fix bug in box pushing IK

fancy_gym/examples/table_tennis_reproducebility.py

@@ -0,0 +1,22 @@
+import fancy_gym
+import numpy as np
+
+env_1 = fancy_gym.make("TableTennis4DProDMP-v0", seed=0)
+env_2 = fancy_gym.make("TableTennis4DProDMP-v0", seed=0)
+
+obs_1 = env_1.reset()
+obs_2 = env_2.reset()
+assert np.all(obs_1 == obs_2), "The observations should be the same"
+for i in range(100000):
+    action = env_1.action_space.sample()
+    obs_1, reward_1, done_1, info_1 = env_1.step(action)
+    obs_2, reward_2, done_2, info_2 = env_2.step(action)
+    assert np.all(obs_1 == obs_2), "The observations should be the same"
+    assert np.all(reward_1 == reward_2), "The rewards should be the same"
+    assert np.all(done_1 == done_2), "The done flags should be the same"
+    for key in info_1:
+        assert np.all(info_1[key] == info_2[key]), f"The info fields: {key} should be the same"
+    if done_1 and done_2:
+        obs_1 = env_1.reset()
+        obs_2 = env_2.reset()
+        assert np.all(obs_1 == obs_2), "The observations should be the same"