NoopTracerImpl implements NoopTracer { @Override public Span activeSpan() { return NoopSpanImpl.INSTANCE; }  @Override ScopeManager scopeManager(); @Override Span activeSpan(); @Override Scope activateSpan(Span span); @Override SpanBuilder buildSpan(String operationName); @Override void inject(SpanContext spanContext, Format<C> format, C carrier); @Override SpanContext extract(Format<C> format, C carrier); @Override void close(); @Override String toString();  }
@Test public void activeSpanValueToleratesUseTest() { try { final Span activeSpan = NoopTracerImpl.INSTANCE.activeSpan(); assertNotNull(activeSpan); Tags.ERROR.set(activeSpan, true); } catch (final NullPointerException e) { fail("NoopTracer.activeSpan() should return a usable span"); } }