public IThrowableRenderer<ILoggingEvent> getThrowableRenderer() {
        return throwableRenderer;
    }
@Test
    public void testAppendThrowable() throws Exception {
        StringBuilder buf = new StringBuilder();
        PubThrowableProxy tp = new PubThrowableProxy();
        tp.setClassName("test1");
        tp.setMessage("msg1");

        StackTraceElement ste1 = new StackTraceElement("c1", "m1", "f1", 1);
        StackTraceElement ste2 = new StackTraceElement("c2", "m2", "f2", 2);

        StackTraceElementProxy[] stepArray = { new StackTraceElementProxy(ste1), new StackTraceElementProxy(ste2) };
        tp.setStackTraceElementProxyArray(stepArray);
        DefaultThrowableRenderer renderer = (DefaultThrowableRenderer) layout.getThrowableRenderer();

        renderer.render(buf, tp);
        System.out.println(buf.toString());
        String[] result = buf.toString().split(CoreConstants.LINE_SEPARATOR);
        System.out.println(result[0]);
        assertEquals("test1: msg1", result[0]);
        assertEquals(DefaultThrowableRenderer.TRACE_PREFIX + "at c1.m1(f1:1)", result[1]);
    }