
using Xunit;
using System;
using System.IO;

namespace ConsoleApp {
    public class ProgramTests {
        [Fact(DisplayName = "GreetUser prints greeting message with provided name")] 
        public void GreetUser_PrintsGreetingWithGivenName() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.GreetUser("Charlie");
            string output = sw.ToString().Trim();

            Assert.Contains("Charlie", output);
            Assert.Contains("Hello", output);
            Assert.Contains("Welcome", output);

            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }
        
        [Fact(DisplayName = "GreetUser prints correct greeting for different names")] 
        public void GreetUser_PrintsCorrectGreetingForDifferentNames() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.GreetUser("Alice");
            string output1 = sw.ToString();
            sw.GetStringBuilder().Clear();

            Program.GreetUser("Bob");
            string output2 = sw.ToString();

            Assert.Contains("Alice", output1);
            Assert.Contains("Bob", output2);

            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }

        [Fact(DisplayName = "GreetUser uses a single output statement")] 
        public void GreetUser_UsesSingleOutputStatement() 
        {
            var sw = new StringWriter();
            Console.SetOut(sw);

            Program.GreetUser("Dana");
            string output = sw.ToString();
            int lineCount = output.Split(new[] { '\\n', '\\r' }, StringSplitOptions.RemoveEmptyEntries).Length;

            Assert.Equal(1, lineCount);

            Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true });
        }
    }
}

ProgramTests.cs

Master the art of writing modular, reusable, and clear code in C# by learning how to create, use, and reason about methods. This course guides you from the basics of function signatures to advanced modularization techniques, with engaging real-world challenges and step-by-step explanations.

Explore the fundamentals of C# methods, including defining, calling, and understanding different parameter and return types. Practice writing and using methods with a variety of signatures.

Learn how to write methods that return arrays, and how to refactor repetitive loops into reusable functions for cleaner code.

Explore the concepts of pure and impure functions, and learn how to break down complex problems into smaller, manageable methods using stepwise decomposition.

Challenge: Personalized Greetings

解答