'When --add-header is specified, the resource is a composition that adds
headers.'

def test_add_header_resource(self):

    options = Options()
    options.parseOptions(['--add-header', 'K1:    V1', '--add-header', 'K2:    V2'])
    service = makeService(options)
    resource = service.services[0].factory.resource
    self.assertIsInstance(resource, _AddHeadersResource)
    self.assertEqual(resource._headers, [('K1', 'V1'), ('K2', 'V2')])
    self.assertIsInstance(resource._originalResource, demo.Test)
