c# - How to mock non virtual methods?

Question

[TestMethod]
public void TestMethod1()
{
    var mock = new Mock<EmailService>();
    mock.Setup(x => x.SendEmail()).Returns(true);
    var cus = new Customer();
    var result = cus.AddCustomer(mock.Object);
    Assert.IsTrue(result);
}

public class Customer
{
    public bool AddCustomer(EmailService emailService)
    {
        emailService.SendEmail();
        Debug.WriteLine("new customer added");
        return true;
    }
}

public class EmailService
{            
    public virtual bool SendEmail()
    {
        throw  new Exception("send email failed cuz bla bla bla");
    }
}

The EmailService.SendEmail method must be virtual to mock it. Is there any way to mock non virtual methods?

Answer 1

Moq cannot mock non virtual methods on classes. Either use other mocking frameworks such as Type mock Isolator which actually weaves IL into your assembly or place an interface on EmailService and mock that.