Index: tests/db.php
===================================================================
--- tests/db.php	(revision 1337)
+++ tests/db.php	(working copy)
@@ -79,7 +79,9 @@
 		foreach ( $current_locales as $locale_setting ) {
 			if ( false !== strpos( $locale_setting, '=' ) ) {
 				list( $category, $locale ) = explode( '=', $locale_setting );
-				setlocale( constant( $category ), $locale );
+				if( defined( $category ) ) {
+					setlocale( constant( $category ), $locale );
+				}
 			} else {
 				setlocale( LC_ALL, $locale_setting );
 			}