newbie problem with knob

Hello, I am a beginner and I am using grove shield. I post here because it looks like a bug or something missing on my side concerning programming. I just wanted to test a knob on analog A0 input and output to serial port only when the value changes… The code is this:

int knob = A0;
int test_value = 0.;
int knob_level = 0.;
void setup() {
// put your setup code here, to run once:
void loop() {
knob_level = analogRead(knob);
if (test_value != knob_level) {
int test_value = knob_level;
Serial.print("test_value = ");
Serial.print("knob_level = ");

It just keep sending out values even if the knob is not moving (and so the new and old value are the same) it works only for ZERO… am i missing something?
Thanks a lot, sorry for the newbie question
Screen Shot 2015-04-30 at 21.48.44.png


int test_value = knob_level;

try to delete int.

test_value = knob_level;