subscription and user is now uniquely constrained

2 files changed, 28 insertions, 0 deletions

diff --git a/pyblackbird_cc/payments/models.py b/pyblackbird_cc/payments/models.py
index cbf462c..174e3fe 100644
--- a/pyblackbird_cc/payments/models.py
+++ b/pyblackbird_cc/payments/models.py
@@ -57,5 +57,8 @@ class Subscription(models.Model):
     start_date = models.DateTimeField(null=True, blank=True)
     end_date = models.DateTimeField(null=True, blank=True)
 
+    class Meta:
+        constraints = [models.UniqueConstraint(fields=["user", "plan"], name="unique_user_plan")]
+
     def __str__(self):
         return f"Subscription for {self.user.username}"
diff --git a/pyblackbird_cc/payments/tests/test_models.py b/pyblackbird_cc/payments/tests/test_models.py
index 132d025..467d6e4 100644
--- a/pyblackbird_cc/payments/tests/test_models.py
+++ b/pyblackbird_cc/payments/tests/test_models.py
@@ -1,6 +1,7 @@
 import pytest
 from allauth.account.signals import user_signed_up
 from django.contrib.auth import get_user_model
+from django.db import IntegrityError
 from django.test import RequestFactory
 
 from pyblackbird_cc.payments.models import Subscription
@@ -15,6 +16,30 @@ def user_data():
 
 
 @pytest.mark.django_db
+def test_subscription_user_unique():
+    # Ensure the free plan exists
+    free_plan, _ = SubscriptionPlan.objects.get_or_create(
+        name="Free Plan",
+        defaults={
+            "price": 0,
+            "description": "Free plan description",
+            "allowed_downloads": 10,
+        },
+    )
+
+    # Create a new user
+    user_data = {"email": "testuser@example.com", "password": "testpassword123"}
+    user = User.objects.create_user(**user_data)
+
+    # Create a subscription for the user
+    subscription = Subscription.objects.create(user=user, plan=free_plan)
+
+    # Try to create another subscription for the same user
+    with pytest.raises(IntegrityError):
+        Subscription.objects.create(user=user, plan=free_plan)
+
+
+@pytest.mark.django_db
 def test_user_signup_assigns_free_subscription(user_data):
     # Ensure the free plan exists
     free_plan, _ = SubscriptionPlan.objects.get_or_create(