空手道：有没有办法从Examples变量中获取JSON对象键的长度？

Question

我有空手道测试通过：

  Scenario Outline: Find all the the prime factors in the range from <start> to <end> are <result>
    Given path '/primefactors'
    And param start = <start>
    And param end = <end>
    When method get
    Then status 200
    And match header content-type contains 'application/json'
    And match header content-type contains 'charset=utf-8'
    And match response == {numbers:<result>, start:<start>, end:<end>, count:<count>, type:PrimeFactors}
    Examples:
      | start | end | result                                       | count
      | 8     | 10  | {8: [2,2,2], 9:[3,3], 10:[2,5]}              | 3
      | 13    | 16  | {13: [13], 14:[2,7], 15:[3,5], 16:[2,2,2,2]} | 4

但是，我想要做的是没有来自Examples：部分的count变量，只是通过这种方式从结果对象变量中的键数的长度派生计数：

 Scenario Outline: Find all the the prime factors in the range from <start> to <end> are <result>
    Given path '/primefactors'
    And param start = <start>
    And param end = <end>
    When method get
    Then status 200
    And match header content-type contains 'application/json'
    And match header content-type contains 'charset=utf-8'
    And def result = <result>
    And match response == {numbers:<result>, start:<start>, end:<end>, count:'#(Object.keys(result).length)', type:PrimeFactors}
    Examples:
      | start | end | result                                        
      | 8     | 10  | {8: [2,2,2], 9:[3,3], 10:[2,5]}               
      | 13    | 16  | {13: [13], 14:[2,7], 15:[3,5], 16:[2,2,2,2]}  

当我尝试这个时，我收到一个错误：

primefactors.feature:33 - javascript evaluation failed: Object.keys(result).length, TypeError: {8=[2,2,2], 9=[3,3], 10=[2,5]} is not an Object in <eval> at line number 1

而且测试失败了。

鉴于Object.keys(result).length是有效的JS（使用Chrome开发控制台）：

result = {8: [2,2,2], 9:[3,3], 10:[2,5]} 
{8: Array(3), 9: Array(2), 10: Array(2)}
Object.keys(result).length
3

我究竟做错了什么？ 这样做的正确方法是什么？

更新（2019年4月9日）以下成功：

  Background:
    * url baseUrl
    * configure lowerCaseResponseHeaders = true
    * def keys = function(o){ return o.keySet() }
    * def values = function(o){ return o.values() }
    * def size = function(o){ return o.size() }

  Scenario Outline: Find all the the prime factors in the range from <start> to <end> are <result>
    Given path '/primefactors'
    And param start = <start>
    And param end = <end>
    When method get
    Then status 200
    And match header content-type contains 'application/json'
    And match header content-type contains 'charset=utf-8'
    And def result = <result>
    And match response == {numbers:<result>, start:<start>, end:<end>, count: '#(size(result))', type:PrimeFactors}
    Examples:
      | start | end | result
      | 8     | 10  | {8: [2,2,2], 9:[3,3], 10:[2,5]}
      | 13    | 16  | {13: [13], 14:[2,7], 15:[3,5], 16:[2,2,2,2]}

Answer 1

是的，空手道中的JS并不是你在野外看到的JS，当我们搬到Graal时，这可能会改变

同时请使用此技巧从JSON获取密钥，大小（和值）：

Scenario: json behaves like a java map within functions
  * def payload = { a: 1, b: 2 }
  * def keys = function(o){ return o.keySet() }
  * def values = function(o){ return o.values() }
  * def size = function(o){ return o.size() }
  * json result = keys(payload)
  * match result == ['a', 'b']
  * json result = values(payload)
  * match result == [1, 2]
  * def length = size(payload)
  * match length == 2

您应该能够在嵌入式表达式中使用函数，例如： '#(keys(foo))'

将来我们计划添加一个karate.keysOf()和karate.sizeOf() API来使这更容易。