Anyone remember a swimming pool test?

I am still struggling to remember a lot and I wanted to know if anyone was ever taken on a suprise field trip to an in ground indoor pool because I was and I want to hear your experiences.

It was me and a select few kids who went. Maybe 10 - 15 kids from different classes. It was probably 2nd grade for me. I remember being weirded out by being with kids from other 2nd grade classes that I didn't usually see.

It was in a building in Philadelphia with an indoor basement underground pool. I remember we all changed into uniform navy blue swim suites that were 1 piece, the boys too.

Then they tested us one at a time in the pool. And I remember being so uncomfortable.

Then my memory goes blank.

Anyone remember anything like this? I asked my mom about it and she said she never saw or signed a permission slip to go swimming at a pool or to leave the school.