Code review fixes (3/x)

- Add test_encrypted_fields_cannot_be_null

Author: aclark4life

django_mongodb_backend/fields/encryption.py

@@ -5,6 +5,8 @@ class EncryptedFieldMixin:
     encrypted = True
 
     def __init__(self, *args, queries=None, **kwargs):
+        if kwargs.get("null", False):
+            raise ValueError("'null=True' is not supported for encrypted fields.")
         self.queries = queries
         super().__init__(*args, **kwargs)
 

tests/encryption_/test_fields.py

@@ -5,6 +5,8 @@
 from django.conf import settings
 from django.db import connections
 
+from django_mongodb_backend.fields import EncryptedFieldMixin
+
 from .models import (
     Appointment,
     Billing,
@@ -153,3 +155,11 @@ def test_encrypted_patient_record_in_unencrypted_database(self):
                 patientrecords = new_connection[db_name].encryption__patientrecord.find()
                 ssn = patientrecords[0]["ssn"]
                 self.assertTrue(isinstance(ssn, Binary))
+
+    def test_encrypted_fields_cannot_be_null(self):
+        class Field(EncryptedFieldMixin):
+            pass
+
+        msg = "'null=True' is not supported for encrypted fields."
+        with self.assertRaisesMessage(ValueError, msg):
+            Field(null=True)