feat: improved compatability layer and responses api handing

tests/test_cache.py

@@ -127,6 +127,84 @@ def test_stream_cache_miss(mock_make_redis):
     mock_redis_instance.set.assert_called_once()
 
 
+@pytest.mark.unit
+@patch("application.cache.get_redis_instance")
+def test_stream_cache_preserves_json_chunk_types(mock_make_redis):
+    mock_redis_instance = MagicMock()
+    mock_make_redis.return_value = mock_redis_instance
+    mock_redis_instance.get.return_value = json.dumps({
+        "version": 1,
+        "chunks": ["text", {"type": "thought", "thought": "reasoning"}],
+    }).encode("utf-8")
+
+    @stream_cache
+    def mock_function(self, model, messages, stream, tools):
+        yield "new_chunk"
+
+    result = list(mock_function(
+        None,
+        "model",
+        [{"role": "user", "content": "test"}],
+        stream=True,
+        tools=None,
+    ))
+
+    assert result == ["text", {"type": "thought", "thought": "reasoning"}]
+    mock_redis_instance.set.assert_not_called()
+
+
+@pytest.mark.unit
+@patch("application.cache.get_redis_instance")
+def test_stream_cache_does_not_stringify_protocol_objects(mock_make_redis):
+    mock_redis_instance = MagicMock()
+    mock_make_redis.return_value = mock_redis_instance
+    mock_redis_instance.get.return_value = None
+    terminal_chunk = MagicMock(name="responses_terminal_choice")
+
+    @stream_cache
+    def mock_function(self, model, messages, stream, tools):
+        yield "partial"
+        yield terminal_chunk
+
+    result = list(mock_function(
+        None,
+        "model",
+        [{"role": "user", "content": "test"}],
+        stream=True,
+        tools=None,
+    ))
+
+    assert result[0] == "partial"
+    assert result[1] is terminal_chunk
+    mock_redis_instance.set.assert_not_called()
+
+
+@pytest.mark.unit
+@patch("application.cache.get_redis_instance")
+def test_stream_cache_rejects_legacy_protocol_object_repr(mock_make_redis):
+    mock_redis_instance = MagicMock()
+    mock_make_redis.return_value = mock_redis_instance
+    mock_redis_instance.get.return_value = json.dumps([
+        "partial",
+        "<application.llm.openai._RespChoice object at 0x123>",
+    ]).encode("utf-8")
+
+    @stream_cache
+    def mock_function(self, model, messages, stream, tools):
+        yield "fresh"
+
+    result = list(mock_function(
+        None,
+        "model",
+        [{"role": "user", "content": "test"}],
+        stream=True,
+        tools=None,
+    ))
+
+    assert result == ["fresh"]
+    mock_redis_instance.delete.assert_called_once()
+
+
 # ── get_redis_instance ──────────────────────────────────────────────────────