There is not such a solution, however you have two choices:
Use IntellJ: To re-run the previous test(s) in IntellJ, you press shift + F10
.
Write a watcher: Write a file/directory watcher such as this question/answer here, and then as soon as there are changes, the program, re-runs the test command, such as sbt clean compile test
or activator compile test
.
Little advice auto running tests: I don't know how complicated your application is, but as soon as you have couple of injections here and there and with additional concurrency; you do not want to run the tests as soon as you put a char
in.
Little advice on Test Driven Development: Your approach should be the other way around! You write a test, which fails because there is no implementation; then you leave it alone. You go and write the implementation, then rerun the test to pass it or to get a feedback. Again, you need your cpu/memory power to focus on one thing, you don't want to brute force your implementation. Hope this makes sense!.
Little advice on your Play version: The Play 2.6 is way much better than Play 2.3; you should slowly but surely update your application; at least for the sake of security.