diff --git a/core/modules/block/src/Tests/BlockCacheTest.php b/core/modules/block/src/Tests/BlockCacheTest.php
index f6a6ae9..89c55f3 100644
--- a/core/modules/block/src/Tests/BlockCacheTest.php
+++ b/core/modules/block/src/Tests/BlockCacheTest.php
@@ -24,8 +24,25 @@ class BlockCacheTest extends WebTestBase {
    */
   public static $modules = array('block', 'block_test', 'test_page_test');
 
+  /**
+   * A user with permission to create and edit books and to administer blocks.
+   *
+   * @var object
+   */
   protected $adminUser;
+
+  /**
+   * An authenticated user to test block caching.
+   *
+   * @var object
+   */
   protected $normalUser;
+
+  /**
+   * Another authenticated user to test block caching.
+   *
+   * @var object
+   */
   protected $normalUserAlt;
 
   /**