tennis_spec.rb

class Score
  attr_reader :server_score, :receiver_score

  def initialize(server_score, receiver_score)
    @server_score = server_score
    @receiver_score = receiver_score
  end

  def server_wins_ball
    @server_score = increment_score(@server_score)
    deuce
  end

  def receiver_wins_ball
    @receiver_score = increment_score(@receiver_score)
    deuce
  end

  private

  def increment_score(score)
    if score == 30
      score += 10
    elsif score == 40
      score = "A"
    else
      score += 15
    end
    score
  end

  def deuce
    if @server_score == 'A' and @receiver_score == 'A'
      @server_score = 40
      @receiver_score = 40
    end
  end
end

describe 'Tennis score' do

  context "when the score is 0 - 0" do
    context "and server wins a point" do
      it "the score is 15 - 0" do
        score = Score.new(0, 0)

        score.server_wins_ball

        expect(score.server_score).to eq(15)
        expect(score.receiver_score).to eq(0)
      end
    end
  end

  context "when the score is 15 - 15" do
    context "and receiver wins a point" do
      it "the score is 15 - 30" do
        score = Score.new(15, 15)

        score.receiver_wins_ball

        expect(score.server_score).to eq(15)
        expect(score.receiver_score).to eq(30)
      end
    end
  end

  context "when the score is 30 - 30" do
    context "and server wins a point" do
      it "the score is 40 - 30" do
        score = Score.new(30, 30)

        score.server_wins_ball

        expect(score.server_score).to eq(40)
        expect(score.receiver_score).to eq(30)
      end
    end

    context "and receiver wins a point" do
      it "the score is 30 - 40" do
        score = Score.new(30, 30)

        score.receiver_wins_ball

        expect(score.server_score).to eq(30)
        expect(score.receiver_score).to eq(40)
      end
    end
  end

  #caso de 40 iguales
  context "given the score to A:40 and receiver wins a point"  do
    it "Deuce 40 ==" do
      score = Score.new('A',40)
      score.receiver_wins_ball

      expect(score.server_score).to eq(40)
      expect(score.receiver_score).to eq(40)
    end
  end

  context "when the score is 40 - 40" do
    it "and the receiver wins a point" do
      score = Score.new(40,40)

      score.receiver_wins_ball

      expect(score.server_score).to eq(40)
      expect(score.receiver_score).to eq("A")
    end
  end
end