AppEngineTraceService implements TraceService { @Override public Tracer getTracer() { return tracer; } AppEngineTraceService(); @VisibleForTesting  AppEngineTraceService(com.google.appengine.api.labs.trace.TraceService traceService); @Override Tracer getTracer(); @Override SpanContextHandler getSpanContextHandler(); @Override SpanContextFactory getSpanContextFactory();  }
@Test public void getTracer() { Tracer tracer = traceService.getTracer(); assertThat(tracer).isNotNull(); assertThat(tracer).isInstanceOf(AppEngineTracer.class); }