Add test to verify tag pool and battery stats history size from existing battery history

        }

    }

    /**

     * Writes all available history items to history buffer.

     *

     * @param elapsedRealtimeMs used to find delta and to identify the currunt history item.

     * @param uptimeMs used to identify the device is not in sleep mode.

     * @param cur the History item about to write in history buffer.

     */

    @VisibleForTesting

    public void writeAllHistoryItem(long elapsedRealtimeMs, long uptimeMs, HistoryItem cur) {

        synchronized (this) {

            writeHistoryItem(elapsedRealtimeMs, uptimeMs, cur);

        }

    }

    /**

     * Writes the current history item to history.

     */

/*

 * Copyright (C) 2025 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.server.power.stats;

import static org.junit.Assert.assertNotNull;

import static org.junit.Assert.assertTrue;

import android.content.Context;

import android.content.res.Resources;

import android.os.BatteryStats.HistoryItem;

import android.os.ConditionVariable;

import android.platform.test.annotations.DisabledOnRavenwood;

import android.util.Log;

import androidx.test.platform.app.InstrumentationRegistry;

import androidx.test.runner.AndroidJUnit4;

import com.android.internal.os.BackgroundThread;

import com.android.internal.os.BatteryStatsHistory;

import com.android.internal.os.BatteryStatsHistoryIterator;

import com.android.internal.os.MonotonicClock;

import org.junit.Before;

import org.junit.Ignore;

import org.junit.Rule;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.mockito.Mock;

import org.mockito.junit.MockitoJUnit;

import org.mockito.junit.MockitoRule;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.nio.file.Files;

import java.nio.file.StandardCopyOption;

import java.util.zip.ZipEntry;

import java.util.zip.ZipInputStream;

/**

 * Test case for BatteryStatsHistory that reads from existing history files and writes to new

 * history files to compute the tagpool size.

 */

@RunWith(AndroidJUnit4.class)

@DisabledOnRavenwood(reason = "BatteryStatsHistoryTests not supported under Ravenwood")

@Ignore("Skipping in presubmit")

public class BatteryStatsHistoryReadWriteHistoryTest {

    private static final String TAG = "BatteryStatsHistoryReadWriteHistoryTest";

    private static final int MAX_HISTORY_BUFFER_SIZE = 128 * 1024;

    // The INPUT_MONOTONIC_CLOCK_BASE and OUTPUT_MONOTONIC_CLOCK_BASE are arbitrary values

    // that are used to initialize the MonotonicClock objects. These values do not have any

    // specific relationship with the BH_Files.

    private static final long INPUT_MONOTONIC_CLOCK_BASE = 9852452119L;

    private static final int MAX_FILE_SIZE = 6194304;

    private static final long OUTPUT_MONOTONIC_CLOCK_BASE = 4852452119L;

    private static final long START_NEXT_FRAGMENT_TIME = 4940304651L;

    @Rule public final MockitoRule mMockitoRule = MockitoJUnit.rule();

    private final MockClock mClock = new MockClock();

    private final MonotonicClock mInputMonotonicClock =

            new MonotonicClock(INPUT_MONOTONIC_CLOCK_BASE, mClock);

    private final MonotonicClock mOutputMonotonicClock =

            new MonotonicClock(OUTPUT_MONOTONIC_CLOCK_BASE, mClock);

    @Mock private BatteryStatsHistory.EventLogger mInputEventLogger;

    @Mock private BatteryStatsHistory.EventLogger mOutputEventLogger;

    private BatteryHistoryDirectory mInputDirectory;

    private BatteryHistoryDirectory mOutputDirectory;

    private File mTestInputHistoryDir;

    private File mTestOutputHistoryDir;

    private File mSystemDir;

    private static void awaitCompletion() {

        ConditionVariable done = new ConditionVariable();

        BackgroundThread.getHandler().post(done::open);

        done.block();

    }

    @Before

    public void setUp() throws Exception {

        mSystemDir = Files.createTempDirectory("BatteryStatsHistoryReadWriteHistoryTest").toFile();

        mTestInputHistoryDir = new File(mSystemDir, "battery-history-input");

        // Copy the actual existing history files from the external path to our writable test input

        // directory.

        copyExistingFilesToTestInput();

        mTestOutputHistoryDir = new File(mSystemDir, "battery-history-output");

