New _register_dataset tests

[dfsp-spirit]

Changes Summary

• Add tests that use _register_dataset() on SpikeData and EventData instances.

Reviewer Checklist

• Are testing routines present?
• Do objects in the global package namespace perform proper parsing of their input?
• Are all docstrings complete and accurate?
• Is the CHANGELOG.md up to date?

[codecov]

Codecov Report

Base: 67.79% // Head: 68.13% // Increases project coverage by +0.34% 🎉

Coverage data is based on head (116f657) compared to base (5df8e15).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #436      +/-   ##
==========================================
+ Coverage   67.79%   68.13%   +0.34%     
==========================================
  Files          81       81              
  Lines        9833     9833              
  Branches     2032     2032              
==========================================
+ Hits         6666     6700      +34     
+ Misses       2622     2595      -27     
+ Partials      545      538       -7     

Impacted Files	Coverage Δ
syncopy/datatype/methods/show.py	58.33% <0.00%> (-3.34%)	⬇️
syncopy/specest/compRoutines.py	91.91% <0.00%> (+2.35%)	⬆️
syncopy/specest/mtmconvol.py	93.54% <0.00%> (+6.45%)	⬆️
syncopy/specest/stft.py	83.33% <0.00%> (+7.14%)	⬆️
syncopy/specest/freqanalysis.py	69.09% <0.00%> (+7.27%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[tensionhead]

Lgtm 🙂