public void ShouldLogError() { var format = Substitute.For<IProtocolWriterFormat>(); var writer = Substitute.For<IWriteNext>(); var reader = Substitute.For<IStormReader>(); var subjectUnderTest = new StandardSpoutWriter(writer, format, reader); subjectUnderTest.LogError("ERROR!!!!!!"); writer.Received().AlternativeErrorStream("ERROR!!!!!!"); format.DidNotReceiveWithAnyArgs().LogError(""); }