class Spy::Nest

def add(spy)
  if @constant_spies[spy.constant_name]
    raise AlreadyStubbedError, "#{spy.constant_name} has already been stubbed"
  else
    @constant_spies[spy.constant_name] = spy
  end
  self
end

def all
  @all ||= {}
end

def fetch(base_module)
  all[base_module.name] ||= self.new(base_module)
end

def get(constant_name)
  @constant_spies[constant_name]
end

def get(base_module)
  all[base_module.name]
end

def hooked?(constant_name)
  !!get(constant_name)
end

def hooked_constants
  @constant_spies.keys
end

def initialize(base_module)
  raise ArgumentError, "#{base_module} is not a kind of Module" unless base_module.is_a?(Module)
  @base_module = base_module
  @constant_spies = {}
end

def remove(spy)
  if @constant_spies[spy.constant_name] == spy
    @constant_spies.delete(spy.constant_name)
  else
    raise NoSpyError, "#{spy.constant_name} was not stubbed on #{base_module.name}"
  end
  self
end