tests/test_api_contract.py

import pytest

fastapi = pytest.importorskip("fastapi")
from fastapi.testclient import TestClient  # noqa: E402

from app import app  # noqa: E402


def test_root_serves_ui_without_redirect() -> None:
    client = TestClient(app)

    response = client.get("/", follow_redirects=False)

    assert response.status_code == 200
    assert "text/html" in response.headers["content-type"]


def test_api_chat_valid_request() -> None:
    client = TestClient(app)

    response = client.post(
        "/api/chat",
        json={
            "message": "Give me a risk reward mechanic for stamina.",
            "project_context": "Tactical fantasy RPG.",
            "mode": "balance",
            "retrieval_k": 0,
        },
    )

    assert response.status_code == 200
    body = response.json()
    assert set(body) == {"answer", "citations", "retrieved_chunks", "warnings"}
    assert "No approved source context" in body["answer"]


def test_api_chat_rejects_empty_message() -> None:
    client = TestClient(app)

    response = client.post(
        "/api/chat",
        json={"message": " ", "project_context": "", "mode": "balance", "retrieval_k": 4},
    )

    assert response.status_code == 422


def test_api_chat_rejects_bad_mode_and_k() -> None:
    client = TestClient(app)

    response = client.post(
        "/api/chat",
        json={
            "message": "Test",
            "project_context": "",
            "mode": "bad_mode",
            "retrieval_k": 20,
        },
    )

    assert response.status_code == 422