shared_examples "a popular model" do

  describe '.befriend' do
    it 'creates a one way friendship' do
      popular_model.befriend another_popular_model

      expect( popular_model.friends ).to match_array [another_popular_model]
    end
  end

  describe '#friends_with?' do
    it 'returns true if a popular_model is friends with a given popular_model' do
      expect( popular_model ).to_not be_friends_with another_popular_model
    end
    it 'returns true if a popular_model is friends with a given popular_model' do
      popular_model.befriend another_popular_model

      expect( popular_model ).to be_friends_with another_popular_model
    end
  end

  describe '.unfriend' do
    it 'destroys a friendship' do
      [:befriend, :unfriend].each do |method|
        popular_model.send method, another_popular_model
      end

      expect( popular_model.friends ).to be_empty
    end
  end

end