cucumber.js 并且不是一个函数

Question

我正在练习使用 cucmber.js 通过 BDD 编写一些单元测试。当我尝试使用“And”语句时。该错误表明

TypeError: And is not a function

这是我的代码

。特征

Feature: dataTable
Scenario Outline: <a> + <b> + <c> = <answer>
  Given I had number <a>
    And I add another number <b>
  When I add with <c>   
  Then I got answer <answer>

Examples:
|a|b|c|answer|
|1|2|3|6|
|10|15|25|50|

.stepDefinition

defineSupportCode(function({Given,When,Then,And}){
  let ans = 0;
  Given('I had number {int}', function(input){
    ans = input
  })
  And('I add another number {int}',function(input){
    ans += input
  })
  When('I add with {int}',function(input){
    ans += input
  })
  Then('I got answer {int}', function(input){
    assert.equal(ans,input)
  })
})

错误消息如下：

TypeError: Add is not a function
    at ...  // my file location
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! test_cucumber@1.0.0 cucumber: `cucumber.js ./test/e2e/Features -r ./test/e2e/StepDefinition`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the test_cucumber@1.0.0 cucumber script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/lab1321_mac_air/.npm/_logs/2018-01-04T08_15_28_568Z-debug.log

我想知道我是否写错了什么。谢谢！

Answer 1

And和But是特征文件的语法糖 - 换句话说，它们是Given,When和 的别名Then。

当您定义步骤时，您应该使用Given,When和Then来描述该步骤试图实现的目标（先决条件、操作或结果），然后如果您有多个先决条件、操作或结果，请在您的步骤中使用And或But仅功能文件。