boolean contains2 = thread.contains("concurrent1");

        assertNotNull(output1);
        assertNotNull(output2);
        assertTrue(contains2);
    }

    public void test_getOutput_specialCharacters() throws InterruptedException {
        String input = "Special: !@#$%^&*()\nUnicode: \u3042\u3044\u3046";
        InputStream is = new ByteArrayInputStream(input.getBytes(StandardCharsets.UTF_8));