csharp-mstestlisted

# 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` ```csharp [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 - **Prefer constructors over `[TestInitialize]`** - enables `readonly` fields and follows standard C# patterns - Use `[TestCleanup]` for cleanup that must run even if test fails - Combine constructor with async `[TestInitialize]` when async setup is needed ```csharp [TestClass] public sealed class ServiceTests { private readonly MyService _service; // readonly enabled by constructor public ServiceTests() { _servic