I'm having trouble having a unique implementation of search from this module pattern setup I have (MyConnection.js) - here's similar to what I have:
// MyConnection.js
const MyConnection = () => {
const search = async (q) => {
//...some functionality
};
return {
search,
};
};
//JEST TESTS
const MyConnection = require('../MyConnection')
// this works - but it sets the search implementation
// for the whole test file I believe
jest.mock('../MyConnection', () => {
return jest.fn(()=>{
search: ()=> ['mocked', 'fn', 'results']
})
})
//the jest tests - I want different
// implementations of search in each test
describe('connection tests', ()=>{
it('test one', ()=>{
//Not sure if its something like this to set 'search' for each test? This doesn't work as is
MyConnection.search.mockImplementation((q)=>{`You searched ${q}`})
})
it('test two', ()=>{
MyConnection.search.mockImplementation((q)={q.length>32? 'a': 'b' }})
})
})
How can I get unique Jest mock implementations of that search function for each test?
You should make sure that mock MyConnection always returns the same connection object in your test file and the module you want to test.
MyConnection.js:
const MyConnection = () => {
const search = async (q) => {};
return {
search,
};
};
module.exports = MyConnection;
main.js:
const MyConnection = require('./MyConnection');
async function main(q) {
const conn = MyConnection();
return conn.search(q);
}
module.exports = main;
main.test.js:
const MyConnection = require('./MyConnection');
const main = require('./main');
jest.mock('./MyConnection', () => {
console.log('MyConnection module gets mocked');
const conn = { search: jest.fn() };
return jest.fn(() => conn);
});
const mConn = MyConnection();
describe('connection tests', () => {
it('test one', async () => {
mConn.search.mockImplementation((q) => {
return `You searched ${q}`;
});
const actual = await main('teresa teng');
expect(actual).toBe('You searched teresa teng');
});
it('test two', async () => {
mConn.search.mockImplementation((q) => {
return q.length > 32 ? 'a' : 'b';
});
const actual = await main('_');
expect(actual).toBe('b');
});
});
test result:
PASS examples/70132655/main.test.js (10.454 s)
connection tests
✓ test one (2 ms)
✓ test two (1 ms)
console.log
MyConnection module gets mocked
at examples/70132655/main.test.js:5:11
Test Suites: 1 passed, 1 total
Tests: 2 passed, 2 total
Snapshots: 0 total
Time: 10.903 s
You can't mock it like this:
jest.mock('./MyConnection', () => {
console.log('MyConnection module gets mocked');
return jest.fn(() => { search: jest.fn() });
});
Why? Because every time you call the MyConnection() function in the test file or the file you want to test. It will return a new mock object({ search: jest.fn() }), the mock objects in file under test and test case are not same.
My NodeJS application has to do some API requests, so I'm mocking their return as my tests are just for my application's business logic. However, there's two things that I quite didn't understand.
I'm using jest's mockImplementation method to change the return of my service, but I can't make it work without calling jest.mock with the service beforehand.
Also, if I try to set automock: true in my jest.config.js, it returns me an error:|
TypeError: Cannot set property 'gracefulify' of undefined
Here's my test.js code in where I'm testing a function that calls automation.js, which has my application logic and make the calls for my services:
const automation = require('../automations/fake.automation');
// MOCKS
const mockedBlingProduct = require('../mocks/bling-product.mocks.json');
const mockedShopifyCreatedProduct = require('../mocks/shopify-created-product.mocks.json');
// SERVICES
const BlingProductService = require('../services/bling-product.service');
const ShopifyProductService = require('../services/shopify-product.service');
jest.mock('../services/bling-product.service');
jest.mock('../services/shopify-product.service');
describe('Automation test', () => {
beforeEach(() => {
const blingMockedReturn = jest.fn(() => {
return mockedBlingProduct;
});
const shopifyMockedReturn = jest.fn(() => {
return mockedShopifyCreatedProduct;
});
BlingProductService.mockImplementation(() => {
return {
list: blingMockedReturn
};
});
ShopifyProductService.mockImplementation(() => {
return {
create: shopifyMockedReturn
};
});
});
it('should return status SUCCESS', async () => {
const result = await
.run();
expect(result).toEqual({ status: 'SUCCESS' });
});
});
And here's the code of one of my services, keep in mind that the logic behind the API calls is abstracted from the service. In the mockImplementation I'm trying to overwrite the list and create functions inside them:
