attributeに関数を指定できなかったが、別の方法を考えてみた

こちらの内容の課題

　fx = fn x -> rem(x, 2) == 0 end

の部分がパラメータ化できてない

現時点の結論だめでした…　

あえて、失敗例を載せます

defmodule HogeTest do
  use ExUnit.Case
  doctest Hoge

  params = [
    [true, 1, "s"],
    [true, nil, true],
    [true, 1, false]
  ]

  for param <- params do
    @param param
    test "Hoge.all?/1 param #{inspect(@param)}" do
      assert Hoge.all?(@param) == Enum.all?(@param)
    end
  end

  params = [
    [[2, 4, 6], fn x -> rem(x, 2) == 0 end],
    [[2, 4, 5], fn x -> rem(x, 2) == 0 end]
  ]

  for [param, fx] <- params do

    @param param
    @fx fx
    test "Hoge.all?/2 param #{inspect(@param)}" do
      assert Hoge.all?(@param, @fx) == Enum.all?(@param, @fx)
    end
  end

end

** (ArgumentError) cannot inject attribute @fx into function/macro because cannot escape #Function<2.123583373 in file:test/hoge_test.exs>. The supported values are: lists, tuples, maps, atoms, numbers, bitstrings, PIDs and remote functions in the format &Mod.fun/arity
    (elixir 1.13.4) lib/kernel.ex:3509: Kernel.do_at/5
    (elixir 1.13.4) expanding macro: Kernel.@/1
    test/hoge_test.exs:28: HogeTest."test Hoge.all?/2 param [2, 4, 6]"/1
    (ex_unit 1.13.4) expanding macro: ExUnit.Assertions.assert/1
    test/hoge_test.exs:28: HogeTest."test Hoge.all?/2 param [2, 4, 6]"/1

エラーメッセージの通り、だめっぽい
だが…

無理やり動かす方法を考えた

defmodule HogeTest do
  use ExUnit.Case
  doctest Hoge

  params = [
    [true, 1, "s"],
    [true, nil, true],
    [true, 1, false]
  ]

  for param <- params do
    @param param
    test "Hoge.all?/1 param #{inspect(@param)}" do
      assert Hoge.all?(@param) == Enum.all?(@param)
    end
  end

  params = [
    [[2, 4, 6], "fn x -> rem(x, 2) == 0 end"],
    [[2, 4, 5], "fn x -> rem(x, 2) == 0 end"]
  ]

  for param <- params do
    @param param
    test "Hoge.all?/2 param #{inspect(@param)}" do
      [list, fx_string] = @param
      fx = Code.eval_string(fx_string) |> elem(0)
      assert Hoge.all?(list, fx) == Enum.all?(list, fx)
    end
  end
end

つまり、文字列として渡す
その後にCode.eval_stringで文字列から関数を作成する