/** Test real guard can both allow and deny access. */
public void testGuard() {
    final String message = "test message";
    final StringBuffer objBuffer = new StringBuffer("235345 t");
    GuardedObject go = new GuardedObject(objBuffer, new Guard() {

        public void checkGuard(Object object) throws SecurityException {
            if (object == objBuffer && objBuffer.length() == 0) {
                throw new SecurityException(message);
            }
        }
    });
    assertEquals(objBuffer, go.getObject());

    objBuffer.setLength(0);
    try {
        go.getObject();
        fail("SecurityException is not thrown");
    } catch (Exception ok) {
        assertEquals(message, ok.getMessage());
    }
}