assertTrue(stackTraceOutput.contains("IOException"));
        assertTrue(stackTraceOutput.contains("IO error"));
    }

    /**
     * Test exception chaining
     */
    public void test_exceptionChaining() {
        Exception level3 = new IllegalArgumentException("Level 3 - Root cause");
        Exception level2 = new IllegalStateException("Level 2", level3);
        Exception level1 = new IOException("Level 1", level2);