Setting cookies before page load in a CasperJS test.

casper.cookies.spec.js

casper.test.setUp(function () {
  casper.echo('Cookies enabled?: ' + phantom.cookiesEnabled);
  phantom.addCookie({
      domain: '.localhost',
      name: 'sessionId',
      value: '12345abcd6789efg'
  });
  casper.start("http://localhost:8000/test_index.html#pageRequiringLogin", function () {
    casper.echo('Start callback has cookie: ' + JSON.stringify(phantom.cookies));
  });
});
casper.test.begin("Should do usefull stuff", function (test) {
  // …
});