Javascript 使用“测试函数”；新"；sinon中的关键字

我在ES6类中有一个函数，它使用“new”关键字调用另一个类的构造函数。当我使用sinon测试该类时，我得到一个错误，在测试中声明如下：“TypeError:Game不是构造函数”。下面是我需要测试的函数的代码：

createMatch(hostID, pub) {
    let matchID = mongoose.Types.ObjectId().toString();
    let game = new Game(matchID);
    game.init();
    game.setHost(hostID);
    ....
}

这是测试本身。我尝试过使用createStubInstance（）、callsFake等，但没有任何效果：

it("Need to group private and public games into separate maps.", () => {
    //Tried to stub the constructor here
    const publicMatch = MatchManager.createMatch("aHost1", true);
    const privateMatch = MatchManager.createMatch("aHost2", false);
    notEqual(publicMatch, undefined);notEqual(publicMatch, null);
    notEqual(privateMatch, undefined);notEqual(privateMatch, null);
    notEqual(publicMatch.matchID, undefined);
    notEqual(privateMatch.matchID, undefined);
    notEqual(publicMatch.matchID, null);
    notEqual(privateMatch.matchID, null);
    notEqual(MatchManager.publicMatches.get("aHost1"), undefined);
    equals(MatchManager.publicMatches.get(publicMatch.matchID), true);
    equals(MatchManager.privateMatches.get("aHost1"), undefined);
    
    notEqual(MatchManager.privateMatches.get("aHost2"), undefined)
    equals(MatchManager.privateMatches.get(privateMatch.matchID), false);
    notEqual(MatchManager.publicMatches.get("aHost2"), undefined)
});