Fix tests

dirty_models/models.py

@@ -469,7 +469,7 @@ def __new__(cls, *args, **kwargs):
         return super(DynamicModel, new_class).__new__(new_class)
 
     def __setattr__(self, name, value):
-        if not hasattr(self, name):
+        if not self.__hasattr__(name):
             if not self.get_read_only() or not self.is_locked():
                 field_type = self._get_field_type(name, value)
                 if not field_type:
@@ -481,6 +481,19 @@ def __setattr__(self, name, value):
     def __getattr__(self, name):
         return self.get_field_value(name)
 
+    def __hasattr__(self, name):
+        try:
+            getattr(super(DynamicModel, self), name)
+        except AttributeError:
+            try:
+                self.__dict__[name]
+            except KeyError:
+                try:
+                    self.__class__.__dict__[name]
+                except KeyError:
+                    return False
+        return True
+
     def __reduce__(self):
         """
         Reduce function to allow dumpable by pickle

tests/dirty_models/tests_models.py

@@ -947,8 +947,7 @@ def test_set_list_value(self):
     def test_set_empty_list_value(self):
         self.model.test1 = []
 
-        with self.assertRaises(AttributeError):
-            self.model.test1
+        self.assertIsNone(self.model.test1)
 
     def test_set_invalid_type_field_fail(self):
         with self.assertRaisesRegexp(TypeError, "Invalid parameter: test34. Type not supported."):