Add unit test for TelephonyHistogram class

/*

 * Copyright (C) 2016 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.

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package com.android.internal.telephony;

import android.telephony.TelephonyHistogram;

import android.test.suitebuilder.annotation.SmallTest;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

import org.junit.Assert;

import static org.junit.Assert.*;

public class TelephonyHistogramTest {

    private TelephonyHistogram mHistogram = null;

    @After

    public void tearDown() throws Exception {

        mHistogram = null;

    }

    @Before

    public void setUp() throws Exception {

        mHistogram = new TelephonyHistogram(TelephonyHistogram.TELEPHONY_CATEGORY_RIL, 1, 3);

    }

    @Test

    @SmallTest

    public void testTelephonyHistogramConstructor() {

        assertEquals(TelephonyHistogram.TELEPHONY_CATEGORY_RIL, mHistogram.getCategory());

        assertEquals(1, mHistogram.getId());

        assertEquals(Integer.MAX_VALUE, mHistogram.getMinTime());

        assertEquals(0, mHistogram.getMaxTime());

        assertEquals(0, mHistogram.getAverageTime());

        assertEquals(0, mHistogram.getSampleCount());

        assertEquals(3, mHistogram.getBucketCount());

        // Test to verify that an exception is thrown when bucketCount <= 1

        mHistogram = null;

        try {

            mHistogram = new TelephonyHistogram(TelephonyHistogram.TELEPHONY_CATEGORY_RIL, 1, 1);

            Assert.fail("TelephonyHistogram should throw exception for bucketCount <= 1");

        } catch (IllegalArgumentException ex) {

            mHistogram = new TelephonyHistogram(TelephonyHistogram.TELEPHONY_CATEGORY_RIL, 1, 3);

        }

    }

    @Test

    @SmallTest

    public void testAddTimeTaken() {

        // Test when addTimeTaken is called less than 10 times

        mHistogram.addTimeTaken(10);

        mHistogram.addTimeTaken(20);

        mHistogram.addTimeTaken(30);

        mHistogram.addTimeTaken(40);

        mHistogram.addTimeTaken(50);

        assertEquals(10,mHistogram.getMinTime());

        assertEquals(50, mHistogram.getMaxTime());

        assertEquals(5, mHistogram.getSampleCount());

        assertEquals(30, mHistogram.getAverageTime());

        assertArrayEquals(new int[]{23, 36}, mHistogram.getBucketEndPoints());

        assertArrayEquals(new int[]{2, 1, 2}, mHistogram.getBucketCounters());

        // Test when addTimeTaken is called more than 10 times

        mHistogram.addTimeTaken(60);

        mHistogram.addTimeTaken(70);

        mHistogram.addTimeTaken(80);

        mHistogram.addTimeTaken(90);

        mHistogram.addTimeTaken(100);

        mHistogram.addTimeTaken(10);

        mHistogram.addTimeTaken(100);

        assertEquals(10,mHistogram.getMinTime());

        assertEquals(100, mHistogram.getMaxTime());

        assertEquals(12, mHistogram.getSampleCount());

        assertEquals(54, mHistogram.getAverageTime());

        assertArrayEquals(new int[]{40, 70}, mHistogram.getBucketEndPoints());

        assertArrayEquals(new int[]{5, 3, 4}, mHistogram.getBucketCounters());

    }

}