WCF Service Method - Refactoring for Unit Test and Mocking - wcf

Question

I've a WCF service with the following method:
Public Function ScheduleEmail(ByVal request As ScheduleEmailRequest) As ScheduleEmailResponse _
Implements EmailProtocol.ISchedulingService.ScheduleEmail
Try
If Not Email.IsValidEmailAddress(request.EmailAddress) Then
EmailSchedulerTrace.Source.WriteError(String.Format("Email with template '{0}' was not sent to '{1}' because it the address is invalid.", request.EmailName, request.EmailAddress))
Else
Dim mgr As New JobManager
Dim job As New EmailJob
Dim suppression As New SuppressionManager
Dim emailItem As Email = Email.GetEmailByName(request.EmailName)
If suppression.CheckSuppresion(emailItem, request.EmailAddress) Then
job.JobGuid = Guid.NewGuid
job.EmailAddress = request.EmailAddress
job.EmailGuid = emailItem.ID
job.ScheduledSendTime = request.ScheduledTime
job.CustomAttributes = request.CustomAttributes
job.ConsumerID = Email.GetConsumerId(request.CustomAttributes)
mgr.ScheduleJob(job)
Else
EmailSchedulerTrace.Source.WriteWarning(String.Format("Email with template '{0}' was not sent to '{1}' because it was suppressed.", request.EmailName, request.EmailAddress))
End If
End If
Catch ex As Exception
EmailSchedulerTrace.Source.WriteError(ex)
Throw
End Try
Return New ScheduleEmailResponse
End Function
I need to write Unit Test for this Method. Please help me out with
Do i need to change anything in my method?
What should I mock?
Your help is greatly appreciated. Thanks in advance.
Regards,
Sachin

Answer 1

You need to be able to swap out any 'services' (classes that you new up in a method or fields in the class) which connect to other systems (database, email server etc) so you need to create interfaces for the classes and inject the correct implementation at runtime and in your unit test, you can create mock or fake implementations for testing purposes.
A good start would be to define an interface for:
JobManager
EmailSchedulerTrace
SuppressionManager
You also might need to move the functionality of your static methods on Email
GetEmailByName
GetConsumerId
if they encapsulate database access or any other service which you cannot isolate.