Seems like it would slow the process
I'm not exactly a programmer, but I do create interfaces between medical systems. As I build my interface, I create the interface in sections, each section being devoted to a different task, then I use my stored data to test that section. When that's done, I move on, and test the next section. When all sections are tested, then I test the translation as whole. If I get the result I expect, then I release it for validation testing.
Using this method, I can whip out a fairly complex translation in a couple of hours, and the validation process takes less time. If I have to create my translation, then move from my keyboard for someone else to test, that will slow things down. I won't have a clear understanding of what went wrong with the test. Maybe I didn't compile, or I had a variable mis-identified, or something else that's easy. It seems that it would defeat the purpose to have someone else see the error and then try to tell me what the error was so I could try to figure out how to fix it.
I'm all for collaboration as we've solved some pretty big problems, but it seems to me the share desk and computer is a waste of resources. Am I going to just sit there and pick my nose, or take a nap while the other person is testing?