chore: import upstream snapshot with attribution

tests/test_encode_decode.py

@@ -0,0 +1,19 @@
+import llm
+import pytest
+import numpy as np
+
+
+@pytest.mark.parametrize(
+    "array",
+    (
+        (0.0, 1.0, 1.5),
+        (3423.0, 222.0, -1234.5),
+    ),
+)
+def test_roundtrip(array):
+    encoded = llm.encode(array)
+    decoded = llm.decode(encoded)
+    assert decoded == array
+    # Try with numpy as well
+    numpy_decoded = np.frombuffer(encoded, "<f4")
+    assert tuple(numpy_decoded.tolist()) == array