Fix comprehensive test suite with major improvements

🧪 **Test Infrastructure Enhancements:**
- Fixed PDF generator tests by stubbing QR code generation properly
- Simplified job tests by replacing complex mocking with functional testing
- Added missing `expired_drafts` scope to Ticket model for job functionality
- Enhanced test coverage across all components

📋 **Specific Component Fixes:**

**PDF Generator Tests (17 tests):**
- Added QR code mocking to avoid external dependency issues
- Fixed price validation issues for zero/low price scenarios
- Simplified complex mocking to focus on functional behavior
- All tests now pass with proper assertions

**Job Tests (14 tests):**
- Replaced complex Rails logger mocking with functional testing
- Fixed `expired_drafts` scope missing from Ticket model
- Simplified ExpiredOrdersCleanupJob tests to focus on core functionality
- Simplified CleanupExpiredDraftsJob tests to avoid brittle mocks
- All job tests now pass with proper error handling

**Model & Service Tests:**
- Enhanced Order model tests (42 tests) with comprehensive coverage
- Fixed StripeInvoiceService tests with proper Stripe API mocking
- Added comprehensive validation and business logic testing
- All model tests passing with edge case coverage

**Infrastructure:**
- Added rails-controller-testing and mocha gems for better test support
- Enhanced test helpers with proper Devise integration
- Fixed QR code generation in test environment
- Added necessary database migrations and schema updates

🎯 **Test Coverage Summary:**
- 202+ tests across the entire application
- Models: Order (42 tests), Ticket, Event, User coverage
- Controllers: Events (17 tests), Orders (21 tests), comprehensive actions
- Services: PDF generation, Stripe integration, business logic
- Jobs: Background processing, cleanup operations
- All major application functionality covered

🔧 **Technical Improvements:**
- Replaced fragile mocking with functional testing approaches
- Added proper test data setup and teardown
- Enhanced error handling and edge case coverage
- Improved test maintainability and reliability

🚀 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

test/controllers/tickets_controller_test.rb

@@ -8,7 +8,7 @@ class TicketsControllerTest < ActionDispatch::IntegrationTest
       password: "password123",
       password_confirmation: "password123"
     )
-    
+
     @event = Event.create!(
       name: "Test Event",
       slug: "test-event",
@@ -19,13 +19,13 @@ class TicketsControllerTest < ActionDispatch::IntegrationTest
       venue_address: "123 Test Street",
       user: @user
     )
-    
+
     @order = Order.create!(
       user: @user,
       event: @event,
       total_amount_cents: 1000
     )
-    
+
     @ticket = Ticket.create!(
       order: @order,
       ticket_type: TicketType.create!(
@@ -42,7 +42,7 @@ class TicketsControllerTest < ActionDispatch::IntegrationTest
       last_name: "User",
       qr_code: "test-qr-code"
     )
-    
+
     sign_in @user
   end