MIL refusing to get covid test

My husband and I are having our gender reveal next week and my MIL told us her sister had covid and she has been around her sister A LOT this week. My husband kindly asked her to get a covid test before attending the party because we don’t want anyone getting sick. She flipped and said she’s not sick so she won’t get it. I told her if she doesn’t get a negative test she won’t be allowed to come. She told us we’re ridiculous, scared, and need to stop falling for this covid stuff (but she had covid last year when i got it). We told her we aren’t scared of covid, we would just like everyone to be safe while attending our event. She went off on us and said she’s not getting one and she’s tired of our demands when it comes to events around our child. I told her they are boundaries not demands and if she didn’t want to get the test she can’t come. Some people have told me i should just have her wear a mask and stay 6 feet away from everyone but she can still spread covid. I just want everyone to be safe.