Add mascot get/set tests

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -729,6 +729,7 @@ def set_mascot(%{assigns: %{user: user}} = conn, %{"file" => file}) do
         |> json(rendered)
       else
         conn
+        |> put_resp_content_type("application/json")
         |> send_resp(415, Jason.encode!(%{"error" => "mascots can only be images"}))
       end
     end

test/web/mastodon_api/mastodon_api_controller_test.exs

@@ -1455,6 +1455,71 @@ test "media upload", %{conn: conn} do
     assert object.data["actor"] == User.ap_id(user)
   end
 
+  test "mascot upload", %{conn: conn} do
+    user = insert(:user)
+
+    non_image_file = %Plug.Upload{
+      content_type: "audio/mpeg",
+      path: Path.absname("test/fixtures/sound.mp3"),
+      filename: "sound.mp3"
+    }
+
+    conn =
+      conn
+      |> assign(:user, user)
+      |> put("/api/v1/pleroma/mascot", %{"file" => non_image_file})
+
+    assert json_response(conn, 415)
+
+    file = %Plug.Upload{
+      content_type: "image/jpg",
+      path: Path.absname("test/fixtures/image.jpg"),
+      filename: "an_image.jpg"
+    }
+
+    conn =
+      build_conn()
+      |> assign(:user, user)
+      |> put("/api/v1/pleroma/mascot", %{"file" => file})
+
+    assert %{"id" => _, "type" => image} = json_response(conn, 200)
+  end
+
+  test "mascot retrieving", %{conn: conn} do
+    user = insert(:user)
+    # When user hasn't set a mascot, we should just get pleroma tan back
+    conn =
+      conn
+      |> assign(:user, user)
+      |> get("/api/v1/pleroma/mascot")
+
+    assert %{"url" => url} = json_response(conn, 200)
+    assert url =~ "pleroma-fox-tan-smol"
+
+    # When a user sets their mascot, we should get that back
+    file = %Plug.Upload{
+      content_type: "image/jpg",
+      path: Path.absname("test/fixtures/image.jpg"),
+      filename: "an_image.jpg"
+    }
+
+    conn = 
+      build_conn()
+      |> assign(:user, user)
+      |> put("/api/v1/pleroma/mascot", %{"file" => file})
+    assert json_response(conn, 200)
+
+    user = User.get_cached_by_id(user.id)
+
+    conn =
+      build_conn()
+      |> assign(:user, user)
+      |> get("/api/v1/pleroma/mascot")
+
+    assert %{"url" => url, "type" => "image"} = json_response(conn, 200)
+    assert url =~ "an_image"
+  end
+
   test "hashtag timeline", %{conn: conn} do
     following = insert(:user)