fails:Numeric#<=> returns 0 if self equals other
fails:Numeric#<=> returns nil if self does not equal other
fails:Numeric#<=> with subclasses of Numeric is called when instances are compared with #<
fails:Numeric#<=> with subclasses of Numeric is called when instances are compared with #<=
fails:Numeric#<=> with subclasses of Numeric is called when instances are compared with #>
fails:Numeric#<=> with subclasses of Numeric is called when instances are compared with #>=
