The only thing better than having tests is not needing tests. That's what a robust type system gives you.
Type systems don't eliminate all testing, but they do eliminate a large swath of possible errors that need to be tested for, like the one that has (had?) been afflicting Sinatra.
Type systems don't eliminate all testing, but they do eliminate a large swath of possible errors that need to be tested for, like the one that has (had?) been afflicting Sinatra.