写单元测试如何接收异步nsnotification？

Question

我使用完成处理程序调用其余的Web服务，如果成功，我将发送NSNotification。

问题是如何编写单元测试以断言在成功的情况下将发送通知。

任何帮助将不胜感激。

Answer 1

您可以为通知添加期望：

expectationForNotification("BlaBlaNotification", object: nil) { (notification) -> Bool in

// call the method that fetches the data
sut.fetchData()  

waitForExpectationsWithTimeout(5, handler: nil)

但是我个人将这分为两个测试。一种用于获取数据（使用存根进行了测试），另一种用于发送通知。

Answer 2

这是我测试通知的方式：

func testDataFetched() {

    weak var expectation = self.expectation(description: "testDataFetched")

    //set the notification name to whatever you called it
    NotificationCenter.default.addObserver(forName: NSNotification.Name("dataWasFetched"), object: nil, queue: nil) { notification in

        //if we got here, it means we got our notification within the timeout limit

        //optional: verify userInfo in the notification if it has any

        //call fulfill and your test will succeed; otherwise it will fail
        expectation?.fulfill()
    }

    //call your data fetch here
    sut.fetchData()

    //you must call waitForExpectations or your test will 'succeed'
    // before the notification can be received!
    // also, set the timeout long enough for your data fetch to complete
    waitForExpectations(timeout: 1.0, handler: nil)
}