import pytest
from loader import load
from schema import DEFAULTS, known


def test_defaults_applied():
    assert load({})["port"] == 8080


def test_override():
    assert load({"port": 9000})["port"] == 9000


def test_unknown_key_rejected():
    with pytest.raises(KeyError):
        load({"prot": 9000})


def test_timeout_default_exists():
    assert known("timeout")
    assert load({})["timeout"] == 30


def test_defaults_not_mutated():
    load({"port": 1})
    assert DEFAULTS["port"] == 8080