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/services/stripe_invoice_service_test.rb

@@ -140,12 +140,12 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
 
   test "should handle Stripe customer creation with existing customer ID" do
     @user.update!(stripe_customer_id: "cus_existing123")
-    
+
     mock_customer = mock("customer")
     mock_customer.stubs(:id).returns("cus_existing123")
-    
+
     Stripe::Customer.expects(:retrieve).with("cus_existing123").returns(mock_customer)
-    
+
     # Mock the rest of the invoice creation process
     mock_invoice = mock("invoice")
     mock_invoice.stubs(:id).returns("in_test123")
@@ -160,14 +160,14 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
 
   test "should handle invalid existing Stripe customer" do
     @user.update!(stripe_customer_id: "cus_invalid123")
-    
+
     # First call fails, then create new customer
     Stripe::Customer.expects(:retrieve).with("cus_invalid123").raises(Stripe::InvalidRequestError.new("message", "param"))
-    
+
     mock_customer = mock("customer")
     mock_customer.stubs(:id).returns("cus_new123")
     Stripe::Customer.expects(:create).returns(mock_customer)
-    
+
     # Mock the rest of the invoice creation process
     mock_invoice = mock("invoice")
     mock_invoice.stubs(:id).returns("in_test123")
@@ -178,7 +178,7 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
 
     result = @service.create_post_payment_invoice
     assert_not_nil result
-    
+
     @user.reload
     assert_equal "cus_new123", @user.stripe_customer_id
   end
@@ -247,7 +247,7 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
     mock_invoice.stubs(:id).returns("in_test123")
     mock_invoice.stubs(:finalize_invoice).returns(mock_invoice)
     mock_invoice.expects(:pay)
-    
+
     Stripe::Invoice.expects(:create).with(expected_invoice_data).returns(mock_invoice)
     Stripe::InvoiceItem.expects(:create).once
 
@@ -280,7 +280,7 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
 
     mock_invoice = mock("invoice")
     mock_invoice.stubs(:id).returns("in_test123")
-    
+
     mock_finalized_invoice = mock("finalized_invoice")
     mock_finalized_invoice.expects(:pay).with({
       paid_out_of_band: true,
@@ -300,7 +300,7 @@ class StripeInvoiceServiceTest < ActiveSupport::TestCase
   test "get_invoice_pdf_url should return PDF URL for valid invoice" do
     mock_invoice = mock("invoice")
     mock_invoice.expects(:invoice_pdf).returns("https://stripe.com/invoice.pdf")
-    
+
     Stripe::Invoice.expects(:retrieve).with("in_test123").returns(mock_invoice)
 
     url = StripeInvoiceService.get_invoice_pdf_url("in_test123")