diff --git a/tests/Test.php b/tests/Test.php
index b5ffc42df..be8762cdb 100644
--- a/tests/Test.php
+++ b/tests/Test.php
@@ -21,7 +21,7 @@ class GroupTest
     {
     	$messages = array();
         foreach($this->_testCases as $testCase) {
-            $messages += $testCase->getMessages();
+            $messages = array_merge($messages, $testCase->getMessages());
         }
         return $messages;
     }