swift-tdd-workflow

Swift Test-Driven Development Workflow

This skill ensures all iOS development follows TDD principles with comprehensive test coverage.

When to Activate

• Writing new features or functionality
• Fixing bugs or issues
• Refactoring existing code
• Adding API integrations
• Creating new SwiftUI views or UIKit components

Core Principles

1. Tests BEFORE Code

ALWAYS write tests first, then implement code to make tests pass.

2. Coverage Requirements

• Minimum 80% coverage (unit + integration + UI)
• All edge cases covered
• Error scenarios tested
• Boundary conditions verified

3. Test Types

Unit Tests (XCTest)

• Individual functions and methods
• ViewModels and business logic
• Pure functions
• Helpers and utilities

Integration Tests

• API client operations
• Database operations
• Service interactions
• External API calls

UI Tests (XCUITest)

• Critical user flows
• Complete workflows
• Screen navigation
• UI interactions

TDD Workflow Steps

Step 1: Write User Stories

As a [role], I want to [action], so that [benefit]

Example:
As a user, I want to search for markets semantically,
so that I can find relevant markets even without exact keywords.

Step 2: Generate Test Cases

For each user story, create comprehensive test cases:

import XCTest
@testable import MyApp

final class MarketSearchServiceTests: XCTestCase {

    var sut: MarketSearchService!
    var mockAPIClient: MockAPIClient!

    override func setUp() {
        super.setUp()
        mockAPIClient = MockAPIClient()
        sut = MarketSearchService(apiClient: mockAPIClient)
    }

    override func tearDown() {
        sut = nil
        mockAPIClient = nil
        super.tearDown()
    }

    func test_search_returnsRelevantMarkets() async throws {
        // Test implementation
    }

    func test_search_handlesEmptyQueryGracefully() async throws {
        // Test edge case
    }

    func test_search_fallsBackToLocalSearch_whenNetworkUnavailable() async throws {
        // Test fallback behavior
    }

    func test_search_sortsByRelevanceScore() async throws {
        // Test sorting logic
    }
}