Method check_peek

python/python3/tornado/test/iostream_test.py:1218–1225

(self, buf, expected)

        return buf

    def check_peek(self, buf, expected):
        size = 1
        while size < 2 * len(expected):
            got = self.to_bytes(buf.peek(size))
            self.assertTrue(got)  # Not empty
            self.assertLessEqual(len(got), size)
            self.assertTrue(expected.startswith(got), (expected, got))
            size = (size * 3 + 1) // 2

    def check_append_all_then_skip_all(self, buf, objs, input_type):
        self.assertEqual(len(buf), 0)