Fix subscription update for empty/false-like values

djstripe/stripe_objects.py

@@ -1481,7 +1481,7 @@ def update(self, plan=None, application_fee_percent=None, coupon=None, prorate=N
         stripe_subscription = self.api_retrieve()
 
         for kwarg, value in kwargs.items():
-            if value:
+            if value is not None:
                 setattr(stripe_subscription, kwarg, value)
 
         return stripe_subscription.save()

tests/test_subscription.py

@@ -8,6 +8,7 @@
 
 import calendar
 from copy import deepcopy
+from decimal import Decimal
 
 from django.contrib.auth import get_user_model
 from django.test import TestCase
@@ -145,6 +146,21 @@ def test_update(self, customer_retrieve_mock, subscription_retrieve_mock, plan_r
 
         self.assertEqual(4, new_subscription.quantity)
 
+    @patch("stripe.Plan.retrieve", return_value=deepcopy(FAKE_PLAN))
+    @patch("stripe.Subscription.retrieve")
+    @patch("stripe.Customer.retrieve", return_value=deepcopy(FAKE_CUSTOMER))
+    def test_update_set_empty_value(self, customer_retrieve_mock, subscription_retrieve_mock, plan_retrieve_mock):
+        subscription_fake = deepcopy(FAKE_SUBSCRIPTION)
+        subscription_fake.update({'tax_percent': Decimal(20.0)})
+        subscription_retrieve_mock.return_value = subscription_fake
+        subscription = Subscription.sync_from_stripe_data(subscription_fake)
+
+        self.assertEqual(Decimal(20.0), subscription.tax_percent)
+
+        new_subscription = subscription.update(tax_percent=Decimal(0.0))
+
+        self.assertEqual(Decimal(0.0), new_subscription.tax_percent)
+
     @patch("stripe.Plan.retrieve", return_value=deepcopy(FAKE_PLAN))
     @patch("stripe.Subscription.retrieve", return_value=deepcopy(FAKE_SUBSCRIPTION))
     @patch("stripe.Customer.retrieve", return_value=deepcopy(FAKE_CUSTOMER))