possibility to reset a value

test/test_config.py

@@ -34,7 +34,7 @@ def test_base_config():
     dm = cfg.unwrap_from_path('dummy')
     assert dm._name == 'dummy'
 
-def test_toto():
+def test_reset_value():
     descr = make_description()
     cfg = Config(descr)
     assert cfg.gc.dummy == False