fix(grouped-by): Current usage with in advance aggregation

app/services/billable_metrics/aggregations/base_service.rb

@@ -96,12 +96,12 @@ def support_grouped_aggregation?
         false
       end
 
-      def empty_results(options: {})
+      def empty_results
         empty_result = BaseService::Result.new
         empty_result.grouped_by = grouped_by.index_with { nil }
         empty_result.aggregation = 0
         empty_result.count = 0
-        empty_result.current_usage_units = 0 if options[:is_pay_in_advance]
+        empty_result.current_usage_units = 0
 
         result.aggregations = [empty_result]
         result

app/services/billable_metrics/aggregations/sum_service.rb

@@ -38,7 +38,7 @@ def compute_aggregation(options: {})
       #       with the grouped_by_values filter
       def compute_grouped_by_aggregation(options: {})
         aggregations = event_store.grouped_sum
-        return empty_results(options:) if aggregations.blank?
+        return empty_results if aggregations.blank?
 
         counts = event_store.grouped_count
 

app/services/charges/validators/standard_service.rb

@@ -5,6 +5,7 @@ module Validators
     class StandardService < Charges::Validators::BaseService
       def valid?
         validate_amount
+        validate_grouped_by
 
         super
       end
@@ -15,6 +16,10 @@ def amount
         properties['amount']
       end
 
+      def grouped_by
+        properties['grouped_by']
+      end
+
       def validate_amount
         return if ::Validators::DecimalAmountService.new(amount).valid_amount?
 
@@ -25,7 +30,7 @@ def validate_grouped_by
         return if grouped_by.blank?
         return if grouped_by.is_a?(Array) && grouped_by.all? { |f| f.is_a?(String) }
 
-        add_error(field: :grouped_by, error_code: 'invalid_grouped_by')
+        add_error(field: :grouped_by, error_code: 'invalid_type')
       end
     end
   end

spec/services/charges/validators/standard_service_spec.rb

@@ -49,5 +49,38 @@
 
       it { expect(standard_service).to be_valid }
     end
+
+    describe 'grouped_by' do
+      let(:properties) { { 'amount' => '12', 'grouped_by' => grouped_by } }
+      let(:grouped_by) { [] }
+
+      it { expect(standard_service).to be_valid }
+
+      context 'when attribute is not an array' do
+        let(:grouped_by) { 'group' }
+
+        it 'is invalid' do
+          aggregate_failures do
+            expect(standard_service).not_to be_valid
+            expect(standard_service.result.error).to be_a(BaseService::ValidationFailure)
+            expect(standard_service.result.error.messages.keys).to include(:grouped_by)
+            expect(standard_service.result.error.messages[:grouped_by]).to include('invalid_type')
+          end
+        end
+      end
+
+      context 'when attribute is not a list of string' do
+        let(:grouped_by) { [12, 45] }
+
+        it 'is invalid' do
+          aggregate_failures do
+            expect(standard_service).not_to be_valid
+            expect(standard_service.result.error).to be_a(BaseService::ValidationFailure)
+            expect(standard_service.result.error.messages.keys).to include(:grouped_by)
+            expect(standard_service.result.error.messages[:grouped_by]).to include('invalid_type')
+          end
+        end
+      end
+    end
   end
 end