test: porting helpers to the PR desc

Author: rNoz

test/ex_image_info_test/images/isobmff_test.exs

@@ -242,7 +242,7 @@ defmodule ExImageInfoTest.Images.ISOBMFFTest do
   end
 
   defp fetch_binary(url, tmp_dir, debug? \\ false) do
-    Enum.all?([:inets, :ssl], &(:ok = Application.ensure_started(&1)))
+    true = Enum.all?([:inets, :ssl], &Application.ensure_started/1)
 
     filename = Path.basename(url)
     tmp_file = Path.join([tmp_dir, filename])

test/ex_image_info_test/mocks/isobmff_test.exs

@@ -440,21 +440,4 @@ defmodule ExImageInfoTest.Mocks.ISOBMFFTest do
       assert info(image_truncated) == nil
     end
   end
-end
-
-defmodule HexConverter do
-  def convert(hex_string) do
-    hex_string
-    |> String.split(" ", trim: true)
-    |> Enum.chunk_every(4)
-    |> Enum.map(fn chunk ->
-      chunk
-      |> Enum.join("")
-      |> then(&("0x" <> &1 <> "::32"))
-    end)
-    |> Enum.chunk_every(4)
-    |> Enum.map(&Enum.join(&1, ", "))
-    |> Enum.join(",\n")
-    |> then(&"<<\n#{&1}\n>>")
-  end
-end
+end