import unittest
from hanoi import hanoi  # Assuming the code is in a file named hanoi.py

class TestHanoi(unittest.TestCase):
   
   def test_hanoi_with_one_disk(self):
       with self.subTest(n=1, source='A', auxiliary='B', target='C'):
           expected_output = "Move disk 1 from A to C\n"
           with unittest.mock.patch('sys.stdout', new=io.StringIO()) as mock_stdout:
               hanoi(1, 'A', 'B', 'C')
               self.assertEqual(mock_stdout.getvalue(), expected_output)
   
   def test_hanoi_with_two_disks(self):
       with self.subTest(n=2, source='A', auxiliary='B', target='C'):
           expected_output = "Move disk 1 from A to B\nMove disk 2 from A to C\nMove disk 1 from B to C\n"
           with unittest.mock.patch('sys.stdout', new=io.StringIO()) as mock_stdout:
               hanoi(2, 'A', 'B', 'C')
               self.assertEqual(mock_stdout.getvalue(), expected_output)
   
   def test_hanoi_with_three_disks(self):
       with self.subTest(n=3, source='A', auxiliary='B', target='C'):
           expected_output = "Move disk 1 from A to C\nMove disk 2 from A to B\nMove disk 1 from C to B\nMove disk 3 from A to C\nMove disk 1 from B to A\nMove disk 2 from B to C\nMove disk 1 from A to C\n"
           with unittest.mock.patch('sys.stdout', new=io.StringIO()) as mock_stdout:
               hanoi(3, 'A', 'B', 'C')
               self.assertEqual(mock_stdout.getvalue(), expected_output)
   
   def test_hanoi_with_zero_disks(self):
       with self.subTest(n=0, source='A', auxiliary='B', target='C'):
           expected_output = ""
           with unittest.mock.patch('sys.stdout', new=io.StringIO()) as mock_stdout:
               hanoi(0, 'A', 'B', 'C')
               self.assertEqual(mock_stdout.getvalue(), expected_output)
   
   def test_hanoi_with_negative_disks(self):
       with self.subTest(n=-1, source='A', auxiliary='B', target='C'):
           expected_output = ""
           with unittest.mock.patch('sys.stdout', new=io.StringIO()) as mock_stdout:
               hanoi(-1, 'A', 'B', 'C')
               self.assertEqual(mock_stdout.getvalue(), expected_output)

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