Merge branch 'tusooa/3055-instance-languages' into 'develop'

Allow customizing instance languages

Closes #3055

See merge request pleroma/pleroma!3835

test/pleroma/web/mastodon_api/controllers/instance_controller_test.exs

@@ -92,4 +92,18 @@ defmodule Pleroma.Web.MastodonAPI.InstanceControllerTest do
 
     assert ["peer1.com", "peer2.com"] == Enum.sort(result)
   end
+
+  test "instance languages", %{conn: conn} do
+    assert %{"languages" => ["en"]} =
+             conn
+             |> get("/api/v1/instance")
+             |> json_response_and_validate_schema(200)
+
+    clear_config([:instance, :languages], ["aa", "bb"])
+
+    assert %{"languages" => ["aa", "bb"]} =
+             conn
+             |> get("/api/v1/instance")
+             |> json_response_and_validate_schema(200)
+  end
 end