diff --git a/docs/en/docs/tutorial/query-params-str-validations.md b/docs/en/docs/tutorial/query-params-str-validations.md
index 8dd962d5aa..47003dab62 100644
--- a/docs/en/docs/tutorial/query-params-str-validations.md
+++ b/docs/en/docs/tutorial/query-params-str-validations.md
@@ -262,7 +262,7 @@ In other words, `None` is not an acceptable runtime value for query parameters 
 
 If you want to accept special values (like `"None"` or an empty string) and interpret them as `None` in your application, you can handle them manually in your function:
 
-{* ../../docs_src/query_params_str_validations/tutorial006d_an_py310.py hl[10:13,18] *}
+{* ../../docs_src/query_params_str_validations/tutorial006c_an_py310.py hl[9:12,17] *}
 
 /// note
 
diff --git a/docs_src/query_params_str_validations/tutorial006c_an_py310.py b/docs_src/query_params_str_validations/tutorial006c_an_py310.py
index 2995d9c979..d5c3d3058a 100644
--- a/docs_src/query_params_str_validations/tutorial006c_an_py310.py
+++ b/docs_src/query_params_str_validations/tutorial006c_an_py310.py
@@ -1,12 +1,21 @@
 from typing import Annotated
 
 from fastapi import FastAPI, Query
+from pydantic import BeforeValidator
 
 app = FastAPI()
 
 
+def nullable_str(val: str) -> str | None:
+    if val in ("None", "", "null"):
+        return None
+    return val
+
+
 @app.get("/items/")
-async def read_items(q: Annotated[str | None, Query(min_length=3)]):
+async def read_items(
+    q: Annotated[str | None, Query(min_length=3), BeforeValidator(nullable_str)],
+):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial006c_an_py39.py b/docs_src/query_params_str_validations/tutorial006c_an_py39.py
index 76a1cd49ac..79516eb1d8 100644
--- a/docs_src/query_params_str_validations/tutorial006c_an_py39.py
+++ b/docs_src/query_params_str_validations/tutorial006c_an_py39.py
@@ -1,12 +1,21 @@
 from typing import Annotated, Union
 
 from fastapi import FastAPI, Query
+from pydantic import BeforeValidator
 
 app = FastAPI()
 
 
+def nullable_str(val: str) -> Union[str, None]:
+    if val in ("None", "", "null"):
+        return None
+    return val
+
+
 @app.get("/items/")
-async def read_items(q: Annotated[Union[str, None], Query(min_length=3)]):
+async def read_items(
+    q: Annotated[Union[str, None], Query(min_length=3), BeforeValidator(nullable_str)],
+):
     results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
     if q:
         results.update({"q": q})
diff --git a/docs_src/query_params_str_validations/tutorial006c_py310.py b/docs_src/query_params_str_validations/tutorial006c_py310.py
deleted file mode 100644
index 88b499c7af..0000000000
--- a/docs_src/query_params_str_validations/tutorial006c_py310.py
+++ /dev/null
@@ -1,11 +0,0 @@
-from fastapi import FastAPI, Query
-
-app = FastAPI()
-
-
-@app.get("/items/")
-async def read_items(q: str | None = Query(min_length=3)):
-    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
-    if q:
-        results.update({"q": q})
-    return results
diff --git a/docs_src/query_params_str_validations/tutorial006c_py39.py b/docs_src/query_params_str_validations/tutorial006c_py39.py
deleted file mode 100644
index 0a0e820da3..0000000000
--- a/docs_src/query_params_str_validations/tutorial006c_py39.py
+++ /dev/null
@@ -1,13 +0,0 @@
-from typing import Union
-
-from fastapi import FastAPI, Query
-
-app = FastAPI()
-
-
-@app.get("/items/")
-async def read_items(q: Union[str, None] = Query(min_length=3)):
-    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
-    if q:
-        results.update({"q": q})
-    return results
diff --git a/docs_src/query_params_str_validations/tutorial006d_an_py310.py b/docs_src/query_params_str_validations/tutorial006d_an_py310.py
deleted file mode 100644
index 344cf38e53..0000000000
--- a/docs_src/query_params_str_validations/tutorial006d_an_py310.py
+++ /dev/null
@@ -1,20 +0,0 @@
-from typing import Optional, Union
-
-from fastapi import FastAPI, Query
-from pydantic import BeforeValidator
-from typing_extensions import Annotated
-
-app = FastAPI()
-
-
-def nullable_str(val: str) -> Union[str, None]:
-    if val in ("None", "", "null"):
-        return None
-    return val
-
-
-@app.get("/items/")
-async def read_items(
-    q: Annotated[Optional[str], Query(min_length=3), BeforeValidator(nullable_str)],
-):
-    return {"q": q}
diff --git a/tests/test_tutorial/test_query_params_str_validations/test_tutorial006c.py b/tests/test_tutorial/test_query_params_str_validations/test_tutorial006c.py
index f287b5dcd8..af1d74315b 100644
--- a/tests/test_tutorial/test_query_params_str_validations/test_tutorial006c.py
+++ b/tests/test_tutorial/test_query_params_str_validations/test_tutorial006c.py
@@ -9,8 +9,6 @@ from ...utils import needs_py310
 @pytest.fixture(
     name="client",
     params=[
-        pytest.param("tutorial006c_py39"),
-        pytest.param("tutorial006c_py310", marks=needs_py310),
         pytest.param("tutorial006c_an_py39"),
         pytest.param("tutorial006c_an_py310", marks=needs_py310),
     ],
@@ -23,24 +21,26 @@ def get_client(request: pytest.FixtureRequest):
     return client
 
