@Test
public void withFormBody() throws Exception {

    RequestBody body = new FormBody.Builder()
          .add("status", "Hello Ladies + Gentlemen, a signed OAuth request!")
          .build();
    Request request = new Request.Builder()
          .url("https://api.twitter.com/1/statuses/update.json?include_entities=true")
          .post(body)
          .build();
    Request signed = oauth1.signRequest(request);
    assertAuthHeader(signed, "tnnArxj06cWHq44gCs1OSKk%2FjLY%3D");
}