chore: decoding old fraction formats tests

[eqimd]

Description

Make fraction decoding tests work with old formats

---

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.10%. Comparing base (70af159) to head (17fe85e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #560      +/-   ##
==========================================
+ Coverage   77.93%   79.10%   +1.17%     
==========================================
  Files         249      249              
  Lines       18844    18844              
==========================================
+ Hits        14686    14907     +221     
+ Misses       4158     3937     -221     

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