diff --git a/tests/mocks/core/utf8.php b/tests/mocks/core/utf8.php
index c8214a6..3a6282e 100644
--- a/tests/mocks/core/utf8.php
+++ b/tests/mocks/core/utf8.php
@@ -5,12 +5,15 @@
 	/**
 	 * We need to define UTF8_ENABLED the same way that
 	 * CI_Utf8 constructor does.
-	 *
-	 * @covers CI_Utf8::__construct()
 	 */
 	public function __construct()
 	{
-		defined('UTF8_ENABLED') OR define('UTF8_ENABLED', TRUE);
+		if (defined('UTF8_ENABLED'))
+		{
+			return;
+		}
+
+		parent::__construct();
 	}
 
 }
\ No newline at end of file