I agree that "tested" aligns better with the sinlessness and deity of Christ, and that the whole ordeal was a demonstration to the devil that Christ is sinless. I agree that God cannot be tempted. I agree with James' explanation of sin....
However, I don't accept it as exhaustive because it doesn't explain Adam's sin. It would require that Adam had sin in his heart
before eating the fruit. There is no Scripture supporting that conclusion. God didn't ask Adam if he
desired the forbidden fruit, but whether he
ate it, and the consequences are declared upon his admission that he
ate it.
Further, I struggle to accept that "tested" is the right translation when we consider the words "as we are, yet without sin". If it were directly in regard to any regular human, we would have no trouble interpreting it as "tempted". There seems to be some circular reasoning involved in selecting "tested". We aren't "tested"; we are
tempted, so "as we are" strongly indicates
significant similarity
. Being "tempted" doesn't indicate the degree of likelihood of failure. In Jesus' case, we might quantify it as the smallest possible positive number, but still not 'zero'.
As I (think I) have said previously, this makes perfect sense if Jesus, in His humanity, was actually
tempted and actually able to fail the "test". I believe that His "nature" was as that of Adam prior to eating the fruit: innocent of all sin but capable of choosing.
I also don't believe this is a salvific issue, though from some responses I suspect others do.