There's less functionality to test if you've described your business constraints in concise type declarations. The type contract is short enough to be validated

There's less functionality to test if you've described your business constraints in concise type declarations. The type contract is short enough to be validated at a glance. I'm having a hard time imagining a situation in which static typing could replace even one single test, let alone it being a common occurence. In any such case I can come up with, the test is needlessly limited in scope and can be replaced by a much more comprehensive test. What specifically did you have in mind?