refactor: prepare for free ticket

test/controllers/orders_controller_test.rb

@@ -125,7 +125,7 @@ class OrdersControllerTest < ActionDispatch::IntegrationTest
     assert_equal "draft", new_order.status
     assert_equal @user, new_order.user
     assert_equal @event, new_order.event
-    assert_equal @ticket_type.price_cents + 100, new_order.total_amount_cents # includes 1€ service fee
+    assert_equal @ticket_type.price_cents, new_order.total_amount_cents # Service fee deducted from promoter payout, not added to customer
 
     assert_redirected_to checkout_order_path(new_order)
     assert_equal new_order.id, session[:draft_order_id]

test/models/order_test.rb

@@ -603,4 +603,22 @@ class OrderTest < ActiveSupport::TestCase
     result = order.stripe_invoice_pdf_url
     assert_nil result
   end
+
+  test "free? should return true for zero amount orders" do
+    free_order = Order.create!(
+      user: @user, event: @event, total_amount_cents: 0,
+      status: "draft", payment_attempts: 0
+    )
+
+    assert free_order.free?
+  end
+
+  test "free? should return false for non-zero amount orders" do
+    paid_order = Order.create!(
+      user: @user, event: @event, total_amount_cents: 1000,
+      status: "draft", payment_attempts: 0
+    )
+
+    assert_not paid_order.free?
+  end
 end

test/models/ticket_type_test.rb

@@ -244,4 +244,38 @@ class TicketTypeTest < ActiveSupport::TestCase
     )
     assert_not ticket_type.save
   end
+
+  test "should allow free tickets with zero price" do
+    user = User.create!(
+      email: "test@example.com",
+      password: "password123",
+      password_confirmation: "password123"
+    )
+
+    event = Event.create!(
+      name: "Test Event",
+      slug: "test-event",
+      description: "Valid description for the event that is long enough",
+      latitude: 48.8566,
+      longitude: 2.3522,
+      venue_name: "Test Venue",
+      venue_address: "123 Test Street",
+      user: user
+    )
+
+    ticket_type = TicketType.new(
+      name: "Free Ticket",
+      description: "Valid description for the free ticket type",
+      price_cents: 0,
+      quantity: 50,
+      sale_start_at: Time.current,
+      sale_end_at: Time.current + 1.day,
+      event: event
+    )
+
+    assert ticket_type.save
+    assert ticket_type.free?
+    assert_equal 0, ticket_type.price_cents
+    assert_equal 0.0, ticket_type.price_euros
+  end
 end