如何编写接收NSNotification异步的单元测试？

Question

我使用完成处理程序调用rest web服务，如果成功，我会发送NSNotification。

问题是如何编写单元测试来断言在成功的情况下是否发送了通知。

任何帮助将不胜感激。

- Abdelrahman

---

例如，xctestexpectation 可以作为解决您的 异步调用 问题的工具。 - gaussblurinc

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)

但是我个人会将其分为两个测试。一个用于获取数据（使用存根进行测试），另一个用于发送通知。

- dasdom

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"SUT" 是 "System Under Test" 的缩写。 - dasdom

Answer 2

This is how I test notifications:

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)
}

- Mike Taverne