I think it's either tSQLt or the MS Unit Testing Framework.

tSQLt is all in T-SQL, it's easier to write tests for db people, and it includes more scaffolding that's DB specific.

the MS framework is in C#, but more integrated into VS. You do more work coding tests, but you'll build patterns quickly. If you're entirely in VS/TFS, you might find it easier to integrate into CI, but it's debatable.

Both work well.