@Test
public void testGetSpanReportListenersHolder() throws Exception {

    SpanReportListener listener1 = new SpanReportListener() {
        @Override
        public void onSpanReport(SofaTracerSpan sofaTracerSpan) {
        }
    };
    SpanReportListener listener2 = new SpanReportListener() {
        @Override
        public void onSpanReport(SofaTracerSpan sofaTracerSpan) {
        }
    };
    SpanReportListenerHolder.addSpanReportListener(listener1);
    SpanReportListenerHolder.addSpanReportListener(listener2);
    //2
    assertEquals(2, SpanReportListenerHolder.getSpanReportListenersHolder().size());
    SpanReportListenerHolder.clear();
    assertEquals(0, SpanReportListenerHolder.getSpanReportListenersHolder().size());
    List<SpanReportListener> listenerList = new ArrayList<SpanReportListener>();
    listenerList.add(listener1);
    listenerList.add(listener2);
    SpanReportListenerHolder.addSpanReportListeners(listenerList);
    assertEquals(2, SpanReportListenerHolder.getSpanReportListenersHolder().size());
}