when(req.getPathInfo()).thenReturn(ACCESS_TOKEN_PATH);
when(req.getMethod()).thenReturn("GET");
Map<String, String[]> params = getDoExchangeTokenParams();
when(req.getParameterMap()).thenReturn(params);
doThrow(new URISyntaxException("", "")).when(validator).validateMessage(
any(OAuthMessage.class), any(OAuthAccessor.class));
servlet.doGet(req, resp);
verify(validator).validateMessage(any(OAuthMessage.class), any(OAuthAccessor.class));