def test_next_line(self):
"""A test of the next_line method of the JavaLikeScanner class."""
scanner = JavaLikeScanner("one two three\nfour\tfive six")
self.assertEqual(scanner.next_line(), "one two three")
self.assertEqual(scanner.next_line(), "four\tfive six")
self.assertEqual(scanner.next_line(), None)
self.assertEqual(scanner.contents, "")
scanner = JavaLikeScanner("")
self.assertEqual(scanner.next_line(), None)
