+(assert (null (class-prototype (find-class 'null))))
+\f
+;;; simple consistency checks for the SB-PCL (perhaps AKA SB-MOP)
+;;; package: all of the functionality specified in AMOP is in
+;;; functions:
+(assert (null (loop for x being each external-symbol in "SB-PCL"
+ unless (fboundp x) collect x)))
+;;; and all generic functions in SB-PCL have at least one specified
+;;; method, except for UPDATE-DEPENDENT
+(assert (null (loop for x being each external-symbol in "SB-PCL"
+ unless (or (eq x 'update-dependent)
+ (not (typep (fdefinition x) 'generic-function))
+ (> (length (generic-function-methods
+ (fdefinition x)))
+ 0))
+ collect x)))