erver.requests = [];

            // Explicitly setting url to '' works too.
            ajax = fixture('BlankUrl');
            ajax.url = '';
            return timePasses(1);
          }).then(function() {
            expect(server.requests.length).to.be.equal(1);
          });
        });

        test('requestUrl remains empty despite valid queryString', function() {
          ajax = fixture('BlankUrl');
          expect(ajax.url).to.be.equal(undefined);
          expect(ajax.queryString).to.be.equal('