--- a
+++ b/tests/test.rollback.py
@@ -0,0 +1,20 @@
+from osim.env import L2RunEnv
+import opensim
+
+env = L2RunEnv(visualize=True)
+observation = env.reset()
+
+s = 0
+for s in range(80):
+    d = False
+
+    if s == 30:
+        state_old = env.osim_model.get_state()
+        print("State stored")
+        print(state_old)
+    if s % 50 == 49:
+        env.osim_model.set_state(state_old)
+        print("Rollback")
+        print(state_old)
+
+    o, r, d, i = env.step(env.action_space.sample())