diff -u b/core/lib/Drupal/Component/Utility/Random.php b/core/lib/Drupal/Component/Utility/Random.php
--- b/core/lib/Drupal/Component/Utility/Random.php
+++ b/core/lib/Drupal/Component/Utility/Random.php
@@ -46,7 +46,8 @@
    * @param int $length
    *   Length of random string to generate.
    * @param bool $unique
-   *   Ensure that the random string returned is unique.
+   *   (optional) If TRUE ensures that the random string returned is unique.
+   *   Defaults to FALSE.
    *
    * @return string
    *   Randomly generated string.
@@ -86,7 +87,8 @@
    * @param int $length
    *   Length of random string to generate.
    * @param bool $unique
-   *   Ensure that the random name returned is unique.
+   *   (optional) If TRUE ensures that the random string returned is unique.
+   *   Defaults to FALSE.
    *
    * @return string
    *   Randomly generated string.
diff -u b/core/tests/Drupal/Tests/Component/Utility/RandomTest.php b/core/tests/Drupal/Tests/Component/Utility/RandomTest.php
--- b/core/tests/Drupal/Tests/Component/Utility/RandomTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/RandomTest.php
@@ -31,7 +31,7 @@
    *
    * @see \Drupal\Component\Utility\Random::name()
    */
-  function testRandomStringUniqueness() {
+  public function testRandomStringUniqueness() {
     $strings = array();
     for ($i = 0; $i <= 50; $i++) {
       $str = Random::string(1, TRUE);
@@ -45,7 +45,7 @@
    *
    * @see \Drupal\Component\Utility\Random::string()
    */
-  function testRandomNamesUniqueness() {
+  public function testRandomNamesUniqueness() {
     $names = array();
     for ($i = 0; $i <= 10; $i++) {
       $str = Random::name(1, TRUE);