module Spy class Error < StandardError; end class AlreadyStubbedError < Error def message "Spy is already stubbed." end end class AlreadyHookedError < Error def message "Spy is already hooked." end end class NotHookedError < Error def message "Spy was not hooked." end end class NeverHookedError < Error def message "Spy was never hooked." end end class NoSpyError < Error def message "Spy could not be found" end end end