xCode 8 / Swift 3中的iOS异步单元测试(waitForExpectations失败)

override func setUp() {
        super.setUp()
        validationExpectation = expectation(description: "Validation")
}

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func testSymbolrequest(){

        _ = MyCocoapod.makeSymbolrequest(symbol: "ABC",success: { (symbolObject) in
            self.validationExpectation.fulfill()
            XCTAssert(true)
        }) { (error) in
            self.validationExpectation.fulfill()
            XCTFail(error.description)
        }

        waitForrequestToFinish()
}

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func waitForrequestToFinish(){
    waitForExpectations(timeout: 60.0) { (error) in
        if let error = error {
            XCTFail(error.localizedDescription)
        }
    }
}

waitForExpectations函数根本没有等待.被叫后立即失败.我还确认这与我的实际网络代码无关,并且请求在我的Cocoapod示例项目中完美运行.我正在使用Alamofire.我不认为这是问题,但我认为值得一提.打印出的错误消息是“未知错误”.