I tried experimenting with the following code, but the test didn’t end. Although the behavior has changed, it didn’t return “:ok” as I wanted it to. The issue is not resolved, but the Patch library itself looks promising.
use Patch
test "test" do
patch(Process, :send_after, fn _, _, _ -> :ok end)
assert :ok == Process.send_after(self(), :hi, 1_000)
end
Thank you for advice 
