Add websocket-undertow smoke test

Closes gh-73

websocket-undertow/src/main/java/com/example/websocket/undertow/WebSocketConfig.java

@@ -0,0 +1,31 @@
+package com.example.websocket.undertow;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.socket.client.WebSocketClient;
+import org.springframework.web.socket.client.standard.StandardWebSocketClient;
+import org.springframework.web.socket.config.annotation.EnableWebSocket;
+import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
+import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
+
+@Configuration
+@EnableWebSocket
+public class WebSocketConfig implements WebSocketConfigurer {
+
+	private final EchoWebSocketHandler echoWebSocketHandler;
+
+	public WebSocketConfig(EchoWebSocketHandler echoWebSocketHandler) {
+		this.echoWebSocketHandler = echoWebSocketHandler;
+	}
+
+	@Override
+	public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
+		registry.addHandler(this.echoWebSocketHandler, "/echo");
+	}
+
+	@Bean
+	public WebSocketClient webSocketClient() {
+		return new StandardWebSocketClient();
+	}
+
+}