         File.mkdir_p!(invalid)
       end
     end
-
-    defp io_error?(result) do
-      {:error, errorcode} = result
-      errorcode in [:enotdir, :eio, :enoent, :eisdir]
-    end
   end
 
-  defmodule Rm do
-    use Elixir.FileCase
-
+  describe "rm" do
     test "rm file" do
       fixture = tmp_path("tmp_test.txt")
       File.write(fixture, "test")

  end

  defp io_error?(result) do
    {:error, errorcode} = result
    errorcode in [:enotdir, :eio, :enoent, :eisdir]
  end
end

    # other tests
    # {:error, :enoent} -> rename unknown source
    # :ok               -> rename preserves mode
    test "rename file to existing file default behaviour" do
      src = tmp_fixture_path("file.txt")
      dest = tmp_path("tmp.file")
