It comes down to placing the world's largest bet on a highly complex theory - with no experimentation to test the theory first.

Who ever said not to test? Testing intelligent machines may have its risks - but you can't not test! That would be a very silly thing to do.

I suppose there are things like this:

I intend to plunge into the decision theory of self-modifying decision systems and never look back. (And finish the decision theory and implement it and run the AI, at which point, if all goes well, we Win.)

...that don't explicitly mention testing. Perhaps Holden is extrapolating from such material. Anyway, not testing would obviously be very stupid. See if you can find anyone who actually advocates it.