Probably the best strategy for these tests is to use a Mock Objects type framework.
These tests will exercise the interactions with the container. (Cactus)
These unit tests will let you test the returned values from your server code. This is for example HttpUnit (Note that HttpUnit also performs standard functional testing - as opposed to functional unit testing -, which let you test full use cases - a login use case for example, which is comprised of several requests/responses).