🧪 Add schema tests for docname in select and validate

[ubmarco]

Test that docname can be used for both select and validate in schema rules.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.84%. Comparing base (4e10030) to head (cb695ab).
⚠️ Report is 242 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1650      +/-   ##
==========================================
+ Coverage   86.87%   88.84%   +1.96%     
==========================================
  Files          56       70      +14     
  Lines        6532     9988    +3456     
==========================================
+ Hits         5675     8874    +3199     
- Misses        857     1114     +257     

Flag	Coverage Δ
pytests	88.84% <ø> (+1.96%)	⬆️

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