fails:Kernel#sleep is a private method
fails:Kernel#sleep pauses execution for approximately the duration requested
fails:Kernel#sleep returns the rounded number of seconds asleep
fails:Kernel#sleep raises an ArgumentError when passed a negative duration
fails:Kernel#sleep raises a TypeError when passed a non-numeric duration
fails:Kernel#sleep accepts a Rational
fails:Kernel#sleep pauses execution indefinitely if not given a duration
fails:Kernel.sleep needs to be reviewed for spec completeness
fails:Kernel#sleep raises a TypeError when passed nil
fails:Kernel#sleep raises a TypeError when passed a String
slow:Kernel#sleep accepts a Float
slow:Kernel#sleep accepts a Rational
