I'm coming from Java experience with spring framework and looking for the most elegant way to write tests with mocks in nodejs.
For java its look like this:
#RunWith(SpringJUnit4ClassRunner.class)
public class AccountManagerFacadeTest {
#InjectMocks
AccountManagerFacade accountManagerFacade;
#Mock
IService service
#Test
public void test() {
//before
here you define specific mock behavior
//when
//then
}
}
Looking for something similar for nodeJS, any suggestions?
Mocking with node.js is much easier than Java thanks to javascript flexibility.
Here is a full example of class mocking, with the following class:
// lib/accountManager.js
class AccountManager {
create (name) {
this._privateCreate(name);
}
update () {
console.log('update')
}
delete () {
console.log('delete')
}
_privateCreate() {
console.log('_privateCreate')
}
}
module.exports = AccountManager
You could mock it like this:
// test/accountManager.test.js
const
sinon = require('sinon'),
should = require('should')
AccountManager = require('../lib/accountManager');
require('should-sinon'); // Required to use sinon helpers with should
describe('AccountManager', () => {
let
accountManager,
accountManagerMock;
beforeEach(() => {
accountManagerMock = {
_privateCreate: sinon.stub() // Mock only desired methods
};
accountManager = Object.assign(new AccountManager(), accountManagerMock);
});
describe('#create', () => {
it('call _privateCreate method with good arguments', () => {
accountManager.create('aschen');
should(accountManagerMock._privateCreate).be.calledOnce();
should(accountManagerMock._privateCreate).be.calledWith('aschen');
})
});
});
Here you can find more example on mocking classes and dependencies: https://github.com/Aschen/workshop-tdd/blob/master/step2/test/file.test.js
Related
We mock our modules using __mocks__. I'd like to spyOn a module function in my test but it doesn't seem to be working. Related question, I'd also like to override a mocked module function for a test (ie throw an exception). How can I do this?
├──__mocks__
| └──DB-Utils.js
| └──controllers
| └──myController.js
├──node_modules
__mocks__/DB-Utils.js:
const { MyController } = require('./controllers/myController');
module.exports = {
MyController,
};
__mocks__/controllers/myController.js:
class MyController {
async setAvailability(id, availability) {
return true;
}
}
module.exports = {
MyController,
};
test.spec.js:
const { MyController } = require('DB-Utils');
const myController = new MyController();
describe('Register Tests', () => {
fit('myController setAvailability', async () => {
---code that calls a class that ends up calling myController.setAvailability---
expect(myController.setAvailability).toHaveBeenCalledWith('foo', 'bar');
});
});
My tests pass in that the mock myController is called, however it fails the toHaveBeenCalledWith with an error of Number of calls: 0
How can I spy setAvailability?
For the related question I'd also like to be able to do something like the following:
describe('Register Tests', () => {
fit('myController setAvailability throws', async () => {
jest.spyOn(myController, 'setAvailability').mockImplementation(() => {
throw new Error()
});
expect(---code that calls a class that ends up calling myController.setAvailability---).toThrow();
});
});
I have one class as below
nx-user.js
class NXUser {
constructor() {}
view(guid, data) {
//do something
}
}
Then I have user controller module as below which has dependency of NxUser class
userController.js
const userDb = new NXUser();
import NXUser from "../../../persistence/nx-user";
const allUsers = () => {
return userDb.view()
}
export {allUsers }
I have below code written for stubbing view function of NxUser class for controller unit tests. But its not working. It always calling actual one instated of stubbed one
userController-test.js
let userdb=NXUser();
describe("user controller", function () {
let stubValue = [{
"name": "Urvashi Parmar",
"email": "urvashi.parmar#nationalexpress.com"]}
it("Should create user", () => {
sinon.stub(userdb, 'create').resolves(stubValue);
userController.allUsers ().then((body) => {
expect(body[0].name).to.equal(stubValue .name);
done();
});
})
}
Because I can not comment yet, so I need to give full answer.
