I am looking at the Unit Tests I wrote for an email service (using SMTP) and I am wondering if one test in particular is sufficient. Here is a snippet of my email service:

```
[PluginFamily("EmailService")]
public interface IEmailService
{
    Boolean SendEmail( string toAddress, string fromAddress, string bccAddress,  string ccAddress, string subject,
                       string body, bool html );
}
[Pluggable("EmailService")]
public class EmailService : IEmailService
{
    private IConfigurationReader _configReader;
    public EmailService(IConfigurationReader configurationReader)
    {
        _configReader = configurationReader;
    }
    public bool SendEmail( string toAddress, string fromAddress, string bccAddress, string ccAddress, string subject, string body, bool isHtml )
    {
        MailMessage email = new MailMessage();

        try
        {
            if (_configReader.TestMode)
            {
                toAddress = _configReader.TestEmailAddress;
            }
        }

        //send email here
     }
}

```

I am mocking IConfigurationReader (basically a wrapper for ConfigurationManager) and setting the test mode to true in order to test if I can send an email in my "test mode". So my unit test looks something like this (This is one of my unit tests on the method. I have 100% code coverage):

```
    [Test]
    public void Validate_Send_Email_In_Test_Mode()
    {
        bool result;
        MockRepository mockRepository = new MockRepository();
        var mockConfigReader = mockRepository.StrictMock<IConfigurationReader>();

        using (mockRepository.Record())
        {

            SetupResult.For(mockConfigReader.TestMode).Return(true);
            SetupResult.For(mockConfigReader.TestEmailAddress).Return("test@test.com");
            SetupResult.For(mockConfigReader.EmailContentLocation).Return("test");
            SetupResult.For( mockConfigReader.SmtpHost ).Return( "test.mail.com" );
        }

        ObjectFactory.InjectStub(typeof(IConfigurationReader), mockConfigReader);
        emailService = ObjectFactory.GetInstance<IEmailService>();

        using (mockRepository.Playback())
        {
            result = emailService.SendEmail( "testemail@test.com",
                                                  "test@test.com", "", "",
                                                  "this is a unit test - config in test mode", "body of unit test", true );

        }

        Assert.That( result, Is.True );
        ObjectFactory.ResetDefaults();

    }

```

Is this sufficient enough for a unit test? What can I do to improve it?

I am concerned that just checking that my method is returning true is not a sufficient unit test.