public void zoom_should_be_visited_by_unix() { IModem zoom = new Zoom(); var mockLogger = new Mock <ILogger>(); IModemVisitor configureForUnixVisitor = new ConfigureForUnixVisitor(mockLogger.Object); zoom.Accept(configureForUnixVisitor); mockLogger.Verify(logger => logger.Info("Zoom used with Unix configurator."), Times.Once); }