missing serialization test from prev git

Signed-off-by: Filinto Duran <[email protected]>

Author: filintod

tests/durabletask/test_serialization.py

@@ -0,0 +1,74 @@
+from collections import namedtuple
+from dataclasses import dataclass
+from types import SimpleNamespace
+
+from durabletask.internal.shared import AUTO_SERIALIZED, from_json, to_json
+
+
+@dataclass
+class SamplePayload:
+    count: int
+    name: str
+
+
+def test_to_json_roundtrip_dataclass():
+    payload = SamplePayload(count=5, name="widgets")
+    encoded = to_json(payload)
+
+    assert AUTO_SERIALIZED in encoded
+
+    decoded = from_json(encoded)
+    assert isinstance(decoded, SimpleNamespace)
+    assert decoded.count == 5
+    assert decoded.name == "widgets"
+
+
+def test_to_json_roundtrip_simplenamespace():
+    payload = SimpleNamespace(foo="bar", baz=42)
+    encoded = to_json(payload)
+
+    assert AUTO_SERIALIZED in encoded
+
+    decoded = from_json(encoded)
+    assert isinstance(decoded, SimpleNamespace)
+    assert decoded.foo == "bar"
+    assert decoded.baz == 42
+
+
+def test_to_json_plain_dict_passthrough():
+    payload = {"foo": "bar", "baz": 1}
+    encoded = to_json(payload)
+
+    assert AUTO_SERIALIZED not in encoded
+
+    decoded = from_json(encoded)
+    assert isinstance(decoded, dict)
+    assert decoded == {"foo": "bar", "baz": 1}
+
+
+def test_to_json_namedtuple_roundtrip():
+    Point = namedtuple("Point", ["x", "y"])
+    payload = Point(3, 4)
+    encoded = to_json(payload)
+
+    assert AUTO_SERIALIZED in encoded
+
+    decoded = from_json(encoded)
+    assert isinstance(decoded, SimpleNamespace)
+    assert decoded.x == 3
+    assert decoded.y == 4
+
+
+def test_to_json_nested_dataclass_collection():
+    payload = [
+        SamplePayload(count=1, name="first"),
+        SamplePayload(count=2, name="second"),
+    ]
+    encoded = to_json(payload)
+
+    assert encoded.count(AUTO_SERIALIZED) >= 2
+
+    decoded = from_json(encoded)
+    assert isinstance(decoded, list)
+    assert [item.count for item in decoded] == [1, 2]
+    assert [item.name for item in decoded] == ["first", "second"]