i often see set-values like those in the marked lines, either directly set on some objects or on mock-objects. Later, these values are checked by looking at fields or getters. No problem, so far.
However, using always the same value does not protect against copies or ‘twisted’ assignments.
I would propose to use slightly varying values, like 10.0, 11.0, 12.0 and check those at the other end.