Please see our help and tips page for testing your account here, which covers how to check various aspects of your account:
The best first test you can do is to make one live purchase from yourself. That will allow you to download your own file and make sure it looks right, let you see everything that your buyers will see during the purchase, and most importantly it will confirm that your payment processor is communicating with your E-junkie account properly.
After that other tests can be done to just send yourself a free download link to test your file and see your product emails, etc.
If you run into a problem when testing please send us an email to firstname.lastname@example.org or post here with all the details you can provide and we'll be glad to help direct you further.