diff --git a/src/device/keyboard.rs b/src/device/keyboard.rs
index 562e41b..78840c5 100644
--- a/src/device/keyboard.rs
+++ b/src/device/keyboard.rs
@@ -50,7 +50,7 @@ impl Keyboard {
 
     /// Query if key is down
     pub fn query_key_down(&self, key_num: u8) -> bool {
-        (self.bitflags | 1 << key_num) == (1 << key_num)
+        (self.bitflags & (1 << key_num)) == (1 << key_num)
     }
 
     fn update_keyboard_state(&mut self, keyboard_event: KeyboardEvent) {
@@ -67,11 +67,53 @@ impl Keyboard {
 
 #[cfg(test)]
 mod tests {
-    use super::Key;
+    use super::{Key, Keyboard};
 
     #[test]
     fn test_key_assignment(){
         assert_eq!(0,Key::K0 as u16);
         assert_eq!(15,Key::KF as u16);
     }
+
+    #[test]
+    fn test_key_at_nothing_pressed(){
+        let (_sender,receiver) = std::sync::mpsc::sync_channel(1);
+        let keyboard = Keyboard::new(receiver);
+        assert_no_key_pressed(&keyboard);
+        
+    }
+
+    #[test]
+    fn test_key_down_then_up(){
+        let (sender,receiver) = std::sync::mpsc::sync_channel(1);
+        let mut keyboard = Keyboard::new(receiver);
+        assert_no_key_pressed(&keyboard);
+        
+        
+        sender.try_send(super::KeyboardEvent::KeyDown(Key::K0)).expect("Could not send");
+        keyboard.update_keyboard_registers().expect("Could not update keyboard");
+        
+        
+        assert_eq!(1,keyboard.bitflags);
+        assert_eq!(true,keyboard.query_key_down(0));
+        for i in 1..=0xF {
+            assert_eq!(false,keyboard.query_key_down(i));
+        }
+
+
+        
+        sender.try_send(super::KeyboardEvent::KeyUp(Key::K0)).expect("Could not send");
+        keyboard.update_keyboard_registers().expect("Could not update keyboard");
+        assert_no_key_pressed(&keyboard);
+    }
+
+    fn assert_no_key_pressed(keyboard: &Keyboard){
+        assert_eq!(0,keyboard.bitflags);
+        for i in 0..=0xF {
+            assert_eq!(false,keyboard.query_key_down(i),"Failed to match at index {}, bitflags at {}",i,keyboard.bitflags);
+        }
+    }
+
+    
+
 }