[Fact] public void CalculateTax_ShouldReturnTwentyPercent_WhenIncomeIsHigh() { // Arrange var calculator = new TaxCalculator(); decimal income = 100000; // Act var result = calculator.Calculate(income); // Assert Assert.Equal(20000, result); } [Fact] public void CalculateTax_ShouldReturnTwentyPercent_WhenIncomeIsHigh() { // Arrange var calculator = new TaxCalculator(); decimal income = 100000; // Act var result = calculator.Calculate(income); // Assert Assert.Equal(20000, result); } [Fact] public void CalculateTax_ShouldReturnTwentyPercent_WhenIncomeIsHigh() { // Arrange var calculator = new TaxCalculator(); decimal income = 100000; // Act var result = calculator.Calculate(income); // Assert Assert.Equal(20000, result); } [Fact] public void IsAdult_ShouldReturnTrue_WhenAgeIsAbove18() { var user = new User(); var result = user.IsAdult(25); Assert.True(result); } [Fact] public void IsAdult_ShouldReturnTrue_WhenAgeIsAbove18() { var user = new User(); var result = user.IsAdult(25); Assert.True(result); } [Fact] public void IsAdult_ShouldReturnTrue_WhenAgeIsAbove18() { var user = new User(); var result = user.IsAdult(25); Assert.True(result); } [Theory] [InlineData(10, 20, 30)] [InlineData(-1, 1, 0)] [InlineData(0, 0, 0)] public void Add_ShouldReturnCorrectSum(int a, int b, int expected) { var math = new SimpleMath(); var result = math.Add(a, b); Assert.Equal(expected, result); } [Theory] [InlineData(10, 20, 30)] [InlineData(-1, 1, 0)] [InlineData(0, 0, 0)] public void Add_ShouldReturnCorrectSum(int a, int b, int expected) { var math = new SimpleMath(); var result = math.Add(a, b); Assert.Equal(expected, result); } [Theory] [InlineData(10, 20, 30)] [InlineData(-1, 1, 0)] [InlineData(0, 0, 0)] public void Add_ShouldReturnCorrectSum(int a, int b, int expected) { var math = new SimpleMath(); var result = math.Add(a, b); Assert.Equal(expected, result); } var mockService = new Mock<IEmailService>(); mockService .Setup(service => service.Send(It.IsAny<string>())) .Returns(true); var controller = new UserController(mockService.Object); var mockService = new Mock<IEmailService>(); mockService .Setup(service => service.Send(It.IsAny<string>())) .Returns(true); var controller = new UserController(mockService.Object); var mockService = new Mock<IEmailService>(); mockService .Setup(service => service.Send(It.IsAny<string>())) .Returns(true); var controller = new UserController(mockService.Object); FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build WORKDIR /src COPY . . RUN dotnet test "MyProject.Tests.csproj" -c Release FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build WORKDIR /src COPY . . RUN dotnet test "MyProject.Tests.csproj" -c Release FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build WORKDIR /src COPY . . RUN dotnet test "MyProject.Tests.csproj" -c Release - Ensures correctness of business logic - Prevents regressions during future changes - Improves developer confidence - Enables faster refactoring - xUnit (modern, fast, recommended) - Arrange: Prepare required objects and data - Act: Execute the method under test - Assert: Validate the result - The test has fixed input - Only one scenario needs validation - Multiple input combinations must be tested - You want to avoid duplicate test methods - Email services - Slow execution - Flaky tests - Hard-to-maintain code - A fake email service is created - Behavior is predefined - No real email is sent during testing - Faster tests - Reliable results - True isolation of business logic - Ensures environment consistency - Prevents “works on my machine” issues - Integrates easily with CI/CD pipelines - Detect runtime errors - Monitor performance - Track system behavior - .NET Introduction - C# Documentation - Java Documentation - Python Documentation - Why tests are written - How to structure them properly - How to isolate dependencies - How to integrate them into your pipeline