chore: import upstream snapshot with attribution

tests/utils/test_json.py

@@ -0,0 +1,43 @@
+import json
+from types import MappingProxyType
+
+from openai.types.responses.response_output_message_param import ResponseOutputMessageParam
+from openai.types.responses.response_output_text_param import ResponseOutputTextParam
+
+from agents.util._json import _to_dump_compatible
+
+
+def test_to_dump_compatible():
+    # Given a list of message dictionaries, ensure the returned list is a deep copy.
+    input_iter = [
+        ResponseOutputMessageParam(
+            id="a75654dc-7492-4d1c-bce0-89e8312fbdd7",
+            content=[
+                ResponseOutputTextParam(
+                    type="output_text",
+                    text="Hey, what's up?",
+                    annotations=[],
+                    logprobs=[],
+                )
+            ].__iter__(),
+            role="assistant",
+            status="completed",
+            type="message",
+        )
+    ].__iter__()
+    # this fails if any of the properties are Iterable objects.
+    # result = json.dumps(input_iter)
+    result = json.dumps(_to_dump_compatible(input_iter))
+    assert (
+        result
+        == """[{"id": "a75654dc-7492-4d1c-bce0-89e8312fbdd7", "content": [{"type": "output_text", "text": "Hey, what's up?", "annotations": [], "logprobs": []}], "role": "assistant", "status": "completed", "type": "message"}]"""  # noqa: E501
+    )
+
+
+def test_to_dump_compatible_preserves_non_dict_mapping_values():
+    # A non-dict Mapping (e.g. MappingProxyType) must be preserved as an object,
+    # recursing into its values, instead of collapsing to a list of its keys.
+    out = _to_dump_compatible({"config": MappingProxyType({"timeout": 30, "retries": 3})})
+    assert out == {"config": {"timeout": 30, "retries": 3}}
+    # A top-level mapping is preserved as an object, not flattened to its keys.
+    assert _to_dump_compatible(MappingProxyType({"a": 1, "b": 2})) == {"a": 1, "b": 2}