Add functions for validating metadata against JSON Schema and use in tests

[jwodder]

Closes #332.

[codecov]

Codecov Report

Merging #338 (603391e) into master (fe3b74e) will increase coverage by 0.31%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #338      +/-   ##
==========================================
+ Coverage   82.37%   82.68%   +0.31%     
==========================================
  Files          55       55              
  Lines        5105     5157      +52     
==========================================
+ Hits         4205     4264      +59     
+ Misses        900      893       -7     

Flag	Coverage Δ
unittests	82.68% <100.00%> (+0.31%)	⬆️

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Impacted Files	Coverage Δ
dandi/tests/test_validate.py	100.00% <ø> (ø)
dandi/metadata.py	79.48% <100.00%> (+4.72%)	⬆️
dandi/models.py	82.41% <100.00%> (+0.06%)	⬆️
dandi/tests/test_metadata.py	100.00% <100.00%> (ø)

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[yarikoptic]

Looks good to me. If I get it right, I think we might need to get back to license to become a list in a conversion code when we try to migrate existing dandiset.yaml s .

@satra -- ok with changes to the model (that TempOptional etc)?

[satra]

we are still using unvalidated in the tests. is that still intended?

just a note that all the tempoptionals are readonly in the sense we expect these to be set on the server side. but perhaps we should insert them in the test data.

[yarikoptic]

hm, indeed... but may be one step at a time, i.e. get this merged/used and then "re-introduce" them when server is populating them or does it already?

[satra]

i leave it to you.