anchor.diff:  (defun shell (str)
     (evaluate-shell-string str))
   
  -(defun exit-ok (thing)
  +(defun exit-ok (thing &optional description)
     (ok (and (typep thing 'exit-info)
              (exit-info-true-p thing))
  -      "Expecting truthy status"))
  +      (or description "Expecting truthy status")))
   
  -(defun exit-fail (thing)
  +(defun exit-fail (thing &optional description)
     (ok (and (typep thing 'exit-info)
              (exit-info-false-p thing))
  -      "Expecting falsey status"))
  +      (or description "Expecting falsey status")))
   
   (define-builtin testing-assert-equal (args)
     (let ((set (fset:convert 'fset:set (fset:less-first args))))
  
positive.code: (deftest capture
    (is (capture (:stdout) (shell "echo   \f'o'\"o\"   "))
        (format nil "foo~%")
        :test #'equal)
    (is (capture (:stdout :stderr 3) (shell "echo foo && echo bar >&2 ; echo baz >&3"))
        (format nil "foo~%bar~%baz~%")
        :test #'equal))
  
  (deftest splice
    (let ((lexical-variable "ABC"))
      (is (capture (:stdout) (evaluate-constant-shell-string "echo ,lexical-variable" :readtable *splice-table*))
          (format nil "ABC~%")
          :test #'equal))
  
    (let ((lexical-vector #("A " "b")))
      (is (capture (:stdout) (evaluate-constant-shell-string "echo ,@lexical-vector" :readtable *splice-table*))
          (format nil "A  b~%")
          :test #'equal))
  
    (let ((lexical-seq (fset:seq "A " "b")))
      (is (capture (:stdout) (evaluate-constant-shell-string "echo ,@lexical-seq" :readtable *splice-table*))
          (format nil "A  b~%")
          :test #'equal)))
  
  (deftest test-infrastructure
    (run "testing-assert-equal 0 0"
  
negative.code:       (or description (format nil "Command exited with code 0: ~A" s))))
  
  (deftest check-result
    (exit-ok
     (shell "true")
     "True is true")
    (exit-fail
     (shell "false")
     "False is false")
    (exit-ok
     (check-result () (shell "true"))
     "check-result doesn't interfere with true")
    (exit-fail
     (let (signaled)
       (handler-bind
  