class BlingPriceService {
async list(query = {}) {
const httpMethod = 'GET';
const resource = 'produtos/page={pageNumber}/json';
const options = {
queryString: query,
urlParams: {
pageNumber: 1,
}
};
return blingComponent.request(httpMethod, resource, options);
}
}
module.exports = BlingPriceService;
const automation = require('../automations/fake.automation');
// MOCKS
const mockedBlingProduct = require('../mocks/bling-product.mocks.json');
const mockedShopifyCreatedProduct = require('../mocks/shopify-created-product.mocks.json');
// SERVICES
const BlingProductService = require('../services/bling-product.service');
const ShopifyProductService = require('../services/shopify-product.service');
describe('Automation test', () => {
beforeAll(() => {
jest.spyOn(BlingProductService.prototype, 'list').mockImplementation(() => Promise.resolve(mockedBlingProduct));
jest.spyOn(ShopifyProductService.prototype, 'list').mockImplementation(() => Promise.resolve(mockedShopifyCreatedProduct));
});
afterAll(() => {
jest.restoreAllMocks();
});
it('should return status SUCCESS', async () => {
const result = await automation.run();
expect(result).toEqual({ status: 'SUCCESS' });
});
});
I'm testing a cloud function named myCloudFn in my functions/send.js module. My tests are in functions/test/send.test.js:
// send.js
const { getCompareDate } = require('../utils.js');
async function myCloudFn(myTestDate) {
const compareDate = await getCompareDate(argToTest);
const isOlder = myTestDate < compareDate;
return isOlder ? 'older' : 'newer';
}
module.exports = { myCloudFn };
// send.test.js
const send = require('../send.js');
jest.mock('../utils', () => ({
getCompareDate: jest.fn(() => new Date('2020-01-31')) // default
.mockResolvedValueOnce(new Date('2020-04-04'))
.mockResolvedValueOnce(new Date('2020-02-02')),
}));
describe('send.js', () => {
it('returns date comparison from myCloudFn()', async () => {
const myTestDate = '2020-03-03';
const returnValues = ['older', 'newer'];
const responsePromises = returnValues.map(() => send.myCloudFn(myTestDate));
const responses = await Promise.all(responsePromises);
expect(responses[0]).toBe(returnValues[0]);
expect(responses[1]).toBe(returnValues[1]);
});
});
The test functions correctly and passes as expected when I mock getCompareDate in this way, but for flexibility, I would rather provide custom input values for getCompareDate inside my tests and not 'globally'. Here's what I've tried:
const mockGetCompareDate = jest.fn();
jest.mock('../utils', () => ({
getCompareDate: mockGetCompareDate,
}));
it('returns date comparison from myCloudFn()', async () => {
mockGetCompareDate
.mockResolvedValueOnce(new Date('2020-04-04'))
.mockResolvedValueOnce(new Date('2020-02-02'));
const myTestDate = '2020-03-03';
const returnValues = ['older', 'newer'];
const responsePromises = returnValues.map(() => send.myCloudFn(myTestDate));
const responses = await Promise.all(responsePromises);
expect(responses[0]).toBe(returnValues[0]);
expect(responses[1]).toBe(returnValues[1]);
});
This method, however, is not working and throws an error:
ReferenceError: Cannot access 'mockGetCompareDate' before initialization
I've used this method with other tests as noted in the solution in this question, but I am not seeing similar results here. What am I missing?
Jest is hoisting the mocked function to the top of the module, and hence throws this error. The mock should instead be used right before you run the test. Further reading.
Try this:
const { getCompareDate } = require('../utils.js');
const mockGetCompareDate = jest.fn(() => new Date('2020-01-31'));
jest.mock('../utils.js', () => ({
__esModule: true,
getCompareDate: jest.fn(),
default: jest.fn()
}));
beforeAll(() => {
getCompareDate.mockImplementation(mockGetCompareDate);
});
To provide custom values do as you did before, when initialising the mock function. Source
Like this:
const mockGetCompareDate = jest.fn()
.mockResolvedValueOnce(new Date('2020-04-04'))
.mockResolvedValueOnce(new Date('2020-02-02'));
Or do as you did before inside the test. Source
Like this:
it('returns date comparison from myCloudFn()', async () => {
mockGetCompareDate
.mockResolvedValueOnce(new Date('2020-04-04'))
.mockResolvedValueOnce(new Date('2020-02-02'));
I have a js file which supplies some db operations. This file works with promises only which can be chained. To test that class I work with an async function.
The problem is, that whenever I work with promises inside my test function the it function gets blocked for every other test later.
