public async Task SignUpTaskAsyncTestTask()
    {
        // テストデータ作成
        NCMBUser user = new NCMBUser();

        user.UserName = "******";
        user.Password = "******";
        user.Email    = "*****@*****.**";

        // 会員登録
        var result = await user.SignUpTaskAsync();

        Assert.AreEqual("dummyObjectId", result.ObjectId);

        // 登録成功の確認
        Assert.IsNotEmpty(NCMBUser._getCurrentSessionToken());
        Assert.True(NCMBTestSettings.CallbackFlag);
    }