ruby 测试中的 Rspec 通过测试

Question

我有一个 Rspec 测试如下：

it "calculates highest count words across lines to be will, it, really" do
  solution.analyze_file

  expect(solution.highest_count_words_across_lines).to be nil

  solution.calculate_line_with_highest_frequency

  words_found = solution.highest_count_words_across_lines.map(&:highest_wf_words).flatten
  expect(words_found).to match_array ["will", "it", "really"] 
end  

报错

Solution#calculate_line_with_highest_frequency calculates highest count words across lines to be will, it, really
     Failure/Error: words_found solution.highest_count_words_across_lines.map(&:highest_wf_words).flatten
   NoMethodError:
       undefined method `highest_wf_words' for "really":String
     # ./spec/solution_spec.rb:38:in `map'
     # ./spec/solution_spec.rb:38:in `block (3 levels) in <top (required)>'

另一方面，如果我写这个测试没有

.map(&:highest_wf_words).flatten

然后就通过了。

@highest_count_words_across_lines = ["really","will","it"]

我怎样才能使这个测试通过，同时包括映射：

.map(&:highest_wf_words).flatten?

Answer 1

solution.highest_count_words_across_lines 是一个字符串数组。当您执行此操作时：solution.highest_count_words_across_lines.map(&:highest_wf_words) 您正在对每个数组项调用 highest_wf_words，并且没有为字符串定义该方法（这就是错误消息所说的）。

我猜实际上你想要这样的东西：

words_found = solution.highest_count_words_across_lines.map( |x| highest_wf_words(x)).flatten

---

更新

如果您的映射目的是让 words_found 仅包含 highest_wf_words，假设这是一个数组，那么您可以这样做：

words_found = solution.highest_count_words_across_lines.flatten & highest_wf_words

.

[1,2,3] & [2,3,4]
=> [2, 3]