Add simple tests for billing

uncloud/uncloud_pay/tests.py

@@ -1,9 +1,118 @@
 from django.test import TestCase
-from .models import Order, Bill
+from django.contrib.auth import get_user_model
+from datetime import datetime, date, timedelta
 
-class BillTestCase(TestCase):
+from .models import *
+
+class BillingTestCase(TestCase):
     def setUp(self):
-        pass
+        self.user = get_user_model().objects.create(
+                username='jdoe',
+                email='john.doe@domain.tld')
 
     def test_truth(self):
         self.assertEqual(1+1, 2)
+
+    def test_basic_monthly_billing(self):
+        one_time_price = 10
+        recurring_price = 20
+        description = "Test Product 1"
+
+        # Three months: full, full, partial.
+        starting_date = datetime.fromisoformat('2020-03-01')
+        ending_date   = datetime.fromisoformat('2020-05-08')
+
+        # Create order to be billed.
+        order = Order.objects.create(
+                owner=self.user,
+                starting_date=starting_date,
+                ending_date=ending_date,
+                recurring_period=RecurringPeriod.PER_MONTH)
+        order.add_record(one_time_price, recurring_price, description)
+
+        # Generate & check bill for first month: full recurring_price + setup.
+        first_month_bills = Bill.generate_for(2020, 3, self.user)
+        self.assertEqual(len(first_month_bills), 1)
+        self.assertEqual(first_month_bills[0].total, one_time_price + recurring_price)
+
+        # Generate & check bill for second month: full recurring_price.
+        second_month_bills = Bill.generate_for(2020, 4, self.user)
+        self.assertEqual(len(second_month_bills), 1)
+        self.assertEqual(second_month_bills[0].total, recurring_price)
+
+        # Generate & check bill for third and last month: partial recurring_price.
+        third_month_bills = Bill.generate_for(2020, 5, self.user)
+        self.assertEqual(len(third_month_bills), 1)
+        # 31 days in May.
+        self.assertEqual(float(third_month_bills[0].total),
+                round((7/31) * recurring_price, AMOUNT_DECIMALS))
+
+        # Check that running Bill.generate_for() twice does not create duplicates.
+        self.assertEqual(len(Bill.generate_for(2020, 3, self.user)), 0)
+
+    def test_basic_yearly_billing(self):
+        one_time_price = 10
+        recurring_price = 150
+        description = "Test Product 1"
+
+        starting_date = datetime.fromisoformat('2020-03-31T08:05:23')
+
+        # Create order to be billed.
+        order = Order.objects.create(
+                owner=self.user,
+                starting_date=starting_date,
+                recurring_period=RecurringPeriod.PER_YEAR)
+        order.add_record(one_time_price, recurring_price, description)
+
+        # Generate & check bill for first year: recurring_price + setup.
+        first_year_bills = Bill.generate_for(2020, 3, self.user)
+        self.assertEqual(len(first_year_bills), 1)
+        self.assertEqual(first_year_bills[0].starting_date.date(),
+                date.fromisoformat('2020-03-31'))
+        self.assertEqual(first_year_bills[0].ending_date.date(),
+                date.fromisoformat('2021-03-30'))
+        self.assertEqual(first_year_bills[0].total,
+                recurring_price + one_time_price)
+
+        # Generate & check bill for second year: recurring_price.
+        second_year_bills = Bill.generate_for(2021, 3, self.user)
+        self.assertEqual(len(second_year_bills), 1)
+        self.assertEqual(second_year_bills[0].starting_date.date(),
+                date.fromisoformat('2021-03-31'))
+        self.assertEqual(second_year_bills[0].ending_date.date(),
+                date.fromisoformat('2022-03-30'))
+        self.assertEqual(second_year_bills[0].total, recurring_price)
+
+        # Check that running Bill.generate_for() twice does not create duplicates.
+        self.assertEqual(len(Bill.generate_for(2020, 3, self.user)), 0)
+        self.assertEqual(len(Bill.generate_for(2020, 4, self.user)), 0)
+        self.assertEqual(len(Bill.generate_for(2020, 2, self.user)), 0)
+        self.assertEqual(len(Bill.generate_for(2021, 3, self.user)), 0)
+
+    def test_basic_hourly_billing(self):
+        one_time_price = 10
+        recurring_price = 1.4
+        description = "Test Product 1"
+
+        starting_date = datetime.fromisoformat('2020-03-31T08:05:23')
+        ending_date   = datetime.fromisoformat('2020-04-01T11:13:32')
+
+        # Create order to be billed.
+        order = Order.objects.create(
+                owner=self.user,
+                starting_date=starting_date,
+                ending_date=ending_date,
+                recurring_period=RecurringPeriod.PER_HOUR)
+        order.add_record(one_time_price, recurring_price, description)
+
+        # Generate & check bill for first month: recurring_price + setup.
+        first_month_bills = Bill.generate_for(2020, 3, self.user)
+        self.assertEqual(len(first_month_bills), 1)
+        self.assertEqual(float(first_month_bills[0].total),
+                round(16 * recurring_price, AMOUNT_DECIMALS) + one_time_price)
+
+        # Generate & check bill for first month: recurring_price.
+        second_month_bills = Bill.generate_for(2020, 4, self.user)
+        self.assertEqual(len(second_month_bills), 1)
+        self.assertEqual(float(second_month_bills[0].total),
+                round(12 * recurring_price, AMOUNT_DECIMALS))