tests(core): add additional session utilities and serializer edge-cas…

…e tests - Add tests for _session_file_stem encoding and edge cases - Add tests for _contains_non_finite_float nested detection - Add tests for default state encoder/decoder error and pydantic decoder Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Hassan Abu zead (HASSanHASSgit) · Jul 31, 2026 · Jul 31, 2026 · Jul 31, 2026 · Aug 1, 2026 · Jul 31, 2026
commit 7f9cf7721567e29e1461f43a867c3196929ee763
@@ -0,0 +1,94 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Additional tests for session utilities and serializers.
+
+These target edge cases not covered by the main test suite:
+- filename-safe session stem encoding
+- non-finite float detection in nested structures
+- default state encoder/decoder error paths
+"""
+
+from __future__ import annotations
+
+import math
+import pytest
+
+from agent_framework import _sessions as sessions
+from pydantic import BaseModel
+
+
+class TestSessionFileStem:
+    def test_literal_safe_session_stem(self):
+        # ASCII alnum + separators allowed
+        assert sessions._is_literal_session_file_stem_safe("session-123") is True
+        assert sessions._session_file_stem("session-123", encoded_prefix="sess-") == "session-123"
+
+    def test_reserved_windows_name_encoded(self):
+        # Windows reserved stem must be encoded
+        session_id = "CON"
+        stem = sessions._session_file_stem(session_id, encoded_prefix="sess-")
+        assert stem != session_id
+        assert stem.startswith("sess-")
+
+    def test_control_characters_encoded(self):
+        # Control characters should force encoding
+        session_id = "bad\x01id"
+        stem = sessions._session_file_stem(session_id, encoded_prefix="s-")
+        assert stem.startswith("s-")
+        assert "\x01" not in stem
+
+    def test_long_encoded_falls_back_to_hash(self):
+        # Very long literal-safe IDs may be returned unchanged; otherwise the encoded
+        # representation should start with the provided prefix or the sha256 fallback.
+        long_id = "x" * 1000
+        stem = sessions._session_file_stem(long_id, encoded_prefix="p-")
+        assert stem == long_id or stem.startswith("p-") or stem.startswith("p-sha256-")
+
+
+class TestNonFiniteFloatDetection:
+    def test_contains_non_finite_float_direct(self):
+        assert sessions._contains_non_finite_float(float("nan")) is True
+        assert sessions._contains_non_finite_float(float("inf")) is True
+        assert sessions._contains_non_finite_float(1.0) is False
+
+    def test_contains_non_finite_float_nested(self):
+        data = {"a": [1.0, float("nan")], "b": {"c": float("inf")}}
+        assert sessions._contains_non_finite_float(data) is True
+
+    def test_contains_non_finite_float_sequences(self):
+        assert sessions._contains_non_finite_float([1.0, 2.0]) is False
+        assert sessions._contains_non_finite_float((1.0, float("nan"))) is True
+
+
+class _BadToDict:
+    def to_dict(self):
+        # Return a non-mapping type to exercise encoder error path
+        return [1, 2, 3]
+
+
+class TestDefaultStateEncoderDecoder:
+    def test_default_state_encoder_raises_on_non_mapping_to_dict(self):
+        encoder = sessions._default_state_encoder(_BadToDict)
+        with pytest.raises(TypeError):
+            encoder(_BadToDict())
+
+    def test_default_state_decoder_for_pydantic(self):
+        class Model(BaseModel):
+            x: int
+
+        decoder = sessions._default_state_decoder(Model)
+        obj = decoder({"x": 5})
+        assert isinstance(obj, Model)
+        assert obj.x == 5
+
+    def test_resolve_state_type_id_custom_priority(self):
+        class WithType:
+            TYPE = "custom_type"
+
+        # explicit type_id overrides
+        assert sessions._resolve_state_type_id(WithType, "explicit-id") == "explicit-id"
+        # fallback to TYPE attribute
+        assert sessions._resolve_state_type_id(WithType, None) == "custom_type"
+
+
+# End of file