Add test to verify no crash on selecting brightness level.

/*

 * Copyright (C) 2017 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License

 */

package com.android.settings;

import static android.support.test.espresso.Espresso.onView;

import static android.support.test.espresso.action.ViewActions.click;

import static android.support.test.espresso.matcher.ViewMatchers.withText;

import android.app.Instrumentation;

import android.content.Context;

import android.content.Intent;

import android.support.test.InstrumentationRegistry;

import android.support.test.filters.SmallTest;

import android.support.test.runner.AndroidJUnit4;

import android.support.test.uiautomator.UiDevice;

import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;

@RunWith(AndroidJUnit4.class)

@SmallTest

public class DisplaySettingsTest {

    private Instrumentation mInstrumentation;

    private Context mContext;

    private UiDevice mDevice;

    @Before

    public void setUp() {

        mInstrumentation = InstrumentationRegistry.getInstrumentation();

        mContext = mInstrumentation.getTargetContext();

        mDevice = UiDevice.getInstance(mInstrumentation);

    }

    @Test

    public void launchBrightnessLevel_shouldNotCrash() {

        mInstrumentation.startActivitySync(

                new Intent(mContext, DisplaySettings.class));

        onView(withText(mContext.getString(R.string.brightness))).perform(click());

        // should not crash

        mDevice.pressBack(); // dismiss the brightness dialog

    }

}