Note that the warnings are new, as we only recently started testing the coverage of constructors. Therefore, all fixes have to do with testing of constructors.
Here the constructors were not tested, and not present in the source code either. Hence, there is the default public constructor. However, since these classes are not supposed to be instantiated, I added private constructors making exactly that impossible. Private constructors do not have to be tested, and hence fix these warnings.
The next unit test tests the exact same. This remove unit test is a left over from a past version where a constructor existed that took an Object as parameter.