test(blockchain-utils): increase unit tests coverage

[sebastijankuzner]

Summary

Checklist

• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.95%. Comparing base (72cd6f1) to head (839356d).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1288      +/-   ##
===========================================
+ Coverage    56.67%   56.95%   +0.28%     
===========================================
  Files         1123     1126       +3     
  Lines        64897    65327     +430     
  Branches      1771     1850      +79     
===========================================
+ Hits         36782    37209     +427     
- Misses       27885    27886       +1     
- Partials       230      232       +2     

Flag	Coverage Δ
contracts	98.60% <ø> (?)
packages	56.68% <ø> (+<0.01%)	⬆️

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