Tests are supposed to ensure functionality, not implementation. No useful unit test has ever been made obsolete by a type system. Likewise, if your tests claim your program fulfills its functionality, the type system ads no additional information to the discussion.
My point was that without a type system you need an impossible 100% code coverage, to be sure that you didn’t accidentally mess up some variable assignment or parameter somewhere, since you have nothings to easily and automatically catch those errors.
I understand your point, I just choose to reject it for the reasons given.