Confusion: at your userController-test.js, you are trying to test NXUser.create, while at file nx-user.js has no definition of create.
Assume: you are trying to test NXUser.view.
This example is created based on your code, and is working fine. Console log "Called" will not get called.
Highlight:
Stub NXUser view directly, not userdb.create;
I use async-await inside test.
const sinon = require('sinon');
const { expect } = require('chai');
class NXUser {
constructor() {}
view(guid, data) {
console.log('Called');
return new Promise((resolve) => resolve([]));
}
// Add this only for dummy.
create() {
return new Promise((resolve) => resolve([]));
}
}
const userController = {
allUsers() {
const userDb = new NXUser();
return userDb.view();
}
}
describe('user controller', function () {
// Suppose you test view user.
it('should view user', async function () {
const stubValue = [{
name: 'Urvashi Parmar',
email: 'urvashi.parmar#nationalexpress.com'
}];
// Suppose you stub method view and not create.
const stubUserDBView = sinon.stub(NXUser.prototype, 'view');
stubUserDBView.resolves(stubValue);
const body = await userController.allUsers();
expect(body).to.be.an('array').that.have.lengthOf(1);
expect(body[0]).to.have.property('name', stubValue[0].name);
// Restore stub.
stubUserDBView.restore();
});
});
$ npx mocha stackoverflow.js
user controller
✓ should view user
1 passing (11ms)
$
Hope this helps.
Trying to write test scripts for my nestjs application.
I have controller/service framework, that looks like this:
Controller:
export class MyController {
constructor(
protected _svc: MyService
) {}
#Get()
async getAll(): Promise<Array<Person>> {
return await this._svc.findAll();
}
}
Service:
#Injectable()
export class MyService extends DbService < Person > {
constructor(
private _cache: CacheService
) {
super(...);
}
async findAll() {
return super.findAll().then(res => {
res.map(s => {
this._cache.setValue(`key${s.ref}`, s);
});
return res;
});
}
Base class:
#Injectable()
export abstract class DbService<T> {
constructor() {}
async findAll(): Promise<Array<T>> {
...
}
}
My controller is the entry point when calling an endpoint on the API. This calls the service, which extends the DbService, which is what communicates with my database. There are a lot of services which all extend this DbService. In this case, the MyService class overrides the DbService "findAll" method to do some cache manipulation.
My test script has this:
let myController: MyController;
let myService: MyService;
describe("MyController", async () => {
let spy_findall, spy_cacheset;
beforeAll(() => {
this._cacheService = {
// getValue, setValue, delete methods
};
myService = new MyService(this._cacheService);
myController = new MyController(myService);
spy_findall = jest.spyOn(myService, "findAll").mockImplementation(async () => {
return [testPerson];
});
spy_cacheset = jest.spyOn(this._cacheService, "setValue");
});
beforeEach(async () => {
jest.clearAllMocks();
});
describe("getAll", () => {
it("should return an array of one person", async () => {
await myController.getAll().then(r => {
expect(r).toHaveLength(1);
expect(spy_findall).toBeCalledTimes(1);
expect(spy_cacheset).toBeCalledTimes(1);
expect(r).toEqual([testPerson]);
});
});
});
});
Now, obviously the mockImplementation of findAll mocks the "findAll" on MyService, so the test fails because spy_cacheset is never called.
What I would like to do is mock only the base method "findAll" from DbService, so that I maintain the extra functionality that exists in MyService.
Is there a way of doing this without just renaming the methods in MyService, which I would rather avoid doing?
Edited to add:
Thanks to #Jonatan lenco for such a comprehensive reponse, which I have taken on board and implemented.
I have one further question. CacheService, DbService and a whole lot of other stuff (some of which I want to mock, other that I don't) is in an external library project, "shared".
cache.service.ts
export class CacheService {...}
index.ts
export * from "./shared/cache.service"
export * from "./shared/db.service"
export * from "./shared/other.stuff"
....
