExample.createCandyBox = function(config) {
this.getCandies(config.candyUrl)
.catch(() => {
return {};
})
.then((candies) => {
Advertisements.pushCandyBox(config, candies);
});
};
I want to test a scenario when the config.candyUrl is incorrect(404, etc) with something like:
it('should return to an empty array when url is incorrect', sinon.test(function() {
// Fixture is an element I created for testing.
var configStub = SetExample.getCandyConfig(fixture);
var createCandyBoxMock = sinon.mock(config);
createCandyBoxMock.expects('catch');
SetExample. createCandyBox(configStub);
}));
When I do this, term is error => Can't find variable: config.
What did I do wrong? can someone help and explain? I am new to Sinon :( Thx in advance!
You can use sinon.stub() to stub this.getCandies and its resolved/rejected value. And stub Advertisements.pushCandyBox, then make an assertion to check if it has been called or not.
E.g.
SetExample.js:
const Advertisements = require('./Advertisements');
function SetExample() {}
SetExample.getCandies = async function (url) {
return 'your real getCandies implementation';
};
SetExample.createCandyBox = function (config) {
return this.getCandies(config.candyUrl)
.catch(() => {
return {};
})
.then((candies) => {
Advertisements.pushCandyBox(config, candies);
});
};
module.exports = SetExample;
Advertisements.js:
function Advertisements() {}
Advertisements.pushCandyBox = function (config, candies) {
return 'your real pushCandyBox implementation';
};
module.exports = Advertisements;
SetExample.test.js
const SetExample = require('./SetExample');
const Advertisements = require('./Advertisements');
const sinon = require('sinon');
describe('38846337', () => {
describe('#createCandyBox', () => {
afterEach(() => {
sinon.restore();
});
it('should handle error', async () => {
const err = new Error('timeout');
sinon.stub(SetExample, 'getCandies').withArgs('wrong url').rejects(err);
sinon.stub(Advertisements, 'pushCandyBox');
await SetExample.createCandyBox({ candyUrl: 'wrong url' });
sinon.assert.calledWithExactly(SetExample.getCandies, 'wrong url');
sinon.assert.calledWithExactly(Advertisements.pushCandyBox, { candyUrl: 'wrong url' }, {});
});
});
});
unit test result:
38846337
#createCandyBox
✓ should handle error
1 passing (7ms)
-------------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-------------------|---------|----------|---------|---------|-------------------
All files | 81.82 | 100 | 42.86 | 81.82 |
Advertisements.js | 66.67 | 100 | 0 | 66.67 | 4
SetExample.js | 87.5 | 100 | 60 | 87.5 | 6
-------------------|---------|----------|---------|---------|-------------------