RSpec - Helpers

Sometimes your RSpec examples need an easy way to share reusable code. The best way to accomplish this is with Helpers. Helpers are basically regular Ruby methods which you share across examples. To illustrate the benefit of using helpers, let’s consider this code −

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

This code is clear, but it’s always a good idea to reduce repeated code whenever possible. We can take the above code and reduce some of this repetition with a helper method called create_and_walk_dog().

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

When you run the above code, you will see this output −

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

As you can see, we were able to push the logic for creating and walking a dog object into a Helper which allows our examples to be shorter and cleaner.