TestUtil.java

package treehou.se.habit;

import android.app.Application;
import android.content.Context;
import android.support.annotation.NonNull;
import android.test.RenamingDelegatingContext;

import io.realm.Realm;
import treehou.se.habit.data.TestAndroidModule;

public class TestUtil {

    public static DaggerActivityTestRule<MainActivity> TestRule() {

        Realm realm = Realm.getDefaultInstance();
        realm.beginTransaction();
        realm.deleteAll();
        realm.commitTransaction();

        return new DaggerActivityTestRule<>(MainActivity.class, new DaggerActivityTestRule.OnBeforeActivityLaunchedListener<MainActivity>() {
            @Override
            public void beforeActivityLaunched(@NonNull Application application, @NonNull MainActivity activity) {
                ((HabitApplication) application).setTestComponent(createComponent(application));
                Context renamedContext = new RenamingDelegatingContext(application, "Testus");
                DatabaseUtil.init(renamedContext);
            }
        });
    }

    protected static HabitApplication.ApplicationComponent createComponent(Context context){
        HabitApplication.ApplicationComponent component = DaggerHabitApplication_ApplicationComponent.builder()
                .androidModule(new TestAndroidModule(context))
                .build();
        return component;
    }
}