test(server): add server tests

Author: klarkc

template/server/server.spec.js

@@ -1,11 +1,104 @@
-import app from './server';
-
-describe('Application', () => {
-  it('should start the server', (done) => {
-    app.once('started', () => {
-      app.close();
-      done();
-    });
-    app.start();
+/* eslint-disable global-require */
+describe('server', () => {
+  let loopback, boot;
+  const mockApp = {};
+  const getApp = () => require('./server').default;
+
+  beforeEach(() => {
+    jest.resetModules();
+    jest.mock('loopback');
+    jest.mock('loopback-boot');
+    loopback = require('loopback');
+    boot = require('loopback-boot');
+    loopback.mockReturnValue(mockApp);
+  });
+
+  it('instances loopback', () => {
+    getApp();
+    expect(loopback).toBeCalled();
+  });
+
+  it('adds start function', () => {
+    expect(getApp().start).toBeInstanceOf(Function);
+  });
+
+  it('adds close function', () => {
+    expect(getApp().close).toBeInstanceOf(Function);
+  });
+
+  it('boot application', () => {
+    getApp();
+    expect(boot).toBeCalledWith(
+      mockApp,
+      expect.objectContaining({
+        appRootDir: __dirname,
+        scriptExtensions: expect.arrayContaining([
+          '.js', '.json', '.node', '.ejs',
+        ]),
+      }),
+      expect.any(Function),
+    );
+  });
+
+  it('throws when application boot fails', () => {
+    boot.mockImplementation((a, o, done) => done('foo'));
+    expect(getApp).toThrowError('foo');
+  });
+
+  it('not throws when application boot success', () => {
+    boot.mockImplementation((a, o, done) => done());
+    expect(getApp).not.toThrow();
+  });
+
+  it('calls express listen when start is called', () => {
+    const listen = jest.fn();
+    loopback.mockReturnValue({ listen });
+    getApp().start();
+    expect(listen).toBeCalledWith(expect.any(Function));
+  });
+
+  it('emit started when start is called', () => {
+    const get = jest.fn(() => 'foo');
+    const listen = jest.fn(cb => cb());
+    const emit = jest.fn();
+    loopback.mockReturnValue({ listen, get, emit });
+    getApp().start();
+    expect(emit).toBeCalledWith('started');
+  });
+
+  it('log api endpoint when start is called', () => {
+    const get = jest.fn(() => 'foo');
+    const listen = jest.fn(cb => cb());
+    const emit = jest.fn();
+    console.log = jest.fn();
+    loopback.mockReturnValue({ listen, get, emit });
+    getApp().start();
+    expect(console.log).toBeCalledWith(
+      expect.any(String),
+      'foo/api',
+    );
+  });
+
+  it('log explorer url when start is called', () => {
+    const get = jest.fn(term => (term === 'url' ? 'url' : { mountPath: 'foo' }));
+    const listen = jest.fn(cb => cb());
+    const emit = jest.fn();
+    console.log = jest.fn();
+    loopback.mockReturnValue({ listen, get, emit });
+    getApp().start();
+    expect(console.log).toBeCalledWith(
+      expect.any(String),
+      'url',
+      'foo',
+    );
+  });
+
+  it('close server when close is called', () => {
+    const close = jest.fn();
+    const listen = jest.fn(() => ({ close }));
+    loopback.mockReturnValue({ listen });
+    getApp().start();
+    getApp().close();
+    expect(close).toBeCalled();
   });
 });