diff --git a/tests/mocks/ci_testconfig.php b/tests/mocks/ci_testconfig.php
index f80adc5..afdb710 100644
--- a/tests/mocks/ci_testconfig.php
+++ b/tests/mocks/ci_testconfig.php
@@ -1,20 +1,20 @@
 <?php
 
-class CI_TestConfig {
+class CI_TestConfig extends CI_Config {
 
 	public $config = array();
 	public $_config_paths = array(APPPATH);
 	public $loaded = array();
 
-	public function item($key)
+	public function item($key, $index = '')
 	{
 		return isset($this->config[$key]) ? $this->config[$key] : FALSE;
 	}
 
-	public function load($file, $arg2 = FALSE, $arg3 = FALSE)
+	public function load($file = '', $use_sections = FALSE, $fail_gracefully = FALSE)
 	{
 		$this->loaded[] = $file;
 		return TRUE;
 	}
 
-}
\ No newline at end of file
+}