private String retrieveAuthCode(OkHttpClient client) throws IOException {
    Request.Builder builder = new Request.Builder().url(authRetrievalUrl);

    try (Response authResponse = client.newCall(builder.build()).execute()) {
      ResponseBody authBody = authResponse.body();
      if (authBody == null) {
        throw new AssertionError("AUTH ERROR: " + authResponse.code() + ":" + "<empty body>");
      }
      String authCode = new String(authBody.bytes());

      // System.out.println("AUTH: " + authResponse.code() + ":" + authCode);

      return authCode;
    }
  }
Performs an OAuth flow using the general AuthDataGenerator, returning a token.

@return the token
extensions/auth/portability-auth-harness-microsoft/src/main/java/org/datatransferproject/auth/microsoft/harness/AuthTestDriver.java