Update test infrastructure for embedded checkout support

This commit updates the test infrastructure to support the new embedded
checkout interfaces while maintaining compatibility with existing tests.

CheckoutViewControllerTests changes:
- Updated MockCheckoutWebViewController initializations to include new parameters
- Added createEmptyCheckoutCompletedPayload() helper for embedded checkout tests
- Maintained backward compatibility with existing test methods

MockCheckoutWebViewDelegate changes:
- Added embedded checkout delegate method implementations
- Added properties to capture embedded checkout event payloads
- Added XCTestExpectation properties for embedded checkout event testing
- Maintained all existing legacy delegate method functionality

All existing tests continue to pass while new embedded checkout
functionality can be tested using the extended mock interfaces.

Author: tiagocandido

Tests/ShopifyCheckoutSheetKitTests/CheckoutViewControllerTests.swift

@@ -38,7 +38,7 @@ class CheckoutViewDelegateTests: XCTestCase {
             $0.title = customTitle ?? "Checkout"
         }
         viewController = MockCheckoutWebViewController(
-            checkoutURL: checkoutURL, delegate: delegate
+            checkoutURL: checkoutURL, delegate: delegate, entryPoint: nil, options: nil
         )
 
         navigationController = UINavigationController(rootViewController: viewController)
@@ -209,7 +209,7 @@ class CheckoutViewDelegateTests: XCTestCase {
 
     func testCloseButtonUsesSystemDefaultWhenTintColorIsNil() {
         ShopifyCheckoutSheetKit.configuration.closeButtonTintColor = nil
-        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate)
+        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate, entryPoint: nil, options: nil)
 
         let closeButton = controller.navigationItem.rightBarButtonItem
         XCTAssertNotNil(closeButton)
@@ -220,7 +220,7 @@ class CheckoutViewDelegateTests: XCTestCase {
     func testCloseButtonUsesCustomImageAndTintWhenColorIsSet() {
         let customColor = UIColor.red
         ShopifyCheckoutSheetKit.configuration.closeButtonTintColor = customColor
-        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate)
+        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate, entryPoint: nil, options: nil)
 
         let closeButton = controller.navigationItem.rightBarButtonItem
         XCTAssertNotNil(closeButton)
@@ -231,7 +231,7 @@ class CheckoutViewDelegateTests: XCTestCase {
 
     func testCloseButtonImageIsXMarkCircleFill() {
         ShopifyCheckoutSheetKit.configuration.closeButtonTintColor = .blue
-        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate)
+        let controller = MockCheckoutWebViewController(checkoutURL: checkoutURL, delegate: delegate, entryPoint: nil, options: nil)
 
         let closeButton = controller.navigationItem.rightBarButtonItem
         let expectedImage = UIImage(systemName: "xmark.circle.fill")
@@ -249,6 +249,10 @@ protocol Dismissible: AnyObject {
 
 extension CheckoutWebViewController: Dismissible {}
 
+func createEmptyCheckoutCompletedPayload() -> CheckoutCompletePayload {
+    return CheckoutCompletePayload(orderID: "test_order_123")
+}
+
 class MockCheckoutWebViewController: CheckoutWebViewController {
     private(set) var dismissCalled = false
 

Tests/ShopifyCheckoutSheetKitTests/Mocks/MockCheckoutWebViewDelegate.swift

@@ -84,4 +84,36 @@ class MockCheckoutWebViewDelegate: CheckoutWebViewDelegate {
         completedEventReceived = event
         didEmitCheckoutCompletedEventExpectation?.fulfill()
     }
+    
+    // MARK: - Embedded Checkout Delegate Methods
+    
+    var stateChangePayloadReceived: CheckoutStatePayload?
+    var completePayloadReceived: CheckoutCompletePayload?
+    var errorsReceived: [ErrorPayload]?
+    var webPixelsPayloadReceived: WebPixelsPayload?
+    
+    var didChangeStateExpectation: XCTestExpectation?
+    var didCompleteEmbeddedCheckoutExpectation: XCTestExpectation?
+    var didFailEmbeddedCheckoutExpectation: XCTestExpectation?
+    var didEmitEmbeddedWebPixelEventExpectation: XCTestExpectation?
+    
+    func checkoutViewDidChangeState(state: CheckoutStatePayload) {
+        stateChangePayloadReceived = state
+        didChangeStateExpectation?.fulfill()
+    }
+    
+    func checkoutViewDidComplete(payload: CheckoutCompletePayload) {
+        completePayloadReceived = payload
+        didCompleteEmbeddedCheckoutExpectation?.fulfill()
+    }
+    
+    func checkoutViewDidFail(errors: [ErrorPayload]) {
+        errorsReceived = errors
+        didFailEmbeddedCheckoutExpectation?.fulfill()
+    }
+    
+    func checkoutViewDidEmitWebPixelEvent(payload: WebPixelsPayload) {
+        webPixelsPayloadReceived = payload
+        didEmitEmbeddedWebPixelEventExpectation?.fulfill()
+    }
 }