test: improve test coverage

[johnmanjiro13]

No description provided.

[codecov]

Codecov Report

Merging #38 (01b8f35) into main (e38274d) will increase coverage by 32.95%.
The diff coverage is 70.83%.

@@             Coverage Diff             @@
##             main      #38       +/-   ##
===========================================
+ Coverage   36.65%   69.60%   +32.95%     
===========================================
  Files           2        2               
  Lines         221      227        +6     
===========================================
+ Hits           81      158       +77     
+ Misses        135       59       -76     
- Partials        5       10        +5     

Impacted Files	Coverage Δ
bump/bumper.go	61.84% <70.83%> (+43.88%)	⬆️

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[johnmanjiro13]

promptui has a data race bug.
So I removed -race option from test of ci temporarily.
manifoldco/promptui#169