public void MessageBuilder_From(string address) { var messageBuilder = new MessageBuilder(); var stepBuilder = messageBuilder.From(address); stepBuilder .Should() .NotBeNull() .And.BeOfType <MessageBuilder.BuildFromStep>() .Which.As <IBuilderContext>() .Message.From .Should() .NotBeNull() .And.BeOfType <MessageSender>() .Which .EmailAddress .Should() .Be(address) .And .BeEquivalentTo( messageBuilder.As <IBuilderContext>() ? .Message? .From? .EmailAddress); }