From 4f958bfd99e50babdf7eb2c58baf922ece5882f2 Mon Sep 17 00:00:00 2001
From: Yurii Motov <yurii.motov.monte@gmail.com>
Date: Sun, 16 Nov 2025 20:22:06 +0100
Subject: [PATCH] Add tests for extra parameter lists

---
 ..._query_cookie_header_model_extra_params.py | 111 ++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 tests/test_query_cookie_header_model_extra_params.py

diff --git a/tests/test_query_cookie_header_model_extra_params.py b/tests/test_query_cookie_header_model_extra_params.py
new file mode 100644
index 000000000..2e51544ea
--- /dev/null
+++ b/tests/test_query_cookie_header_model_extra_params.py
@@ -0,0 +1,111 @@
+from fastapi import Cookie, FastAPI, Header, Query
+from fastapi._compat import PYDANTIC_V2
+from fastapi.testclient import TestClient
+from pydantic import BaseModel
+
+app = FastAPI()
+
+
+class Model(BaseModel):
+    param: str
+
+    if PYDANTIC_V2:
+        model_config = {"extra": "allow"}
+    else:
+
+        class Config:
+            extra = "allow"
+
+
+@app.get("/query")
+async def query_model_with_extra(data: Model = Query()):
+    return data
+
+
+@app.get("/header")
+async def header_model_with_extra(data: Model = Header()):
+    return data
+
+
+@app.get("/cookie")
+async def cookies_model_with_extra(data: Model = Cookie()):
+    return data
+
+
+def test_query_pass_extra_list():
+    client = TestClient(app)
+    resp = client.get(
+        "/query",
+        params={
+            "param": "123",
+            "param2": ["456", "789"],  # Pass a list of values as extra parameter
+        },
+    )
+    assert resp.status_code == 200
+    assert resp.json() == {
+        "param": "123",
+        "param2": ["456", "789"],
+    }
+
+def test_query_pass_extra_single():
+    client = TestClient(app)
+    resp = client.get(
+        "/query",
+        params={
+            "param": "123",
+            "param2": "456",
+        },
+    )
+    assert resp.status_code == 200
+    assert resp.json() == {
+        "param": "123",
+        "param2": "456",
+    }
+
+
+
+def test_header_pass_extra_list():
+    client = TestClient(app)
+
+    resp = client.get(
+        "/header",
+        headers=[
+            ("param", "123"),
+            ("param2", "456"),  # Pass a list of values as extra parameter
+            ("param2", "789"),
+        ],
+    )
+    assert resp.status_code == 200
+    resp_json = resp.json()
+    assert "param2" in resp_json
+    assert resp_json["param2"] == ["456", "789"]
+
+
+def test_header_pass_extra_single():
+    client = TestClient(app)
+
+    resp = client.get(
+        "/header",
+        headers=[
+            ("param", "123"),
+            ("param2", "456"),
+        ],
+    )
+    assert resp.status_code == 200
+    resp_json = resp.json()
+    assert "param2" in resp_json
+    assert resp_json["param2"] == "456"
+
+
+def test_cookie_pass_extra_list():
+    client = TestClient(app)
+    client.cookies = [
+        ("param", "123"),
+        ("param2", "456"),  # Pass a list of values as extra parameter
+        ("param2", "789"),
+    ]
+    resp = client.get("/cookie")
+    assert resp.status_code == 200
+    resp_json = resp.json()
+    assert "param2" in resp_json
+    assert resp_json["param2"] == "789"  # Cookies only keep the last value