Testing a service with mock models and a stub

thought-service.test.js

describe('listThoughts test', () => {
  it('should list Thoughts', () => {
    /* Mock model to imitate the find function */
    const MockModel = {
      find: () => {}
    }
    /* We create a stub to imitate chained methods */
    sinon.stub(MockModel, 'find').callsFake(() => {
      return {
        sort: () => {
          return {
            limit: sinon.stub().returns()
          }
        }
      }
    })
    const thoughtService = ThoughtService(MockModel)
    thoughtService.listThoughts()
    const expected = true
    const actual = MockModel.find.calledOnce
    expect(actual).toEqual(expected)
  })
}),