URL redirection with retaining the original on browsers

"user would try to access www.test.com but it needs to be redirected to www.test.abc.com"

The elephant in the room is whether you actually own test.com.

After that, you don't need rewrites or redirection, you simply need to point the DNS record to the same IP as www.test.abc.com and tell the web servers that serve www.test.abc.com to serve the same page(s) when the HTTP "Host:" header contains www.test.com.

Of course if your webpages contain hard links (rather than relative ones) you'll need to do some STREAM changes to alter URLs-on-the-fly, per the post from Minn.