module ActionController::TestCase::Behavior

def xml_http_request(request_method, action, parameters = nil, session = nil, flash = nil)
  @request.env['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
  @request.env['HTTP_ACCEPT'] ||=  [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
  __send__(request_method, action, parameters, session, flash).tap do
    @request.env.delete 'HTTP_X_REQUESTED_WITH'
    @request.env.delete 'HTTP_ACCEPT'
  end
end