Android unit test for Marshmallow PermissionHelper

I wanna learn Robolectric to use it for unit tests on an Android Marshmallow app. I wrote a PermissionHelper with some methods to make permission handling a bit easier. To get started with unit tests for this class, I am trying to test the most simple method:

public static boolean hasPermissions(Activity activity, String[] permissions) {
    for (String permission : permissions) {
        int status = ActivityCompat.checkSelfPermission(activity, permission);
        if (status == PackageManager.PERMISSION_DENIED) {
            return false;
        }
    }
    return true;
}

Here is the Robolectric test that I wrote so far:

@RunWith(RobolectricTestRunner.class)
@Config(constants = BuildConfig.class)
public class PermissionHelperTest {

    private PermissionHelper permissionHelper;
    private ShadowApplication application;

    @Before
    public void setup() {
        PictureActivity activity = Robolectric.buildActivity(PictureActivity.class).get();
        permissionHelper = new PermissionHelper(activity, activity, 1);
        application = new ShadowApplication();
    }

    @Test
    public void testHasPermission() throws Exception {
        String[] permissions = new String[]{Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE};
        boolean hasPermissions = permissionHelper.hasPermissions(permissions);
        Assert.assertEquals(false, hasPermissions);

        application.grantPermissions(permissions);
        hasPermissions = permissionHelper.hasPermissions(permissions);
        Assert.assertEquals(true, hasPermissions);
    }
}

The first Assert works (no permission granted). But after granting all permissions via the ShadowApplication they are still denied in the next Assert.

I think that the PictureActivity created with Robolectric.buildActivity() is not using the ShadowApplication for the permission checks. But PictureActivity.getApplication() does not give me a ShadowApplication to call grantPermissions on. How can I test this?

I am new to Robolectric and unit testing on Android...so if there is any other framework that makes this easier/possible: I am open for suggestions.