'Wrapper utility that returns a test server.
This wrapper utility calls the common create test server and
returns a test server. The purpose of this wrapper is to minimize
the impact on the code of the tests already using this
function.
:param validatable: Whether the server will be pingable or sshable.
:param volume_backed: Whether the instance is volume backed or not.'

@classmethod
def create_test_server(cls, validatable=False, volume_backed=False, **kwargs):

    if ('name' not in kwargs):
        kwargs['name'] = data_utils.rand_name((cls.__name__ + '-server'))
    request_version = api_version_request.APIVersionRequest(cls.request_microversion)
    v2_37_version = api_version_request.APIVersionRequest('2.37')
    if ((request_version >= v2_37_version) and ('networks' not in kwargs)):
        kwargs['networks'] = 'none'
    tenant_network = cls.get_tenant_network()
    (body, servers) = compute.create_test_server(cls.os_primary, validatable, validation_resources=cls.validation_resources, tenant_network=tenant_network, volume_backed=volume_backed, **kwargs)
    cls.servers.extend(servers)
    return body
