+;;; in FORMAT, ~^ inside ~:{ should go to the next case, not break
+;;; iteration, even if one argument is just a one-element list.
+(assert (string= (format nil "~:{~A~^~}" '((A) (C D))) "AC"))
+
+;;; errors should be raised if pprint and justification are mixed
+;;; injudiciously...
+(dolist (x (list "~<~:;~>~_" "~<~:;~>~I" "~<~:;~>~W"
+ "~<~:;~>~:T" "~<~:;~>~<~:>" "~_~<~:;~>"
+ "~I~<~:;~>" "~W~<~:;~>" "~:T~<~:;~>" "~<~:>~<~:;~>"))
+ (assert (raises-error? (format nil x nil)))
+ (assert (raises-error? (format nil (eval `(formatter ,x)) nil))))
+;;; ...but not in judicious cases.
+(dolist (x (list "~<~;~>~_" "~<~;~>~I" "~<~;~>~W"
+ "~<~;~>~:T" "~<~;~>~<~>" "~_~<~;~>"
+ "~I~<~;~>" "~W~<~;~>" "~:T~<~;~>" "~<~>~<~;~>"
+ "~<~:;~>~T" "~T~<~:;~>"))
+ (assert (format nil x nil))
+ (assert (format nil (eval `(formatter ,x)) nil)))
+
+;;; bug 350: bignum printing so memory-hungry that heap runs out
+;;; -- just don't stall here forever on a slow box
+(handler-case
+ (with-timeout 10
+ (print (ash 1 1000000)))
+ (timeout ()
+ (print 'timeout!)))
+
+;;; bug 371: bignum print/read inconsistency
+(defvar *bug-371* -7043009959286724629649270926654940933664689003233793014518979272497911394287216967075767325693021717277238746020477538876750544587281879084559996466844417586093291189295867052594478662802691926547232838591510540917276694295393715934079679531035912244103731582711556740654671309980075069010778644542022/670550434139267031632063192770201289106737062379324644110801846820471752716238484923370056920388400273070254958650831435834503195629325418985020030706879602898158806736813101434594805676212779217311897830937606064579213895527844045511878668289820732425014254579493444623868748969110751636786165152601)
+(let ((*print-base* 5)
+ (*read-base* 5)
+ (*print-radix* nil))
+ (assert (= *bug-371* (read-from-string (prin1-to-string *bug-371*)))))
+
+;;; a spot of random-testing for rational printing
+(defvar *seed-state* (make-random-state))
+(print *seed-state*) ; so that we can reproduce errors
+(let ((seed (make-random-state *seed-state*)))
+ (loop repeat 42
+ do (let ((n (random (ash 1 1000) seed))
+ (d (random (ash 1 1000) seed)))
+ (when (zerop (random 2 seed))
+ (setf n (- n)))
+ (let ((r (/ n d)))
+ (loop for base from 2 to 36
+ do (let ((*print-base* base)
+ (*read-base* base)
+ (*print-radix* nil))
+ (assert (= r (read-from-string (prin1-to-string r))))
+ (if (= 36 base)
+ (decf *read-base*)
+ (incf *read-base*))
+ (assert (not (eql r (read-from-string (prin1-to-string r)))))
+ (let ((*print-radix* t))
+ (assert (= r (read-from-string
+ (princ-to-string r)))))))))
+ (write-char #\.)
+ (finish-output)))
+
+;;;; Bugs, found by PFD
+;;; NIL parameter for ~^ means `not supplied'
+(loop for (format arg result) in
+ '(("~:{~D~v^~D~}" ((3 1 4) (1 0 2) (7 nil) (5 nil 6)) "341756")
+ ("~:{~1,2,v^~A~}" ((nil 0) (3 1) (0 2)) "02"))
+ do (assert (string= (funcall #'format nil format arg) result))
+ do (assert (string= (with-output-to-string (s)
+ (funcall (eval `(formatter ,format)) s arg))
+ result)))
+
+;;; NIL first parameter for ~R is equivalent to no parameter.
+(assert (string= (format nil "~VR" nil 5) "five"))
+(assert (string= (format nil (formatter "~VR") nil 6) "six"))
+
+;;; CSR inserted a bug into Burger & Dybvig's float printer. Caught
+;;; by Raymond Toy
+(assert (string= (format nil "~E" 1d23) "1.0d+23"))
+
+;;; Fixed-format bugs from CLISP's test suite (reported by Bruno
+;;; Haible, bug 317)
+(assert (string= (format nil "~1F" 10) "10."))
+(assert (string= (format nil "~0F" 10) "10."))
+(assert (string= (format nil "~2F" 1234567.1) "1234567."))
+
+;;; here's one that seems to fail most places. I think this is right,
+;;; and most of the other answers I've seen are definitely wrong.
+(assert (string= (format nil "~G" 1d23) "100000000000000000000000. "))
+
+;;; Adam Warner's test case
+(assert (string= (format nil "~@F" 1.23) "+1.23"))
+