fix(serialization-json): serialize nested arrays recursively

packages/serialization/json/kiota_serialization_json/json_serialization_writer.py

@@ -487,6 +487,8 @@ def write_any_value(self, key: Optional[str], value: Any) -> Any:
                 self.write_collection_of_primitive_values(key, value)
             elif all(isinstance(x, dict) for x in value):
                 self.__write_collection_of_dict_values(key, value)
+            elif all(isinstance(x, list) for x in value):
+                self.write_collection_of_primitive_values(key, value)
             else:
                 raise TypeError(
                     f"Encountered an unknown collection type during serialization {type(value)}\

packages/serialization/json/tests/unit/test_json_serialization_writer.py

@@ -1,3 +1,4 @@
+import json
 from datetime import date, datetime
 from uuid import UUID
 
@@ -208,6 +209,47 @@ def test_write_collection_of_primitive_values():
     assert content_string == '{"businessPhones": ["+1 412 555 0109", 1]}'
 
 
+@pytest.mark.parametrize("key", [None, "matrix"])
+@pytest.mark.parametrize("value", [
+    [[1, 2, 3]],
+    [[], [[1], [2, 3]]],
+    [[1, None], [False], [{"nested": [[], [3]]}]],
+])
+def test_write_any_value_nested_lists(key, value):
+    writer = JsonSerializationWriter()
+    writer.write_any_value(key, value)
+    expected = {key: value} if key else value
+    assert json.loads(writer.get_serialized_content()) == expected
+
+
+def test_write_additional_data_nested_lists():
+    writer = JsonSerializationWriter()
+    value = {"matrix": [[1, 2], [3, 4]]}
+    writer.write_additional_data_value(value)
+    assert json.loads(writer.get_serialized_content()) == value
+
+
+def test_write_any_value_nested_lists_serializes_models(user_2):
+    writer = JsonSerializationWriter()
+    writer.write_any_value(None, [[user_2], [date(2022, 1, 27)]])
+    assert json.loads(writer.get_serialized_content()) == [
+        [{"display_name": "John Doe", "age": 32}], ["2022-01-27"]
+    ]
+
+
+def test_write_any_value_nested_lists_rejects_unsupported_values():
+    writer = JsonSerializationWriter()
+    with pytest.raises(TypeError):
+        writer.write_any_value(None, [[object()]])
+
+
+@pytest.mark.parametrize("value", [[1, [2]], [{"value": 1}, [2]], [[1], None]])
+def test_write_any_value_rejects_mixed_collection_types(value):
+    writer = JsonSerializationWriter()
+    with pytest.raises(TypeError, match="Encountered an unknown collection type"):
+        writer.write_any_value(None, value)
+
+
 def test_write_collection_of_object_values(user_1, user_2):
     json_serialization_writer = JsonSerializationWriter()
     json_serialization_writer.write_collection_of_object_values("users", [user_1, user_2])