Remove a few empty 'mock' classes
diff --git a/tests/mocks/database/db/driver.php b/tests/mocks/database/db/driver.php
index 2cf54b9..86f7efd 100644
--- a/tests/mocks/database/db/driver.php
+++ b/tests/mocks/database/db/driver.php
@@ -37,4 +37,4 @@
 
 }
 
-class CI_DB extends Mock_Database_DB_QueryBuilder {}
\ No newline at end of file
+class CI_DB extends CI_DB_query_builder {}
\ No newline at end of file