### Question:
TracerShim extends BaseShimObject implements Tracer { @Override public void close() { isClosed = true; } TracerShim(TelemetryInfo telemetryInfo); @Override ScopeManager scopeManager(); @Override Span activeSpan(); @Override Scope activateSpan(Span span); @Override SpanBuilder buildSpan(String operationName); @Override void inject(SpanContext context, Format<C> format, C carrier); @SuppressWarnings("ReturnMissingNullable") @Override SpanContext extract(Format<C> format, C carrier); @Override void close();  }### Answer:
@Test void close() { tracerShim.close(); Span otSpan = tracerShim.buildSpan(null).start(); io.opentelemetry.trace.Span span = ((SpanShim) otSpan).getSpan(); assertTrue(span instanceof DefaultSpan); }