class HTMLProofer::UrlValidator::Internal

def hash_exists_for_url?(url)

=> returns nil if the has could not be verified
verify the hash w/o just based on the URL, w/o looking at the target file 
def hash_exists_for_url?(url)
ash = url.hash
 true if blank?(href_hash)
 true unless @runner.options[:check_internal_hash]
ents searching files we didn't ask about
 false unless url.known_extension?
 false unless url.has_hash?
d_href_hash = Addressable::URI.unescape(href_hash)
nt_ids = [href_hash, decoded_href_hash]
s://www.w3.org/TR/html5/single-page.html#scroll-to-fragid
f fragment_ids.include?("top")