jest testing framework code example
Example 1: what is jest
Jest is a JavaScript testing framework maintained by Facebook, Inc. with a
focus on simplicity.
It works with projects using: Babel, TypeScript, Node.js, React, Angular and
Vue.js.
It aims to work out of the box and config free.
Example 2: jest
beforeAll(() => console.log('1 - beforeAll'));
afterAll(() => console.log('1 - afterAll'));
beforeEach(() => console.log('1 - beforeEach'));
afterEach(() => console.log('1 - afterEach'));
test('', () => console.log('1 - test'));
describe('Scoped / Nested block', () => {
beforeAll(() => console.log('2 - beforeAll'));
afterAll(() => console.log('2 - afterAll'));
beforeEach(() => console.log('2 - beforeEach'));
afterEach(() => console.log('2 - afterEach'));
test('', () => console.log('2 - test'));
});
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Example 3: write unit test jest first before json function
const axios = require('axios');
const Users = require('./users');
jest.mock('axios');
test('should fetch users', () => {
const users = [{
"id": 1,
"first_name": "Robert",
"last_name": "Schwartz",
"email": "[email protected]"
}, {
"id": 2,
"first_name": "Lucy",
"last_name": "Ballmer",
"email": "[email protected]"
}];
const resp = { data : users };
axios.get.mockImplementation(() => Promise.resolve(resp));
Users.all().then(resp => expect(resp.data).toEqual(users));
});