swift-protocol-di-testing
Protocol-based dependency injection for testable Swift code — mock file system, network, and external APIs using focused protocols and Swift Testing.
npx skills add mturac/everything-openai-codex --skill swift-protocol-di-testing --agent codex
Same command for any agent — swap --agent for claude-code, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Swift Protocol-Based Dependency Injection for Testing Patterns for making Swift code testable by abstracting external dependencies (file system, network, iCloud) behind small, focused protocols. Enables deterministic tests without I/O. ## When to Activate - Writing Swift code that accesses file system, network, or external APIs - Need to test error handling paths without triggering real failures - Building modules that work across environments (app, test, SwiftUI preview) - Designing testable architecture with Swift concurrency (actors, Sendable) ## Core Pattern ### 1. Define Small, Focused Protocols Each protocol handles exactly one external concern. ```swift // File system access public protocol FileSystemProviding: Sendable { func containerURL(for purpose: Purpose) -> URL? } // File read/write operations public protocol FileAccessorProviding: Sendable { func read(from url: URL) throws -> Data func write(_ data: Data, to url: URL) throws func fileExists(at url: URL) -> Bool } // Bookmark storage (e.g., for sandboxed apps) public protocol BookmarkStorageProviding: Sendable { func saveBookmark(_ data: Data, for key: String) throws func loadBookmark(for key: String) throws -> Data
- When to Activate
- Core Pattern
- 1. Define Small, Focused Protocols
- 2. Create Default (Production) Implementations
- 3. Create Mock Implementations for Testing
- 4. Inject Dependencies with Default Parameters
- 5. Write Tests with Swift Testing
- Best Practices
- Anti-Patterns to Avoid
- When to Use
What does the swift-protocol-di-testing skill do?
Protocol-based dependency injection for testable Swift code — mock file system, network, and external APIs using focused protocols and Swift Testing.
How do I install it?
Run `npx skills add mturac/everything-openai-codex --skill swift-protocol-di-testing --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From mturac/everything-openai-codex, a repository with 84 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.