func testAddRemoveListeners()

in AppSyncRealTimeClientTests/ConnectionProvider/ConnectionProviderTests.swift [70:125]
42 lines of code
2 McCabe index (conditional complexity)

    func testAddRemoveListeners() {
        receivedNotConnected.isInverted = true
        receivedError.isInverted = true

        let onConnect: MockWebsocketProvider.OnConnect = { _, _, delegate in
            self.websocketDelegate = delegate
            DispatchQueue.global().async {
                delegate?.websocketDidConnect(provider: self.websocket)
            }
        }

        let receivedDisconnect = expectation(description: "receivedDisconnect")
        let onDisconnect: MockWebsocketProvider.OnDisconnect = {
            receivedDisconnect.fulfill()
        }

        let onWrite: MockWebsocketProvider.OnWrite = { message in
            guard RealtimeConnectionProviderTestBase.messageType(of: message, equals: "connection_init") else {
                XCTFail("Incoming message did not have 'connection_init' type")
                return
            }

            self.websocketDelegate.websocketDidReceiveData(
                provider: self.websocket,
                data: RealtimeConnectionProviderTestBase.makeConnectionAckMessage()
            )
        }

        websocket = MockWebsocketProvider(
            onConnect: onConnect,
            onDisconnect: onDisconnect,
            onWrite: onWrite
        )

        // Retain the provider so it doesn't release prior to executing callbacks
        let provider = createProviderAndConnect(listeners: ["1", "2", "3", "4"])

        wait(
            for: [receivedInProgress, receivedConnected, receivedNotConnected, receivedError],
            timeout: 1
        )

        XCTAssertFalse(provider.listeners.isEmpty)

        let listenersToRemove = provider.listeners.map { $0.key }

        // Removing all the listeners will disconnect the websocket connection
        for identifier in listenersToRemove {
            provider.removeListener(identifier: identifier)
        }

        // Since removing listeners is asynchronous, we have to wait for the disconnect
        wait(for: [receivedDisconnect], timeout: 1)
        XCTAssertTrue(provider.listeners.isEmpty)
        XCTAssertEqual(provider.status, .notConnected)
    }