skills.rest
ibytechaos
ibytechaosCOMMUNITY
Explore all skills by this author →
GitHub

swift-protocol-di-testing

Implements protocol-based dependency injection for testable Swift code with mockable external dependencies.

1|Updated Oct 11, 2025
Search Tags:#unit testing#swift#dependency injection#mocking#protocols#sendable#swift testing
One-click install
npx skills add https://github.com/ibytechaos/claude --skill swift-protocol-di-testing-ibytechaos
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: swift-protocol-di-testing
Source: https://github.com/ibytechaos/claude/tree/main/plugins/everything-claude-code/skills/swift-protocol-di-testing
Command: npx skills add https://github.com/ibytechaos/claude --skill swift-protocol-di-testing-ibytechaos

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Swift code that directly accesses the file system, network, or external APIs is hard to test deterministically, making error-handling paths nearly impossible to verify without triggering real failures. ## Core Features & Use Cases - Focused Protocol Design: Define small, single-responsibility protocols (FileSystemProviding, FileAccessorProviding, BookmarkStorageProviding) that abstract each external concern. - Mock Implementations: Build configurable mocks with in-memory storage and injectable error properties to simulate failure paths without real I/O. - Swift Testing Integration: Write deterministic tests using Swift Testing (@Test, #expect) with actors and Sendable-safe concurrency. - Use Case: You have a SyncManager actor that reads from an iCloud container. Inject a MockFileAccessor that throws a read error, then verify the manager surfaces the correct SyncError without touching the disk. ## Quick Start Ask the AI to refactor a Swift class that reads files so its file system access sits behind an injectable protocol with a mock for Swift Testing.

Frequently Asked Questions about swift-protocol-di-testing

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I make Swift code testable with dependency injection?▼

Define small protocols for each external dependency (file system, network), provide production implementations as default parameter values, and inject mock implementations in tests. This lets tests run deterministically without real I/O.

How to mock file system access in Swift tests?▼

Create a mock conforming to your FileAccessorProviding protocol backed by an in-memory dictionary of URLs to Data. Add configurable error properties so tests can simulate read and write failures on demand.

Does protocol-based mocking work with Swift actors and Sendable?▼

Yes, but protocols used across actor boundaries must conform to Sendable. Reference-type mocks can use @unchecked Sendable when their mutable state is only accessed within tests.

Should I use one big protocol or many small protocols in Swift?▼

Use many small, single-responsibility protocols. A large protocol covering all external access is an anti-pattern that makes mocks bloated and couples unrelated concerns together.

When should I not create a protocol for a Swift type?▼

Skip protocols for types with no external dependencies. Only mock boundaries like file system, network, and APIs; mocking internal pure-logic types adds indirection without testing benefit.

Related Skills

Explore More Software Engineering Skills→
arbisoftarbisoft
4

swift-protocol-di-testing

Abstract external dependencies behind small protocols for deterministic Swift testing.

Official
Advanced
bocanbocan
27

ci-cd-setup

Generate CI/CD pipelines for iOS and macOS apps using GitHub Actions, Xcode Cloud, or fastlane.

Community
Intermediate
femitzfemitz

swift-concurrency

Diagnose and resolve Swift concurrency issues in Swift 6.3+ projects.

Community
Advanced
PacktPublishingPacktPublishing
30

swinject-to-factory

Migrates Swift projects from Swinject runtime DI to compile-time Factory.

Official
Advanced