docsify/test/unit/example.test.js

128 lines
4.2 KiB
JavaScript

import { jest } from '@jest/globals';
import { greet } from './fixtures/greet';
import { getTimeOfDay } from './fixtures/get-time-of-day';
import * as _getTimeOfDayModule from './fixtures/get-time-of-day';
// ES Modules are non-extensible objects, so clone this one into an extensible object.
const getTimeOfDayModule = { ..._getTimeOfDayModule };
// Suite
// -----------------------------------------------------------------------------
describe(`Example Tests`, function () {
// Tests
// ---------------------------------------------------------------------------
describe('Jest & JSDOM basics', function () {
test('dom manipulation (jsdom)', () => {
const testText = 'This is a test';
const testHTML = `<h1>Test</h1><p>${testText}</p>`;
// Inject HTML
document.body.innerHTML = testHTML;
// Add class to <body> element and verify
document.body.classList.add('foo');
// Test HTML
expect(document.body.getAttribute('class')).toEqual('foo');
expect(document.body.textContent).toMatch(/Test/);
expect(document.querySelectorAll('p')).toHaveLength(1);
expect(document.querySelector('p').textContent).toBe(testText);
expect(document.querySelector('table')).toBeNull();
});
// Snapshot Testing
// https://jestjs.io/docs/en/snapshot-testing
test('snapshot (jsdom)', () => {
const testText = 'This is a test';
const testHTML = `<h1>Test</h1><p>${testText}</p>`;
// Inject HTML
document.body.innerHTML = testHTML;
// Add class to <body> element and verify
document.body.classList.add('foo');
const documentHTML = document.documentElement.outerHTML;
// Test snapshots
expect(documentHTML).toMatchSnapshot(); // See __snapshots__
expect(documentHTML).toMatchInlineSnapshot(
`"<html><head></head><body class=\\"foo\\"><h1>Test</h1><p>This is a test</p></body></html>"`
);
});
});
describe('Fake Timers', function () {
test('data & time', () => {
const fakeDate = new Date().setHours(1);
jest.useFakeTimers('modern');
jest.setSystemTime(fakeDate);
const timeOfDay = getTimeOfDay();
expect(timeOfDay).toBe('morning');
});
});
describe('Mocks & Spys', function () {
// It is not yet possible to mock/spy on ES Modules, but they're working on it (https://github.com/facebook/jest/issues/10025).
// For now, don't mock/spy on modules. The alternative is to mock/spy on objects exported from modules.
// {{{
test.skip('mock import/require dependency using jest.fn()', async () => {
const testModule = { ...(await import('./fixtures/get-time-of-day.js')) };
const { greet: testGreet } = await import('./fixtures/greet.js');
testModule.getTimeOfDay = jest.fn(() => 'day');
const timeOfDay = testModule.getTimeOfDay();
const greeting = testGreet('John');
expect(timeOfDay).toBe('day');
expect(greeting).toBe(`Good day, John!`);
});
test.skip('mock import/require dependency using jest.doMock()', async () => {
const mockModulePath = './fixtures/get-time-of-day.js';
jest.doMock(mockModulePath, () => ({
__esModule: true,
getTimeOfDay: jest.fn(() => 'night'),
}));
const mockGetTimeOfDay = (await import(mockModulePath)).getTimeOfDay;
const { greet: testGreet } = await import('./fixtures/greet.js');
const timeOfDay = mockGetTimeOfDay();
const greeting = testGreet('John');
expect(timeOfDay).toBe('night');
expect(greeting).toBe(`Good night, John!`);
});
test.skip('spy on import/require dependency using jest.spyOn()', () => {
jest
.spyOn(getTimeOfDayModule, 'getTimeOfDay')
.mockImplementation(() => 'night');
const timeOfDay = getTimeOfDay();
const greeting = greet('John');
expect(timeOfDay).toBe('night');
expect(greeting).toBe(`Good night, John!`);
});
// }}}
test('spy on native method using jest.spyOn()', () => {
// Replace Math.random() implementation to return fixed value
jest.spyOn(Math, 'random').mockImplementation(() => 0.1);
expect(Math.random()).toEqual(0.1);
expect(Math.random()).toEqual(0.1);
expect(Math.random()).toEqual(0.1);
});
});
});