It is possible, albeit counterproductive, to write a unit test which executes some code, and asserts truth. This is a deliberately extreme, and simplified example – I’m sure most people have come across tests which execute code without actually making use of it.
Are there any code coverage tools which assess whether code covered is actually used as part of the assertions of the test?
What you want in essence is to compute the intersection between the covered code, and a backward code slice (minus the unit test itself) on the assertion in the covered test.
If that intersection is empty, the assertion doesn’t test any part of the application.
Most code coverage tools don’t compute slices, so I’d guess the answer to your question is “no”.