Updates checkout tests

Adds out of stock check as helper

spec/support/checkout_helper.rb

@@ -66,4 +66,12 @@ module CheckoutHelper
     click_on "Complete order"
     expect(page).to have_content "Back To Store"
   end
+
+  def out_of_stock_check(step)
+    visit checkout_step_path(step)
+
+    expect(page).not_to have_selector 'closing', text: "Checkout now"
+    expect(page).to have_selector 'closing', text: "Your shopping cart"
+    expect(page).to have_content "An item in your cart has become unavailable"
+  end
 end

spec/system/consumer/checkout/details_spec.rb

@@ -82,6 +82,18 @@ describe "As a consumer, I want to checkout my order" do
       visit checkout_path
     end
 
+    context "when a line item is out of stock" do
+      before do
+        variant.on_demand = false
+        variant.on_hand = 0
+        variant.save!
+      end
+
+      it "returns me to the cart with an error message" do
+        out_of_stock_check(:details)
+      end
+    end
+
     context "when no selecting a shipping method" do
       before do
         fill_out_details

spec/system/consumer/checkout/payment_spec.rb

@@ -27,7 +27,6 @@ describe "As a consumer, I want to checkout my order" do
                    ship_address_id: nil, state: "cart",
                    line_items: [create(:line_item, variant:)])
   }
-
   let(:fee_tax_rate) { create(:tax_rate, amount: 0.10, zone:, included_in_price: true) }
   let(:fee_tax_category) { create(:tax_category, tax_rates: [fee_tax_rate]) }
   let(:enterprise_fee) { create(:enterprise_fee, amount: 1.23, tax_category: fee_tax_category) }
@@ -58,6 +57,18 @@ describe "As a consumer, I want to checkout my order" do
       visit checkout_path
     end
 
+    context "when a line item is out of stock" do
+      before do
+        variant.on_demand = false
+        variant.on_hand = 0
+        variant.save!
+      end
+
+      it "returns me to the cart with an error message" do
+        out_of_stock_check(:payment)
+      end
+    end
+
     context "payment step" do
       let(:order) { create(:order_ready_for_payment, distributor:) }
 

spec/system/consumer/checkout/summary_spec.rb

@@ -35,6 +35,11 @@ describe "As a consumer, I want to checkout my order" do
     create(:shipping_method, require_ship_address: true,
                              name: "A Free Shipping with required address")
   }
+  let!(:payment_with_fee) {
+    create(:payment_method, distributors: [distributor],
+                            name: "Payment with Fee", description: "Payment with fee",
+                            calculator: Calculator::FlatRate.new(preferred_amount: 1.23))
+  }
 
   before do
     add_enterprise_fee enterprise_fee
@@ -51,6 +56,18 @@ describe "As a consumer, I want to checkout my order" do
       visit checkout_path
     end
 
+    context "when a line item is out of stock" do
+      before do
+        variant.on_demand = false
+        variant.on_hand = 0
+        variant.save!
+      end
+
+      it "returns me to the cart with an error message" do
+        out_of_stock_check(:summary)
+      end
+    end
+
     context "summary step" do
       let(:order) {
         create(:order_ready_for_confirmation, distributor:)