Go testing websockets

I am trying to write testing for my chat API in go, but I am pretty new to testing in go. I can't find proper examples on how to test more complex functions. For example I have this function where I send messages from a particular websocket to the broadcast channel, however I can't imagine a way to test it. Could someone help me? here is the function:

func sendMessages(ws *websocket.Conn){
for {
    var msg Message
    // Read in a new message as JSON and map it to a Message object
    err := ws.ReadJSON(&msg)
    if err != nil {
        log.Printf("error: %v", err)
        delete(clients, ws)
        break
    }
    // Send the newly received message to the broadcast channel
    broadcast <- msg
    saveMessage(msg)
}

}