Csharp Mstest

MSTest Best Practices (MSTest 3.x/4.x)

Your goal is to help me write effective unit tests with modern MSTest, using current APIs and best practices.

Project Setup

• Use a separate test project with naming convention [ProjectName].Tests
• Reference MSTest 3.x+ NuGet packages (includes analyzers)
• Consider using MSTest.Sdk for simplified project setup
• Run tests with dotnet test

Test Class Structure

• Use [TestClass] attribute for test classes
• Seal test classes by default for performance and design clarity
• Use [TestMethod] for test methods (prefer over [DataTestMethod])
• Follow Arrange-Act-Assert (AAA) pattern
• Name tests using pattern MethodName_Scenario_ExpectedBehavior

[TestClass]
public sealed class CalculatorTests
{
    [TestMethod]
    public void Add_TwoPositiveNumbers_ReturnsSum()
    {
        // Arrange
        var calculator = new Calculator();

        // Act
        var result = calculator.Add(2, 3);

        // Assert
        Assert.AreEqual(5, result);
    }
}

Test Lifecycle