1. A method for automatically verifying validity of application of a refinement rule, the method comprising: using a processor, calculating a set of currently calculated values, each currently calculated value characterizing an element in a hierarchy of elements after a modification of a hardware emulation code, wherein an element at each level of the hierarchy is more broadly applicable than an element at a lower level, and storing the currently calculated values in a storage device, at least one of the elements including one or more unnamed entities; using the processor, comparing a currently calculated value of the set for a first element at a highest level of the hierarchy with a previously calculated value that is stored in the storage device and that characterized the first element at a previous time when a refinement rule that specifies an unnamed entity of said one or more unnamed entities that is excluded from test coverage was defined; determining that application of the refinement rule remains valid if the currently calculated value that characterizes the first element is the same as the previously calculated value that characterized the first element at the previous time; and if the currently calculated value that characterizes the first element is different from the previously calculated value that characterized the first element at the previous time: using the processor, comparing each currently calculated value that characterizes a lower level element at a lower level of the hierarchy with a corresponding previously calculated value that is stored in the storage device and that characterized that lower level element at the previous time to identify a change in an element of the lower level elements; and using the processor, determining whether the identified change, invalidates application of the refinement rule to that unnamed entity.