Clarification needed on select_time_slice() behavior and failing test case

[Sachin-G13]

Hi team,
My recent PR: openclimatefix/ocf-data-sampler#128 failed due to a test issue in select_time_slice().
Could you please clarify:
Should select_time_slice() fill missing timestamps with NaNs or return only available data?
Should the test test_select_time_slice_out_of_bounds expect complete timestamps or only existing ones?

[AUdaltsova]

Hi @Sachin-G13! Thanks for your PR, it's always great to see people willing to contribute and dedicate their time!

By default, select_time_slice() does not fill in missing data. However, it has an option to do so, which is one of the things test_select_time_slice_out_of_bounds () tests for, and why your PR is failing it (since you've deleted the option).

It's a good spot that we don't really use this functionality in the code and there is no user control over it; I'd agree that it should be stripped out! I'll add further comments to your PR just so there's more context.