# Property-Based Testing with PropEr, Erlang, and Elixir: Question 6 (page 417)

**URL:** <https://forum.devtalk.com/t/property-based-testing-with-proper-erlang-and-elixir-question-6-page-417/10863>\
**Category:** PragProg Customers\
**Tags:** question, book-property-based-testing-with-proper-erlang-and-elixir\
**Created:** [26 June 2021 10:56 UTC](https://forum.devtalk.com/t/property-based-testing-with-proper-erlang-and-elixir-question-6-page-417/10863 "2021-06-26T10:56:31Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![rustkas](https://forum.devtalk.com/user_avatar/forum.devtalk.com/rustkas/32/2933_2.png) [@rustkas](https://forum.devtalk.com/u/rustkas)\
**Post date:** [26 June 2021 10:56 UTC](https://forum.devtalk.com/t/property-based-testing-with-proper-erlang-and-elixir-question-6-page-417/10863/1 "2021-06-26T10:56:31Z")

</div>

**Chapter 4**  
_Question 6_

I [implemented](https://github.com/rustkas/Property-Based-Testing-with-PropEr-Erlang-and-Elixir-conding-experience/tree/main/code/ch04/exercises/ex06_file_generator) property and even tried to make an example more interesting and I would like to improve my realization.

Please, explain me, how could I use the [PropEr API](https://proper-testing.github.io/api.html) to delete a temporary file after performing all tests? I have not yet learned to use it to fully. In EUnit tests for this there are functions like `setup` and `teardown` (a sort of). How is this function in PropEr implemented? Could you demonstrate the work of such functionality?

I note also that when I replaced `'$call'` to `call` (I would check _Symbolic Calls_ works too and found strange behavior - symbolic calls are not called (when I run property). Please, tell me, where is my mistake. ([link to Symbolic call project](https://github.com/rustkas/Property-Based-Testing-with-PropEr-Erlang-and-Elixir-conding-experience/tree/main/code/ch04/exercises/ex06_symbolic_call))