Swagger失败的Mocha单元测试

Question

我对Node JS非常陌生。我已经编写了一个swagger API，现在我正在使用mocha库为其编写测试用例。以下是我的test.js文件，但出现错误。

var assert = require("assert");
var should = require('chai').should();
var testAssistants = require("swagger-test");

describe('Test API', function () {
    var invokeAPI;
    before(function (done) {
        testAssistants.parse('../api/swagger.yaml',
            function (authInvoker, error) {
                if (error) {
                    console.log("Cannot proceed: Swagger file is invalid");
                    error.every(function (error) {
                        console.log(error);
                    });
                    process.exit();
                } else {
                    invokeAPI = authInvoker;
                }
                done();
            });
    });

    describe('http://localhost:8080/v1/id/123/test', function () {
        it('should give results', function (done) {
            this.timeout(10000);
            var result = invokeAPI("GET", "/v1/id/123/test", {});
            let resJson = result._getJSON();
            testAssistants.assertSwaggerResult(result, 200);
            result.response.body.length.should.be.greaterThan(0);
            should.equal(resJson.length, 2);
            done();
        });
    });
})

我正在使用node_modules/.bin/mocha运行测试类，并出现以下错误：

"before all" hook in "Test API":
     Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (D:\test-node-api\test\test.js)

我想念什么？