“Cannot run program null” when trying to run tests

[klazuka]

Reported by MickeyV on Slack

Having problem running tests, I get

cannot run program null (in directory "/Users/me/path/to/project"): error=2, No such file or directory

[klazuka]

After some debugging, we determined that the problem was caused by upgrading from the elm-test-runner plugin. Maybe there was a stale run configuration laying around?

In any case, the fix was to open IntelliJ Settings -> “Languages & Frameworks” -> “Elm” and then explicitly set the path to elm-test.