[transaction] handle ``mode`` default value in Transaction The transaction mode is now explicitly passed at creation time and always read from the Transaction object. Note that there is a slight behavior change. The transaction mode is now set at the creation of the transaction. Changes made to the default value have no longer any effect on existing transaction.

/*
 * cubicweb js mock for unit tests
 * This module defines variables and functions used in quite a few places
 * in cw js framework that can't be used or guessed without a real CW server
 */

var pageid = 'my-page-id';

function _(message) {
    return message;
}