add sketch used for testing

Author: umbynos

test/test_ws.py

@@ -20,7 +20,7 @@ def test_list(socketio):
     assert any("Ports" in i for i in message)
     assert any("Network" in i for i in message)
 
-# NOTE run the following tests on linux with a board connected to the PC and with this sketch on it: https://gist.github.com/Protoneer/96db95bfb87c3befe46e
+# NOTE run the following tests on linux with a board connected to the PC and with the sketch found in test/testdata/SerialEcho.ino on it
 @pytest.mark.skipif(
     running_on_ci(),
     reason="VMs have no serial ports",

test/testdata/SerialEcho.ino

@@ -0,0 +1,18 @@
+int incomingByte = 0;    // for incoming serial data
+
+void setup() {
+    Serial.begin(9600);    // opens serial port, sets data rate to 9600 bps
+}
+
+void loop() {
+  // send data only when you receive data:
+  if (Serial.available() > 0) {
+  
+    // read the incoming byte:
+    incomingByte = Serial.read();
+  
+    // say what you got:
+    Serial.print((char)incomingByte);
+  }
+  
+}