import unittest
from unittest.mock import MagicMock, patch

import pymysql

import server


class DatabaseReadyTests(unittest.TestCase):
    @patch("server.pymysql.connect")
    def test_returns_true_for_select_one(self, connect):
        connection = MagicMock()
        cursor = connection.cursor.return_value
        cursor.fetchone.return_value = (1,)
        connect.return_value = connection

        self.assertTrue(server.database_ready())
        cursor.execute.assert_called_once_with("SELECT 1")
        cursor.close.assert_called_once()
        connection.close.assert_called_once()

    @patch("server.pymysql.connect", side_effect=pymysql.MySQLError("unavailable"))
    def test_returns_false_when_database_is_unavailable(self, connect):
        self.assertFalse(server.database_ready())
        connect.assert_called_once()


if __name__ == "__main__":
    unittest.main()