with_constants

# see http://stackoverflow.com/questions/1698335/can-i-use-rspec-mocks-to-stub-out-version-constants
class Object
  def self.with_constants(constants, &block)
    saved_constants = {}
    constants.each do |constant, val|
      saved_constants[ constant ] = const_get( constant )
      Kernel::silence_warnings { const_set( constant, val ) }
    end

    begin
      block.call
    ensure
      constants.each do |constant, val|
        Kernel::silence_warnings { const_set( constant, saved_constants[ constant ] ) }
      end
    end
  end
end

class Module
  def with_constants(constants, &block)
    saved_constants = {}
    constants.each do |constant, val|
      saved_constants[ constant ] = const_get( constant )
      Kernel::silence_warnings { const_set( constant, val ) }
    end

    begin
      block.call
    ensure
      constants.each do |constant, val|
        Kernel::silence_warnings { const_set( constant, saved_constants[ constant ] ) }
      end
    end
  end
end