feat(dunning): Validate dunning campaign has at least one threshold

app/services/dunning_campaigns/create_service.rb

@@ -11,7 +11,7 @@ def initialize(organization:, params:)
 
     def call
       return result.forbidden_failure! unless organization.auto_dunning_enabled?
-      # TODO: At least one threshold currency/amount pair is needed
+      return result.validation_failure!(errors: { thresholds: ["can't be blank"] }) if params[:thresholds].blank?
 
       ActiveRecord::Base.transaction do
         if params[:applied_to_organization]

spec/services/dunning_campaigns/bulk_process_service_spec.rb

@@ -390,7 +390,7 @@
       end
     end
 
-    context "when neither organizaiton nor customer has an applied dunning campaign" do
+    context "when neither organization nor customer has an applied dunning campaign" do
       let(:dunning_campaign) { create :dunning_campaign, organization:, applied_to_organization: false }
 
       let(:dunning_campaign_threshold) do
@@ -403,7 +403,6 @@
       end
 
       before do
-        dunning_campaign
         dunning_campaign_threshold
         invoice_1
       end

spec/services/dunning_campaigns/create_service_spec.rb

@@ -121,6 +121,20 @@
             expect(result.error.messages[:code]).to eq(["value_already_exist"])
           end
         end
+
+        context "without thresholds" do
+          let(:thresholds) { [] }
+
+          it "returns an error" do
+            result = create_service.call
+
+            aggregate_failures do
+              expect(result).not_to be_success
+              expect(result.error).to be_a(BaseService::ValidationFailure)
+              expect(result.error.messages[:thresholds]).to eq(["can't be blank"])
+            end
+          end
+        end
       end
     end
   end