
using Xunit;
using System;
using System.IO;

namespace ConsoleApp {
    public class ProgramTests {
        [Fact(DisplayName = "PrintTicTacToeBoard prints all three rows of the board")] 
        public void Prints_AllThreeRows() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);
            char[,] board = new char[3, 3]
            {
                { 'X', 'O', 'X' },
                { ' ', 'X', 'O' },
                { 'O', ' ', 'X' }
            };
            Program.PrintTicTacToeBoard(board);
            string output = sw.ToString();
            Assert.Contains("X | O | X", output);
            Assert.Contains("  | X | O", output);
            Assert.Contains("O |   | X", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "PrintTicTacToeBoard displays correct characters in order")] 
        public void Prints_CorrectCharactersInOrder() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);
            char[,] board = new char[3, 3]
            {
                { 'A', 'B', 'C' },
                { 'D', 'E', 'F' },
                { 'G', 'H', 'I' }
            };
            Program.PrintTicTacToeBoard(board);
            string output = sw.ToString();
            Assert.Contains("A | B | C", output);
            Assert.Contains("D | E | F", output);
            Assert.Contains("G | H | I", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "PrintTicTacToeBoard separates columns with | and rows with --+---+-- except after last row")] 
        public void Prints_SeparatorsCorrectly() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);
            char[,] board = new char[3, 3]
            {
                { '1', '2', '3' },
                { '4', '5', '6' },
                { '7', '8', '9' }
            };
            Program.PrintTicTacToeBoard(board);
            string output = sw.ToString();
            int separatorCount = output.Split(new string[] { "--+---+--" }, StringSplitOptions.None).Length - 1;
            Assert.Equal(2, separatorCount);
            Assert.Contains("1 | 2 | 3", output);
            Assert.Contains("4 | 5 | 6", output);
            Assert.Contains("7 | 8 | 9", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }
    }
}

ProgramTests.cs

Master the essentials and advanced techniques of working with arrays in C#. This course guides you from the basics of declaring and initializing arrays, through practical manipulation, searching, and advanced operations like sorting and matrix calculations. Each section blends engaging theory with real-world themed challenges to ensure a hands-on, beginner-friendly learning experience.

Challenge: Tic-Tac-Toe Board

Solution