public void ShouldLogInfo() { var log = JsonStrings.CommandLogOut(); var format = Substitute.For<IProtocolWriterFormat>(); format.LogInfo("hello world!").Returns(log); var writer = Substitute.For<IWriteNext>(); var reader = Substitute.For<IStormReader>(); var subjectUnderTest = new StandardSpoutWriter(writer, format, reader); subjectUnderTest.LogInfo("hello world!"); writer.Received().Write(log); }