Sorry but I can't agree with you there. It's true that the Constitution forbids the government from establishing a religious test. But individuals are entirely free to vote on any basis they want, certainly including the religion of the candidate.
People make the same mistake when it comes to the presumption of innocence. That applies to the judicial system. It surely doesn't apply to individuals.
For example, if Joseph Smith, the guy recently convicted of Carlie Brucia, and whose abduction of her was caught on tape, came and applied for a daycare job with you, would you be violating the spirit of the Constitution by failing to apply the presumption of innocence? Of course not. Same thing as to religious tests.
Well, in that case, there would be no presumption of innocence since he was already convicted.