Added check for null metadata.

    }

    public static String mediaMetadataToString(MediaMetadata metadata) {

        if (metadata == null) return null;

        return metadata.getDescription().toString();

    }

/*

 * 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.systemui.volume;

import android.media.MediaMetadata;

import android.support.test.filters.SmallTest;

import com.android.systemui.SysuiTestCase;

import junit.framework.Assert;

import org.junit.Test;

@SmallTest

public class UtilTest extends SysuiTestCase {

    @Test

    public void testMediaMetadataToString_null() {

        Assert.assertEquals(null, Util.mediaMetadataToString(null));

    }

    @Test

    public void testMediaMetadataToString_notNull() {

        Assert.assertNotNull(Util.mediaMetadataToString(new MediaMetadata.Builder().build()));

    }

}