Messaging.SendEmailResult Type cannot be constructed?

Question

I'm trying to create a simple mock of messaging Messaging.sendEmail and in my code I'm trying to do the following to construct mocked instances of Messaging.SendEmailResult

Messaging.SendEmailResult result = new Messaging.SendEmailResult();

Compiler is giving the following error:

Type cannot be constructed: Messaging.SendEmailResult

Is there a work around?

Edit:

This doesn't work either:

Type t = Type.forName('Messaging', 'SendEmailResult');
Messaging.SendEmailResult newObj = (Messaging.SendEmailResult)t.newInstance();

Bummer...

Answer 1

Yes you can construct the Messaging.SendEmailResult using the JSON deserializer

Messaging.SendEmailResult  er =(Messaging.SendEmailResult) JSON.deserialize('{}', Messaging.SendEmailResult.class);
System.debug(er);

Get your instance. Happy Days.

Answer 2

Since the properties of this class are not in the official salesforce documentation, hopefully this helps someone. If you need to create an instance of this that return false for isSuccess()

Messaging.SendEmailResult failedMessageResult = (Messaging.SendEmailResult)JSON.deserialize('{"success":false}', Messaging.SendEmailResult.class);