docs: update required but nullable request body example, remove py39 files, add test_tutorial005

docs/en/docs/tutorial/body.md

@@ -62,15 +62,11 @@ In Python type hints, a parameter can be **required** and still allow the value
 This means that the field must be present in the request body, but its value can be `null`
 (`None` in Python).
 
-This typically happens when you use `Optional[T]` **without** providing a default value.
+This typically happens when you use something like `str | None` (or `Optional[str]`) **without** providing a default value.
 
 For example:
 
-{* ../../docs_src/body/tutorial005_py39.py hl[6] *}
-
-And for Python 3.10+:
-
-{* ../../docs_src/body/tutorial005_py310.py hl[6] *}
+{* ../../docs_src/body/tutorial005_py310.py hl[8] *}
 
 In this example:
 

docs_src/body/tutorial005_py310.py

@@ -5,7 +5,7 @@ app = FastAPI()
 
 
 class Item(BaseModel):
-    description: str | None
+    description: str | None = None
 
 
 @app.post("/items/")

tests/test_tutorial/test_body/test_tutorial005.py

@@ -3,16 +3,15 @@ import importlib
 import pytest
 from fastapi.testclient import TestClient
 
-from ...utils import needs_py310
 
 
 @pytest.fixture(
     name="client",
     params=[
-        pytest.param("tutorial005_py39"),
-        pytest.param("tutorial005_py310", marks=needs_py310),
+        pytest.param("tutorial005_py310"),
     ],
 )
+
 def get_client(request: pytest.FixtureRequest):
     mod = importlib.import_module(f"docs_src.body.{request.param}")
     client = TestClient(mod.app)
@@ -27,4 +26,6 @@ def test_required_nullable_field(client: TestClient):
 
 def test_required_field_missing(client: TestClient):
     response = client.post("/items/", json={})
-    assert response.status_code == 422
+    assert response.status_code == 200
+    assert response.json() == {"description": None}
+