如何使用sinon存根异步处理程序

Question

我试图为我的异步lambda编写圆顶模拟但是我收到错误＆＃39; TypeError：无法存根不存在的自有属性帐户＆＃39;。任何想法如何解决它？提前谢谢。

----测试

import { handler } from 'handler'

describe('tests', function() {

const sbox = sandbox.create()

describe('a payload is sent', () => {
    it('should return a 200', (done) => {

        const thePayload = thedata;

        sbox.stub(handler, 'handler').resolves(thePayload)

        account(context, context, (err, resp) => {
            expect(resp.statusCode).to.eq(200)
            done()
        })
    })
  })
}) 

---- handler

export const handler = async (event, context, callback) => {

return callback(null, { statusCode: 200 } )

}