This is then compiled and included as a package in node_modules.
In the project where I am writing the tests:
import { CacheService, DocumentService, OtherStuff } from "shared";
Can I still use jest.mock() for just the CacheService, without mocking the whole "shared" project?
In this case since you want to spy on an abstract class (DbService), you can spy on the prototype method:
jest.spyOn(DbService.prototype, 'findAll').mockImplementation(async () => {
return [testPerson];
});
Also here some recommendations for your unit tests with NestJS and Jest:
Use jest.mock() in order to simplify your mocking (in this case for CacheService). See https://jestjs.io/docs/en/es6-class-mocks#automatic-mock.
When you do jest.spyOn(), you can assert the method execution without the need of the spy object. Instead of:
spy_findall = jest.spyOn(myService, "findAll").mockImplementation(async () => {
return [testPerson];
});
...
expect(spy_findall).toBeCalledTimes(1);
You can do:
jest.spyOn(DbService.prototype, 'findAll').mockImplementation(async () => {
return [testPerson];
});
...
expect(DbService.prototype.findAll).toBeCalledTimes(1);
If you are mocking a class properly, you do not need to spy on the method (if you do not want to mock its implementation).
Use the Testing utilities from NestJS, it will help you a lot specially when you have complex dependency injection. See https://docs.nestjs.com/fundamentals/testing#testing-utilities.
Here is an example that applies these 4 recommendations for your unit test:
import { Test } from '#nestjs/testing';
import { CacheService } from './cache.service';
import { DbService } from './db.service';
import { MyController } from './my.controller';
import { MyService } from './my.service';
import { Person } from './person';
jest.mock('./cache.service');
describe('MyController', async () => {
let myController: MyController;
let myService: MyService;
let cacheService: CacheService;
const testPerson = new Person();
beforeAll(async () => {
const module = await Test.createTestingModule({
controllers: [MyController],
providers: [
MyService,
CacheService,
],
}).compile();
myService = module.get<MyService>(MyService);
cacheService = module.get<CacheService>(CacheService);
myController = module.get<MyController>(MyController);
jest.spyOn(DbService.prototype, 'findAll').mockImplementation(async () => {
return [testPerson];
});
});
beforeEach(async () => {
jest.clearAllMocks();
});
describe('getAll', () => {
it('Should return an array of one person', async () => {
const r = await myController.getAll();
expect(r).toHaveLength(1);
expect(DbService.prototype.findAll).toBeCalledTimes(1);
expect(cacheService.setValue).toBeCalledTimes(1);
expect(r).toEqual([testPerson]);
});
});
});
NOTE: for the testing utilities to work and also for your application to work well, you will need to add the #Controller decorator on the class MyController:
import { Controller, Get } from '#nestjs/common';
...
#Controller()
export class MyController {
...
}
About mocking specific items of another package (instead of mocking the whole package) you could do this:
Create a class in your spec file (or you can create it in another file that you import, or even in your shared module) which has a different name but has the same public method names. Note that we use jest.fn() since we do not need to provide an implementation, and that already spies in the method (no need to later do jest.spyOn() unless you have to mock the implementation).
class CacheServiceMock {
setValue = jest.fn();
}
When setting up the providers of your testing module, tell it that you are "providing" the original class but actually providing the mocked one:
const module = await Test.createTestingModule({
controllers: [MyController],
providers: [
MyService,
{ provide: CacheService, useClass: CacheServiceMock },
],
}).compile();
For more info about providers see https://angular.io/guide/dependency-injection-providers (Nest follows the same idea of Angular).
I have a class
class Dummy {
constructor() {
this.prop1 = null;
this.prop2 = null;
this.prop3 = setInterval(() => {
this.method1()
}, 1000);
}
method1() {
// Method logic
}
}
var dummyObject = new Dummy();
module.exports = dummyObject;
I'd like to write tests to verify that method1 is being invoked after every 1s.
