Cat UTI test - how to ensure she does not pee before test

Hey, so my cat has a UTI test first thing tomorrow morning. The vet said it’s best if she has a full bladder so remove litter box night before her test. She is normally good about using the litter box but if there isn’t one available I’m afraid she will use the bathroom on the carpet anyway if she feels like she has no other option.

So I don’t want to remove the box before I go to bed bc I think that would make it worse with those extra few hours she’d have to hold it in, I think I will set an alarm and get up at like 3 or 4 and do it then and then stay up so I can keep an eye on her. I think that’s my best bet to ensure she doesn’t use the bathroom then.

She used to do that every so often (if she felt litter box was too full) on carpet, and it would always be in the middle of the night when everyone is sleeping bc she knows shes not supposed to. She has not done that in a long time and been good though. But once she does it once, that’s when she tends to do it again in the same spot soon after, so I want to do everything I can to avoid this, plus ensure her bladder is full for her appointment.

Kind of a long shot I know, but does anyone have any tips or ideas to ensure she keeps her bladder full? I feel so bad doing this bc I know it will stress her out! I don’t think she has a UTI either, it’s kind of a precautionary thing to ensure her medication is working properly