I doubt many programmers already using Jython, Beanshell, Apache Groovy, Xtend, Rhino, or Nashorn will change to the Java 9 JShell. I switched from Groovy to Clojure for scripty stuff a few years ago, mainly for the macros. A well-placed macro can avoid a lot of clutter in repetitive testing -- a far better solution than some heavy-weight testing framework.