Fix misleading line for creating list of models in rollout_test.py

PiperOrigin-RevId: 717582208
Change-Id: I1b4e40fc5ccbfe68fb7dc240715c704f1f68d9fe

python/mujoco/rollout_test.py

@@ -15,6 +15,7 @@
 """tests for rollout function."""
 
 import concurrent.futures
+import copy
 import threading
 
 from absl.testing import absltest
@@ -23,6 +24,7 @@ import mujoco
 from mujoco import rollout
 import numpy as np
 
+
 # -------------------------- models used for testing ---------------------------
 
 TEST_XML = r"""
@@ -473,7 +475,7 @@ class MuJoCoRolloutTest(parameterized.TestCase):
     def thread_initializer():
       thread_local.data = mujoco.MjData(model)
 
-    model_list = [model] * nroll
+    model_list = [copy.copy(model) for _ in range(nroll)]
 
     def call_rollout(initial_state, control, state, sensordata):
       rollout.rollout(