1  const db = require('../../src/persistence');
 2  const getItems = require('../../src/routes/getItems');
 3  const ITEMS = [{ id: 12345 }];
 4  
 5  jest.mock('../../src/persistence', () => ({
 6      getItems: jest.fn(),
 7  }));
 8  
 9  test('it gets items correctly', async () => {
10      const req = {};
11      const res = { send: jest.fn() };
12      db.getItems.mockReturnValue(Promise.resolve(ITEMS));
13  
14      await getItems(req, res);
15  
16      expect(db.getItems.mock.calls.length).toBe(1);
17      expect(res.send.mock.calls[0].length).toBe(1);
18      expect(res.send.mock.calls[0][0]).toEqual(ITEMS);
19  });