adding gun adapter

test/gun/gun_test.exs

@@ -0,0 +1,33 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.GunTest do
+  use ExUnit.Case
+  alias Pleroma.Gun
+
+  @moduletag :integration
+
+  test "opens connection and receive response" do
+    {:ok, conn} = Gun.open('httpbin.org', 443)
+    assert is_pid(conn)
+    {:ok, _protocol} = Gun.await_up(conn)
+    ref = :gun.get(conn, '/get?a=b&c=d')
+    assert is_reference(ref)
+
+    assert {:response, :nofin, 200, _} = Gun.await(conn, ref)
+    assert json = receive_response(conn, ref)
+
+    assert %{"args" => %{"a" => "b", "c" => "d"}} = Jason.decode!(json)
+  end
+
+  defp receive_response(conn, ref, acc \\ "") do
+    case Gun.await(conn, ref) do
+      {:data, :nofin, body} ->
+        receive_response(conn, ref, acc <> body)
+
+      {:data, :fin, body} ->
+        acc <> body
+    end
+  end
+end