@Test
public void testSetPrefix() {

    SLF4JSegmentListener listener = (SLF4JSegmentListener) AWSXRay.getGlobalRecorder().getSegmentListeners().get(0);
    listener.setPrefix("");
    Segment seg = new SegmentImpl(AWSXRay.getGlobalRecorder(), "test", traceID);
    listener.onSetEntity(null, seg);
    Assert.assertEquals(traceID.toString() + "@" + seg.getId(), MDC.get(TRACE_ID_KEY));
}