anchor.diff:        (or description (format nil "Command exited with code 0: ~A" s))))
   
   (deftest check-result
  -  (exit-ok (shell "true"))
  -  (exit-fail (shell "false"))
  -  (exit-ok (check-result () (shell "true")))
  +  (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
  
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: (defun shell (str)
    (evaluate-shell-string str))
  
  (defun exit-ok (thing &optional description)
    (ok (and (typep thing 'exit-info)
             (exit-info-true-p thing))
        (or description "Expecting truthy status")))
  
  (defun exit-fail (thing &optional description)
    (ok (and (typep thing 'exit-info)
             (exit-info-false-p thing))
        (or description "Expecting falsey status")))
  
  (define-builtin testing-assert-equal (args)
    (let ((set (fset:convert 'fset:set (fset:less-first args))))
  