AppEngineTraceService implements TraceService { @Override public SpanContextHandler getSpanContextHandler() { throw new UnsupportedOperationException( "#getSpanContextHandler is not supported because the context " + "is managed by the App Engine runtime"); } AppEngineTraceService(); @VisibleForTesting  AppEngineTraceService(com.google.appengine.api.labs.trace.TraceService traceService); @Override Tracer getTracer(); @Override SpanContextHandler getSpanContextHandler(); @Override SpanContextFactory getSpanContextFactory();  }
@Test(expected = UnsupportedOperationException.class) public void getSpanContextHandler() { traceService.getSpanContextHandler(); }