Can you explain what you mean by "verify" the instruction ?
Do you want to prove that it works the way that Rockwell Automation says it works ?
If so, what makes you think that the instruction is not working as it is designed to work ?
In my experience the CPS instruction works well when you are trying to prevent updates of arrays of data from an I/O connection from occurring midway through a COP instruction.
So to verify the CPS, you would have to create a connection that brings in a large array of data that changes every connection cycle, then set up COP and CPS instructions in the same program, then write some detection logic to see when the COP fails to preserve data integrity but the CPS preserves it.
The timing of I/O connection RPI expiration is not synchronized to program execution, so it could be difficult to intentionally make them interfere.