Question

我是新手，并且无法确定如何测试嵌套在promises中的结果。具体做法是：

myMethod: function (e) {
  let self = this
  self.resetErrors()

  Parser.parseFile(this.form.uploadFile).then(res => {
    const hasErrors = self.validFile(res)
    if (!hasErrors) {
      self.processFile(res)
    }
  })
}

我想测试以确保假设hasErrors为假，self.processFile会触发。这是我目前（失败）的最佳努力：

describe("if the provided data is valid", () => {
  it('runs processFile', () => {
    const mockProcessFile = jest.fn()
    mockParser = jest.fn(() => {
      new Promise((resolve, reject) => {
        return ValidMockData
      }).then((loanData) => {
        expect(mockProcessFile).toBeCalled()
      })
    })

    CsvParser.parseFile = mockParser

    wrapper.vm.validFile = jest.fn(true)
    wrapper.vm.processFile = mockProcessFile
    wrapper.vm.store().resolve((data) => {
      expect(mockProcessFile).toBeCalled()
    })
  })
})

目前我收到Cannot read property 'then' of undefined错误 - 这是有道理的，但我不确定我究竟应该如何在then（）调用中破解期望。任何想法赞赏

Answer 1

您需要在测试中存储您创建的Promise，这样您就可以使用await让测试在解决后完成：

describe("if the provided data is valid", async() => {
  it('runs processFile', () => {
    const mockProcessFile = jest.fn()
    const p = Promise.resolve(ValidMockData)
    CsvParser.parseFile = jest.fn(() => p)


    wrapper.vm.validFile = jest.fn(true)
    wrapper.vm.processFile = mockProcessFile
    wrapper.vm.store()

    await p

    expect(mockProcessFile).toBeCalled()
    expect(mockProcessFile).toBeCalled()


  })
})

Jest：测试嵌套的promise

1 个答案: