basic:

"basic" language and library tests. These need run only with File read 
permission to read files under "test/script" or subdirs and property read
permission to read properties named "nashorn.test.*"

error:

scripts that should result in compile-time error. The expected files check
for the error message format etc.

currently-failing: 

Tests that fail currently - but should pass eventually.
These are excluded for now.

sandbox:

Tests to check that sandbox scripts cannot access security sensitive resources.
Scripts under this directory run with no special permissions other than
what is given to all "sandbox" scripts.

trusted:

These tests run under AllPermission. Put only those scripts that really need
AllPermission - say for eg. creating class loader, full reflective access.