anchor.diff:  
   ;;; Print failures
   
  -(defgeneric print-failure (result)
  +(defgeneric print-failures (result)
     (:documentation
      "Report the results of the failed assertion."))
   
  -(defmethod print-failure :around ((result assert-result))
  +(defmethod print-failures :around ((result assert-result))
     "Failure header and footer output."
     (format t "~& | Failed Form: ~S" (form result))
     (call-next-method)
  
positive.code:            :failed-tests
             :error-tests
             :missing-tests
             :summarize-results)
    ;; Utility predicates
    (:export :logically-equal :set-equal))
  
negative.code:       (incf (exerr results))
        (push test-name (error-tests results)))
      ;; Running output
      (when *print-failures* (print-failures result))
      (when *print-errors* (print-errors result))
      (when (or *print-summary* *print-failures* *print-errors*)
        (print-summary result))))
  
  (defun summarize-results (results)
    "Print a summary of all results."
  