Refs #29147 --- Added JSONField serialization tests.

tests/postgres_tests/test_json.py

@@ -323,18 +323,28 @@ class TestChecks(PostgreSQLTestCase):
 
 class TestSerialization(PostgreSQLTestCase):
     test_data = (
-        '[{"fields": {"field": {"a": "b", "c": null}, "field_custom": null}, '
+        '[{"fields": {"field": %s, "field_custom": null}, '
         '"model": "postgres_tests.jsonmodel", "pk": null}]'
     )
+    test_values = (
+        # (Python value, serialized value),
+        ({'a': 'b', 'c': None}, '{"a": "b", "c": null}'),
+        ('abc', '"abc"'),
+        ('{"a": "a"}', '"{\\"a\\": \\"a\\"}"'),
+    )
 
     def test_dumping(self):
-        instance = JSONModel(field={'a': 'b', 'c': None})
-        data = serializers.serialize('json', [instance])
-        self.assertJSONEqual(data, self.test_data)
+        for value, serialized in self.test_values:
+            with self.subTest(value=value):
+                instance = JSONModel(field=value)
+                data = serializers.serialize('json', [instance])
+                self.assertJSONEqual(data, self.test_data % serialized)
 
     def test_loading(self):
-        instance = list(serializers.deserialize('json', self.test_data))[0].object
-        self.assertEqual(instance.field, {'a': 'b', 'c': None})
+        for value, serialized in self.test_values:
+            with self.subTest(value=value):
+                instance = list(serializers.deserialize('json', self.test_data % serialized))[0].object
+                self.assertEqual(instance.field, value)
 
 
 class TestValidation(PostgreSQLTestCase):