diff --git a/lib/phpunit/classes/util.php b/lib/phpunit/classes/util.php
index 1fa42d4a46c..4b10ce061f0 100644
--- a/lib/phpunit/classes/util.php
+++ b/lib/phpunit/classes/util.php
@@ -655,6 +655,9 @@ class phpunit_util {
         if (class_exists('available_update_checker')) {
             available_update_checker::reset_caches(true);
         }
+        if (class_exists('available_update_deployer')) {
+            available_update_deployer::reset_caches(true);
+        }
 
         // purge dataroot directory
         self::reset_dataroot();
diff --git a/lib/pluginlib.php b/lib/pluginlib.php
index 4d69ffe60ae..e3878476635 100644
--- a/lib/pluginlib.php
+++ b/lib/pluginlib.php
@@ -1469,6 +1469,17 @@ class available_update_deployer {
         return self::$singletoninstance;
     }
 
+    /**
+     * Reset caches used by this script
+     *
+     * @param bool $phpunitreset is this called as a part of PHPUnit reset?
+     */
+    public static function reset_caches($phpunitreset = false) {
+        if ($phpunitreset) {
+            self::$singletoninstance = null;
+        }
+    }
+
     /**
      * Is automatic deployment enabled?
      *