procurement-ingest/tests/test_web_ui_auth.py

"""web_ui_auth.is_authenticated coverage (constraint 5c) -- 0% before Phase 8.

Auth is the mandatory-review surface, so this pins: fail-closed on an unset ARN
(read at import -> reload), fail-closed on a Secrets-Manager exception, the TTL
cache refresh, the Bearer / X-Auth-Token / case-insensitivity header matrix,
wrong-token, and the non-ASCII-token TypeError (a documenting pin -- the module
is frozen this phase, so the fix is deferred).

Loaded through the shared loader (``load_lambda_module("shared", "web_ui_auth")``)
and reloaded per test because the secret ARN is read at module-import time.
"""

import pytest

from tests.support import load_lambda_module

_ARN = "arn:aws:secretsmanager:us-east-1:000000000000:secret:web-ui-auth-token"


class _FakeSecrets:
    def __init__(self, value):
        self.value = value

    def get_secret_value(self, SecretId):  # noqa: N803 (boto3 kwarg name)
        return {"SecretString": self.value}


class _RaisingSecrets:
    def get_secret_value(self, SecretId):  # noqa: N803
        raise RuntimeError("secretsmanager access denied")


@pytest.fixture
def load_auth(monkeypatch):
    """Return a loader that (re)imports web_ui_auth with a chosen ARN env, so the
    module-level ``_WEB_UI_AUTH_TOKEN_SECRET_ARN`` (read at import) reflects it."""
    mod = load_lambda_module("shared", "web_ui_auth")

    def _load(arn=_ARN):
        if arn is None:
            monkeypatch.delenv("WEB_UI_AUTH_TOKEN_SECRET_ARN", raising=False)
        else:
            monkeypatch.setenv("WEB_UI_AUTH_TOKEN_SECRET_ARN", arn)
        # Re-exec the module body in place (importlib.reload can't re-find a
        # file-path-loaded module by name). This re-reads the ARN env and resets
        # _auth_token_cache / _auth_token_cached_at to their module defaults.
        mod.__spec__.loader.exec_module(mod)
        return mod

    return _load


def _evt(**headers):
    return {"headers": headers}


def test_fail_closed_on_unset_arn(load_auth):
    mod = load_auth(arn=None)
    assert mod.is_authenticated(_evt(**{"x-auth-token": "anything"})) is False


def test_fail_closed_on_secrets_manager_exception(load_auth, monkeypatch):
    mod = load_auth()
    monkeypatch.setattr(mod.boto3, "client", lambda *a, **k: _RaisingSecrets())
    # Fails closed (False) and does NOT raise -- the except in _get_auth_token.
    assert mod.is_authenticated(_evt(**{"x-auth-token": "anything"})) is False


def test_ttl_cache_refresh_picks_up_rotated_secret(load_auth, monkeypatch):
    mod = load_auth()
    fake = _FakeSecrets("tok1")
    monkeypatch.setattr(mod.boto3, "client", lambda *a, **k: fake)
    clock = [1000.0]
    monkeypatch.setattr(mod.time, "monotonic", lambda: clock[0])

    assert mod._get_auth_token() == "tok1"  # first fetch, cached at t=1000

    fake.value = "tok2"  # secret rotated
    clock[0] = 1000.0 + 299  # still within the 300s TTL
    assert mod._get_auth_token() == "tok1"  # served from cache

    clock[0] = 1000.0 + 301  # TTL elapsed
    assert mod._get_auth_token() == "tok2"  # refetched, rotation picked up


@pytest.mark.parametrize(
    ("headers", "expected"),
    [
        ({"x-auth-token": "SECRET"}, True),
        ({"X-Auth-Token": "SECRET"}, True),  # header-name case-insensitive
        ({"Authorization": "Bearer SECRET"}, True),
        ({"authorization": "bearer SECRET"}, True),  # scheme case-insensitive
        # X-Auth-Token takes precedence over an Authorization header.
        ({"X-Auth-Token": "SECRET", "Authorization": "Bearer WRONG"}, True),
        ({"x-auth-token": "WRONG"}, False),
        ({"Authorization": "Bearer WRONG"}, False),
        ({"Authorization": "SECRET"}, False),  # no Bearer prefix
        ({}, False),  # no credentials at all
        ({"x-auth-token": ""}, False),  # empty presented token
    ],
)
def test_header_matrix(load_auth, monkeypatch, headers, expected):
    mod = load_auth()
    monkeypatch.setattr(mod, "_get_auth_token", lambda: "SECRET")
    assert mod.is_authenticated(_evt(**headers)) is expected


@pytest.mark.xfail(
    strict=True,
    reason="web_ui_auth is frozen this phase: is_authenticated raises TypeError on "
    "a non-ASCII presented token (hmac.compare_digest is ASCII-only) and surfaces "
    "as a 500 instead of failing closed to False. Asserting the DESIRED behavior "
    "under xfail(strict) documents the intended fix and auto-fails (xpass) the moment "
    "the module is corrected, forcing the marker's removal. Tracked as a follow-up.",
    raises=TypeError,
)
def test_non_ascii_token_should_fail_closed(load_auth, monkeypatch):
    mod = load_auth()
    monkeypatch.setattr(mod, "_get_auth_token", lambda: "SECRET")
    assert mod.is_authenticated(_evt(**{"x-auth-token": "SÉCRET"})) is False