Change tests to include html content

Author: antulik

test/caching_test.rb

@@ -66,8 +66,8 @@ def forbidden
   end
 
   def with_layout
-    @cache_this = MockTime.now.to_f.to_s
-    render html: @cache_this, layout: true
+    @cache_this = MockTime.now.to_f.to_s + "<div />"
+    render html: @cache_this.html_safe, layout: true
   end
 
   def with_format_and_http_param