Template: Unit Test

Patterns and ready-to-copy scaffolding for deterministic unit + integration tests. See standards/testing_standards.md and the testing skills.

Folder Structure

Tests/
├── {{Type}}Tests.swift          // behavior tests (AAA)
├── Mocks/
│   ├── Stub{{Dependency}}.swift  // simple fakes
│   └── MockURLProtocol.swift     // network stubbing for integration tests
└── Fixtures/
    ├── {{resource}}_success.json
    └── {{resource}}_error.json

Files in this bundle

• ExampleTests.swift — Swift Testing unit tests (AAA, success + error paths) with a fake.
• MockURLProtocol.swift — drop-in URLProtocol stub for integration tests.

Conventions

• Swift Testing (@Test/#expect) for new code; XCTest only for legacy.
• AAA structure; names read as method_condition_expectedResult.
• Deterministic: inject Date/ids/clients; no real network/disk/sleep.
• Simple fakes over heavy mocking frameworks; fixtures stored as JSON files.
• Coverage: success + error + empty + boundary; bug fixes get a failing-first regression test.

Quick reference

@Test func methodName_condition_expectedResult() async throws {
    // Arrange
    let sut = SystemUnderTest(dependency: StubDependency(result: .success(.sample)))
    // Act
    let result = try await sut.run()
    // Assert
    #expect(result == .expected)
}