shahryarjb

Req application/octet-stream tar file mock test

Hello friends, Imagine you want to download a tar file from hex.pm website.

I have this function and do not want to install req hex plugin. as you see I find the "contents.tar.gz" and it is the binary of file.

  @spec download(download_type, pkg) :: okey_return | error_return
  def download(:hex, %{app: app, tag: tag_name}) when not is_nil(tag_name) do
    case build_url("https://repo.hex.pm/tarballs/#{app}-#{tag_name}.tar") do
      %Req.Response{status: 200, body: body} ->
        converted = Map.new(body, fn {key, value} -> {to_string(key), value} end)
        {:ok, converted["contents.tar.gz"]}

      _ ->
        mix_global_err()
    end
  end

And downloader function:

  defp build_url(location) do
    [base_url: location]
    |> Keyword.merge(Application.get_env(:mishka_installer, :downloader_req_options, []))
    |> Keyword.merge(Application.get_env(:mishka_installer, :proxy, []))
    |> Req.request!()
  end

Now I want to mock it, so this is the place I can not be able to fix.

One of my function test is what does not work:

body = [
        {~c"VERSION", "3"},
        {~c"CHECKSUM", "1D5EC32825E5AF1B5CF58933F4C918909BC79E4391EBE2B9315B02705145B18F"},
        {~c"metadata.config", "{<<\"app\">>,<<\"mishka_installer\">>}.\n{<<\"build_tools\">>"},
        {~c"contents.tar.gz", <<31, 139, 8, 0, 0, 0>>}
      ]

      body_iolist_to_binary =
        Enum.reduce(body, "", fn {key, value}, acc -> acc <> "#{key}:#{value}\n" end)
        |> :erlang.iolist_to_binary()

      Req.Test.expect(Downloader, fn conn ->
        conn
        |> Plug.Conn.put_resp_content_type("application/octet-stream")
        |> Plug.Conn.send_resp(200, body_iolist_to_binary)
      end)

If I put body directly I have error!! I have no idea how can simulate the hex output.

It should be noted my function works as well, my problem is located in testing this

Thank you in advance

9 comments

#mock #test #req

1 811 9

2024-06-24 08:33:15 UTC

Most Liked

wojtekmach

Hex Core Team

Even if you end up not using req_hex, I’d still consider using hex_core to get more realistic tests. Here is an example:

Mix.install([
  :req,
  :plug,
  :hex_core
])

Req.Test.expect(Downloader, fn conn ->
  {:ok, %{tarball: tarball}} =
    :hex_tarball.create(
      %{
        "name" => "foo",
        "version" => "1.0.0"
      },
      [
        {~c"mix.exs",
         """
         defmodule Foo.MixProject do
           use Mix.Project
           def project do
             [app: :foo, version: "1.0.0"]
           end
         end
         """}
      ]
    )

  conn
  |> Plug.Conn.put_resp_content_type("application/octet-stream", nil)
  |> Plug.Conn.send_resp(200, tarball)
end)

Req.get!(url: "/foo.tar", plug: {Req.Test, Downloader})
|> IO.inspect()

Thanks @LostKobrakai for reporting the format detection bug btw. application/octet-stream; charset=utf-8 is not a proper content-type for tar, these bytes are not utf8. I’ll see if I can make any improvements anyway though.

Post #9

LostKobrakai

Good point. I didn’t really think about that tbh. So Plug.Conn.put_resp_content_type(conn, "application/octet-stream", nil) is actually the way to go then, not just a workaround.

Post #10

LostKobrakai

A tar file is not some kind of map, like you’re building here in your test. The body you get from Req has the tar already extracted, which gives you a map (see Req.Steps — req v0.5.0). In your mock you need to build a proper .tar file, e.g. by using :erl_tar.

Post #2