Hello all, is there any way to test a `RecyclerView.Adapter` on a local VM? I have mocked some stuff...

# android

[alex.tavella]

Hello all, is there any way to test a RecyclerView.Adapter on a local VM? I have mocked some stuff but I'm getting a NPE when notifyDataSetChanged gets called

[alex.tavella]

java.lang.NullPointerException
	at androidx.recyclerview.widget.RecyclerView$AdapterDataObservable.notifyChanged(RecyclerView.java:11996)
	at androidx.recyclerview.widget.RecyclerView$Adapter.notifyDataSetChanged(RecyclerView.java:7070)

[starke]

http://robolectric.org/

although it’s probably easier to extract the logic to a plain java class that doesn’t have any dependencies on android stuff

[alex.tavella]

I want to test diffing and itemCount and stuff which are specific to the adapter

[starke]

oo my itemCount method is usually as simple as items.size() although nowadays I tend to use groupie which handles that for you

[starke]

and allows you to create pure java classes to hold the diffing logic

[starke]

all to say - it is possible to extract that logic if you don’t want to deal with the headaches of testing w/ android classes

[alex.tavella]

You don't use ListAdapter then?

[alex.tavella]

Bc DiffUtil is heavily coupled with Android fwk

[Chris Craik]

DiffUtil is not heavily coupled with android, there's actually only one method that takes an adapter that prevents it from being in an Android-free .jar library. I somewhat regret we didn't move DiffUtil to a separate package with the androidx refactor, to help us eventually move it to a .jar library on its own.

[alex.tavella]

Yea, sorry about the "heavily". Theres just that one class which obliges me to use a non-mocked android.jar