jQuery完成或失败不触发

Question

我在这里错过了什么：

var Services = {
    TestService: {
        init: function() {
            var promises = [];
            for (var i = 0; i < 3; i++) {
                var def = $.Deferred();
                Services.TestService.test(i).then(function(a) {
                    def.resolve();
                }, function() {
                    console.log("test rejected");
                    def.reject();
                });
                promises.push(def.promise());
            }

            $.when.apply($, promises).then(function() {
                console.log("Finished all promises");
            }, function() {
                console.log("eror");
            });
        },
        test: function(i) {
            var def = $.Deferred();
            setTimeout(function() {
                console.log("test timeout expired: " + i.toString());
                def.resolve("ok: " + i.toString());
            }, 1000);
            return def.promise();
        }
    }
}

Services.TestService.init();

它只打印：

test timeout expired: 0
test timeout expired: 1
test timeout expired: 2

为什么没有when完成或失败（当时实施）启动。我错过了什么细节？使用jQuery 1.9.1。 （<script type="text/javascript" src="http://code.jquery.com/jquery-1.9.1.js"></script>）