diff --git a/test/classes/navigation/PMA_Node_Column_test.php b/test/classes/navigation/PMA_Node_Column_test.php
index 625815b5b2..2032f6834c 100644
--- a/test/classes/navigation/PMA_Node_Column_test.php
+++ b/test/classes/navigation/PMA_Node_Column_test.php
@@ -56,6 +56,7 @@ class Node_Column_Test extends PHPUnit_Framework_TestCase
         $dbNode->addChild($tableNode);
         $colNode = PMA_NodeFactory::getInstance('Node_Column', 'colName', Node::OBJECT);
         $tableNode->addChild($colNode);
+        $origDbi = $GLOBALS['dbi'];
 
         $dbi = $this->getMockBuilder('PMA_DatabaseInterface')
             ->disableOriginalConstructor()
@@ -65,6 +66,8 @@ class Node_Column_Test extends PHPUnit_Framework_TestCase
             ->with($query);
         $GLOBALS['dbi'] = $dbi;
         $colNode->getComment();
+
+        $GLOBALS['dbi'] = $origDbi;
     }
 }
 ?>
diff --git a/test/classes/navigation/PMA_Node_test.php b/test/classes/navigation/PMA_Node_test.php
index ac632c3fa1..5d5daeefb4 100644
--- a/test/classes/navigation/PMA_Node_test.php
+++ b/test/classes/navigation/PMA_Node_test.php
@@ -306,6 +306,7 @@ class Node_Test extends PHPUnit_Framework_TestCase
         // It would have been better to mock _getWhereClause method
         // but stangely, mocking private methods is not supported in PHPUnit
         $node = PMA_NodeFactory::getInstance();
+        $origDbi = $GLOBALS['dbi'];
 
         $dbi = $this->getMockBuilder('PMA_DatabaseInterface')
             ->disableOriginalConstructor()
@@ -315,6 +316,8 @@ class Node_Test extends PHPUnit_Framework_TestCase
             ->with($expectedSql);
         $GLOBALS['dbi'] = $dbi;
         $node->getData('', $pos);
+
+        $GLOBALS['dbi'] = $origDbi;
     }
 
     /**
@@ -343,6 +346,7 @@ class Node_Test extends PHPUnit_Framework_TestCase
         // It would have been better to mock _getWhereClause method
         // but stangely, mocking private methods is not supported in PHPUnit
         $node = PMA_NodeFactory::getInstance();
+        $origDbi = $GLOBALS['dbi'];
 
         $dbi = $this->getMockBuilder('PMA_DatabaseInterface')
             ->disableOriginalConstructor()
@@ -352,6 +356,8 @@ class Node_Test extends PHPUnit_Framework_TestCase
             ->with($query);
         $GLOBALS['dbi'] = $dbi;
         $node->getPresence();
+
+        $GLOBALS['dbi'] = $origDbi;
     }
 
     /**
@@ -374,6 +380,7 @@ class Node_Test extends PHPUnit_Framework_TestCase
         $GLOBALS['cfg']['Servers'][0]['DisableIS'] = true;
 
         $node = PMA_NodeFactory::getInstance();
+        $origDbi = $GLOBALS['dbi'];
 
         // test with no search clause
         $dbi = $this->getMockBuilder('PMA_DatabaseInterface')
@@ -394,6 +401,8 @@ class Node_Test extends PHPUnit_Framework_TestCase
             ->with("SHOW DATABASES LIKE '%dbname%' ");
         $GLOBALS['dbi'] = $dbi;
         $node->getPresence('', 'dbname');
+
+        $GLOBALS['dbi'] = $origDbi;
     }
 
     public function testComment()