Fix error saving data on new Calculator

app/controllers/spree/admin/payment_methods_controller.rb

@@ -182,6 +182,11 @@ module Spree
             end
           end
 
+          # Ensure the calculator to be updated is the correct type
+          if params_for_update["calculator_type"] && params_for_update["calculator_attributes"]
+            add_type_to_calculator_attributes(params_for_update)
+          end
+
           params_for_update
         end
       end
@@ -191,6 +196,10 @@ module Spree
           Rails.cache.delete(@payment_method.calculator.preference_cache_key(key))
         end
       end
+
+      def add_type_to_calculator_attributes(hash)
+        hash["calculator_attributes"]["type"] = hash["calculator_type"]
+      end
     end
   end
 end

spec/system/admin/payment_method_spec.rb

@@ -415,4 +415,72 @@ describe '
       expect(page).not_to have_unchecked_field "payment_method_distributor_ids_#{@distributors[0].id}"
     end
   end
+
+  context 'when updating payment method with invalid data and changing calculator type' do
+    let(:payment_method) { create(:payment_method, :flat_rate, amount: 10) }
+
+    # Persist preferences to test that when preferred values are not found in the cache,
+    # they are fetched from the database and displayed correctly
+    before do
+      Spree::Preferences::Store.instance.persistence = true
+      login_as_admin_and_visit spree.edit_admin_payment_method_path payment_method
+      fill_in 'payment_method_name', with: ''
+      fill_in 'payment_method_description', with: 'Edited description'
+      uncheck "payment_method_distributor_ids_#{@distributors[0].id}"
+      select2_select 'Flat Percent', from: 'calc_type'
+      click_button 'Update'
+    end
+
+    after do
+      Spree::Preferences::Store.instance.persistence = false
+    end
+
+    it 'displays the number of errors' do
+      expect(page).to have_content('2 errors')
+    end
+
+    it 'displays error messages' do
+      expect(page).to have_content("Name can't be blank")
+      expect(page).to have_content('At least one hub must be selected')
+    end
+
+    it 'displays the new calculator fields' do
+      expect(page).to have_field 'Flat Percent'
+    end
+
+    it 'highlights invalid fields' do
+      within '.field_with_errors:has(#payment_method_name)' do
+        expect(page).to have_field 'payment_method_name'
+      end
+
+      within '#hubs' do
+        expect(page).to have_selector('.red')
+      end
+    end
+
+    it 'keeps information that was just edited, even after multiple unsuccessful updates' do
+      expect(page).to have_field 'payment_method_name', with: ''
+      expect(page).to have_field 'payment_method_description', with: 'Edited description'
+      expect(page).to have_unchecked_field "payment_method_distributor_ids_#{@distributors[0].id}"
+
+      fill_in 'payment_method_name', with: 'Test name'
+      fill_in 'Flat Percent', with: 'invalid string'
+      click_button 'Update'
+
+      expect(page).to have_field 'payment_method_name', with: 'Test name'
+      expect(page).to have_field 'Flat Percent', with: 'invalid string'
+      expect(page).to have_field 'payment_method_description', with: 'Edited description'
+      expect(page).to have_unchecked_field "payment_method_distributor_ids_#{@distributors[0].id}"
+    end
+
+    it 'displays data fetched from the database after navigating away from the page' do
+      click_link 'Back To Payment Methods List'
+      click_link href: /#{spree.edit_admin_payment_method_path(payment_method)}/
+
+      expect(page).to have_field 'Amount', with: '10.0'
+      expect(page).not_to have_field 'payment_method_name', with: ''
+      expect(page).not_to have_field 'payment_method_description', with: 'Edited description'
+      expect(page).not_to have_unchecked_field "payment_method_distributor_ids_#{@distributors[0].id}"
+    end
+  end
 end