Improve promotion code batch

legacy_promotions/app/models/spree/promotion_code/batch_builder.rb

@@ -31,7 +31,8 @@ def build_promotion_codes
   private
 
   def generate_random_codes
-    created_codes = 0
+    created_codes = promotion_code_batch.promotion_codes.count
+
     batch_size = @options[:batch_size]
 
     while created_codes < number_of_codes
@@ -40,12 +41,14 @@ def generate_random_codes
       new_codes = Array.new(max_codes_to_generate) { generate_random_code }.uniq
       codes_for_current_batch = get_unique_codes(new_codes)
 
-      codes_for_current_batch.each do |value|
+      codes_for_current_batch.filter! do |value|
         Spree::PromotionCode.create!(
           value: value,
           promotion: promotion,
           promotion_code_batch: promotion_code_batch
         )
+      rescue ActiveRecord::RecordInvalid
+        false
       end
       created_codes += codes_for_current_batch.size
     end

legacy_promotions/spec/models/spree/promotion_code/batch_builder_spec.rb

@@ -72,6 +72,35 @@
         subject.build_promotion_codes
         expect(promotion.codes.size).to eq(number_of_codes)
       end
+
+      context "when promotion_code creation returns an error" do
+        before do
+          raise_exception = true
+          allow(Spree::PromotionCode).to receive(:create!) do
+            if raise_exception
+              raise_exception = false
+              raise(ActiveRecord::RecordInvalid)
+            else
+              create(:promotion_code, promotion: promotion)
+            end
+          end
+        end
+
+        it "creates the correct number of codes anyway" do
+          subject.build_promotion_codes
+          expect(promotion.codes.size).to eq(number_of_codes)
+        end
+      end
+
+      context "when same promotion_codes are already present" do
+        before do
+          create_list(:promotion_code, 11, promotion: promotion, promotion_code_batch: promotion_code_batch)
+        end
+
+        it "creates only the missing promotion_codes" do
+          expect { subject.build_promotion_codes }.to change { promotion.codes.size }.by(39)
+        end
+      end
     end
   end