Hm.. just thought about it, adding a new property will actually not be covered, as long as it is not altered by clear.

`clear` as it is also very plain to read. I would suggest to reduce the testcase to call clear on a `ModelCriteria` and check it is "equal" to a new one, which is the purpose of clear, this will verify it's at least reset correctly and clear does not set up a different state.