android – getSupportActionBar()使用Robolectric返回null

这是我的简单测试用例：

package com.mobile.test;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertthat;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricTestRunner;
import android.app.Activity;
import android.content.Intent;
import com.mobile.android.core.R;
import com.mobile.android.core.activity.MainActivity;
import com.mobile.android.core.activity.TestActivity;

@RunWith(RobolectricTestRunner.class)
public class NavigationDrawerTest {
private Activity activity;

@Test
public void testNavigationDrawer() {
    activity = Robolectric.buildActivity(MainActivity.class).create().get();
    String hello = activity.getResources().getString(R.string.drawer_open);
    System.out.println(hello);
    assertEquals(hello,"Menu");
}
}

这是我的Activity类：

public class MainActivity extends ActionBaractivity {
// Drawer related
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
String[] mDrawerOptions;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // enable ActionBar app icon to behave as action to toggle nav-drawer
    if (getSupportActionBar() != null) {
        getSupportActionBar().setdisplayHomeAsUpEnabled(true);
        getSupportActionBar().setHomeButtonEnabled(true);
    }
}
}

关于hwo的任何好主意都要解决这个问题？
我是否必须写一些影子活动,或者是否有人知道如何使用RObolectric解决这些操作栏问题？

谢谢你的帮助