using System;

using NUnit.Framework;

​

public class Program

{

​

    public class BowlingGame

    {

        private int _pinsKnocked = 0;

        private int[] _rolls = new int[21];

        private int _index = 0;

        public void Roll(int pinsKnocked) { _rolls[_index++] = pinsKnocked;}

        public int GameScore()

        {

            var score = 0;

            var ci = 0;

            for (var i = 0; i < 10; i++)

                if ( _rolls[ci] == 10 )

                {

                    score += 10 + _rolls[ci + 1] + _rolls[ci + 2];

                    ci++;

                }

                else if (_rolls[ci] + _rolls[ci + 1] == 10)

                {

                    score += 10 + _rolls[ci + 2];

                    ci+=2;

                }

                else{

                    score += _rolls[ci] + _rolls[ci + 1];

                    ci+=2;

                }

            return score;

        }

    }

    [TestFixture]

    public class BowlingGameTest

    {

        [Test]

        public void Roll_WhenCalledOnParamOf_0_ReturnScoreOf_0()

        {

            var game = new BowlingGame();

            game.Roll(0);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(0));

        }

        [Test]

        public void Roll_WhenCalledOnParamOf_1_ReturnScoreOf_1()

        {

            var game = new BowlingGame();

            game.Roll(1);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(1));

        }

        [Test]

        public void GameScore_WhenCalledOnAfterGutterGame_0_ReturnScoreOf_0()

        {

            var game = new BowlingGame();

            SimulateRolls(game, 20, 0);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(0));

        }

        [Test]

        public void GameScore_WhenCalledOnAfter20_1sHaveBeenRolled_ReturnScoreOf_0()

        {

            var game = new BowlingGame();

            SimulateRolls(game, 20,  1);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(20));

        }

        public void GameScore_WhenCalledOnAfter5_5_3_SpareGame_ReturnScoreOf_16()

        {

            var game = new BowlingGame();

            game.Roll(5);

            game.Roll(5);

            game.Roll(3);

            SimulateRolls(game, 17, 0);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(16));

        }

        [Test]

        public void GameScore_WhenCalledOnAfterX_5_3_SpareGame_ReturnScoreOf_42()

        {

            var game = new BowlingGame();

            game.Roll(10);

            game.Roll(5);

            game.Roll(3);

            SimulateRolls(game, 16, 1);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(18 + 8 + 16));

        }

        [Test]

        public void GameScore_WhenCalledOnAfterPerfectGame_ReturnScoreOf_300()

        {

            var game = new BowlingGame();

​

            SimulateRolls(game, 12, 10);

            var actual = game.GameScore();

            Assert.That(actual, Is.EqualTo(300));

        }

        private static void SimulateRolls(BowlingGame game, int rolls, int pinsKnocked)

        {

            for ( var i = 0; i < rolls; i++ ) game.Roll(pinsKnocked);

        }

    }

    public static void Main()

    {

        var test = new BowlingGameTest();

        try

        {

            test.Roll_WhenCalledOnParamOf_0_ReturnScoreOf_0();

            test.Roll_WhenCalledOnParamOf_1_ReturnScoreOf_1();

            test.GameScore_WhenCalledOnAfterGutterGame_0_ReturnScoreOf_0();

            test.GameScore_WhenCalledOnAfter20_1sHaveBeenRolled_ReturnScoreOf_0();

            test.GameScore_WhenCalledOnAfter5_5_3_SpareGame_ReturnScoreOf_16();

            test.GameScore_WhenCalledOnAfterX_5_3_SpareGame_ReturnScoreOf_42();

            test.GameScore_WhenCalledOnAfterPerfectGame_ReturnScoreOf_300();

            Console.WriteLine("Passed");

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.ToString());

        }

    }

}