From 1e71e31fd6f49d5473b277fdf3e5ef9d8e82af45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebasti=C3=A1n=20Ram=C3=ADrez?= <tiangolo@gmail.com>
Date: Wed, 3 Sep 2025 17:26:06 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=A7=AA=20Add=20test=20for=20dependencies?=
 =?UTF-8?q?=20with=20yield=20with=20streaming?=
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---
 .../test_dependency_after_yield_streaming.py  | 80 +++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 tests/test_dependency_after_yield_streaming.py

diff --git a/tests/test_dependency_after_yield_streaming.py b/tests/test_dependency_after_yield_streaming.py
new file mode 100644
index 000000000..0010453bf
--- /dev/null
+++ b/tests/test_dependency_after_yield_streaming.py
@@ -0,0 +1,80 @@
+from contextlib import contextmanager
+from typing import Annotated, Any, Generator
+
+from fastapi import Depends, FastAPI
+from fastapi.responses import StreamingResponse
+from fastapi.testclient import TestClient
+
+
+class Session:
+    def __init__(self) -> None:
+        self.data = ["foo", "bar", "baz"]
+        self.open = True
+
+    def __iter__(self) -> Generator[str, None, None]:
+        for item in self.data:
+            if self.open:
+                yield item
+            else:
+                raise ValueError("Session closed")
+
+
+@contextmanager
+def acquire_session() -> Generator[Session, None, None]:
+    session = Session()
+    try:
+        yield session
+    finally:
+        session.open = False
+
+
+def dep_session() -> Any:
+    with acquire_session() as s:
+        yield s
+
+
+SessionDep = Annotated[Session, Depends(dep_session)]
+
+app = FastAPI()
+
+
+@app.get("/data")
+def get_data(session: SessionDep) -> Any:
+    data = list(session)
+    return data
+
+
+@app.get("/stream-simple")
+def get_stream_simple(session: SessionDep) -> Any:
+    def iter_data():
+        yield from ["x", "y", "z"]
+
+    return StreamingResponse(iter_data())
+
+
+@app.get("/stream-session")
+def get_stream_session(session: SessionDep) -> Any:
+    def iter_data():
+        yield from session
+
+    return StreamingResponse(iter_data())
+
+
+def session_explode() -> None:
+    with acquire_session() as s:
+        iter_s = iter(s)
+        print(next(iter_s))
+    print(next(iter_s))
+
+
+client = TestClient(app)
+
+
+def test_stream_simple():
+    response = client.get("/stream-simple")
+    assert response.text == "xyz"
+
+
+def test_stream_session():
+    response = client.get("/stream-session")
+    assert response.text == "foobarbaz"