Fix JsonField from_db_value + better unit tests

.venv

@@ -0,0 +1 @@
+drm

rest_models/backend/utils.py

@@ -25,6 +25,13 @@ def message_from_response(response):
     class JSONField(JSONFieldLegacy):
         def get_prep_value(self, value):
             return value
+
+        def from_db_value(self, value, expression, connection):
+            try:
+                return super().from_db_value(value, expression, connection)
+            except TypeError:
+                return value
+
 except NameError:
     def JSONField(*args, **kwargs):
         return None

rest_models/tests/tests_queryset.py

@@ -235,9 +235,9 @@ def test_many2many_clear(self):
 
 
 @skipIf(settings.DATABASES['default']['ENGINE'] == 'django.db.backends.sqlite3', 'no json in sqlite')
-@skipIf('year' in DynamicFilterBackend.VALID_FILTER_OPERATORS, 'skip check not compatible with current drest')
 class TestJsonField(TestCase):
     fixtures = ['data.json']
+    databases = ["default", "api"]
 
     def test_jsonfield_create(self):
         t = client_models.Topping.objects.create(
@@ -277,6 +277,12 @@ def test_jsonfield_update(self):
             {k: v for k, v in t2.__dict__.items() if k in ('name', 'cost', 'metadata')}
         )
 
+
+@skipIf(settings.DATABASES['default']['ENGINE'] == 'django.db.backends.sqlite3', 'no json in sqlite')
+@skipIf('year' in DynamicFilterBackend.VALID_FILTER_OPERATORS, 'skip check not compatible with current drest')
+class TestJsonLookup(TestCase):
+    fixtures = ['data.json']
+
     def test_jsonfield_lookup_isnull(self):
         t = api_models.Topping.objects.create(
             name='lardons lux',

setup.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 
 import os
 import sys