Add a few tests graphql

[denisart]

Add tests for new data types (graphql enum and graphql union);

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (main@cb5c66c). Click here to learn what that means.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1722   +/-   ##
=======================================
  Coverage        ?   99.28%           
=======================================
  Files           ?       37           
  Lines           ?     4058           
  Branches        ?      942           
=======================================
  Hits            ?     4029           
  Misses          ?       16           
  Partials        ?       13           

Flag	Coverage Δ
unittests	98.96% <0.00%> (?)

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[codspeed-hq]

CodSpeed Performance Report

Merging #1722 will not alter performance

_{Comparing denisart:add-a-few-tests-graphql (e3a9a0e) with main (811cb85)}

Summary

✅ 29 untouched benchmarks