Here are two examples:
'use strict'
const exec = require('child_process').exec
const path = require('path')
const request = require('request')
const expect = require('chai').expect
const createTableStatements = require('../data')
test()
async function test () {
await testGetUser()
console.log('1')
await testGetFaculties()
}
function testGetUser () {
return new Promise((resolve1) => {
describe('test get user', function () {
const db = require('../dbInterface')
it('test get user should be complete', function () {
db.dbFunctions.dropAll()
.then(onResolve => {
return db.dbFunctions.createTable(createTableStatements.createTableStatements.user)
}
)
.then(() => {
console.log('success create user table')
return db.dbFunctions.addUser('1', 'firstName', 'lastName', 'email')
})
.then(resolve => {
return db.dbFunctions.getUser('email', undefined)
})
.then(result => {
expect(result.toString().includes('dummy')).to.equal(false)
})
.then(resolve => {
return db.dbFunctions.dropAll()
})
.then(resolve => {
console.log('resolve')
resolve1()
})
.catch(err => console.log(err))
})
})
})
}
function testGetFaculties () {
return new Promise(resolve => {
describe('test get faculties', function () {
let db
before(function () {
db = require('../dbInterface')
})
console.log('displayed')
it('should work', function () {
console.log('locked')
expect(db.dbFunctions.getFaculties('hsa')).to.be.an('array').that.does.include('Science')
resolve()
})
})
})
}
And this is the output
resolve
1
displayed
As you can see console.log('locked') is not being processed.
What i figured out so far, that I only have this issue when I call expect within a then function. But this is necessary for my tests.
The test () function should contain much more tests, only for this question I shortened it.
And for clarification: If I only test methods type of testGetFaculties () which don't contains another promise chain inside it works like it should.
Any idea why this is like it is?
Most probably the console.log( 'locked' ); doesn't do anything, because your previous test case was not finished at all.
Writing describe, it, before inside a Promise and containing unreturned Promises is something that you should not do.
Much better test case would look like :
'use strict'
const exec = require('child_process').exec
const path = require('path')
const request = require('request')
const expect = require('chai').expect
const createTableStatements = require('../data')
// You use this in both test cases anyway
const db = require('../dbInterface');
describe('test get user', function () {
it('test get user should be complete', function () {
return db
// ^ returning promise will make sure that the test ends when the promise ends.
.dbFunctions
.dropAll()
.then(onResolve => { ... } )
...
)
} );
} );
describe('test get faculties', function () {
it('should work', function () {
return db
// ^ returning promise will make sure that the test ends when the promise ends.
.dbFunctions
.getFaculties('hsa')
.then( value => {
// ^ You actually need to test the value of the resolve promise
expect( value ).to.be.an('array').that.does.include('Science');
} )
} );
} );
I have two tests in my test group. One of the tests use it and the other one uses test. Both of them seem to be working very similarly. What is the difference between them?
describe('updateAll', () => {
it('no force', () => {
return updateAll(TableName, ["fileName"], {compandId: "test"})
.then(updatedItems => {
let undefinedCount = 0;
for (let item of updatedItems) {
undefinedCount += item === undefined ? 1 : 0;
}
// console.log("result", result);
expect(undefinedCount).toBe(updatedItems.length);
})
});
test('force update', () => {
return updateAll(TableName, ["fileName"], {compandId: "test"}, true)
.then(updatedItems => {
let undefinedCount = 0;
for (let item of updatedItems) {
undefinedCount += item === undefined ? 1 : 0;
}
// console.log("result", result);
expect(undefinedCount).toBe(0);
})
});
});
Update - Nov 2022:
It seems that test and it is interchangeable according to the official API of Jest. As #gwildu described here, you should choose one over the other for the sake of readability.
The Jest docs state it is an alias of test. So they are exactly the same from a functional point of view. They exist both to enable to make a readable English sentence from your test.
They do the same thing, but their names are different and with that their interaction with the name of the test.
test
What you write:
describe('yourModule', () => {
test('if it does this thing', () => {});
test('if it does the other thing', () => {});
});
What you get if something fails:
yourModule > if it does this thing
it
What you write:
describe('yourModule', () => {
it('should do this thing', () => {});
it('should do the other thing', () => {});
});
What you get if something fails:
yourModule > should do this thing
So it's about readability not about functionality.
In my opinion, it really has a point when it comes to read the result of a failing test that you haven't written yourself. It helps to faster understand what the test is about.
Some developer also shorten the Should do this thing to Does this thing which is a bit shorter and also fits semantically to the it notation.
As the other answers have clarified, they do the same thing.
