csharp-mstest

Use [DataRow] attributes for inline values or [DynamicData] pointing to a property returning IEnumerable of ValueTuple or TestDataRow. ValueTuple is preferred since MSTest 3.7 because it provides compile-time type safety, unlike IEnumerable<object[]>.

Use Assert.Throws<TException> to verify an exception type or its derived types, or Assert.ThrowsExactly<TException> for exact type matching. Async variants Assert.ThrowsAsync and Assert.ThrowsExactlyAsync handle async methods, and the returned exception allows message verification.

MSTest 4.x changes Assert.IsInstanceOfType<T> to return the typed result directly instead of using an out parameter, and adds Assert.That for expression-based assertions with auto-captured failure messages. Most other assertion APIs remain consistent across versions.

Yes, MSTest 3.9 and later supports the [Retry(n)] attribute on test methods to automatically re-run failing tests up to n times. This is intended for genuinely flaky tests such as those involving timing or external resources.

Prefer constructors over [TestInitialize] because they enable readonly fields and follow standard C# patterns. Reserve [TestInitialize] for async setup work, and use [TestCleanup] for cleanup that must run even when a test fails.

MSTest 3.10+ provides [OSCondition] to include or exclude tests by operating system, and [CICondition] to run tests only in CI environments or only locally. Combine flags like OperatingSystems.Linux | OperatingSystems.MacOS for multiple targets.