chore: import upstream snapshot with attribution

rllib/utils/postprocessing/tests/test_value_predictions.py

@@ -0,0 +1,48 @@
+import unittest
+
+from ray.rllib.utils.postprocessing.value_predictions import extract_bootstrapped_values
+from ray.rllib.utils.test_utils import check
+
+
+class TestPostprocessing(unittest.TestCase):
+    def test_extract_bootstrapped_values(self):
+        """Tests, whether the extract_bootstrapped_values utility works properly."""
+
+        # Fake vf_preds sequence.
+        # Spaces = denote (elongated-by-one-artificial-ts) episode boundaries.
+        # digits = timesteps within the actual episode.
+        # [lower case letters] = bootstrap values at episode truncations.
+        # '-' = bootstrap values at episode terminals (these values are simply zero).
+        sequence = "012345678a 01234A 0- 0123456b 01c 012- 012345e 012-"
+        sequence = sequence.replace(" ", "")
+        sequence = list(sequence)
+        # The actual, non-elongated, episode lengths.
+        episode_lengths = [9, 5, 1, 7, 2, 3, 6, 3]
+        T = 4
+        result = extract_bootstrapped_values(
+            vf_preds=sequence,
+            episode_lengths=episode_lengths,
+            T=T,
+        )
+        check(result, [4, 8, 3, 1, 5, "c", 1, 5, "-"])
+
+        # Another example.
+        sequence = "0123a 012345b 01234567- 012- 012- 012- 012345- 0123456c"
+        sequence = sequence.replace(" ", "")
+        sequence = list(sequence)
+        episode_lengths = [4, 6, 8, 3, 3, 3, 6, 7]
+        T = 5
+        result = extract_bootstrapped_values(
+            vf_preds=sequence,
+            episode_lengths=episode_lengths,
+            T=T,
+        )
+        check(result, [1, "b", 5, 2, 1, 3, 2, "c"])
+
+
+if __name__ == "__main__":
+    import sys
+
+    import pytest
+
+    sys.exit(pytest.main(["-v", __file__]))