diff --git a/system/libraries/Unit_test.php b/system/libraries/Unit_test.php
index de8c9bb..7a67c72 100644
--- a/system/libraries/Unit_test.php
+++ b/system/libraries/Unit_test.php
@@ -356,12 +356,12 @@
 	 */
 	protected function _parse_template()
 	{
-		if ( ! is_null($this->_template_rows))
+		if ($this->_template_rows !== NULL)
 		{
 			return;
 		}
 
-		if (is_null($this->_template) OR ! preg_match('/\{rows\}(.*?)\{\/rows\}/si', $this->_template, $match))
+		if ($this->_template === NULL OR ! preg_match('/\{rows\}(.*?)\{\/rows\}/si', $this->_template, $match))
 		{
 			$this->_default_template();
 			return;