actually I think you need to put ALL of these (TestDST) tests into the ``TestBase`` object so it will run them for each frequency (you may want to exclude certain of the estoeric ones and/or ones which it does affect); alternatively you can make ``TestDST`` inherit from ``object`` and then just include that class in the offsets that matter.

The reason I think you need to do this is you are adding logic to ``apply``, but a lot of the offsets override ``apply`` and might not call your code. (so its possible we need a common method that ALL offsets call or something).