class RSpec::Matchers::BuiltIn::RaiseError

def initialize(expected_error_or_message=Exception, expected_message=nil, &block)
  @block = block
  @actual_error = nil
  case expected_error_or_message
  when String, Regexp
    @expected_error, @expected_message = Exception, expected_error_or_message
  else
    @expected_error, @expected_message = expected_error_or_message, expected_message
  end
end