text: import unittest
  
  import filesystem.path
  
  
  class Test(unittest.TestCase):
      def test_get_extension(self) -> None:
          ext = filesystem.path.get_file_extension("/path/to/file.txt")
          self.assertEqual(ext, "txt")
          with self.assertRaises(filesystem.path.AmbiguousExtensionError):
              filesystem.path.get_file_extension("/path/to/file.test.txt")
  
  
  if __name__ == "__main__":
      unittest.main()
  