Eclipse — Testng references non-existing project XXX, launch configuration

Question

When trying to run a test as a TestNG suite, I would get a very cryptic error message saying that TestNG can\'t launch because it references a non-existant project. I think

Answer 1

In my case, the error occurred in a Scala project. It had installed the eclipse plugin, but it had not been used yet.

Diagnostics: If all goes well, the project has a blue S for scala project. If not, it has a yellow PC mouse (for whatever that means).

To fix, you need to

sbt eclipse

on the command-line. Eclipse recognizes it as Scala project at the latest on restart.