Add unit tests for `NWWaitingHandler`

[dnadoba]

When we added NWWaitingHandler in #588 we didn’t add a unit test for the NWWaitingHandler. This is because we need to make an enhancement to NIOTransportServices to make the WaitingForConnectivity event initialiser public. This is tracked as a separate issue in apple/swift-nio-transport-services#147 and must be resolved first.

The unit test can be implemented by using an EmbeddedChannel and sending an NIOTSNetworkEvents.WaitingForConnectivity through fireUserInboundEventTriggered(_:). An example usage of EmbeddedChannel and fireUserInboundEventTriggered(_:) can be found here:

async-http-client/Tests/AsyncHTTPClientTests/TLSEventsHandlerTests.swift

Lines 24 to 32 in 3fcd670

	let tlsEventsHandler = TLSEventsHandler(deadline: nil)
	XCTAssertNil(tlsEventsHandler.tlsEstablishedFuture)
	let embedded = EmbeddedChannel(handlers: [tlsEventsHandler])
	XCTAssertNotNil(tlsEventsHandler.tlsEstablishedFuture)
	XCTAssertNoThrow(try embedded.connect(to: .makeAddressResolvingHost("localhost", port: 0)).wait())
	embedded.pipeline.fireUserInboundEventTriggered(TLSUserEvent.handshakeCompleted(negotiatedProtocol: "abcd1234"))
	XCTAssertEqual(try XCTUnwrap(tlsEventsHandler.tlsEstablishedFuture).wait(), "abcd1234")

This should be straight forward and a good first starter issue. If you have more questions please don't hesitate to ask here.

[NiwakaDev]

Hi, @dnadoba.

I'd like to address this issue.

This is tracked as a separate issue in apple/swift-nio-transport-services#147 and must be resolved first.

Have this been resolved already? If so, I'd like to work on this issue next week.

[dnadoba]

Yes, the initialisers are now public and you can address the issue. PRs welcome :)