Implement /api/v1/instance/translation_languages

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

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

@@ -113,4 +113,13 @@ defmodule Pleroma.Web.MastodonAPI.InstanceControllerTest do
     assert get(conn, "/api/v2/instance")
            |> json_response_and_validate_schema(200)
   end
+
+  test "translation languages matrix", %{conn: conn} do
+    clear_config([Pleroma.Language.Translation, :provider], TranslationMock)
+
+    assert %{"en" => ["pl"], "pl" => ["en"]} =
+             conn
+             |> get("/api/v1/instance/translation_languages")
+             |> json_response_and_validate_schema(200)
+  end
 end

test/support/translation_mock.ex

@@ -24,7 +24,16 @@ defmodule TranslationMock do
 
   @impl Provider
   def supported_languages(_) do
-    ["en", "pl"]
+    {:ok, ["en", "pl"]}
+  end
+
+  @impl Provider
+  def languages_matrix do
+    {:ok,
+     %{
+       "en" => ["pl"],
+       "pl" => ["en"]
+     }}
   end
 
   @impl Provider