import { Express } from 'jest-express/lib/express'; import { server } from '../../app.js'; let app; describe('Server', () => { beforeEach(() => { app = new Express(); }); afterEach(() => { app.resetMocked(); }); test('should setup server', () => { const options = { port: 3000, }; server(app, options); expect(app.set).toBeCalledWith('port', options.port); }); });