I believe the two are offered to allow for either 1) "RSpec" style tests like:
const myBeverage = {
delicious: true,
sour: false,
};
describe('my beverage', () => {
it('is delicious', () => {
expect(myBeverage.delicious).toBeTruthy();
});
it('is not sour', () => {
expect(myBeverage.sour).toBeFalsy();
});
});
or 2) "xUnit" style tests like:
function sum(a, b) {
return a + b;
}
test('sum adds 1 + 2 to equal 3', () => {
expect(sum(1, 2)).toBe(3);
});
Documentation:
https://jestjs.io/docs/en/api.html#describename-fn
https://jestjs.io/docs/en/api.html#testname-fn-timeout
As the jest documentation says, they are the same:
it alias
test(name, fn, timeout)
Also under the alias: it(name, fn, timeout)
And describe is just for when you prefer your tests to be organized into groups:
describe
describe(name, fn)
describe(name, fn) creates a block that groups together several related tests. For example, if you have a myBeverage object that is supposed to be delicious but not sour, you could test it with:
const myBeverage = {
delicious: true,
sour: false,
};
describe('my beverage', () => {
test('is delicious', () => {
expect(myBeverage.delicious).toBeTruthy();
});
test('is not sour', () => {
expect(myBeverage.sour).toBeFalsy();
});
});
This isn't required - you can write the test blocks directly at the top level. But this can be handy if you prefer your tests to be organized into groups.
You could replace it() with xit() to temporarily exclude a test from being executed; using it() and xit() is more eloquent than using test() and xit().
see Focusing and Excluding Tests
The following is an excerpt from the document：link
test(name, fn, timeout)
Also under the alias: it(name, fn, timeout)
All you need in a test file is the test method which runs a test. For
example, let's say there's a function inchesOfRain() that should be
zero. Your whole test could be: ......
const request = require('supertest');
const app = require('../app')
const {it, describe} = require('#jest/globals');
const { sequelize } = require('../models');
const {hash} = require('../helpers/bcrypt')
beforeAll(async ()=>{ await sequelize.queryInterface.bulkInsert('Customers', [{ username: "nikita", email:"nikita#mail.com", password: hash("nikita"), createdAt: new Date(), updatedAt: new Date() }]) })
afterAll(async ()=>{ await sequelize.queryInterface.bulkDelete('Customers', null, { truncate: true, cascade: true, restartIdentity: true }) })
describe('POST /customers/register', () => { it('should response with status 201', async ()=> { let customer = { username: "hello" , email:"hello#mail.com", password:"hello", } let response = await request(app) .post('/customers/register').send(customer) expect(response.status).toBe(201) // console.log(response.body, 'ini ressss') expect(response.body).toEqual({ message: "Input data Customer succeed", id: expect.any(Number), email: expect.any(String) }) });
it('should response with status 400', async()=>{ let customer = { username: "hello", password:"hello" } let response = await request(app) .post('/customers/register').send(customer) expect(response.status).toBe(400) // console.log(response.body,"<<<"); expect(response.body[0].message).toBe('Please input email') })
`const request = require('supertest');`
`const app = require('../app')`
`const {it, describe} = require('#jest/globals');`
`const { sequelize, Category, User, News , Customer, Bookmark} = require('../models');`
`const {hash} = require('../helpers/bcrypt');`
`const news = require('../models/news');`
`const {queryInterface} = sequelize`
`beforeAll(async()=>{
let userData = require("../data/user.json")
userData.forEach(el => {
el.password = hash(el.password)
el.createdAt = new Date()
el.updatedAt = new Date()
});`
`afterAll(async ()=>{
await Bookmark.destroy({
truncate: true,
cascade: true,
restartIdentity: true
})`
`describe('GET /customers/news', () => {
it("should response with status 200 1", async () => {
let response = await request(app)
.get('/customers/news')
// .set({access_token})
// console.log(response.body, "<<<<NEWS NIhH");
expect(response.status).toBe(200)
expect(response.body).toBeInstanceOf(Array)
})`
`it("should response with status 200 2", async()=>{
let response = await request(app)
.get('/customers/news?filter=1,2')
expect(response.status).toBe(200)
expect(response.body).toBeInstanceOf(Array)
})`
Jest haven't mentioned why they have two versions for the exact same functionality.
My guess is, it's only for convention. test is for unit tests, and it is for integration tests.
They are the same thing. I am using TypeScript as the programming language, and when I look into the definition file from the Jest package source code from /#types/jest/index.d.ts, I can see the following code.
Obviously, there are lots of different names of 'test', and you can use any of them.
declare var beforeAll: jest.Lifecycle;
declare var beforeEach: jest.Lifecycle;
declare var afterAll: jest.Lifecycle;
declare var afterEach: jest.Lifecycle;
declare var describe: jest.Describe;
declare var fdescribe: jest.Describe;
declare var xdescribe: jest.Describe;
declare var it: jest.It;
declare var fit: jest.It;
declare var xit: jest.It;
declare var test: jest.It;
declare var xtest: jest.It;