@Test
public void explorer() throws IOException {

  req.setRequestURI("/_ah/api/explorer/");
  req.setMethod("GET");
  servlet.service(req, resp);
  assertThat(resp.getStatus()).isEqualTo(HttpServletResponse.SC_FOUND);
  assertThat(resp.getHeader("Location")).isEqualTo(
      "http://apis-explorer.appspot.com/apis-explorer/?base=" + API_ROOT + "&root=" + API_ROOT);
}