由promises创建的回调中的断言超时

Question

我有一个中间件，它根据传递的参数检查用户身份验证。中间件使用一个实现promises的模型来查找并返回要设置为请求参数的用户。

问题是，在运行测试时，如果断言失败，测试会超时，大概是因为失败的断言抛出的异常无法由Mocha处理。

我在next（）函数中执行断言 - 当测试未提供密钥时，它正常工作，我假设因为它不是在promise的上下文中运行。

# Authenticator
var Authentication = function(model) {
    this.model = model;
};

Authentication.prototype.resolve = function(customerKey) {
    return this.model.authenticate(customerKey);
};

module.exports = function(model) {
    return function(req, res, next) {
        if (!req.query.hasOwnProperty('customerKey')) {
            throw new Error('There was no auth key provided');
        }

        var auth = new Authentication(model);

        auth.resolve(req.query.customerKey)
        .then(function(customer) {
            if (!customer) {
                throw new Error('There was no customer found with the supplied auth key');
            }

            req.params.auth = customer;
        })
        .done(next, next);
    };
};

# Test
var should          = require('chai').should(),
    authentication  = require('src/api/middleware/authentication'),
    model           = require('src/models/customer'),
    auth            = authentication(model);

describe('middleware/authentication', function() {
    it('should set the user to the request if the customerKey is valid', function(done) {
        var request = {
            query: {
                customerKey: 'thisIsValid'
            },
            params: {}
        };

        var response = function() {
            // This is a no-op
        };

        var next = function(response) {
            response.should.be.instanceOf(String); // If this assertion fails, the test times out and doesn't work
            response.should.have.property('name');
            response.name.should.be.a('string');

            done();
        };

        // Actually calls the auth 
        auth(request, response, next);
    });
});