Espresso Samples

Anyone has some Espresso testing samples? 

I have problem trying to get some views , I was checking that u2020 project from Mortar has some samples like 
https://github.com/lemonlabs/u2020-mortar/blob/master/app/src/androidTest/java/co/lemonlabs/mortar/tests/BaseTest.java

But Not sure if this library requires extra code to find the views inside the Navigator? 
