fix(timezone): Correct calculation for true-up fee with timezone

app/services/fees/create_true_up_service.rb

@@ -33,11 +33,10 @@ def call
     delegate :charge, :subscription, to: :fee
 
     def prorated_min_amount_cents
-      from_date = boundaries.charges_from_datetime.to_date
-      to_date = boundaries.charges_to_datetime.to_date
-
       # NOTE: number of days between beginning of the period and the termination date
-      number_of_day_to_bill = (to_date + 1.day - from_date).to_i
+      from_datetime = boundaries.charges_from_datetime.to_time
+      to_datetime = boundaries.charges_to_datetime.to_time
+      number_of_day_to_bill = (to_datetime - from_datetime).fdiv(1.day).ceil
 
       date_service.charge_single_day_price(charge:) * number_of_day_to_bill
     end

spec/scenarios/spending_minimum_spec.rb

@@ -26,7 +26,7 @@
 
     it 'creates expected credit note and invoice' do
       ### 8 Jan: Create subscription
-      travel_to(DateTime.new(2023, 1, 8)) do
+      travel_to(DateTime.new(2023, 1, 8, 8)) do
         expect {
           create_subscription(
             {
@@ -51,7 +51,7 @@
       expect(sub_invoice.total_amount_cents).to eq(4645) # 60 / 31 * 24
 
       ### 25 Feb: Create event and Terminate subscription
-      travel_to(DateTime.new(2023, 2, 25)) do
+      travel_to(DateTime.new(2023, 2, 25, 6)) do
         create_event(
           {
             code: metric.code,
@@ -183,7 +183,7 @@
       expect(sub_invoice.total_amount_cents).to eq(4645) # 60 / 31 * 24
 
       ### 25 Feb: Create event and Terminate subscription
-      travel_to(DateTime.new(2023, 2, 25)) do
+      travel_to(DateTime.new(2023, 2, 25, 8)) do
         create_event(
           {
             code: metric.code,

spec/services/fees/create_true_up_service_spec.rb

@@ -12,7 +12,20 @@
 
   let(:charge) { create(:standard_charge, plan:, min_amount_cents: 1000) }
   let(:invoice) { create(:invoice, customer:, organization:) }
-  let(:fee) { create(:charge_fee, amount_cents:, customer:, charge:, invoice:) }
+  let(:fee) do
+    create(
+      :charge_fee,
+      amount_cents:,
+      customer:,
+      charge:,
+      properties: {
+        'from_datetime' => DateTime.parse('2023-08-01 00:00:00'),
+        'to_datetime' => DateTime.parse('2023-08-31 23:59:59'),
+        'charges_from_datetime' => DateTime.parse('2023-08-01 00:00:00'),
+        'charges_to_datetime' => DateTime.parse('2023-08-31 23:59:59'),
+      },
+    )
+  end
   let(:amount_cents) { 700 }
 
   before { tax }
@@ -69,10 +82,10 @@
           amount_cents:,
           charge:,
           properties: {
-            'from_datetime' => Date.parse('2022-08-01 00:00:00'),
-            'to_datetime' => Date.parse('2022-08-15 23:59:59'),
-            'charges_from_datetime' => Date.parse('2022-08-01 00:00:00'),
-            'charges_to_datetime' => Date.parse('2022-08-15 23:59:59'),
+            'from_datetime' => DateTime.parse('2022-08-01 00:00:00'),
+            'to_datetime' => DateTime.parse('2022-08-15 23:59:59'),
+            'charges_from_datetime' => DateTime.parse('2022-08-01 00:00:00'),
+            'charges_to_datetime' => DateTime.parse('2022-08-15 23:59:59'),
           },
         )
       end
@@ -91,5 +104,34 @@
         end
       end
     end
+
+    context 'with customer timezone' do
+      let(:customer) { create(:customer, organization:, timezone: 'Pacific/Fiji') }
+
+      it 'instantiates a true-up fee' do
+        travel_to(DateTime.new(2023, 9, 1)) do
+          result = create_service.call
+
+          aggregate_failures do
+            expect(result).to be_success
+
+            expect(result.true_up_fee).to have_attributes(
+              subscription: fee.subscription,
+              charge: fee.charge,
+              amount_currency: fee.currency,
+              fee_type: 'charge',
+              invoiceable: fee.charge,
+              properties: fee.properties,
+              payment_status: 'pending',
+              units: 1,
+              events_count: 0,
+              group: nil,
+              amount_cents: 300,
+              true_up_parent_fee_id: fee.id,
+            )
+          end
+        end
+      end
+    end
   end
 end