# Copeiro - testing library

**URL:** <https://forum.elixirforum.com/t/copeiro-testing-library/39330>\
**Category:** Announcing\
**Tags:** library, testing, exunit, copeiro\
**Created:** [April 30, 2021, 11:47pm UTC](https://forum.elixirforum.com/t/copeiro-testing-library/39330 "2021-04-30T23:47:13Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![eksperimental](https://forum.elixirforum.com/user_avatar/forum.elixirforum.com/eksperimental/32/1401_2.png) [@eksperimental](https://forum.elixirforum.com/u/eksperimental)\
**Post date:** [May 1, 2021, 1:25am UTC](https://forum.elixirforum.com/t/copeiro-testing-library/39330/3 "2021-05-01T01:25:56Z")

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Personally I wouldn’t use `in` since it is an operator that behaves in a different way. I would use `has` and `has not`, but you will have to flip the arguments. Or name it something else.

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