PHP Rewriting Url Not working

PHP Rewriting Url Not working

Here i'm facing problem with rewriting url. I'm using php(ver. above 5.0)
with xampp.

My current url is
Original url : /localhost/test/signup.php
redirect Url : /localhost/test/signup/
I wrote rewrite rules in htdocs
RewriteEngine On
RewriteBase /test/
RewriteRule ^signup/$ signup.php
it's not working. I was changed httpd.conf setting also. but no use.
any one can help me, please....
Thank you.