    }

    private void copyExistingFilesToTestInput() throws IOException {

        Context context = InstrumentationRegistry.getInstrumentation().getTargetContext();

        Resources resources = context.getResources();

        final String resourceName = "BH_Files";

        int zipResourceId = resources.getIdentifier(resourceName, "raw", context.getPackageName());

        if (context == null) {

            Log.e(TAG, "Invalid arguments: context is null ");

            return;

        }

        InputStream zipInputStreamRaw = null;

        ZipInputStream zipInputStream = null;

        try {

            zipInputStreamRaw = resources.openRawResource(zipResourceId);

            zipInputStream = new ZipInputStream(zipInputStreamRaw);

            ZipEntry entry;

            while ((entry = zipInputStream.getNextEntry()) != null) {

                String entryName = entry.getName();

                if (entry.isDirectory()) {

                    Log.e(TAG, "Skip directory entry: " + entryName);

                    continue;

                }

                File outputFile = new File(mTestInputHistoryDir, entryName);

                File parentDir = outputFile.getParentFile();

                if (parentDir != null && !parentDir.exists()) {

                    parentDir.mkdirs();

                }

                Files.copy(

                        zipInputStream, outputFile.toPath(), StandardCopyOption.REPLACE_EXISTING);

                zipInputStream.closeEntry();

            }

            return;

        } catch (Resources.NotFoundException e) {

            Log.e(TAG, "ZIP resource not found: " + zipResourceId, e);

            return;

        } catch (IOException e) {

            Log.e(TAG, "Error processing ZIP resource: " + e.getMessage(), e);

            return;

        } finally {

            try {

                if (zipInputStream != null) {

                    zipInputStream.close();

                } else if (zipInputStreamRaw != null) {

                    zipInputStreamRaw.close();

                }

            } catch (IOException e) {

                Log.e(TAG, "Error closing ZIP streams: " + e.getMessage(), e);

            }

        }

    }

    @Test

    public void testReadExistingHistoryAndWriteToNewFiles() throws Exception {

        String[] initialFiles = mTestInputHistoryDir.list();

        assertNotNull("Test input history directory should not be null", initialFiles);

        assertTrue(

                "Test input history directory should contain copied battery history files",

                initialFiles.length > 0);

        BatteryHistoryDirectory.Compressor compressor = BatteryHistoryDirectory.DEFAULT_COMPRESSOR;

        mInputDirectory =

                new BatteryHistoryDirectory(mTestInputHistoryDir, MAX_FILE_SIZE, compressor);

        mOutputDirectory =

                new BatteryHistoryDirectory(mTestOutputHistoryDir, MAX_FILE_SIZE, compressor);

        mOutputDirectory.makeDirectoryLockUnconditional();

        BatteryStatsHistory readerBsh =

                new BatteryStatsHistory(

                        null,

                        MAX_HISTORY_BUFFER_SIZE,

                        mInputDirectory,

                        mClock,

                        mInputMonotonicClock,

                        null,

                        mInputEventLogger);

        awaitCompletion();

        BatteryStatsHistory writerBsh =

                new BatteryStatsHistory(

                        null,

                        MAX_HISTORY_BUFFER_SIZE,

                        mOutputDirectory,

                        mClock,

                        mOutputMonotonicClock,

                        null,

                        mOutputEventLogger);

        awaitCompletion();

        writerBsh.forceRecordAllHistory();

        try (BatteryStatsHistoryIterator iterate = readerBsh.iterate(0, -1)) {

            while (iterate.hasNext()) {

                HistoryItem next = iterate.next();

                writerBsh.writeAllHistoryItem(next.time, 0, next);

            }

        }

        writerBsh.startNextFragment(START_NEXT_FRAGMENT_TIME);

        File[] outputFiles = mTestOutputHistoryDir.listFiles();

        long inputDirSize = mInputDirectory.getSize();

        long outputDirSize = mOutputDirectory.getSize();

        assertNotNull("Output directory should not be null", outputFiles);

        assertTrue("Output directory should contain at least one file", outputFiles.length > 0);

        assertTrue("Input History size should be positive integer", inputDirSize > 0);

        assertTrue("Output History size should be positive integer", outputDirSize > 0);

    }

}