Do not "accept error" if bad kwarg is passed to test itself
@@ -29,6 +29,9 @@ def _call_func(self, impl, args, kw):
error = None
tb = None
except Exception as e:
+ if e.__traceback__.tb_next is None:
+ # failed before impl is called, e.g. invalid kw
+ raise e
result = None
error = e
tb = traceback.format_exc()
