add some tests for in and notin

[lunny]

No description provided.

[codecov-io]

Codecov Report

Merging #15 into master will increase coverage by 6.98%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #15      +/-   ##
==========================================
+ Coverage   51.83%   58.82%   +6.98%     
==========================================
  Files          18       18              
  Lines         816      816              
==========================================
+ Hits          423      480      +57     
+ Misses        297      221      -76     
- Partials       96      115      +19

Impacted Files	Coverage Δ
cond_in.go	69.03% <0%> (+17.41%)	⬆️
cond_notin.go	64.51% <0%> (+19.35%)	⬆️

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