What is the main benefit of using protocols for dependency injection in Swift?

Protocols decouple your logic from concrete implementations like FileManager or URLSession, allowing you to swap real dependencies with lightweight mocks for fast, deterministic unit testing.

Should I use this for all my Swift classes?

No. As per the skill guidelines, you should only mock boundaries for external dependencies. Over-engineering internal types that have no external side effects should be avoided.

Does this skill support modern Swift Concurrency?

Yes, it specifically includes patterns for Sendable compliance and Actor-safe DI to ensure your architecture works seamlessly with async/await and structured concurrency.

How does this skill improve SwiftUI development?

By using protocol-based DI, you can inject mock data providers into your views, allowing SwiftUI Previews to show various states (loading, data, error) without running the full app logic.

Swift Protocol DI & Testing

Name: Swift Protocol DI & Testing
Author: xu-xiang

byxu-xiang

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323

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Mobile Development

Implements protocol-based dependency injection to create testable, decoupled Swift code for file systems, networks, and APIs.

This skill provides a standardized framework for Swift developers to implement protocol-based dependency injection, enabling deterministic testing of complex external dependencies like the file system, network requests, and iCloud services. By abstracting boundaries into focused protocols and providing mock implementations, it facilitates high-coverage testing without actual I/O, supports Swift concurrency models with Sendable compliance, and integrates seamlessly with the modern Swift Testing framework. It is ideal for developers building robust iOS or macOS applications who need to test error paths and edge cases that are difficult to trigger in production environments.

主な機能

01Default parameter injection strategies for clean production-to-test transitions

02Standardized protocol abstraction for external dependencies like I/O and Networking

03Deterministic unit testing support using Swift Testing and mock objects

04Concurrency-ready patterns with Sendable compliance for Actor-based architectures

05323 GitHub stars

06Comprehensive guidance on avoiding DI anti-patterns and 'god protocols'

ユースケース

01Simulating file system failures or network errors to test robust error handling

02Isolating Swift components from external system states for faster, reliable CI/CD pipelines

03Providing mock data for SwiftUI Previews to visualize UI states without live backend services

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add xu-xiang/everything-claude-code-zh swift-protocol-di-testing

For use in Claude.ai and ChatGPT

主な機能

01Default parameter injection strategies for clean production-to-test transitions

02Standardized protocol abstraction for external dependencies like I/O and Networking

03Deterministic unit testing support using Swift Testing and mock objects

04Concurrency-ready patterns with Sendable compliance for Actor-based architectures

05323 GitHub stars

06Comprehensive guidance on avoiding DI anti-patterns and 'god protocols'

ユースケース

01Simulating file system failures or network errors to test robust error handling

02Isolating Swift components from external system states for faster, reliable CI/CD pipelines

03Providing mock data for SwiftUI Previews to visualize UI states without live backend services