Allow notebooks to read data #984
Description
Is your enhancement request related to a problem? Please describe.
The tests in #932 were originally all notebooks. One of them requires reading data. The data is not available in CI. It would help a lot if ARTS is consistent between python files and notebook files. Note that the notebooks works as expected when run locally.
Describe the solution you'd like
The solution should allow notebooks and pure python files to work mostly similar. We are already artificially limited to one notebook per folder because of how the CI works. Too many gotchas are not nice - at least we can create a warning message for the one-notebook-per-directory rule.
Describe alternatives you've considered
Otherwise we need to stop using notebooks in the examples and tests. It is incredibly limiting to not allow data ingestion.
Are you willing to help adding this enhancement?
Yes, but @olemke knows this stuff better and it is not urgently needed for anything I am working on.
Additional context
See #932.