fix test

src/test/distributed/checkpoint_test.py

@@ -449,7 +449,12 @@ def run_save_and_load_fsdp_model(dir, model_factory, model_data_factory, pre_ini
 
     # Check optimizer state.
     for p1, p2 in zip(fsdp_model.parameters(), fsdp_model2.parameters()):
-        torch.testing.assert_close(optim.state[p1], optim2.state[p2])
+        if p1.numel() > 0:
+            torch.testing.assert_close(optim.state[p1], optim2.state[p2])
+        else:
+            for key in ("exp_avg", "exp_avg_sq"):
+                assert key not in optim.state or optim.state[p1][key].numel() == 0
+                assert key not in optim2.state or optim2.state[p2][key].numel() == 0
 
     # Check unsharding model state.
     full_model_state = unshard_model_state(dir)