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 my project does exist, I see it in the package explorer!
I have faced the same problem while I was working with raspbian OS for raspberry pi. The problem was the java project was referencing to one of my previous project.
I resolved this problem by doing following steps.
- Go to Project->properties
- In properties window's left pane select "Run/Debug Settings".
- Select "Configure" and click "edit"
- In tab "Main" replace Project to your current project.
- Select "Main class" by clicking on search button(it will be your class name).
- Now hit OK.