diff --git a/src/kernel/thread_manager.rs b/src/kernel/thread_manager.rs
index 962b3f4..2de0449 100644
--- a/src/kernel/thread_manager.rs
+++ b/src/kernel/thread_manager.rs
@@ -443,7 +443,7 @@ mod test {
     }
 
     #[test]
-    fn test_lock(){
+    fn test_lock_single(){
         let mut machine = Machine::new(true, get_debug_configuration());
         let mut thread_manager = ThreadManager::new(true);
         let lock = Lock::new();
@@ -470,6 +470,53 @@ mod test {
         }
     }
 
+    #[test]
+    fn test_lock_multiple() {
+        let mut machine = Machine::new(true, get_debug_configuration());
+        let mut thread_manager = ThreadManager::new(true);
+        let lock = Lock::new();
+        let lock_id = thread_manager.get_obj_addrs().add_lock(lock);
+        let thread_1 = Rc::new(RefCell::new(Thread::new("test_lock_1")));
+        let thread_2 = Rc::new(RefCell::new(Thread::new("test_lock_2")));
+        let thread_test_1 = thread_1.clone();
+        let thread_test_2 = thread_2.clone();
+        thread_manager.ready_to_run(Rc::clone(&thread_1));
+        thread_manager.ready_to_run(Rc::clone(&thread_2));
+        thread_manager.set_g_current_thread(Some(thread_1));
+
+        thread_manager.lock_acquire(lock_id, &mut machine).expect("lock acquire return an error at first iteration: ");
+        {
+            let lock = thread_manager.get_obj_addrs().search_lock(lock_id).unwrap();
+            assert_eq!(lock.owner,Some(thread_test_1.clone()));
+            assert!(!lock.free);
+            assert!(lock.waiting_queue.is_empty());
+        }
+
+        thread_manager.set_g_current_thread(Some(thread_2));
+        thread_manager.lock_acquire(lock_id, &mut machine).expect("lock acquire return an error at second iteration: ");
+        {
+            let lock = thread_manager.get_obj_addrs().search_lock(lock_id).unwrap();
+            assert_eq!(lock.owner,Some(thread_test_1));
+            assert!(!lock.free);
+            assert_eq!(lock.waiting_queue.iter().count(),1);
+        }
+        thread_manager.lock_release(lock_id, &mut machine).expect("lock release return an error at first iteration: ");
+        {
+            let lock = thread_manager.get_obj_addrs().search_lock(lock_id).unwrap();
+            assert_eq!(lock.owner, Some(thread_test_2));
+            assert!(!lock.free);
+            assert!(lock.waiting_queue.is_empty());
+        }
+        thread_manager.lock_release(lock_id, &mut machine).expect("lock release return an error at second iteration: ");
+        {
+            let lock = thread_manager.get_obj_addrs().search_lock(lock_id).unwrap();
+            assert_eq!(lock.owner, None);
+            assert!(lock.free);
+            assert!(lock.waiting_queue.is_empty());
+        }
+    }
+
+
     #[test]
     fn test_semaphore_single() {
         // Init