RSpec - 辅助工具

有时，你的 RSpec 示例需要一种简单的方法来共享可重用的代码。实现这一目标的最佳方法是使用辅助工具。辅助工具基本上是你可以跨多个示例共享的常规 Ruby 方法。为了说明使用辅助工具的好处，我们来考虑一下这段代码 −

class Dog 
   attr_reader :good_dog, :has_been_walked 
   
   def initialize(good_or_not) 
      @good_dog = good_or_not 
      @has_been_walked = false 
   end 
   
   def walk_dog 
      @has_been_walked = true 
   end 
end 

describe Dog do 
   it 'should be able to create and walk a good dog' do 
      dog = Dog.new(true) 
      dog.walk_dog 
      
      expect(dog.good_dog).to be true
      expect(dog.has_been_walked).to be true 
   end 
   
   it 'should be able to create and walk a bad dog' do 
      dog = Dog.new(false) 
      dog.walk_dog 

      expect(dog.good_dog).to be false
      expect(dog.has_been_walked).to be true 
 
   end 
end

这段代码很清晰，但尽可能减少重复的代码始终是一个好建议。我们可以使用名为 create_and_walk_dog() 的辅助方法来获取以上代码并减少其中的某些重复项。

class Dog
   attr_reader :good_dog, :has_been_walked 
   
   def initialize(good_or_not)
      @good_dog = good_or_not 
      @has_been_walked = false 
   end 
   
   def walk_dog 
      @has_been_walked = true 
   end 
end 

describe Dog do 
   def create_and_walk_dog(good_or_bad)
      dog = Dog.new(good_or_bad)
      dog.walk_dog
      return dog 
   end 
   
   it 'should be able to create and walk a good dog' do
      dog = create_and_walk_dog(true)
      
      expect(dog.good_dog).to be true
      expect(dog.has_been_walked).to be true 
   end 
   
   it 'should be able to create and walk a bad dog' do 
      dog = create_and_walk_dog(false)
      
      expect(dog.good_dog).to be false
      expect(dog.has_been_walked).to be true 
   end 
end

当你运行以上代码时，你将会看到以下输出 −

.. 
Finished in 0.002 seconds (files took 0.11401 seconds to load) 
2 examples, 0 failures

正如你所看到的，我们能够将创建和遛狗对象添加到一个辅助工具中，这样一来，我们的示例就会更简短并且清晰。