
using Xunit;
using System;
using System.IO;

namespace ConsoleApp {
    public class ProgramTests {
        [Fact(DisplayName = "DivideNumbers throws DivideByZeroException when denominator is zero")]
        public void DivideNumbers_ThrowsOnZeroDenominator()
        {
            var ex = Assert.Throws<DivideByZeroException>(() => Program.DivideNumbers(5, 0));
            Assert.Contains("Cannot divide by zero", ex.Message);
        }

        [Fact(DisplayName = "DivideNumbers returns correct result for valid inputs")]
        public void DivideNumbers_ReturnsCorrectResult()
        {
            Assert.Equal(5, Program.DivideNumbers(10, 2));
            Assert.Equal(-2, Program.DivideNumbers(-4, 2));
            Assert.Equal(2.5, Program.DivideNumbers(5, 2));
        }

        [Fact(DisplayName = "Main prints result and error message as expected")]
        public void Main_PrintsResultAndErrorMessage()
        {
            var sw = new StringWriter();
            Console.SetOut(sw);
            Program.TestMain(new string[0]);
            string output = sw.ToString();
            Assert.Contains("5", output);
            Assert.Contains("Error: Cannot divide by zero", output);
            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }
    }
}

ProgramTests.cs

Master the art of robust C# programming by learning how to handle, create, and debug exceptions. This hands-on course guides you through real-world error handling scenarios, from basic try-catch to custom exceptions and safe file operations.

Learn the basics of exceptions in C#, how to use try-catch blocks, and why error handling is crucial for robust applications.

Learn to create your own exception types and use guard clauses to prevent invalid states in your code.

Master techniques for validating user input and safely parsing data to prevent runtime errors.

Handle file operations safely and learn to debug exceptions using stack traces and refactoring techniques.

Challenge: Basic Exception Handling

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