Adds "retire_user" to CreditRequest.

openedx/core/djangoapps/credit/models.py

@@ -681,6 +681,21 @@ class CreditRequest(TimeStampedModel):
         unique_together = ('username', 'course', 'provider')
         get_latest_by = 'created'
 
+    @classmethod
+    def retire_user(cls, original_username, retired_username):
+        """
+        Obfuscates CreditRecord instances associated with `original_username`.
+        Empties the records' `parameters` field and replaces username with its
+        anonymized value, `retired_username`.
+        """
+        num_updated_credit_requests = cls.objects.filter(
+            username=original_username
+        ).update(
+            username=retired_username,
+            parameters={},
+        )
+        return num_updated_credit_requests > 0
+
     @classmethod
     def credit_requests_for_user(cls, username):
         """

openedx/core/djangoapps/credit/tests/test_models.py

@@ -10,6 +10,9 @@ from opaque_keys.edx.keys import CourseKey
 
 from openedx.core.djangoapps.credit.models import CreditCourse, CreditRequirement, CreditRequirementStatus
 from student.models import get_retired_username_by_username
+from student.tests.factories import UserFactory
+
+from ..models import CreditRequest, CreditProvider, CreditCourse
 
 
 def add_credit_course(course_key):
@@ -145,7 +148,9 @@ class CreditRequirementStatusTests(TestCase):
         retirement_succeeded = CreditRequirementStatus.retire_user(self.old_username)
         self.assertTrue(retirement_succeeded)
 
-        old_username_records_exist = CreditRequirementStatus.objects.filter(username=self.old_username).exists()
+        old_username_records_exist = CreditRequirementStatus.objects.filter(
+            username=self.old_username
+        ).exists()
         self.assertFalse(old_username_records_exist)
 
         new_username_records_exist = CreditRequirementStatus.objects.filter(username=self.retired_username).exists()
@@ -154,3 +159,66 @@ class CreditRequirementStatusTests(TestCase):
     def test_retire_user_with_data(self):
         retirement_succeeded = CreditRequirementStatus.retire_user(self.retired_username)
         self.assertFalse(retirement_succeeded)
+
+
+class CreditRequestTest(TestCase):
+    """
+    The CreditRequest model's test suite.
+    """
+
+    def setUp(self):
+        super(CreditRequestTest, self).setUp()
+        self.user = UserFactory.create()
+        self.credit_course = CreditCourse.objects.create()
+        self.provider = CreditProvider.objects.create()
+
+    def test_can_retire_user_from_credit_request(self):
+        test_parameters = {'hi': 'there'}
+        CreditRequest.objects.create(
+            username=self.user.username,
+            course=self.credit_course,
+            provider=self.provider,
+            parameters=test_parameters,
+        )
+
+        credit_request_before_retire = CreditRequest.objects.filter(
+            username=self.user.username
+        )[0]
+
+        self.assertEqual(credit_request_before_retire.parameters, test_parameters)
+
+        user_was_retired = CreditRequest.retire_user(
+            original_username=self.user.username,
+            retired_username=get_retired_username_by_username(self.user.username)
+        )
+        credit_request_before_retire.refresh_from_db()
+        credit_requests_after_retire = CreditRequest.objects.filter(
+            username=self.user.username
+        )
+
+        self.assertTrue(user_was_retired)
+        self.assertEqual(credit_request_before_retire.parameters, {})
+        self.assertFalse(credit_requests_after_retire.exists())
+
+    def test_cannot_retire_nonexistent_user(self):
+        test_parameters = {'hi': 'there'}
+        CreditRequest.objects.create(
+            username=self.user.username,
+            course=self.credit_course,
+            provider=self.provider,
+            parameters=test_parameters,
+        )
+        another_user = UserFactory.create()
+
+        credit_request_before_retire = CreditRequest.objects.filter(
+            username=self.user.username
+        )[0]
+
+        was_retired = CreditRequest.retire_user(
+            original_username=another_user.username,
+            retired_username=get_retired_username_by_username(another_user.username)
+        )
+        credit_request_before_retire.refresh_from_db()
+
+        self.assertFalse(was_retired)
+        self.assertEqual(credit_request_before_retire.parameters, test_parameters)