Migrating Junit4 tests to androidx: What causes 'delegate runner could not be loaded'?

Question

I am migrating my app to androidx, I can\'t seem to get my unit tests working. I took example from Google\'s AndroidJunitRunnerSample, which has been updated to use the new

Answer 1

You need to make sure that any class marked with the @BeforeClass annotation is public static . For example:

import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;

import androidx.test.ext.junit.runners.AndroidJUnit4;

@RunWith(AndroidJUnit4.class)
public class EntityParcelTest {

    @BeforeClass
    public static void createEntities() {
        // Setup...
    }

    @Test
    public void someTest() {
        // Testing here
    }