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);
        }