Doesn't a green run refer to a beginner level course? Like a practice ski hill?
"The term “green” refers to the new hardware that will work together to power the stage, and “run” refers to operating all the components together simultaneously for the first time." --https://www.nasa.gov/exploration/systems/sls/green-run-test-...
I still think these tests should be run more than once though, the RS-25's were originally reusable anyway.