Would you be happy for someone if they're promotion was based solely on their race?

If this is true, it's clearly discriminatory, but not racist...that term is way overused. But this is an issue that the company will eventually have to deal with one way or the other. In the meantime, there's nothing written in stone that says you have to be happy for her, but until she has the chance to prove/disprove her capabilities, and if it is true that she had nothing to do with this...it would be absolutely wrong to punish HER for it...let alone quit your job over it. And as for resenting her, it would be wise to remember...for those who decide to stay with the company...that, like it or not, she will be in a position of authority. I would probably resent the company and it's policies more than I would her.