test: Add generate test case

[zombieJ]

cc @iamkun

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[codecov]

Codecov Report

Merging #14 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master     #14   +/-   ##
======================================
  Coverage    99.1%   99.1%           
======================================
  Files          39      39           
  Lines        1670    1670           
  Branches      526     522    -4     
======================================
  Hits         1655    1655           
  Misses         10      10           
  Partials        5       5

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