/**
 * View Data Layer Tests - Sponsor Functionality
 *
 * This test file will cover the view data layer for sponsor functionality.
 *
 * The view data layer is responsible for:
 * - DTO → UI model mapping
 * - Formatting, sorting, and grouping
 * - Derived fields and defaults
 * - UI-specific semantics
 *
 * This layer isolates the UI from API churn by providing a stable interface
 * between the API layer and the presentation layer.
 *
 * Test coverage will include:
 * - Sponsor dashboard data transformation and metrics
 * - Sponsor billing and payment view models
 * - Campaign management data formatting and status tracking
 * - League sponsorship data aggregation and tier calculations
 * - Sponsor settings and configuration view models
 * - Sponsor signup and onboarding data handling
 * - Derived sponsor fields (engagement metrics, ROI calculations, etc.)
 * - Default values and fallbacks for sponsor views
 * - Sponsor-specific formatting (budgets, impressions, clicks, conversions)
 * - Data grouping and categorization for sponsor components (by campaign, league, status)
 * - Sponsor search and filtering view models
 * - Real-time sponsor metrics and state management
 * - Historical sponsor performance data transformation
 */