import unittest
from solution import eval


class Test(unittest.TestCase):

    def test_eval(self):
        self.assertEqual(0, eval(''))
        self.assertEqual(-1, eval('-1'))
        self.assertEqual(1, eval('-1 + 2'))
        self.assertEqual(-2, eval('-1 + 2 - (3)'))
        self.assertEqual(-3, eval('-1 + 2 - (1 - 5)'))
        self.assertEqual(-3, eval('- (3 + ( 2 - 1 ) )'))


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