openswiftui-test-authoring

# OpenSwiftUI Test Authoring ## Testing and Verification - Do not write tests for reversible, low-impact changes that only mirror the implementation. Add tests when they provide meaningful and necessary verification of observable behavior, boundaries, failures, or regression risks. - Run the narrowest relevant tests permitted by `AGENTS.md` and complete required checks. Once those pass, broaden or repeat testing only when new changes, failures, or unresolved concerns justify it; otherwise, continue toward completing the task. ## Shared Conventions - Follow the organization and naming of the nearest tests in the same target. - Sort unconditional imports and conditional import blocks alphabetically by imported module name, treating each block as one unit. Use the first import in the block's first branch as its sort key. - Group mutually exclusive imports in one `#if` / `#elseif` / `#else` block. Never split the block or reorder its branches to alphabetize individual imports. Preserve its conditions, fallback behavior, and import attributes. - Do not add `.aigc` by default. For unit, compatibility, symbol-dual, and similar non-UI tests, add `.tags(.aigc)` only when a test case contains more than 100 lines of AI-written code. Import `OpenSwiftUITestsSupport` when the tag is needed. - UI and UX tests do not need `.aigc`, regardless of their length. - In Swift Testing, prefer `@Test(arguments:)` when cases share the same test body. Keep different behaviors in separate tests. - Give argument collections explicit types when inference is ambiguous, especially tuple elements with integer literals or empty collections. A test parameter type does not necessarily constrain the macro's argument expression; use a typed fixture or values such as `UInt64(0b0011)` when needed. - Start each new Swift test file with this header, substituting the actual file name and the actual test target name: ```swift // // <FileName.swift> // <TestTargetName> ``` Leave one blank line after the target name. Do not add a closing decorative `//` line, and do not copy a target name from an unrelated example. ## Conditional Import Blocks For example, the following blocks sort by `Darwin`, `OpenCombine`, and `UIKit`, respectively, not by modules in their alternative branches. `Foundation` belongs after the entire Darwin/Glibc block, never between its branches: ```swift #if canImport(Darwin) import Darwin #elseif canImport(Glibc) import Glibc #else #error("Unsupported platform") #endif ``` ```swift #if OPENSWIFTUI_OPENCOMBINE import OpenCombine #else import Combine #endif ``` ```swift #if os(iOS) || os(visionOS) import UIKit #elseif os(macOS) import AppKit #endif ``` ## Test-Type Guides Read only the guide that matches the requested test type: - Unit tests: [unit-tests.md](references/unit-tests.md) - Compatibility tests: [compatibility-tests.md](references/compatibility-tests.md) - Symbol-dual tests: [symbol-dual-tests.md](references/symbol-dual-tests.md) - UI tests: [ui-tests.md](references/ui-tests.md)