[zaphar]

As jrockway says in this thread. The REPL is most useful for exploratory coding, which a unit test is not good for.

Why write a unit test for a feature of the language? The Language designer probably already did that and all you need to do is write unit tests for your own code. I do a fair amount of clojure code now and find it highly useful for just running java code to see how it behaves. Which then helps me figure out how to code my actual code, which then will pass the test that I've already written.