How to write Unit Test Cases for Gorilla Websocket - go

Question

I need to write unit test cases for Gorilla Web-socket.
var upgrader = websocket.Upgrader{} // use default options
func socketHandler(w http.ResponseWriter, r *http.Request) {
// Upgrade our raw HTTP connection to a websocket based one
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Print("Error during connection upgradation:", err)
return
}
defer conn.Close()
// The event loop
for {
messageType, message, err := conn.ReadMessage()
if err != nil {
log.Println("Error during message reading:", err)
break
}
log.Printf("Received: %s", message)
err = conn.WriteMessage(messageType, message)
if err != nil {
log.Println("Error during message writing:", err)
break
}
}
}
func home(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Index Page")
}
func main() {
http.HandleFunc("/socket", socketHandler)
http.HandleFunc("/", home)
log.Fatal(http.ListenAndServe("localhost:8080", nil))
}
I want to write the Unit Test case for socketHandler function. How should I go about it?

Answer 1

Spin up an httptest.Server with the websocket endpoint. Dial the server with the websocket client. Send and receive messages as needed.
Here's a simple example:
func TestWs(t *testing.T) {
s := httptest.NewServer(http.HandlerFunc(socketHandler))
defer s.Close()
wsURL := "ws" + strings.TrimPrefix(s.URL, "http")
c, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
if err != nil {
t.Error(err)
}
defer c.Close()
// Write a message.
c.WriteMessage(websocket.TextMessage, []byte("hello"))
// Expect the server to echo the message back.
c.SetReadDeadline(time.Now().Add(time.Second * 2))
mt, msg, err := c.ReadMessage()
if err != nil {
t.Error(err)
}
if mt != websocket.TextMessage || string(msg) != "hello" {
t.Errorf("expected text hello, got %d: %s", mt, msg)
}
}
Run the example on the playground.
To test a client, write a server endpoint that sends as receives messages as needed for a test. Run your client code against the endpoint as above.