QA thread

This time I would like to share with you solution for 'Class ref in pre-verified class resolved to unexpected implementation' issue I got while I was testing my multi-module project. Espresso tests were failing with below issue when I wanted to operate on RecyclerView from com.android.support:appcompat-v7. In my case RecyclerView dependency was defined not in the core-app module (the core module of the app) but in the other one which is set as a library. java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation at com.my.app.fragments.MyFragment.onCreateView(MyFragment.java:190) at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126) at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739) at android.support.v4.app.FragmentManagerImpl.

Currently I'm moving all my tests to Espresso 2.0 and Junit4. And today I was struggling with one nasty issue that you can face with as well and found the solution. So, the problem was noticed on pre-Lollipop devices/emulators. My app under test is configured to target the current latest API level 21. And after adapting some tests to Espresso 2.0 and JUnit4 I was able to successfully run it on emulator with Lollipop but trying to run it on devices/emulators lower then API 21 was failing with below issue: java.lang.NoClassDefFoundError: com.my.app.activities.MyActivity at com.my.app.test.instrumentation.TestMyActivity. (MyActivity.java:52) at java.lang.reflect.Constructor.constructNative(Native Method) at java.lang.reflect.Constructor.newInstance(Constructor.java:417) . . . And solution is to add below peace of code into your build.gradle: configurations { androidTestCompile.exclude group: 'com.android.support', module: 'support-v4' } :)