It's not just a matter of uploading data to the machine but that the machine is capable of understanding and utilising that data.
What is the mind of a person? To me it is both the memories (the data) but also the pathways of decision-making and activity - both conscious and subconscious.
The data element could be uploaded to a machine with little issue, but then all you'd have is a library of information. But this is no more a person than a biography is the person it is about.
To upload a mind is to copy all the ways in which the person responds, acts, as well as those memories.
How would you know that a mind has been uploaded to a computer? For a test, if you leave out certain information about the person's life in the upload, but the person still is able to recite that information after the upload, then this is proof that they were uploaded. DE
If the information left out could only be known from direct experience and not inferred from other data then if you leave out that information the machine has zero chance of recalling it. To the uploaded mind it will simply not be part of its memories.
This is true of humans as well. If we physically remove part of our memory then, yes, our biological brain may try to fill in some gaps (but can get it very wrong in doing so) or more likely we just end up with a gap.
It would be impossible for data enters into a computer to ever give you more information out than you put in.
At best it can infer new information that did logically exist implicitly within the data uploaded.
So the way I see it your test would not work. Other than in science fiction, of course.