1import os
 2import tempfile
 3import unittest
 4from contextlib import contextmanager
 5
 6from bangaranga import does_the_banga_rang, TheBangaDoesNotRangError
 7
 8
 9class DoesTheBangaRangTests(unittest.TestCase):
10    @contextmanager
11    def file_with_content(self, content):
12        fd, path = tempfile.mkstemp(text=True)
13
14        try:
15            with os.fdopen(fd, "w", encoding="utf-8") as file:
16                file.write(content)
17
18            yield path
19        finally:
20            if os.path.exists(path):
21                os.remove(path)
22
23    def assert_bangaranga_count(self, content, expected_count):
24        with self.file_with_content(content) as path:
25            self.assertEqual(does_the_banga_rang(path), expected_count)
26
27    def test_returns_one_when_bangaranga_is_a_whole_word(self):
28        self.assert_bangaranga_count("bangaranga", 1)
29
30    def test_returns_two_when_banga_and_ranga_appear_in_order(self):
31        self.assert_bangaranga_count("The banga is doing some ranga!", 2)
32
33    def test_returns_three_when_three_words_form_bangaranga(self):
34        self.assert_bangaranga_count("bang a small ranga", 3)
35
36    def test_returns_minimum_number_of_words_when_multiple_solutions_exist(self):
37        self.assert_bangaranga_count("bang a banga ranga bangaranga", 1)
38
39    def test_is_case_insensitive(self):
40        self.assert_bangaranga_count("BANGA something RANGA", 2)
41
42    def test_words_must_appear_in_the_correct_order(self):
43        self.assert_bangaranga_count("ranga banga", 0)
44
45    def test_returns_zero_when_words_do_not_form_the_whole_target(self):
46        self.assert_bangaranga_count("Does the banga rang?", 0)
47
48    def test_does_not_use_substrings_inside_larger_words(self):
49        self.assert_bangaranga_count(
50            "xxbangaranga bangaranga1 _bangaranga_",
51            0,
52        )
53
54    def test_returns_zero_when_file_has_no_matching_words(self):
55        self.assert_bangaranga_count("123 !!! ---", 0)
56
57    def test_raises_custom_error_when_file_cannot_be_read(self):
58        with tempfile.TemporaryDirectory() as directory:
59            missing_file_path = os.path.join(directory, "missing.txt")
60
61            with self.assertRaises(TheBangaDoesNotRangError):
62                does_the_banga_rang(missing_file_path)
63
64
65if __name__ == "__main__":
66    unittest.main()