chore: import upstream snapshot with attribution

tests/fastapi/streaming_app.py

@@ -0,0 +1,30 @@
+from collections.abc import AsyncIterator
+
+from fastapi import FastAPI
+from starlette.responses import StreamingResponse
+
+from agents import Agent, Runner, RunResultStreaming
+
+agent = Agent(
+    name="Assistant",
+    instructions="You are a helpful assistant.",
+)
+
+
+app = FastAPI()
+
+
+@app.post("/stream")
+async def stream():
+    result = Runner.run_streamed(agent, input="Tell me a joke")
+    stream_handler = StreamHandler(result)
+    return StreamingResponse(stream_handler.stream_events(), media_type="application/x-ndjson")
+
+
+class StreamHandler:
+    def __init__(self, result: RunResultStreaming):
+        self.result = result
+
+    async def stream_events(self) -> AsyncIterator[str]:
+        async for event in self.result.stream_events():
+            yield f"{event.type}\n\n"

tests/fastapi/test_streaming_context.py

@@ -0,0 +1,41 @@
+import pytest
+from httpx import ASGITransport, AsyncClient
+from inline_snapshot import snapshot
+
+from ..fake_model import FakeModel
+from ..test_responses import get_text_message
+from .streaming_app import agent, app
+
+
+@pytest.mark.asyncio
+async def test_streaming_context():
+    """This ensures that FastAPI streaming works. The context for this test is that the Runner
+    method was called in one async context, and the streaming was ended in another context,
+    leading to a tracing error because the context was closed in the wrong context. This test
+    ensures that this actually works.
+    """
+    model = FakeModel()
+    agent.model = model
+    model.set_next_output([get_text_message("done")])
+
+    transport = ASGITransport(app)
+    async with AsyncClient(transport=transport, base_url="http://test") as ac:
+        async with ac.stream("POST", "/stream") as r:
+            assert r.status_code == 200
+            body = (await r.aread()).decode("utf-8")
+            lines = [line for line in body.splitlines() if line]
+            assert lines == snapshot(
+                [
+                    "agent_updated_stream_event",
+                    "raw_response_event",  # ResponseCreatedEvent
+                    "raw_response_event",  # ResponseInProgressEvent
+                    "raw_response_event",  # ResponseOutputItemAddedEvent
+                    "raw_response_event",  # ResponseContentPartAddedEvent
+                    "raw_response_event",  # ResponseTextDeltaEvent
+                    "raw_response_event",  # ResponseTextDoneEvent
+                    "raw_response_event",  # ResponseContentPartDoneEvent
+                    "raw_response_event",  # ResponseOutputItemDoneEvent
+                    "raw_response_event",  # ResponseCompletedEvent
+                    "run_item_stream_event",  # MessageOutputItem
+                ]
+            )