And add a test for new classes added without being specified in allowed_attrs

Author: danthedeckie

test_simpleeval.py

@@ -1397,6 +1397,15 @@ class Foo:
                 simple_eval("foo.hidden", names={"foo": Foo()}, allowed_attrs=extended_attrs), 42
             )
 
+    def test_disallowed_types(self):
+        class Foo:
+            bar = 42
+
+        assert Foo().bar == 42
+
+        with self.assertRaises(FeatureNotAvailable):
+            simple_eval("foo.bar", names={"foo": Foo()}, allowed_attrs=BASIC_ALLOWED_ATTRS)
+
     def test_breakout_via_generator(self):
         # Thanks decorator-factory
         class Foo: