text: import unittest
  from fizzbuzz import fizzbuzz
  
  class TestFizzBuzz(unittest.TestCase):
    def test_fizzbuzz(self):
      self.assertEqual(fizzbuzz(15), 'FizzBuzz')
  
    def test_fizz(self):
      self.assertEqual(fizzbuzz(3), 'Fizz')
  
    def test_buzz(self):
      self.assertEqual(fizzbuzz(5), 'Buzz')
  
    def test_not_matching(self):
      self.assertEqual(fizzbuzz(2), "2")
  
    def test_zero(self):
      self.assertIsNone(fizzbuzz(0))
  
    def test_negative_number(self):
      self.assertIsNone(fizzbuzz(-1))
  
  if __name__ == '__main__':
    unittest.main()