jest-mock-server

import { MockServer } from 'jest-mock-server'; import fetch from 'node-fetch'; // Or any other http client like axios describe('Testing HTTP client with jest-mock-server', () => { const server = new MockServer(); // Start and stop the mock server for each test suite beforeAll(() => server.start()); afterAll(() => server.stop()); // Reset routes before each test to ensure isolation beforeEach(() => server.reset()); it('handles multiple requests with sequential responses', async () => { // Define a GET route for the root path const route = server .get('/') // Mock the first response to return status 200 .mockImplementationOnce((ctx) => { ctx.status = 200; ctx.body = 'First response'; }) // Mock the second response to return status 201 .mockImplementationOnce((ctx) => { ctx.status = 201; ctx.body = 'Second response'; }); // Get the URL where the server is listening (random free port by default) const url = server.getURL(); // Make the first request const res1 = await fetch(url); expect(res1.status).toBe(200); expect(await res1.text()).toBe('First response'); // Make the second request const res2 = await fetch(url); expect(res2.status).toBe(201); expect(await res2.text()).toBe('Second response'); // Make a third request - since only two mocks were defined, it will return 404 by default const res3 = await fetch(url); expect(res3.status).toBe(404); // Use Jest's assertion API to verify the route was called three times expect(route).toHaveBeenCalledTimes(3); }); });