public void TestAddThenGetBySubject() { var mailBag = new MailBag(); var message = CreateTestMailMessage(); mailBag.Add(message); var retrievedMessage = mailBag.GetMailsWithSubject(MailMessageData.Subject).First(); Assert.That(mailBag.ContainsMailWithSubject(MailMessageData.Subject)); Assert.That(retrievedMessage, Is.SameAs(message)); }