public void Tracer_ExtractAndInject_ShouldUseTheCorrectCodec() { var carrier = "carrier, yo"; var spanContext = Substitute.For <ILetsTraceSpanContext>(); _mockExtractor.Extract(Arg.Is <string>(c => c == carrier)); _mockInjector.Inject(Arg.Is <ISpanContext>(sc => sc == spanContext), Arg.Is <string>(c => c == carrier)); _builtTracer.Extract(_format, carrier); _builtTracer.Inject(spanContext, _format, carrier); _mockExtractor.Received(1).Extract(Arg.Any <string>()); _mockInjector.Received(1).Inject(Arg.Any <ISpanContext>(), Arg.Any <string>()); }