Database import redirects URL

To test that my backup plugin is working ok I imported a backup of my live journal database into a test journal database. I have may main journal at journal.[myurl].org, and the test is at test.[myurl].org. Now when I go to test.[myurl] the page automatically redirects to journal.[myurl], same for the wp_admin pages etc so I’m completely locked out of it. Fair enough I can delete the test database and get back in, I’m just curious as to the mechanism that causes this to happen?