tests: add missing controller tests.

test/functional/forum_topic_visits_controller_test.rb

@@ -0,0 +1,13 @@
+require "test_helper"
+
+class ForumTopicVisitsControllerTest < ActionDispatch::IntegrationTest
+  context "index action" do
+    should "work for json responses" do
+      @user = create(:user)
+      @visit = as(@user) { create(:forum_topic_visit, user: @user) }
+      get_auth forum_topic_visits_path, @user, as: :json
+
+      assert_response :success
+    end
+  end
+end