Add code comments and unit tests

Signed-off-by: Jialin Ouyang <Jialin.Ouyang@gmail.com>

Author: Jialin

tests/v1/test_outputs.py

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+
+from vllm.v1.outputs import (
+    convert_to_token_id_list,
+    convert_to_token_ids,
+    get_token_count,
+)
+
+
+def test_convert_to_token_id_list():
+    assert convert_to_token_id_list(1) == [1]
+    assert convert_to_token_id_list(2) == [2]
+
+    # Return the original list back without creating new lists
+    vs = [3, 4]
+    assert convert_to_token_id_list(vs) is vs
+    vs = [5, 6, 7]
+    assert convert_to_token_id_list(vs) is vs
+
+
+def test_convert_to_token_ids():
+    assert convert_to_token_ids([10]) == 10
+    assert convert_to_token_ids([20]) == 20
+
+    # Return the original list back without creating new lists
+    vs = [30, 40]
+    assert convert_to_token_ids(vs) is vs
+    vs = [50, 60, 70]
+    assert convert_to_token_ids(vs) is vs
+
+
+def test_get_token_count():
+    assert get_token_count(100) == 1
+    assert get_token_count(200) == 1
+    assert get_token_count([300]) == 1
+    assert get_token_count([400, 500]) == 2
+    assert get_token_count([600, 700, 800]) == 3