String output = thread.getOutput();
        assertTrue(output.contains("Special: !@#$%^&*()"));
        assertTrue(output.contains("Unicode: \u3042\u3044\u3046"));
    }

    @Test
    public void test_contains_emptyString() throws InterruptedException {
        String input = "\nempty\n";
        InputStream is = new ByteArrayInputStream(input.getBytes(StandardCharsets.UTF_8));