import json
from pathlib import Path
from unittest import mock

from config import Config

import unittest


class TestConfig(unittest.TestCase):

    def test_creates_new_config_file_if_not_exists(self):
        config_path = Path("test_config.json")
        if config_path.exists():
            config_path.unlink()
        config = Config(config_file=config_path)
        self.assertTrue(config_path.exists())
        config_path.unlink()

    def test_writes_default_configuration_to_config_file(self):
        config_path = Path("test_config.json")
        if config_path.exists():
            config_path.unlink()
        config = Config(config_file=config_path)
        with open(config_path, "r") as f:
            data = json.load(f)
        self.assertEqual(data, {"database_path": "~/.iottb.db", "log_level": "INFO"})
        config_path.unlink()

    @unittest.mock.patch("builtins.open", side_effect=PermissionError)
    def test_config_file_path_not_writable(self, mock_open):
        config_path = Path("test_config.json")
        with self.assertRaises(PermissionError):
            config = Config(config_file=config_path)
            config.create_default_config()

    def test_config_file_path_is_directory(self):
        config_dir = Path("test_config_dir")
        config_dir.mkdir(exist_ok=True)
        with self.assertRaises(IsADirectoryError):
            config = Config(config_file=config_dir)
            config.create_default_config()
        config_dir.rmdir()