Step by Step App Debugger Checksum === 1 Unit Test to rule them all?

Step by Step App Debugger Checksum === 1 Unit Test to rule them all?

From the standpoint of a debugger, there is a global state, which sums up
the entire global context of an applications run state.
This state, I assume, could be assessed or accumulated into in a single
file, which itself could be summarized as single checksum, at any point in
time.
Therefore, a debugger based step by step global checksum could be used to
easily find where a program differs from where it used to operate, in
comparison to where it currently operates, given of course the exact same
inputs.
Does this exist in any development environment, or as a library/RFC that
could be used cross language?
In my particular case, I'm porting an app from VB6 to C#, and am
constantly walking the code in both environments to find where my port is
broken. It seems to me that if there were some library that existed that
could, in debug mode, store the above detailed checksum, on a step by step
basis, then I could easily find where my port was broken without having to
step through line by line by line.
Thanks for any suggestions!