do we set the php timezone explicitly or is this just accidentally true for you and me as we live in that timezone?

the tests run through for me with jackalope-jackrabbit, and all looks sane so i suggest we merge this.

we might at some point extend the comparison to allow some marging. for example when testing events, we should not compare exact timestamps but allow for a couple of seconds diverging timestamps. but that is totally out of scope here.