[test] fix test_ajax js tests. We have to mock some of our js functions / variables (e.g. _ or pageid) in the test environment
/*
* 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;
}