Improve documentation: Add example of unittest with DI

[skoky]

Hello

could you please add an example of service unit test with DI on service initialization? I have a service with DI but I don't know how to test it. Thank you.

[luizmineo]

Thanks, I'll try to include a more complete example in the docs. Meanwhile, take a look at issue #23. If you have problems or doubts, please let me know.

[skoky]

Yes, this was useful and my tests works now. Thank you.

[luizmineo]

Ok. I'll let this issue open, so I won't forget to update the docs.