test(uitests): cover both add-on and plain-add product flows

The original helper only ever tapped the *first* product's add button
and assumed it went straight to Cart. That's the same single-path
assumption that produced the wrong 'product list never loaded'
diagnosis - the first product on this catalog ('Alcatra') has add-ons
and opens ProductDetailSheet ('Detalhes') instead of adding directly.
Fixing just the button selector would have hidden this and failed
differently on the next run.

Renamed reachCheckoutWithOneItem to reachCheckoutWithProducts(_:count:
Int = 3) and added addProduct(atIndex:in:), which taps the Nth
product's add button and branches on the real outcome: if
ProductDetailSheet appears, confirms via its own main action button
('Atualizar...') and waits for it to dismiss; otherwise the product
already added directly. Loops over the first 3 products (capped by the
actual button count) so both flows are exercised on every run,
regardless of which specific products the real catalog happens to give
add-ons to.

See decisions/2026-09-11-ui-test-shared-login-session.md follow-up.

PediFoodsUITests/CartCheckoutFlowTests.swift

@@ -98,7 +98,7 @@ final class CartCheckoutFlowTests: XCTestCase {
     func testAddProductToCartAndReachCheckout() throws {
         let app = XCUIApplication()
         app.launch()
-        try reachCheckoutWithOneItem(app)
+        try reachCheckoutWithProducts(app)
     }
 
     /// Exercises CheckoutView's payment-method selection and the address
@@ -108,7 +108,7 @@ final class CartCheckoutFlowTests: XCTestCase {
     func testCheckoutPaymentMethodSelectionAndAddressAlterar() throws {
         let app = XCUIApplication()
         app.launch()
-        try reachCheckoutWithOneItem(app)
+        try reachCheckoutWithProducts(app)
 
         XCTAssertTrue(app.staticTexts["MÉTODO DE PAGAMENTO"].waitForExistence(timeout: 5))
 
@@ -167,7 +167,7 @@ final class CartCheckoutFlowTests: XCTestCase {
     func testConfirmarEPagarWithCreditCardOpensCardSelectionWithoutSubmitting() throws {
         let app = XCUIApplication()
         app.launch()
-        try reachCheckoutWithOneItem(app)
+        try reachCheckoutWithProducts(app)
 
         let creditCardRow = app.buttons.matching(NSPredicate(format: "label CONTAINS[c] %@", "Cartão de Crédito")).firstMatch
         XCTAssertTrue(creditCardRow.waitForExistence(timeout: 5), "This store is expected to offer Cartão de Crédito")
@@ -209,7 +209,49 @@ final class CartCheckoutFlowTests: XCTestCase {
         app.swipeDown()
     }
 
-    private func reachCheckoutWithOneItem(_ app: XCUIApplication) throws {
+    /// Taps the Nth product row's add button (0-based, top to bottom) and
+    /// handles both real outcomes on this catalog: a product with add-ons
+    /// (e.g. "Alcatra", the first product) opens `ProductDetailSheet`
+    /// ("Detalhes") and needs its own confirm tap; a plain product (no
+    /// `addonGroups`) adds directly with no sheet at all
+    /// (`StoreDetailView+Components.swift`). Which products have add-ons
+    /// is real catalog data, not something this suite controls, so both
+    /// paths must be handled rather than assumed - asserting "no sheet
+    /// appeared" for a product that genuinely has add-ons is exactly the
+    /// wrong-diagnosis mistake this suite already made once for this same
+    /// screen (see decisions/2026-09-11-ui-test-shared-login-session.md).
+    /// `ProductDetailSheet` requires no addon selection to confirm -
+    /// `quantity` defaults to 1 and addons default to none, so its main
+    /// action button ("Atualizar • <price>") is always tappable as-is.
+    private func addProduct(atIndex index: Int, in app: XCUIApplication) {
+        let addButtons = app.buttons.matching(identifier: "storeDetailProductAddButton")
+        let button = addButtons.element(boundBy: index)
+        XCTAssertTrue(
+            button.waitForExistence(timeout: 25),
+            "Product add button at index \(index) never appeared. \(quickDiagnostics(app))"
+        )
+        button.tap()
+
+        if app.staticTexts["Detalhes"].waitForExistence(timeout: 3) {
+            let confirmButton = app.buttons.matching(NSPredicate(format: "label BEGINSWITH %@", "Atualizar")).firstMatch
+            XCTAssertTrue(
+                confirmButton.waitForExistence(timeout: 5),
+                "ProductDetailSheet's confirm button never appeared for product at index \(index). \(quickDiagnostics(app))"
+            )
+            confirmButton.tap()
+            XCTAssertFalse(
+                app.staticTexts["Detalhes"].waitForExistence(timeout: 3),
+                "ProductDetailSheet never dismissed after confirming product at index \(index)"
+            )
+        }
+    }
+
+    /// Adds the first `count` products from Store Detail's list, top to
+    /// bottom, then reaches Checkout. Defaults to 3 so both the add-on
+    /// flow (first product) and the plain-add flow (later products) are
+    /// both exercised on every run, not just whichever one the first
+    /// product happens to be.
+    private func reachCheckoutWithProducts(_ app: XCUIApplication, count: Int = 3) throws {
         XCTAssertTrue(app.ensureLoggedIn(), "Login never completed")
 
         // ensureLoggedIn can land on whichever tab it detected the
@@ -237,16 +279,17 @@ final class CartCheckoutFlowTests: XCTestCase {
         // clearly rendered on screen while `images.matching(identifier:
         // "plus")` still found nothing, and the same "plus" systemName is
         // separately reused by CartView's quantity stepper, making it an
-        // ambiguous identifier to search by in the first place. Matching
-        // the button itself (not a nested image) also sidesteps the
-        // quantity-badge accessibility-label-merging issue that affected
-        // the tab bar's cart icon elsewhere in this suite.
-        let addButton = app.buttons.matching(identifier: "storeDetailProductAddButton").firstMatch
+        // ambiguous identifier to search by in the first place.
+        let addButtons = app.buttons.matching(identifier: "storeDetailProductAddButton")
         XCTAssertTrue(
-            addButton.waitForExistence(timeout: 25),
+            addButtons.firstMatch.waitForExistence(timeout: 25),
             "Store Detail's product list never loaded. \(quickDiagnostics(app))"
         )
-        addButton.tap()
+
+        let actualCount = min(count, addButtons.count)
+        for index in 0..<actualCount {
+            addProduct(atIndex: index, in: app)
+        }
 
         // Once the cart has items, the tab bar button's accessible label
         // becomes just the badge count ("4") instead of "Shopping Cart" -
@@ -259,7 +302,7 @@ final class CartCheckoutFlowTests: XCTestCase {
         XCTAssertTrue(cartTab.waitForExistence(timeout: 5))
         cartTab.tap()
         XCTAssertTrue(app.staticTexts["Meu Carrinho"].waitForExistence(timeout: 10))
-        XCTAssertFalse(app.staticTexts["Seu carrinho está vazio"].exists, "Cart still shows empty after adding a product")
+        XCTAssertFalse(app.staticTexts["Seu carrinho está vazio"].exists, "Cart still shows empty after adding products")
 
         app.buttons["Ir para o Pagamento"].tap()
         XCTAssertTrue(app.staticTexts["Finalizar Pedido"].waitForExistence(timeout: 10), "Never reached Checkout")