Add unit test

[hoc081098]

Closes #29

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@91c25f3). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #30   +/-   ##
=========================================
  Coverage          ?   10.32%           
  Complexity        ?        7           
=========================================
  Files             ?       38           
  Lines             ?      949           
  Branches          ?       70           
=========================================
  Hits              ?       98           
  Misses            ?      846           
  Partials          ?        5           

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