Jetpack_Client_Server::get_token PHP Method

    function get_token($data)
    {
        $role = Jetpack::translate_current_user_to_role();
        if (!$role) {
            return new Jetpack_Error('role', __('An administrator for this blog must set up the Jetpack connection.', 'jetpack'));
        }
        $client_secret = Jetpack_Data::get_access_token();
        if (!$client_secret) {
            return new Jetpack_Error('client_secret', __('You need to register your Jetpack before connecting it.', 'jetpack'));
        }
        $redirect = isset($data['redirect']) ? esc_url_raw((string) $data['redirect']) : '';
        $redirect_uri = 'calypso' === $data['auth_type'] ? $data['redirect_uri'] : add_query_arg(array('action' => 'authorize', '_wpnonce' => wp_create_nonce("jetpack-authorize_{$role}_{$redirect}"), 'redirect' => $redirect ? urlencode($redirect) : false), menu_page_url('jetpack', false));
        $body = array('client_id' => Jetpack_Options::get_option('id'), 'client_secret' => $client_secret->secret, 'grant_type' => 'authorization_code', 'code' => $data['code'], 'redirect_uri' => $redirect_uri);
        $args = array('method' => 'POST', 'body' => $body, 'headers' => array('Accept' => 'application/json'));
        $response = Jetpack_Client::_wp_remote_request(Jetpack::fix_url_for_bad_hosts(Jetpack::api_url('token')), $args);
        if (is_wp_error($response)) {
            return new Jetpack_Error('token_http_request_failed', $response->get_error_message());
        }
        $code = wp_remote_retrieve_response_code($response);
        $entity = wp_remote_retrieve_body($response);
        if ($entity) {
            $json = json_decode($entity);
        } else {
            $json = false;
        }
        if (200 != $code || !empty($json->error)) {
            if (empty($json->error)) {
                return new Jetpack_Error('unknown', '', $code);
            }
            $error_description = isset($json->error_description) ? sprintf(__('Error Details: %s', 'jetpack'), (string) $json->error_description) : '';
            return new Jetpack_Error((string) $json->error, $error_description, $code);
        }
        if (empty($json->access_token) || !is_scalar($json->access_token)) {
            return new Jetpack_Error('access_token', '', $code);
        }
        if (empty($json->token_type) || 'X_JETPACK' != strtoupper($json->token_type)) {
            return new Jetpack_Error('token_type', '', $code);
        }
        if (empty($json->scope)) {
            return new Jetpack_Error('scope', 'No Scope', $code);
        }
        @(list($role, $hmac) = explode(':', $json->scope));
        if (empty($role) || empty($hmac)) {
            return new Jetpack_Error('scope', 'Malformed Scope', $code);
        }
        if (Jetpack::sign_role($role) !== $json->scope) {
            return new Jetpack_Error('scope', 'Invalid Scope', $code);
        }
        if (!($cap = Jetpack::translate_role_to_cap($role))) {
            return new Jetpack_Error('scope', 'No Cap', $code);
        }
        if (!current_user_can($cap)) {
            return new Jetpack_Error('scope', 'current_user_cannot', $code);
        }
        /**
         * Fires after user has successfully received an auth token.
         *
         * @since 3.9.0
         */
        do_action('jetpack_user_authorized');
        return (string) $json->access_token;
    }

 /**
  * @author scotchfield
  * @runInSeparateProcess
  * @covers Jetpack_Client_Server::get_token
  * @since 3.2
  */
 public function test_jetpack_client_server_get_token()
 {
     $author_id = $this->factory->user->create(array('role' => 'administrator'));
     wp_set_current_user($author_id);
     $client_server = new Jetpack_Client_Server();
     $return_value = $client_server->get_token('test');
     $this->assertInstanceOf('Jetpack_Error', $return_value);
 }