C# Testing NUnit Fixtures

Quick Reference

• Classify test scope first: API, component, or integration.
• Lock runtime constraints before execution: Docker availability, framework target, and explicitly excluded suites.
• Use this skill for test-suite architecture and fixture behavior, not for general service implementation or CI graph refactors.
• Default to two files per handler/use case: <Feature>Fixture.cs and <Feature>Tests.cs.
• For full-cycle API tests, use controller-focused structure: one fixture per controller/test family and one base ApiTest.cs + ApiFixture.cs (split by scenario family only when needed).
• Do not translate SpecFlow/Taffy step definitions into C# line-by-line; rewrite scenario intent into idiomatic API tests.
• For API migrations, avoid one global shared setup fixture; each controller/test family fixture owns its own dependencies.
• Fixture ownership for API tests should include DB launcher + migrators + WireMock + WebApplicationFactory + client.
• Reset mutable state in [SetUp]; dispose all owned infra in [OneTimeTearDown].
• For DB bootstrapping, follow pricing-style DatabaseLauncher + MigratorContainer from tests/utils/Sc.Fin.Pricing.Tests.Utils/Testcontainers.
• Use canonical migrator command dotnet Sc.Tool.FluentMigrator.dll migrateup -m /sql and avoid custom ready-check arguments in tests.
• Keep migrator ordering explicit (dependency migrators first, domain migrator last) and support fixture-level optional migrator toggles when some suites do not need all DBs.
• Add explicit migrator verification tests that assert launcher startup, migrator completion/order, and required tables.
• Use iterative quality loop: code -> build -> run tests -> fix -> repeat.
• For health endpoints, use [Test] + [TestCase] + [CancelAfter(...)] with method signature (string url, CancellationToken cancellationToken); keep [Test] together with [TestCase] to avoid NUnit analyzer issues.
• If user excludes infra-dependent suites (for example component tests requiring Docker), run feasible categories first and report exactly what remains unvalidated.