adding test for deterministic action playback

tests/test_environments/test_action_playback.py

@@ -0,0 +1,74 @@
+"""
+Test script for recording a sequence of random actions and playing them back
+"""
+
+import os
+import h5py
+import argparse
+import random
+import numpy as np
+import json
+
+import robosuite
+from robosuite.controllers import load_controller_config
+
+def test_playback():
+    # set seeds
+    random.seed(0)
+    np.random.seed(0)
+
+    env = robosuite.make(
+        "Lift",
+        robots=["Panda"],
+        controller_configs=load_controller_config(default_controller="OSC_POSE"),
+        has_renderer=False,
+        has_offscreen_renderer=False,
+        ignore_done=True,
+        use_camera_obs=False,
+        reward_shaping=True,
+        control_freq=20,
+    )
+    env.reset()
+
+    # task instance
+    task_xml = env.sim.model.get_xml()
+    task_init_state = np.array(env.sim.get_state().flatten())
+
+    # trick for ensuring that we can play MuJoCo demonstrations back
+    # deterministically by using the recorded actions open loop
+    env.reset_from_xml_string(task_xml)
+    env.sim.reset()
+    env.sim.set_state_from_flattened(task_init_state)
+    env.sim.forward()
+
+    # random actions to play
+    n_actions = 100
+    actions = 0.1 * np.random.uniform(low=-1., high=1., size=(n_actions, env.action_spec[0].shape[0]))
+
+    # play actions
+    print("playing random actions...")
+    states = [task_init_state]
+    for i in range(n_actions):
+        env.step(actions[i])
+        states.append(np.array(env.sim.get_state().flatten()))
+
+    # try playback
+    print("attempting playback...")
+    env.reset()
+    env.reset_from_xml_string(task_xml)
+    env.sim.reset()
+    env.sim.set_state_from_flattened(task_init_state)
+    env.sim.forward()
+
+    for i in range(n_actions):
+        env.step(actions[i])
+        state_playback = env.sim.get_state().flatten()
+        assert(np.all(np.equal(states[i + 1], state_playback)))
+
+    print("test passed!")
+
+
+if __name__ == "__main__":
+
+    test_playback()
+