Angular4单元测试错误`TypeError：ctor不是构造函数`

我试图测试我的路由解析器，测试时我得到了TypeError: ctor is not a constructor，但不知道为什么会发生，而typescript编译时没有错误.

TypeError: ctor is not a constructor
TypeError: ctor is not a constructor
    at _createClass (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42355:26)
    at _createProviderInstance$1 (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42330:26)
    at resolveNgModuleDep (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42315:17)
    at _createClass (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42362:26)
    at _createProviderInstance$1 (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42330:26)
    at resolveNgModuleDep (http://localhost:9877/_karma_webpack_/vendor.bundle.js:42315:17)
    at NgModuleRef_.webpackJsonp../node_modules/@angular/core/@angular/core.es5.js.NgModuleRef_.get (http://localhost:9877/_karma_webpack_/vendor.bundle.js:43401:16)
    at TestBed.webpackJsonp../node_modules/@angular/core/@angular/core/testing.es5.js.TestBed.get (http://localhost:9877/_karma_webpack_/vendor.bundle.js:48412:47)
    at http://localhost:9877/_karma_webpack_/vendor.bundle.js:48418:61
    at Array.map (native)