Try adding require to rails helper

spec/rails_helper.rb

@@ -5,6 +5,7 @@
 require_relative "../config/environment"
 # Prevent database truncation if the environment is production
 abort("The Rails environment is running in production mode!") if Rails.env.production?
+Dir[Rails.root.join("app/middleware/*.{rb}")].each { |file| require file }
 require "rspec/rails"
 require "spec_helper"
 require "webmock/rspec"