import unittest
import io
import sys
from hanoi import tower_of_hanoi, prompt_for_integer

class TestTowerOfHanoi(unittest.TestCase):
    """
    Explanation of Tests:

        test_valid_input(): 
            This test checks the core functionality by moving 3 disks using tower_of_hanoi. 
            It asserts that the function completes without raising errors.

        test_edge_case_single_disk(): 
            This handles the base case of a single disk, ensuring the correct move 
            is printed ("Move disk 1 from A to C").

        test_invalid_input_zero_disks(): 
            This checks that the function raises a ValueError when given zero disks.

        test_prompt_for_integer_valid(): 
            Tests the input function with valid integer input ("3") and asserts it 
            returns the correct value (3).

        test_prompt_for_integer_invalid_negative(): 
            Checks for handling negative integers, expecting a ValueError.

        test_prompt_for_integer_invalid_string(): 
            Tests that invalid string input is handled gracefully and eventually 
            leads to a valid integer being returned.
    """

    def test_valid_input(self):
        self.assertEqual(tower_of_hanoi(3, 'A', 'B', 'C'), None)  # Example with 3 disks

    def test_edge_case_single_disk(self):
        expected_output = "Move disk 1 from A to C\n"
        captured_output = io.StringIO()
        sys.stdout = captured_output
        tower_of_hanoi(1, 'A', 'B', 'C')
        sys.stdout = sys.__stdout__  # Reset stdout
        self.assertEqual(captured_output.getvalue(), expected_output)

    def test_invalid_input_zero_disks(self):
        with self.assertRaises(ValueError):
            tower_of_hanoi(0, 'A', 'B', 'C')

    def test_prompt_for_integer_valid(self):
        with io.StringIO("3\n") as mock_stdin:
            sys.stdin = mock_stdin
            self.assertEqual(prompt_for_integer(), 3)

    def test_prompt_for_integer_invalid_negative(self):
        with io.StringIO("-2\n1\n") as mock_stdin:
            sys.stdin = mock_stdin
            self.assertEqual(prompt_for_integer(), 1)  # Should eventually get a valid integer


    def test_prompt_for_integer_invalid_string(self):
        with io.StringIO("abc\n3\n") as mock_stdin:
            sys.stdin = mock_stdin
            self.assertEqual(prompt_for_integer(), 3)  # Should eventually get a valid integer

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