我试图写一个XCTest测试套接字连接。下面是我的连接代码的大致样子:
public class MyConnection: NSObject, NSStreamDelegate {
private let queue = NSOperationQueue()
private var inputStream: NSInputStream!
private var outputStream: NSOutputStream!
public func connect() {
println("Attempting to connect")
queue.addOperationWithBlock() {
var readStream: Unmanaged<CFReadStream>?
var writeStream: Unmanaged<CFWriteStream>?
CFStreamCreatePairWithSocketToHost(nil,
"[my ip address]",
8333,
&readStream,
&writeStream);
if readStream == nil || writeStream == nil {
println("Connection failed")
return
}
self.inputStream = readStream!.takeUnretainedValue()
self.outputStream = writeStream!.takeUnretainedValue()
self.inputStream.delegate = self
self.outputStream.delegate = self
self.inputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode:NSDefaultRunLoopMode)
self.outputStream.scheduleInRunLoop(NSRunLoop.currentRunLoop(), forMode:NSDefaultRunLoopMode)
self.inputStream.open()
self.outputStream.open()
}
}
// MARK: - NSStreamDelegate
public func stream(stream: NSStream!, handleEvent event: NSStreamEvent) {
println("THIS NEVER GETS CALLED!")
// Notifies delegate that connection opened.
}
}
我编写的XCTestCase基本上只是调用connect()方法,并等待连接成功后调用委托方法。但是,委托方法永远不会被调用。我需要做一些特别的事情来让它在我的测试中起作用吗?
这在我的单元测试中失败的事实是转移注意力。这段代码不能工作是因为NSOperationQueue的工作方式。队列动态地创建和销毁线程。所以我在运行循环中为一个寿命很短的线程调度我的流。因此,我的回调函数永远不会被调用,因为run循环被销毁了。
正确的解决方案是直接创建一个NSThread,并从该线程中使用run循环,而不是尝试使用队列。