public class MailManagerTest
{
[Fact]
public void NotValidEmail()
{
//Arrange
var mailManager = new MailManager();
const string mailAddress = "john.smith.company.com";
//Act
bool isValid = mailManager.IsValidAddress(mailAddress);
//Assert
Assert.False(isValid, $"The email {mailAddress} is valid, but it shouldn’t");
}
}