1import unittest
 2from unittest.mock import patch, mock_open
 3from bangaranga import does_the_banga_rang, TheBangaDoesNotRangError
 4
 5class TestDoesTheBangaRang(unittest.TestCase):
 6    @patch('builtins.open', new_callable=mock_open, read_data="bangaranga")
 7    def test_single_word_match(self, mock_file):
 8        result = does_the_banga_rang("dummy.txt")
 9        self.assertEqual(result, 1)
10
11    @patch('builtins.open', new_callable=mock_open, read_data="The banga is doing some ranga!")
12    def test_two_words_in_sentence(self, mock_file):
13        result = does_the_banga_rang("dummy.txt")
14        self.assertEqual(result, 2)
15
16    @patch('builtins.open', new_callable=mock_open, read_data="The baNGa is doing some RAngA!")
17    def test_case_insensitivity(self, mock_file):
18        result = does_the_banga_rang("dummy.txt")
19        self.assertEqual(result, 2)
20
21    @patch('builtins.open', new_callable=mock_open, read_data="bang a banga ranga bangaranga")
22    def test_correct_search_length(self, mock_file):
23        result = does_the_banga_rang("dummy.txt")
24        self.assertEqual(result, 1)
25
26    @patch('builtins.open', new_callable=mock_open, read_data="b a n g a r a n g a")
27    def test_with_letters(self, mock_file):
28        result = does_the_banga_rang("dummy.txt")
29        self.assertEqual(result, 10)
30
31    @patch('builtins.open', new_callable=mock_open, read_data="banga,ranga.")
32    def test_regex_b(self, mock_file):
33        result = does_the_banga_rang("dummy.txt")
34        self.assertEqual(result, 2)
35
36    @patch('builtins.open', new_callable=mock_open, read_data="ranga is banga")
37    def test_order_correctness(self, mock_file):
38        result = does_the_banga_rang("dummy.txt")
39        self.assertEqual(result, 0)
40
41    @patch('builtins.open', new_callable=mock_open, read_data="bang a rang")
42    def test_particle_match(self, mock_file):
43        result = does_the_banga_rang("dummy.txt")
44        self.assertEqual(result, 0)
45
46    @patch('builtins.open', new_callable=mock_open, read_data="spam_banga ranga_eggs")
47    def test_subwords(self, mock_file):
48        result = does_the_banga_rang("dummy.txt")
49        self.assertEqual(result, 0)
50
51    @patch('builtins.open', new_callable=mock_open, read_data="")
52    def test_empty_file(self, mock_file):
53        result = does_the_banga_rang("dummy.txt")
54        self.assertEqual(result, 0)
55
56    @patch('builtins.open')
57    def test_error(self, mock_file):
58        mock_file.side_effect = OSError("Mocked OS Error")
59        with self.assertRaises(TheBangaDoesNotRangError):
60            does_the_banga_rang("missing_file.txt")
61
62if __name__ == '__main__':
63    unittest.main()