fix checkpoint UT

Author: Saiteja64

tests/unit_tests/test_checkpoint.py

@@ -420,15 +420,15 @@ def test_async_save_calls_async_wait(self, mock_async_save, mock_new_group):
 
         # First save schedules async
         manager.save(curr_step=10, last_step=False)
-        future = manager.async_future
+        future = manager.save_future
         future.result.assert_not_called()
 
         # Second save should wait
         manager.save(curr_step=20, last_step=False)
         future.result.assert_called_once()
 
         # New future created
-        new_future = manager.async_future
+        new_future = manager.save_future
         new_future.result.assert_not_called()
 
     @mock.patch("torch.cuda.Stream")
@@ -461,16 +461,16 @@ def test_ft_async_save_calls_async_wait(
         )
 
         # Initially no future
-        self.assertIsNone(manager.async_future)
+        self.assertIsNone(manager.save_future)
         manager.save(curr_step=5, last_step=False)
-        self.assertIsNotNone(manager.async_future)
+        self.assertIsNotNone(manager.save_future)
 
-        manager.async_future.result.assert_not_called()
-        prev_future = manager.async_future
+        manager.save_future.result.assert_not_called()
+        prev_future = manager.save_future
         manager.save(curr_step=6, last_step=False)
         prev_future.result.assert_called_once()
-        self.assertIsNotNone(manager.async_future)
-        manager.async_future.result.assert_not_called()
+        self.assertIsNotNone(manager.save_future)
+        manager.save_future.result.assert_not_called()
 
     @mock.patch("torch.distributed.get_rank", return_value=0)
     @mock.patch("torchtitan.components.checkpoint.dcp.save")