anchor.diff:                               '("http://child/A3a" nil)
                                '("http://child/A3b" nil)))
         (prove:is (alexandria:hash-table-keys
  -                 (htree:bindings (first (htree:find-nodes tree (first url-owner)))))
  +                 (htree:bindings (first (htree:find-nodes history (first url-owner)))))
                   (if (second url-owner)
  -                    (list (htree:owner tree (second url-owner)))
  +                    (list (htree:owner history (second url-owner)))
                       nil)))
   
  -    (htree:delete-owner tree "parent-owner")
  -    (prove:is (htree:current-owner-identifier tree)
  +    (htree:delete-owner history "parent-owner")
  +    (prove:is (htree:current-owner-identifier history)
                 htree:+default-owner+)
  -    (prove:is (htree:owner tree "parent-owner")
  +    (prove:is (htree:owner history "parent-owner")
                 nil)
  -    (prove:is (hash-table-count (htree:entries tree))
  +    (prove:is (hash-table-count (htree:entries history))
                 9)
   
       (maphash (lambda (entry nodes)
  
positive.code:                "http://example.root/A2"
                (htree:go-to-child
                 "http://example.root/A"
                 (htree:back (make-tree1) 2))))
              '("http://example.root"
                "http://example.root/B"
                "http://example.root/B2" "http://example.root/B1"
  
negative.code:               url2)))
  
  (prove:subtest "Simple branching tree tests."
    (prove:is (htree:value (htree:current-owner-node (make-history1)))
              "http://example.root/B2"))
  
  (prove:subtest "History depth."
    (prove:is (htree:depth (make-history1))
              2))
  
  (prove:subtest "History size."
    (prove:is (htree:size (make-history1))
              7))
  
  (prove:subtest "All contiguous history nodes for current owner."
    (prove:is (htree:all-contiguous-owned-nodes-data (make-history1))
              '("http://example.root"
                "http://example.root/B"
                "http://example.root/B2" "http://example.root/B1"
  