tests: add missing controller tests.

test/functional/pixiv_ugoira_frame_data_controller_test.rb

@@ -0,0 +1,11 @@
+require "test_helper"
+
+class PixivUgoiraFrameDataControllerTest < ActionDispatch::IntegrationTest
+  context "index action" do
+    should "work" do
+      create(:pixiv_ugoira_frame_data)
+      get pixiv_ugoira_frame_data_path, as: :json
+      assert_response :success
+    end
+  end
+end