diff --git a/src/key/keystate.rs b/src/key/keystate.rs
index ac5a426..60b7f8c 100644
--- a/src/key/keystate.rs
+++ b/src/key/keystate.rs
@@ -59,4 +59,16 @@ impl KeyState {
             OsString::from_wide(&out[..null_pos]).to_str().unwrap().to_owned()
         }
     }
-}
\ No newline at end of file
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::key::keystate::KeyState;
+
+    #[test]
+    fn is_aux_key() {
+        let mut k = KeyState::new();
+        k.kbdllstruct.vkCode = 160;
+        assert!(k.is_aux_key());
+    }
+}