builder.addQueryParameter("team", team);
    }

    return builder.build();
  }

  /** See https://api.slack.com/methods/oauth.access. */
  public OAuthSession exchangeCode(String code, HttpUrl redirectUrl) throws IOException {
    HttpUrl url = baseUrl.newBuilder("oauth.access")
        .addQueryParameter("client_id", clientId)
        .addQueryParameter("client_secret", clientSecret)
        .addQueryParameter("code", code)

  public final boolean ok;
  public final String access_token;
  public final String scope;
  public final String user_id;
  public final String team_name;
  public final String team_id;

  public OAuthSession(
      boolean ok, String accessToken, String scope, String userId, String teamName, String teamId) {
    this.ok = ok;
    this.access_token = accessToken;
    this.scope = scope;
    this.user_id = userId;

    }
  }

  /** Starts a real time messaging session. */
  public void startRtm() throws IOException {
    String accessToken;
    synchronized (this) {
      accessToken = session.access_token;
    }

    RtmSession rtmSession = new RtmSession(slackApi);
    rtmSession.open(accessToken);
  }

  public static void main(String... args) throws Exception {

          .setResponseCode(400)
          .setBody("code exchange failed: " + e.getMessage());
    }

    synchronized (this) {
      listeners.remove(state);
    }

    // Success!
    return new MockResponse()
        .setResponseCode(302)
        .addHeader("Location", "https://twitter.com/CuteEmergency/status/789457462864863232");
  }

  public interface Listener {