Background

I have a test file with several describe blocks, each one with a custom setup block, like the following:

defmodule MyAppTest do
  use ExUnit.Case

  describe "group 1" do
    
    setup do
      :persistent_term.put("hello", :world)
      :ok
    end

    test "test 1" do
      assert true
    end

    test "test 2" do
      assert true
    end

  end

# describe group2 ....

end

Here I am setting up a persistent term that I will use along the app. Now, once I reach the end of all tests in the describe block, I want to clean up, meaning I want to delete the "hello" entry from :persistent_term.

To achieve this I am aware of on_exit, but according to my understanding, this callback is only executed once at the end of all tests from all describe blocks.

Questions

1. Is my understanding of on_exit correct?
2. How can I run a clean up function after the tests of each describe block?