I have used annotation as markers for my own pointcuts at method level. I would recommend declaring methods as point cut expressions instead as it is easy to forget to
annotate methods while developing.
As was stated @Test is not a Spring annotation so if you were searching the reference guide for just this you will not find it. However a lot of the annotations are documented in the reference guide. In addition to that and the additional resources others have posted Gordon Dickens did a lot of work identifying Annotations for the Spring projects and more (aspectj, hibernate, junit, mockito etc)