Platform Notes

• Optional helper plugins may help in some environments, but they must not be treated as required for this skill.

iOS Test-Driven Development (TDD)

Use When

• iOS Test-Driven Development standards. Enforces Red-Green-Refactor cycle, test pyramid (70/20/10), layer-specific testing strategies with XCTest and Swift Testing, and CI integration. Use when building or reviewing iOS apps with TDD methodology.
• The task needs reusable judgment, domain constraints, or a proven workflow rather than ad hoc advice.

Do Not Use When

• The task is unrelated to

  ios-tdd

  or would be better handled by a more specific companion skill.
• The request only needs a trivial answer and none of this skill's constraints or references materially help.

Required Inputs

• Gather relevant project context, constraints, and the concrete problem to solve; load

  references

  only as needed.
• Confirm the desired deliverable: design, code, review, migration plan, audit, or documentation.

Workflow

• Read this

  SKILL.md

  first, then load only the referenced deep-dive files that are necessary for the task.
• Apply the ordered guidance, checklists, and decision rules in this skill instead of cherry-picking isolated snippets.
• Produce the deliverable with assumptions, risks, and follow-up work made explicit when they matter.

Quality Standards

• Keep outputs execution-oriented, concise, and aligned with the repository's baseline engineering standards.
• Preserve compatibility with existing project conventions unless the skill explicitly requires a stronger standard.
• Prefer deterministic, reviewable steps over vague advice or tool-specific magic.

Anti-Patterns

• Treating examples as copy-paste truth without checking fit, constraints, or failure modes.
• Loading every reference file by default instead of using progressive disclosure.

Outputs

• A concrete result that fits the task: implementation guidance, review findings, architecture decisions, templates, or generated artifacts.
• Clear assumptions, tradeoffs, or unresolved gaps when the task cannot be completed from available context alone.
• References used, companion skills, or follow-up actions when they materially improve execution.

Evidence Produced

skill-composition-standards/references/test-plan-template.md

docs/ios/tdd-plan-checkout.md

docs/ios/tdd-coverage-2026-04-16.md

References

• Use the

  references/

  directory for deep detail after reading the core workflow below.

Overview

@Test

Quick Reference

Additional Guidance

ios-tdd

• The Red-Green-Refactor Cycle

• Test Pyramid (70/20/10)

• TDD Workflow for iOS Features

• Swift Testing Framework

• Protocol-Based Mocking

• Testing @Observable ViewModels

• URLProtocol for Network Mocking

• SwiftData / Core Data Testing

• XCUITest for Critical Flows

• Test Naming Convention

• Patterns and Anti-Patterns

• Integration with Other Skills

• Additional deep-dive sections continue in the reference file.