public void WhenContextIsNullThenEmptyInstanceOfMailContextIsReturned() { MailService mailService = new MailService(Mock.Of <IClient>(), Mock.Of <IMessageBuilderFactory>()); MailContext mailContext = mailService.BuildMessage(null); mailContext.Should().NotBeNull(); mailContext.EmailContent.Should().NotBeNull(); mailContext.EmailContent.MessageType.Should().Be(MailMessageType.Empty); }