タイトル通り、DrawerLayoutをRobolectric3でテストするメモ

package kinjouj.app.oretter;

import java.lang.reflect.Method;

import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.view.ViewGroup;
import android.widget.TextView;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.Robolectric;
import org.robolectric.RobolectricGradleTestRunner;
import org.robolectric.RuntimeEnvironment;

import static org.junit.Assert.*;
import static org.hamcrest.Matchers.*;

@RunWith(RobolectricGradleTestRunner.class)
public class DrawerLayoutTest {

    private static final int MP = ViewGroup.LayoutParams.MATCH_PARENT;

    // class MainActivity extends AppCompatActivity
    private MainActivity activity;
    private DrawerLayout drawerLayout;
    private ActionBarDrawerToggle actionBarDrawer;

    @Before
    public void setUp() {
        activity = Robolectric.buildActivity(MainActivity.class).attach().get();

        drawerLayout = new DrawerLayout(RuntimeEnvironment.application);
        drawerLayout.addView(
            new TextView(RuntimeEnvironment.application),
            0,
            new DrawerLayout.LayoutParams(MP, MP, GravityCompat.START)
        );

        actionBarDrawer = new ActionBarDrawerToggle(
            activity,
            drawerLayout,
            new Toolbar(RuntimeEnvironment.application),
            R.string.drawer_open,
            R.string.drawer_close
        );
        drawerLayout.setDrawerListener(actionBarDrawer);
        actionBarDrawer.syncState();
    }

    @Test
    public void test() throws Exception {
        assertThat(drawerLayout.isDrawerOpen(GravityCompat.START), is(false));

        drawerLayout.openDrawer(GravityCompat.START);
        assertThat(drawerLayout.isDrawerOpen(GravityCompat.START), is(true));

        drawerLayout.closeDrawer(GravityCompat.START);
        assertThat(drawerLayout.isDrawerOpen(GravityCompat.START), is(false));

        // やらなくてもいいけどActionBarDrawerToggle.toggleメソッドでも開閉は可能
        Method method = ActionBarDrawerToggle.class.getMethod("toggle", null);
        method.invoke(actionBarDrawer, null);

        assertThat(drawerLayout.isDrawerOpen(GravityCompat.START), is(true));
    }
}

DrawerLayoutのインスタンスを生成するだけではopenDrawer等のメソッドを実行するとエラーになるのでaddView等をしておく必要がある模様