if ( !function_exists( 'xdiff_string_rabdiff' ) ) {
$this->markTestSkipped( 'The version of xdiff extension is lower than 1.5.0' );
if ( !function_exists( 'xdiff_string_rabdiff' ) ) {
$this->markTestSkipped( 'The version of xdiff extension is lower than 1.5.0' );