It was only testing the default configuration where overlay-scrolling is TRUE and the policy is POLICY_AUTOMATIC. We should also test FALSE and POLICY_ALWAYS. This commit adds those tests and makes the !overlay && POLICY_ALWAYS case pass by excluding the size of the relevant scrollbar, as we are only interested in whether the content size is as requested. https://bugzilla.gnome.org/show_bug.cgi?id=778853