diff --git a/test/base/test_env.py b/test/base/test_env.py
index 432fdd1..6697b47 100644
--- a/test/base/test_env.py
+++ b/test/base/test_env.py
@@ -40,7 +40,12 @@ def test_async_env(num=8, sleep=0.1):
         env_ids = b.info.env_id
         o.append(b)
         current_index_start += len(action)
+        # len of action may be smaller than len(A) in the end
         action = action_list[current_index_start: current_index_start + len(A)]
+        # truncate env_ids with the first terms
+        # typically len(env_ids) == len(A) == len(action), except for the
+        # last batch when actions are not enough
+        env_ids = env_ids[: len(action)]
     spent_time = time.time() - spent_time
     data = Batch.cat(o)
     # assure 1/7 improvement