import posts plugin; exact blog copy

I want to know if it’s possible to have a main website (blog), and then to have another website/blog that I can use to test plugins and themes. My main website is kenacubed.com. I have a test site at kena3.com. I want to have an exact copy of the main site so that I can test various WP features before I go live on the main site.

So, I exported the the posts and everything else via the WP export command in the Tools menu of the WP admin page. Then, I imported that file into the test site via a WP import plugin. It wound up putting that file in the media folder, but I wanted all the posts to be live on the test site automatically. Is it possible to do what I want to do?