RobolectricGradleTestRunner.java

package your.package.name;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBarActivity;
import org.junit.runners.model.InitializationError;
import org.robolectric.AndroidManifest;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.annotation.Config;
import org.robolectric.res.Fs;

import your.package.BuildConfig;

public class RobolectricGradleTestRunner extends RobolectricTestRunner {

    public RobolectricGradleTestRunner(final Class<?> testClass) throws InitializationError {
        super(testClass);
    }

    public static void startFragment(Fragment fragment) {
        FragmentActivity activity = Robolectric.buildActivity(ActionBarActivity.class)
                .create()
                .start()
                .resume()
                .get();

        FragmentManager fragmentManager = activity.getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(fragment, null);
        fragmentTransaction.commit();
    }

    @Override
    protected AndroidManifest getAppManifest(Config config) {
        String buildVariant = (BuildConfig.FLAVOR.isEmpty() ? "" : BuildConfig.FLAVOR + "/") + BuildConfig.BUILD_TYPE;
        String intermediatesPath = BuildConfig.class.getResource("").toString().replace("file:", "");
        intermediatesPath = intermediatesPath.substring(0, intermediatesPath.indexOf("/classes"));

        String manifestPath = intermediatesPath + "/manifests/full/" + buildVariant + "/AndroidManifest.xml";
        String resPath = intermediatesPath + "/res/" + buildVariant;
        String assetPath = intermediatesPath + "/assets/" + buildVariant;
        AndroidManifest androidManifest = createAppManifest(Fs.fileFromPath(manifestPath),
                Fs.fileFromPath(resPath),
                Fs.fileFromPath(assetPath));
        androidManifest.setPackageName("your.package.name");

        return androidManifest;
    }
}