We believe that integration testing should be no more complex than writing a basic unit test. We created Arquillian to realize that goal. One of the major complaints we've heard about Seam 2 testing (i.e., SeamTest) was, not that it isn't possible, but that it isn't flexible and it's difficult to setup. We wanted to correct those shortcomings with Arquillian.
Testing needs vary greatly, which is why it's so vital that, with Arquillian (and ShrinkWrap), we have decomposed the problem into its essential elements. The result is a completely flexible and portable integration testing framework.