add controller specs

spec/support/expectations/has_content.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require 'rspec/expectations'
+
+RSpec::Matchers.define :has_content do |actual_content|
+  match do |file|
+    file.read == actual_content
+  end
+end