diff --git a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
index e2324c7..ab1c79d 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
@@ -70,8 +70,13 @@ protected function assertElementNotVisible($css_selector, $message = '') {
    *   JS condition to wait until it becomes TRUE.
    * @param int $timeout
    *   (Optional) Timeout in milliseconds, defaults to 1000.
+   * @param string $message
+   *   (optional) A message to display with the assertion. If left blank, a
+   *   default message will be displayed.
    *
    * @throws \PHPUnit_Framework_AssertionFailedError
+   *
+   * @see \Behat\Mink\Driver\DriverInterface::evaluateScript()
    */
   protected function assertJsCondition($condition, $timeout = 1000, $message = '') {
     $message = $message ?: "Javascript condition met:\n" . $condition;