NUnit best practices for standard and data-driven unit testing in .NET projects.

• Organize tests with [TestFixture] classes matching production code, using [Test] methods named MethodName_Scenario_ExpectedBehavior and following Arrange-Act-Assert structure
• Data-driven testing via [TestCase], [TestCaseSource], [Values], [Range], and [Combinatorial] attributes for inline, programmatic, and parameterized test generation
• Use Assert.That with constraint model (Is.EqualTo, Contains.Item) and specialized assertions like CollectionAssert, StringAssert, and Assert.Throws<T> for exceptions
• Manage test lifecycle with [SetUp], [TearDown], [OneTimeSetUp], and [OneTimeTearDown] for per-test and per-class initialization
• Keep tests focused, independent, and idempotent; use [Category], [Order], and [Explicit] for organization and execution control