Add get_zeropoint and more flexible metadata querying to SVO FPS

[keflavich]

There is metadata on SVO FPS that is inaccessible but should be.

#3528 showed the right mechanism to retrieve metadata, but it didn't allow querying on PhotCalID - while data_from_svo allowed specification of this parameter, the mechanism we are using to parse the votable drops the relevant data.

This PR adds a new get_zeropoint mechanism to very explicitly and cleanly retrieve zeropoints and also generalizes get_filter_metadata.

Note that I have made some serious mistakes in recent publications because I failed to realize the default zeropoint was vega, so it's high importance for me to expose the get_zeropoint method with an explicit mag_sys keyword to users.

[codecov]

Codecov Report

❌ Patch coverage is 96.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 73.31%. Comparing base (81ab898) to head (d4ca72b).
⚠️ Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
astroquery/svo_fps/core.py	96.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3545      +/-   ##
==========================================
+ Coverage   73.23%   73.31%   +0.08%     
==========================================
  Files         226      226              
  Lines       21010    21038      +28     
==========================================
+ Hits        15386    15424      +38     
+ Misses       5624     5614      -10     

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[cgobat]

Nice. I like it.

[bsipocz]

The changes look good, and tests are happy.

However, I'm less happy about introducing back the **kwarg approach. Could we maybe expand it out and list all the options explicitly? If nothing else, it would make the docstring more useful.

[bsipocz]

Suggestion for some more docs, and the fix for the RTD failure is in the comments. Also, please rebase to get rid of the merge commit.

[keflavich]

I think the remaining error here is a temporary service access one from rtd, so this should be good for final review.

[bsipocz]

The only actual issue is about testing for the correct exception type we raise, once fixed we should merge this.

[bsipocz]

Ouch, this is really close, but I think the the parameter cases should be fixed before merging it.

[bsipocz]

Now that I'm doing a final go through, I noticed that these are cases all over the place. Could you change all of them to be lower case so the basic astroquery API design is not overriden? We already do a mapping, so it shouldn't really affect code complexity

[keflavich]

This matches the documentation on their website (https://svo2.cab.inta-csic.es/theory/fps/index.php?mode=voservice). I'm OK with switching everything to lowercase everywhere if you prefer, but matching the URLs is easier and maybe more intuitive for users?

[bsipocz]

I like to think that users would read our documentation and docstrings foremost rather than directly want to match webforms, that's the whole point, right?

(also, I haven't checked, but does the server case sensitive to begin with?)

[keflavich]

it is not case-sensitive! so I will change all to lowercase. I think the underscores are ok but I'll review

[keflavich]

ahhh no I was wrong, it is case sensitive, but it still returns something if you get the case wrong.

[bsipocz]

OK, this looks good now. I'll go ahead and rebase: 1) smoke out the test failure, that is unrelated but I haven't seen elsewhere 2) get rid of the merge commit 3) squash out the style fixes, including a new commit that fixes the failure

[bsipocz]

RTD failure is unrelated and looks to be temporary server side outage, so I go ahead with the merge here. Thanks @keflavich!