Question

I have a simple method for sending emails:

public void notifyEmail(string messageSubject, string messageBody)
{
   MailMessage message = new MailMessage(from, to);

   message.Subject = messageSubject;
   message.Body = messageBody;

   SmtpClient client = new SmtpClient(smtp_client);
   client.Send(message);

   message.Dispose();//release everything related
}

And a unit test (I’m learning):

[TestMethod()]
    public void notifyEmailTest()
    {
        eMail target = new eMail("TEST Subject","TEST Body"); // TODO: Initialize to an appropriate value

        bool testSent = true;
        try
        {
            target.notifyEmail();
        }
        catch (Exception)
        {
            testSent = false;
        }

        Assert.IsTrue(testSent);            
    }

I deliberately set the smtp_client variable value to something invalid.

Running the code in my project results in an error.

Running the test method results in a Pass. Should my test or method be structured differently so that errors will fail the test?

Answer 1

I always do everything I can to avoid putting try-catch clauses on my unit tests. Instead try using the ExpectedException attribute (the attribute is the same for NUnit and MSTest) and set the type to the exception you are expecting i.e.

[TestMethod]
[ExpectedException(typeof(NetworkException))]
public void ShouldThrowNetworkExceptionIfSmtpServerIsInvalid)
{
     //... test code here.
}

Another approach that I have used is to create a static class with an AssertExpectedException method since sometimes a method can throw the same type of exception for different reasons and the only way to know for sure if the accurate message is being returned is with custom code since the attribute does not assert the message the thrown exception is returning.

Hope this helps.

Regards.