storybook/lib/builder-webpack4/src/dev-server.test.ts

import ip from 'ip';
import { getServerAddresses } from './dev-server';

jest.mock('ip');
const mockedIp = ip as jest.Mocked<typeof ip>;

describe('getServerAddresses', () => {
  beforeEach(() => {
    mockedIp.address.mockReturnValue('192.168.0.5');
  });

  it('builds addresses with a specified host', () => {
    const { address, networkAddress } = getServerAddresses(9009, '192.168.89.89', 'http');
    expect(address).toEqual('http://localhost:9009/');
    expect(networkAddress).toEqual('http://192.168.89.89:9009/');
  });

  it('builds addresses with local IP when host is not specified', () => {
    const { address, networkAddress } = getServerAddresses(9009, '', 'http');
    expect(address).toEqual('http://localhost:9009/');
    expect(networkAddress).toEqual('http://192.168.0.5:9009/');
  });
});