Frankly, Clojure doesn't need the intense levels of testing that OO languages require, due to immutability. There's a great deal less forking of possible states to examine.

I have a friend who is a strong typing devotee who has worked heavily in Clojure for a couple of years, and he curses the lack of strong typing - but he's comparing to the likes of Haskell and OCaml. As a dynamic typing enthusiast myself, I'm comparing to Ruby, and Clojure is definitely superior in terms of how much it needs to be tested.

What drew me to Clojure over Ruby, though, was actually a matter of data modeling. I'm working with a graph database (Neo4J), and I found that good graph technique is terrible OO technique. I was violating the Law of Demeter constantly, reaching through objects to get to other objects, passing internal state around with the express intent of mutation, etc. Switching to a functional paradigm lined up perfectly with good graph design. No more smells! No more pain! And again, a lot less testing, because I'm no longer fighting against the nature of my data.