wake-alarm/wake_alarm/tests/test_state.py

"""Tests for _state.py — HMAC-signed wake state management."""

from __future__ import annotations

import json
from typing import TYPE_CHECKING
from unittest.mock import patch

import pytest

from wake_alarm._state import (
    _today_str,
    load_wake_state,
    save_trigger_fired,
)

if TYPE_CHECKING:
    from pathlib import Path


@pytest.fixture
def wake_state_file(tmp_path: Path) -> Path:
    """Provide a temporary wake state file path."""
    return tmp_path / "wake_state.json"


@pytest.fixture(autouse=True)
def _patch_wake_state_file(wake_state_file: Path) -> None:
    """Redirect WAKE_STATE_FILE to tmp_path for all tests."""
    with patch(
        "wake_alarm._state.WAKE_STATE_FILE",
        wake_state_file,
    ):
        yield


class TestTodayStr:
    """Tests for _today_str helper."""

    def test_returns_date_string(self) -> None:
        """Return a YYYY-MM-DD string for today."""
        result = _today_str()
        assert len(result) == 10
        assert result[4] == "-"
        assert result[7] == "-"


class TestSaveWakeState:
    """Tests for save_trigger_fired."""

    def test_saves_with_hmac(self, wake_state_file: Path) -> None:
        """Save state with HMAC signature when key is available."""
        with patch(
            "wake_alarm._state.compute_entry_hmac",
            return_value="fakesig",
        ):
            result = save_trigger_fired(fired_at="2026-04-12T07:04:00+00:00")

        assert result is True
        data = json.loads(wake_state_file.read_text())
        assert data["fired_at"] == "2026-04-12T07:04:00+00:00"
        assert data["hmac"] == "fakesig"
        assert data["date"] == _today_str()

    def test_saves_without_hmac(self, wake_state_file: Path) -> None:
        """Save unsigned state when HMAC key is unavailable."""
        with patch(
            "wake_alarm._state.compute_entry_hmac",
            return_value=None,
        ):
            result = save_trigger_fired(fired_at="07:04")

        assert result is True
        data = json.loads(wake_state_file.read_text())
        assert "hmac" not in data

    def test_returns_false_on_write_error(self, wake_state_file: Path) -> None:
        """Return False when file cannot be written."""
        with (
            patch(
                "wake_alarm._state.compute_entry_hmac",
                return_value="sig",
            ),
            patch(
                "wake_alarm._state.WAKE_STATE_FILE",
                wake_state_file / "nonexistent_dir" / "file.json",
            ),
        ):
            result = save_trigger_fired(fired_at="07:04")

        assert result is False


class TestLoadWakeState:
    """Tests for load_wake_state."""

    def test_returns_none_when_file_missing(self) -> None:
        """Return None when state file doesn't exist."""
        assert load_wake_state() is None

    def test_returns_none_for_wrong_date(
        self,
        wake_state_file: Path,
    ) -> None:
        """Return None when state is from a different day."""
        state = {"date": "1999-01-01", "hmac": "x"}
        wake_state_file.write_text(json.dumps(state))
        assert load_wake_state() is None

    def test_returns_none_for_invalid_json(
        self,
        wake_state_file: Path,
    ) -> None:
        """Return None when file contains invalid JSON."""
        wake_state_file.write_text("not json {{{")
        assert load_wake_state() is None

    def test_returns_none_for_non_dict(
        self,
        wake_state_file: Path,
    ) -> None:
        """Return None when file contains a non-dict JSON value."""
        wake_state_file.write_text(json.dumps([1, 2, 3]))
        assert load_wake_state() is None

    def test_returns_none_for_bad_hmac(
        self,
        wake_state_file: Path,
    ) -> None:
        """Return None when HMAC verification fails."""
        state = {
            "date": _today_str(),
            "fired_at": "07:00",
            "hmac": "badsig",
        }
        wake_state_file.write_text(json.dumps(state))
        with patch(
            "wake_alarm._state.verify_entry_hmac",
            return_value=False,
        ):
            assert load_wake_state() is None

    def test_returns_state_for_valid_today(
        self,
        wake_state_file: Path,
    ) -> None:
        """Return state dict when file is valid and for today."""
        state = {
            "date": _today_str(),
            "fired_at": "07:04",
            "hmac": "validsig",
        }
        wake_state_file.write_text(json.dumps(state))
        with patch(
            "wake_alarm._state.verify_entry_hmac",
            return_value=True,
        ):
            result = load_wake_state()

        assert result is not None