Tomcat has some defaults that are messing up the integration-tests (i.e. they provide a default error page). Will need to fix that.
Also, Tomcat automatically lower cases all incoming header names so we lose the case sensitivity. Since there's no way to re-create the case sensitivity as far as I know, I would suggest moving to a different web container. However, some of the integration-tests can be changed to expect lower cases as well.