📘 GraphQLDemoApp-iOS

📱 About This Project

This project is a fully testable SwiftUI iOS app demonstrating clean architecture and protocol-driven GraphQL integration. It fetches and displays a list of users from the GraphQLZero public GraphQL API.

The focus is on separation of concerns, dependency injection, and unit testability, using Swift Testing (@Test, #expect) introduced in Xcode 15+.

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🧰 Tools & Environment

• Xcode: 16.4 (16F6)
• Language: Swift 5.10+
• GraphQL API: https://graphqlzero.almansi.me/api
• No external dependencies (Apollo included but not used for codegen)
• Testing: Swift Testing (native), no XCTest

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🧠 Architecture Decisions

This demo follows an MVVM + DI architecture:

SwiftUI View ⇅ (binds to) ViewModel ⇅ (depends on) GraphQLServiceProtocol ⇄ (implemented by) URLSessionGraphQLService

Key architectural choices:

• ✅ Protocol-oriented design: All business logic depends on GraphQLServiceProtocol, not concrete classes
• ✅ Decoupled networking: The URLSessionGraphQLService implements raw GraphQL queries using JSON and Codable — simple, inspectable, and easy to test
• ✅ No Apollo codegen: Apollo was evaluated but not integrated to keep the demo lightweight and self-contained. Full codegen was unnecessary for the static schema and simple use case.
• ✅ Unit testable: The ViewModel is tested with mock services, and test files are colocated with source for fast TDD workflows
• ✅ Swift Testing over XCTest: Cleaner syntax, native async support, no class boilerplate

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🧪 Test Strategy

• Tests are written using Swift Testing
• UserListViewModelTests.swift verifies:
  • Initial state
  • Successful data loading
  • Error handling when the service fails
• MockGraphQLService lives only in the test target
• No @testable import required — shared files are explicitly included in both targets

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📁 Project Structure

Models/                      ← Shared model types (e.g., User)
Services/                    ← Protocols and service implementations
ViewModels/                  ← Observable ViewModels (testable via DI)
Views/                       ← SwiftUI views

GraphQLDemoApp-iOSTests/
└── Mocks/                   ← Test-only mock services (e.g., MockGraphQLService)

Some test files (like the view model test) live adjacent to the code they test to support TDD workflows.

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🚫 Not Included (On Purpose)

• ❌ No Apollo code generation
• ❌ No unnecessary 3rd-party frameworks

This keeps the demo focused on testability, Swift-native tooling, and architectural clarity.

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🔗 API Reference

This app consumes the users query from:
https://graphqlzero.almansi.me/api

Example query:

query GetUsers {
  users {
    data {
      id
      name
      username
      email
    }
  }
}