Finding useless unit tests with PIT

There is nothing currently built in to pitest, but the data you need to detect useless (in terms of detecting faults) tests is there.

The XML report outputs the killing test for each mutation (often at the level of a test method). Any test that does not kill a mutation could be removed without affecting the mutation score.

Of course tests that don't kill a mutation may still be valuable for other reasons e.g. describing what a unit does.

The extreme case shown in your example would however be more efficiently detected by static analysis - the test clearly doesn't exercise any code so can't possibly detect faults in it