Following is the test code
const dummyObject = require('./dummy.js');
describe("Test setInterval", function () {
it("Test setInterval", function () {
const clock = sinon.useFakeTimers();
const spy = sinon.spy(dummyObject, 'method1');
clock.tick(1001);
expect(spy.calledOnce).to.be.true;
clock.restore();
})
})
When I run the tests however, I get an error 'Expected false to equal to true' and on further digging I realized I am not able to spy on the method which is being called via setInterval.
Please share any thoughts on what I can do to test this scenario?
This is not going to work the way you want it to, because the method (method1) is already called when you require the module and hence there is no chance to spy it afterwards in your test.
I recommend to refactor your Module to export the class, not the instance like:
module.exports = class Dummy {
constructor() {
this.prop1 = null;
this.prop2 = null;
this.prop3 = setInterval(() => {
this.method1()
}, 1000);
}
method1() {
// Method logic
}
}
Then in you test, require the class and spy on the method before you instantiate it:
const sinon = require('sinon');
const Dummy = require('./dummy.js');
describe("Test setInterval", function () {
it("Test setInterval", function () {
const clock = sinon.useFakeTimers();
// Spy on the method using the class' prototype
const spy = sinon.spy(Dummy.prototype, 'method1');
// Initialize the class and make sure its `constructor` is called after you spied on the method
new Dummy();
clock.tick(1001);
expect(spy.calledOnce).to.be.true;
clock.restore();
})
})
in my Node.JS project (a backend for an Angular 5 project) I have created a service that deals with the AWS Authentication... I have called this awsAuthenticationService. All works well but I now need to test it. In my awsAuthenticationService.js I have the following method that has some minor logic and then calls a method provided by the "cognitoIdentityServiceProvider". Here is a snippet of my code (I really have reduced this)
constructor() {
this._cognitoIdentityServiceProvider = new AWS.CognitoIdentityServiceProvider(this.cognitoConfig);
}
toggleUserAccess(userName, type) {
const params = {
Username: userName,
UserPoolId: this.cognitoConfig.userPoolId
};
if (type === null) {
return this._cognitoIdentityServiceProvider.adminEnableUser(params).promise();
}
return this._cognitoIdentityServiceProvider.adminDisableUser(params).promise();
}
As you can see from the toggleUserAccess we pass a few parameters, determine what they are then call the appropriate method. I wish to test this by having a unit test that will call the authenticationService.toggleUserAccess, pass some params and spy on the authenticationService._cognitoIdentityServiceProvider methods to see if they were called. I set it up so...
let authenticationService = require('./awsAuthenticationService');
describe('toggleUserAccess', () => {
beforeEach(() => {
authenticationService._cognitoIdentityServiceProvider = {
adminDisableUser(params) {
return {
promise() {
return Promise.resolve(params);
}
};
}
};
authenticationService._cognitoIdentityServiceProvider = {
adminEnableUser(params) {
return {
promise() {
return Promise.resolve(params);
}
};
}
};
});
it('should call adminEnableUser if the type is null', () => {
authenticationService.toggleUserAccess('TheUser', null);
const spyCognito = sinon.spy(authenticationService._cognitoIdentityServiceProvider, 'adminEnableUser');
expect(spyCognito.calledOnce).to.equal(true);
});
it('should call adminDisableUser if the type is null', () => {
authenticationService.toggleUserAccess('TheUser', '0001');
const spyCognito = sinon.spy(authenticationService._cognitoIdentityServiceProvider, 'adminDisableUser');
expect(spyCognito.calledOnce).to.equal(true);
});
});
My tests aren't passing and I think I have set up my sinon.spys incorrectly - can anyone see what I am doing wrong or give advice please
To stub class of AWS.CognitoIdentityServiceProvider, need to stub with its prototype keyword.
// add require statement for your AWS class
const spyCognito = sinon.spy(AWS.CognitoIdentityServiceProvider.prototype, 'adminDisableUser');
expect(spyCognito.calledOnce).to.equal(true);
Hope it helps