feat(dunning): Prevent creation of payment request when different cur…

…rencies

app/services/payment_requests/create_service.rb

@@ -10,23 +10,15 @@ def initialize(organization:, params:)
     end
 
     def call
-      unless License.premium? && organization.premium_integrations.include?("dunning")
-        return result.not_allowed_failure!(code: "premium_addon_feature_missing")
-      end
-
-      return result.not_found_failure!(resource: "customer") unless customer
-      return result.not_found_failure!(resource: "invoice") if invoices.empty?
-
-      if invoices.exists?(payment_overdue: false)
-        return result.not_allowed_failure!(code: "invoices_not_overdue")
-      end
+      check_preconditions
+      return result if result.error
 
       ActiveRecord::Base.transaction do
         # NOTE: Create payment request for the payable group
         payment_request = customer.payment_requests.create!(
           organization:,
           amount_cents: invoices.sum(:total_amount_cents),
-          amount_currency: invoices.first.currency,
+          amount_currency: currency,
           email:,
           invoices:
         )
@@ -47,6 +39,23 @@ def call
 
     attr_reader :organization, :params
 
+    def check_preconditions
+      unless License.premium? && organization.premium_integrations.include?("dunning")
+        return result.not_allowed_failure!(code: "premium_addon_feature_missing")
+      end
+
+      return result.not_found_failure!(resource: "customer") unless customer
+      return result.not_found_failure!(resource: "invoice") if invoices.empty?
+
+      if invoices.exists?(payment_overdue: false)
+        return result.not_allowed_failure!(code: "invoices_not_overdue")
+      end
+
+      if invoices.pluck(:currency).uniq.size > 1
+        result.not_allowed_failure!(code: "invoices_have_different_currencies")
+      end
+    end
+
     def customer
       @customer ||= organization.customers.find_by(external_id: params[:external_customer_id])
     end
@@ -58,5 +67,9 @@ def invoices
     def email
       @email ||= params[:email] || customer.email
     end
+
+    def currency
+      @currency ||= invoices.first.currency
+    end
   end
 end

spec/services/payment_requests/create_service_spec.rb

@@ -88,6 +88,18 @@
       end
     end
 
+    context "when invoices have different currencies" do
+      before { second_invoice.update!(currency: "USD") }
+
+      it "returns not allowed failure", :aggregate_failures do
+        result = create_service.call
+
+        expect(result).not_to be_success
+        expect(result.error).to be_a(BaseService::MethodNotAllowedFailure)
+        expect(result.error.code).to eq("invoices_have_different_currencies")
+      end
+    end
+
     it "creates a payment request" do
       expect { create_service.call }.to change { customer.payment_requests.count }.by(1)
     end