@Test public void toString_withSpanReporter() {

  tracer = Tracing.newBuilder().addSpanHandler(new SpanHandler() {
    @Override public boolean end(TraceContext context, MutableSpan span, Cause cause) {
      return true;
    }
    @Override public String toString() {
      return "MyHandler";
    }
  }).spanReporter(new Reporter<zipkin2.Span>() {
    @Override public void report(zipkin2.Span span) {
    }
    @Override public String toString() {
      return "MyReporter";
    }
  }).build().tracer();
  assertThat(tracer).hasToString(
    "Tracer{spanHandler=[MyHandler, MyReporter]}"
  );
}