.htaccess allows you to specify how your server should respond to a given request. It does not have the ability to tell the users browser to show a different address.
http is a stateless protocol, which means that each request should have all the information you need to respond. If the user's address bar shows "abc.mysite.com", then that is what their browser will request from your server. Given that request, your .htaccess has no way to know that they want a certain id or view.
If they had the address abc.mysite.com/com_test/test/1 in the address bar, then you can use that because it has all the information you need to complete the request. You can create a .htaccess rule to route that to "mysite.com?index.php&option=com_test&view=test&id=1". But you can't do that with just the base url - the information just isn't there.
What you can do is use an ajax request to get the information without a page reload, and therefore without changing the url shown.