Updated derivation test recipe #1790
I think we had some issues back then when two different derived variables needed the same variables as requirement within the same diagnostic, but I'm not 100% sure. I merged all the diagnostics and the recipe still works, so it is much simpler now.
I ran the recipe_preprocessor_derive_test.yml and as far as I can tell the output looks fine. But I noticed 2 things that look like bugs to me. These two bugs are not related to this PR or ESMValGroup/ESMValCore#754, but would probably be best addressed in ESMValGroup/ESMValCore#754 as it contains already several fixes to other derivation scripts. The 2 bugs are:
@schlunma : Maybe you could briefly look into those two bugs? That does not look like a big thing to fix.
Other than that, thumbs up for this PR and ESMValGroup/ESMValCore#754!