diff -u b/includes/common.inc b/includes/common.inc
--- b/includes/common.inc
+++ b/includes/common.inc
@@ -4218,7 +4218,7 @@
     if (!variable_get('javascript_always_use_jquery', TRUE)) {
       $need_jquery = FALSE;
       foreach ($javascript as $key => $item) {
-        if ($item['type'] != 'setting' && !isset($item['need_jquery']) || $item['need_jquery']) {
+        if ($item['type'] != 'setting' && (!isset($item['need_jquery']) || $item['need_jquery'])) {
           $need_jquery = TRUE;
           break;
         }
diff -u b/modules/simpletest/tests/common.test b/modules/simpletest/tests/common.test
--- b/modules/simpletest/tests/common.test
+++ b/modules/simpletest/tests/common.test
@@ -1344,12 +1344,12 @@
    * Test adding a JavaScript file with a different weight.
    */
   function testDifferentWeight() {
-    drupal_add_js('core/misc/collapse.js', array('weight' => 2));
-    drupal_add_js('core/misc/tabledrag.js', array('weight' => 999));
+    drupal_add_js('misc/collapse.js', array('weight' => 2));
+    drupal_add_js('misc/tabledrag.js', array('weight' => 999));
     drupal_add_js_page_defaults();
     $javascript = drupal_add_js();
-    $this->assertEqual($javascript['core/misc/collapse.js']['weight'], 2.001, t('Adding a JavaScript file with a different weight caches the given weight.'));
-    $this->assertEqual($javascript['core/misc/tabledrag.js']['weight'], 999.002, t('Adding a JavaScript file with a different weight caches the given weight.'));
+    $this->assertEqual($javascript['misc/collapse.js']['weight'], 2.001, t('Adding a JavaScript file with a different weight caches the given weight.'));
+    $this->assertEqual($javascript['misc/tabledrag.js']['weight'], 999.002, t('Adding a JavaScript file with a different weight caches the given weight.'));
   }
 
   /**