 
-@pytest.mark.xfail(
-    reason="Code example is not valid. See https://github.com/fastapi/fastapi/issues/12419"
-)
 def test_query_params_str_validations_no_query(client: TestClient):
     response = client.get("/items/")
-    assert response.status_code == 200
-    assert response.json() == {  # pragma: no cover
-        "items": [{"item_id": "Foo"}, {"item_id": "Bar"}],
+    assert response.status_code == 422
+    assert response.json() == {
+        "detail": [
+            {
+                "type": "missing",
+                "loc": ["query", "q"],
+                "msg": "Field required",
+                "input": None,
+            }
+        ]
     }
 
 
-@pytest.mark.xfail(
-    reason="Code example is not valid. See https://github.com/fastapi/fastapi/issues/12419"
-)
-def test_query_params_str_validations_empty_str(client: TestClient):
-    response = client.get("/items/?q=")
+@pytest.mark.parametrize("q_value", ["None", "null", ""])
+def test_query_params_str_validations_send_explicit_none(client: TestClient, q_value: str):
+    response = client.get("/items/", params={"q": q_value})
     assert response.status_code == 200
-    assert response.json() == {  # pragma: no cover
+    assert response.json() == {
         "items": [{"item_id": "Foo"}, {"item_id": "Bar"}],
     }
 
diff --git a/tests/test_tutorial/test_query_params_str_validations/test_tutorial006d_an_py310.py b/tests/test_tutorial/test_query_params_str_validations/test_tutorial006d_an_py310.py
deleted file mode 100644
index 86c13cd2e9..0000000000
--- a/tests/test_tutorial/test_query_params_str_validations/test_tutorial006d_an_py310.py
+++ /dev/null
@@ -1,27 +0,0 @@
-import pytest
-from fastapi.testclient import TestClient
-
-from tests.utils import needs_pydanticv2
-
-
-@pytest.fixture
-def client():
-    from docs_src.query_params_str_validations.tutorial006d_an_py310 import app
-
-    yield TestClient(app)
-
-
-@needs_pydanticv2
-@pytest.mark.parametrize(
-    "q_value,expected",
-    [
-        ("None", None),
-        ("", None),
-        ("null", None),
-        ("hello", "hello"),
-    ],
-)
-def test_read_items(q_value, expected, client: TestClient):
-    response = client.get("/items/", params={"q": q_value})
-    assert response.status_code == 200
-    assert response.json() == {"q": expected}