Add stripe payment setup spec and make minor tweaks to the code itself.

Also, add a missing . to card_set? that eanbles it! If the card was
already set, it would anyway set the default card. Now it will use the
defined card if there is one already.

engines/order_management/app/services/order_management/subscriptions/stripe_payment_setup.rb

@@ -18,7 +18,7 @@ module OrderManagement
       private
 
       def ensure_payment_source
-        return if !card_required? || card_set?
+        return unless stripe_payment_method? && !card_set?
 
         if saved_credit_card.present? && allow_charges?
           use_saved_credit_card
@@ -27,17 +27,13 @@ module OrderManagement
         end
       end
 
-      def card_required?
+      def stripe_payment_method?
         [Spree::Gateway::StripeConnect,
          Spree::Gateway::StripeSCA].include? @payment.payment_method.class
       end
 
       def card_set?
-        @payment.source is_a? Spree::CreditCard
-      end
-
-      def use_saved_credit_card
-        @payment.update_attributes(source: saved_credit_card)
+        @payment.source.is_a? Spree::CreditCard
       end
 
       def saved_credit_card
@@ -47,6 +43,10 @@ module OrderManagement
       def allow_charges?
         @order.customer.allow_charges?
       end
+
+      def use_saved_credit_card
+        @payment.update_attributes(source: saved_credit_card)
+      end
     end
   end
 end

engines/order_management/spec/services/order_management/subscriptions/stripe_payment_setup_spec.rb

@@ -0,0 +1,109 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+module OrderManagement
+  module Subscriptions
+    describe StripePaymentSetup do
+      let(:order) { create(:order) }
+      let(:payment_setup) { OrderManagement::Subscriptions::StripePaymentSetup.new(order) }
+
+      describe "#call!" do
+        context "when no pending payments are present" do
+          before do
+            allow(order).to receive(:pending_payments).once { [] }
+          end
+
+          it "does nothing" do
+            expect(payment_setup.call!).to eq nil
+          end
+        end
+
+        context "when a payment is present" do
+          let(:payment) { create(:payment, payment_method: payment_method, amount: 10) }
+
+          before { allow(order).to receive(:pending_payments).once { [payment] } }
+
+          context "when the payment method is not a stripe payment method" do
+            let(:payment_method) { create(:payment_method) }
+
+            it "returns the pending payment with no change" do
+              expect(payment).to_not receive(:update_attributes)
+              expect(payment_setup.call!).to eq payment
+            end
+          end
+
+          context "when the payment method is a stripe payment method" do
+            let(:payment_method) { create(:stripe_payment_method) }
+
+            context "and the card is already set (the payment source is a credit card)" do
+              it "returns the pending payment with no change" do
+                expect(payment).to_not receive(:update_attributes)
+                expect(payment_setup.call!).to eq payment
+              end
+            end
+
+            context "and the card is not set (the payment source is not a credit card)" do
+              before { payment.update_attribute :source, nil }
+
+              context "and no default credit card has been saved by the customer" do
+                before do
+                  allow(order).to receive(:user) { instance_double(Spree::User, default_card: nil) }
+                end
+
+                it "adds an error to the order and does not update the payment" do
+                  payment_setup.call!
+
+                  expect(payment).to_not receive(:update_attributes)
+                  expect(payment_setup.call!).to eq payment
+                  expect(order.errors[:base].first).to eq "There are no authorised "\
+                                                            "credit cards available to charge"
+                end
+              end
+
+              context "and a default credit card has been saved by the customer" do
+                let(:saved_credit_card) { create(:credit_card) }
+
+                before do
+                  allow(order).to receive(:user) {
+                    instance_double(Spree::User, default_card: saved_credit_card)
+                  }
+                end
+
+                context "but the customer has not authorised the shop to charge credit cards" do
+                  before do
+                    allow(order).to receive(:customer) {
+                      instance_double(Customer, allow_charges?: false)
+                    }
+                  end
+
+                  it "adds an error to the order and does not update the payment" do
+                    payment_setup.call!
+
+                    expect(payment).to_not receive(:update_attributes)
+                    expect(payment_setup.call!).to eq payment
+                    expect(order.errors[:base].first).to eq "There are no authorised "\
+                                                              "credit cards available to charge"
+                  end
+                end
+
+                context "and the customer has authorised the shop to charge credit cards" do
+                  before do
+                    allow(order).to receive(:customer) {
+                      instance_double(Customer, allow_charges?: true)
+                    }
+                  end
+
+                  it "uses the saved credit card as the source for the payment" do
+                    payment_setup.call!
+                    expect(payment.source).to eq saved_credit_card
+                  end
+                end
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end