test_string.py 文件源码

def test_override_get_value(self):
        class NamespaceFormatter(string.Formatter):
            def __init__(self, namespace={}):
                string.Formatter.__init__(self)
                self.namespace = namespace

            def get_value(self, key, args, kwds):
                if isinstance(key, str):
                    try:
                        # Check explicitly passed arguments first
                        return kwds[key]
                    except KeyError:
                        return self.namespace[key]
                else:
                    string.Formatter.get_value(key, args, kwds)

        fmt = NamespaceFormatter({'greeting':'hello'})
        self.assertEqual(fmt.format("{greeting}, world!"), 'hello, world!')