茉莉花测试承诺未知错误

Question

在使用jasmine + karma + phantomjs + es6-promises（npm lib）进行测试时，发现了以下问题，但我找不到正在发生的事情。我想知道是否有人可以查看并帮助确定问题：

at formatError (/usr/local/lib/node_modules/gulp-cli/lib/versioned/^3.7.0/formatError.js:20:10)
at Gulp.<anonymous> (/usr/local/lib/node_modules/gulp-cli/lib/versioned/^3.7.0/log/events.js:41:15)
at emitOne (events.js:90:13)
at Gulp.emit (events.js:182:7)
at Gulp.Orchestrator._emitTaskDone (/Users/helder/www/coach-test/node_modules/orchestrator/index.js:264:8)
at /Users/helder/www/coach-test/node_modules/orchestrator/index.js:275:23
at finish (/Users/helder/www/coach-test/node_modules/orchestrator/lib/runTask.js:21:8)
at cb (/Users/helder/www/coach-test/node_modules/orchestrator/lib/runTask.js:29:3)
at removeAllListeners (/Users/helder/www/coach-test/node_modules/karma/lib/server.js:379:7)
at Server.<anonymous> (/Users/helder/www/coach-test/node_modules/karma/lib/server.js:390:9)
at Server.g (events.js:273:16)
at emitNone (events.js:85:20)
at Server.emit (events.js:179:7)
at emitCloseNT (net.js:1514:8)
at nextTickCallbackWith1Arg (node.js:464:9)
at process._tickCallback (node.js:386:17)

我有一个执行XHR请求的方法：

function List (params) {
    this.init(params);
}

List.prototype = {
    init: function (params) {
       // ....
    },

    requestData: function (url) {

        var promise = new Promise(function (resolve, reject) {

            var xhr = new XMLHttpRequest();

            xhr.open("GET", url, true);

            xhr.onreadystatechange = function (ev) {
                if (xhr.readyState === 4) {
                    if (xhr.status === 200) {
                        console.log(xhr.responseText);
                        resolve(xhr.responseText);
                    } else {
                        reject(Error(xhr.statusText));
                    }
                }
            };

            xhr.send(null);

        });

        return promise;

    }

};

module.exports = List;

茉莉花测试规范：

describe("List generator", function () {

    var request = null;
    var list = new List({ autoload: false });

    beforeEach(function (done) {

        jasmine.Ajax.install();

        list.requestData(config.api).then(function () {
            done();
        });

        request = jasmine.Ajax.requests.mostRecent();
        expect(request.url).toBe(config.api);
        expect(request.method).toBe('GET');

    });

});