I'm a cashier and I work with this girl who just looooooves shit testing me. Overall pleasant girl we actually get along pretty well. Like 99% of the time except when she gives the "serious shit tests" I'll talk about later

Usually its fun light hearted ribbing to which I don't really give any thought. I'll smile and laugh or shoot something witty back. But twice she has given me particularly NASTY shit tests.

The first time I was cleaning the shopping baskets and she was saying that I'm using way too much disinfectant and wasting it. I said no I'm not. She took the baskets from me, gave them like a single mist and said very seriously with angry tonality and said "This is all you need, you're done" and took the baskets and like stormed off. It triggered like this fight or flight in me, and I chose to fight. I didn't lose control and honestly I had this like pang of anxiety in my gut but I said fuck it let it rip. I didn't yell but pretty damn seriously I went up to her and said "Hey would you feel comfortable licking that shopping basket, because if you don't then there is probably still fucking covid on it. I don't care how much disinfectant I use and neither should you its out of the managers expenses". She just smiled almost a little giggle. I don't know, I guess I failed this test? I presume she was smiling / giggling because she saw it got to me?

The second time I finished cleaning my till at the end of the night, she got in my face and with a really angry kind of expression was like commanding / barking at me that I didn't do a good enough job (tbh she was right) and "Go back and clean it properly now!". Mind you she is not the supervisor and its not her job to monitor my job. Again it triggered this fight or flight in me, pretty damn hard too. This time though I guess I just turned it into a joke. I said "Fine, you're right, but before I go clean it better I want you to finish yelling at me, it gets me excited". And she started laughing.

I have two questions. One is how did I deal with these shit tests, I think the second one I handled pretty well but the first one. Was "fighting back" a failure? Was it weak because it showed she got to me or strength because I stood up for something. The second one is how do I get them to stop.

Would it be a good idea to say something like "Hey I don't mind light hearted jabs and shit those are fun, or you can even "pretend drill sergeant" if you want with a smile that can be fun too, but this angry demeanor is giving me negative feelings. We can go back to our fun vibe now but I'm just saying be careful or I'll have to talk to the manager if it keeps happening."