Add UniquePerAccountSripeObject for Plans

The `stripe_id` for plans is not unique by itself globally (it is not generated
by Stripe), and therefore needs to be unique per account.

pinax/stripe/migrations/0011_auto_20171121_1648.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2017-11-21 16:48
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pinax_stripe', '0010_connect'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='plan',
+            name='stripe_id',
+            field=models.CharField(max_length=191),
+        ),
+        migrations.AlterUniqueTogether(
+            name='plan',
+            unique_together=set([('stripe_id', 'stripe_account')]),
+        ),
+    ]

pinax/stripe/models.py

@@ -26,7 +26,7 @@ class Meta:
         abstract = True
 
 
-class AccountRelatedStripeObject(StripeObject):
+class AccountRelatedStripeObjectMixin(models.Model):
 
     stripe_account = models.ForeignKey(
         "pinax_stripe.Account",
@@ -44,6 +44,22 @@ class Meta:
         abstract = True
 
 
+class AccountRelatedStripeObject(AccountRelatedStripeObjectMixin, StripeObject):
+    """Uses a mixin to support Django 1.8 (name clash for stripe_id)"""
+
+    class Meta:
+        abstract = True
+
+
+class UniquePerAccountStripeObject(AccountRelatedStripeObjectMixin):
+    stripe_id = models.CharField(max_length=191)
+    created_at = models.DateTimeField(default=timezone.now)
+
+    class Meta:
+        abstract = True
+        unique_together = ("stripe_id", "stripe_account")
+
+
 class StripeAccountFromCustomerMixin(object):
     @property
     def stripe_account(self):
@@ -56,7 +72,7 @@ def stripe_account_stripe_id(self):
 
 
 @python_2_unicode_compatible
-class Plan(AccountRelatedStripeObject):
+class Plan(UniquePerAccountStripeObject):
     amount = models.DecimalField(decimal_places=2, max_digits=9)
     currency = models.CharField(max_length=15, blank=False)
     interval = models.CharField(max_length=15)

pinax/stripe/tests/test_models.py

@@ -47,6 +47,12 @@ def test_plan_str_jpy(self):
         p = Plan(amount=decimal.Decimal("5"), name="My Plan", currency="jpy", interval="monthly", interval_count=1)
         self.assertTrue(u"\u00a5" in _str(p))
 
+    def test_plan_per_account(self):
+        Plan.objects.create(stripe_id="plan", amount=decimal.Decimal("100"), interval="monthly", interval_count=1)
+        account = Account.objects.create(stripe_id="acct_A")
+        Plan.objects.create(stripe_id="plan", stripe_account=account, amount=decimal.Decimal("100"), interval="monthly", interval_count=1)
+        self.assertEquals(Plan.objects.count(), 2)
+
     def test_event_processing_exception_str(self):
         e = EventProcessingException(data="hello", message="hi there", traceback="fake")
         self.assertTrue("Event=" in str(e))