'reflects the loading state in the `loading` property', function() {
          var request = ajax.generateRequest();

          expect(ajax.loading).to.be.equal(true);

          server.respond();

          return request.completes.then(function() {
            return timePasses(1);
          }).then(function() {
            expect(ajax.loading).to.be.equal(false);
          });
        });

        test('the `iron-ajax-presend` event gets fired', function() {
          var spy = sinon.spy();
          var