EDIT: after reading through the linked docs a bit more, I have to say that they are quite confusing. I'm not sure what the difference is between Ratifier, Kulvert, and SQL Simulator. I'd recommend finding a potential user and watching them go through the setup/install process and see where they have questions.
If anyone is interested in something similar for postgres, I recently released https://github.com/peterldowns/pgtestdb. It uses template databases and advisory locks to give each test its own unique database with a near-zero marginal cost for each additional test. Combined with a ram/tmpfs-backed postgres server that is tuned for performance, it goes extremely fast.
Currently just for golang but I'm planning on releasing equivalent-capability libraries for Python and Typescript over the next month. If anyone has any thoughts/comments/feedback/suggestions I'd be extremely thankful.