def test_basic(self):
self.assertEqual(solution.first_non_repeating_letter('a'), 'a')
self.assertEqual(solution.first_non_repeating_letter('stress'), 't')
self.assertEqual(solution.first_non_repeating_letter('moonmen'), 'e')
def test_empty_string(self):
self.assertEqual(solution.first_non_repeating_letter(''), '')
def test_odd_characters(self):
self.assertEqual(solution.first_non_repeating_letter('~><#~><'), '#')
self.assertEqual(solution.first_non_repeating_letter('hello world, eh?'), 'w')
def test_upper_case_letters(self):
self.assertEqual(solution.first_non_repeating_letter('sTreSS'), 'T')
self.assertEqual(solution.first_non_repeating_letter('Go hang a salami, I\'m a lasagna hog!'), ',')
def test_repeating_characters(self):
self.assertEqual(solution.first_non_repeating_letter('abba'), '')
self.assertEqual(solution.first_non_repeating_letter('aa'), '')
def test_should_handle_letter_cases(s, result):
assert first_non_repeating_letter(s) == result
def test_should_handle_odd_characters(s, result):
assert first_non_repeating_letter(s) == result
def test_should_handle_all_repeating_strings(s, result):
assert first_non_repeating_letter(s) == result
def test_should_handle_simple_tests(s, result):
assert first_non_repeating_letter(s) == result
