StatsCollectorTest.java

//
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// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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package com.cloud.server;

import static org.mockito.Mockito.when;

import java.lang.reflect.Field;
import java.net.URI;
import java.net.URISyntaxException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.TreeMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;

import com.cloud.utils.DateUtil;
import com.google.gson.JsonSyntaxException;
import org.apache.cloudstack.framework.config.ConfigKey;
import org.apache.cloudstack.network.RoutedIpv4Manager;
import org.apache.cloudstack.storage.datastore.db.StoragePoolVO;
import org.apache.commons.collections.CollectionUtils;
import org.influxdb.InfluxDB;
import org.influxdb.InfluxDBFactory;
import org.influxdb.dto.BatchPoints;
import org.influxdb.dto.BatchPoints.Builder;
import org.influxdb.dto.Point;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Captor;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockedStatic;
import org.mockito.Mockito;
import org.mockito.MockitoAnnotations;
import org.mockito.stubbing.Answer;
import org.springframework.test.util.ReflectionTestUtils;

import com.cloud.agent.api.GetStorageStatsAnswer;
import com.cloud.agent.api.GetStorageStatsCommand;
import com.cloud.agent.api.VmDiskStatsEntry;
import com.cloud.agent.api.VmStatsEntry;
import com.cloud.dc.Vlan.VlanType;
import com.cloud.dc.VlanVO;
import com.cloud.dc.dao.VlanDao;
import com.cloud.hypervisor.Hypervisor;
import com.cloud.network.dao.NetworkDao;
import com.cloud.network.dao.NetworkVO;
import com.cloud.server.StatsCollector.ExternalStatsProtocol;
import com.cloud.storage.StorageStats;
import com.cloud.storage.VolumeStatsVO;
import com.cloud.storage.dao.VolumeStatsDao;
import com.cloud.user.VmDiskStatisticsVO;
import com.cloud.utils.exception.CloudRuntimeException;
import com.cloud.vm.VmStats;
import com.cloud.vm.VmStatsVO;
import com.cloud.vm.dao.VmStatsDaoImpl;
import com.google.gson.Gson;
import com.tngtech.java.junit.dataprovider.DataProvider;
import com.tngtech.java.junit.dataprovider.DataProviderRunner;

@RunWith(DataProviderRunner.class)
public class StatsCollectorTest {

    @InjectMocks
    private StatsCollector statsCollector = Mockito.spy(new StatsCollector());

    private static final int GRAPHITE_DEFAULT_PORT = 2003;
    private static final int INFLUXDB_DEFAULT_PORT = 8086;
    private static final String HOST_ADDRESS = "192.168.16.10";
    private static final String URL = String.format("http://%s:%s/", HOST_ADDRESS, INFLUXDB_DEFAULT_PORT);

    private static final String DEFAULT_DATABASE_NAME = "cloudstack";

    @Mock
    VmStatsDaoImpl vmStatsDaoMock;

    @Mock
    VmStatsEntry statsForCurrentIterationMock;

    @Captor
    ArgumentCaptor<VmStatsVO> vmStatsVOCaptor = ArgumentCaptor.forClass(VmStatsVO.class);

    @Captor
    ArgumentCaptor<Boolean> booleanCaptor = ArgumentCaptor.forClass(Boolean.class);

    @Mock
    VmStatsVO vmStatsVoMock1 = Mockito.mock(VmStatsVO.class);

    @Mock
    VmStatsVO vmStatsVoMock2 = Mockito.mock(VmStatsVO.class);

    @Mock
    VmStatsEntry vmStatsEntryMock = Mockito.mock(VmStatsEntry.class);

    @Mock
    VolumeStatsDao volumeStatsDao = Mockito.mock(VolumeStatsDao.class);

    @Mock
    private StoragePoolVO mockPool;

    @Mock
    private RoutedIpv4Manager routedIpv4Manager;

    @Mock
    private NetworkDao networkDao;

    @Mock
    private VlanDao vlanDao;

    private static Gson gson = new Gson();

    private Gson msStatsGson;

    private MockedStatic<InfluxDBFactory> influxDBFactoryMocked;

    private AutoCloseable closeable;

    @Before
    public void setUp() throws Exception {
        closeable = MockitoAnnotations.openMocks(this);
        statsCollector.vmStatsDao = vmStatsDaoMock;
        statsCollector.volumeStatsDao = volumeStatsDao;
        Field msStatsGsonField = StatsCollector.class.getDeclaredField("msStatsGson");
        msStatsGsonField.setAccessible(true);
        msStatsGson = (Gson) msStatsGsonField.get(null);
    }

    @After
    public void tearDown() throws Exception {
        if (influxDBFactoryMocked != null) {
            influxDBFactoryMocked.close();
        }
        closeable.close();
    }

    @Test
    public void createInfluxDbConnectionTest() {
        configureAndTestCreateInfluxDbConnection(true);
    }

    @Test(expected = CloudRuntimeException.class)
    public void createInfluxDbConnectionTestExpectException() {
        configureAndTestCreateInfluxDbConnection(false);
    }

    private void configureAndTestCreateInfluxDbConnection(boolean databaseExists) {
        statsCollector.externalStatsHost = HOST_ADDRESS;
        statsCollector.externalStatsPort = INFLUXDB_DEFAULT_PORT;
        InfluxDB influxDbConnection = Mockito.mock(InfluxDB.class);
        when(influxDbConnection.databaseExists(DEFAULT_DATABASE_NAME)).thenReturn(databaseExists);
        influxDBFactoryMocked = Mockito.mockStatic(InfluxDBFactory.class);
        influxDBFactoryMocked.when(() -> InfluxDBFactory.connect(URL)).thenReturn(influxDbConnection);

        InfluxDB returnedConnection = statsCollector.createInfluxDbConnection();

        Assert.assertEquals(influxDbConnection, returnedConnection);
    }

    @Test
    public void writeBatchesTest() {
        InfluxDB influxDbConnection = Mockito.mock(InfluxDB.class);
        Mockito.doNothing().when(influxDbConnection).write(Mockito.any(Point.class));
        Builder builder = Mockito.mock(Builder.class);
        BatchPoints batchPoints = Mockito.mock(BatchPoints.class);
        try (MockedStatic<BatchPoints> ignored = Mockito.mockStatic(BatchPoints.class)) {
            Mockito.when(BatchPoints.database(DEFAULT_DATABASE_NAME)).thenReturn(builder);
            when(builder.build()).thenReturn(batchPoints);
            Map<String, String> tagsToAdd = new HashMap<>();
            tagsToAdd.put("hostId", "1");
            Map<String, Object> fieldsToAdd = new HashMap<>();
            fieldsToAdd.put("total_memory_kbs", 10000000);
            Point point = Point.measurement("measure").tag(tagsToAdd).time(System.currentTimeMillis(), TimeUnit.MILLISECONDS).fields(fieldsToAdd).build();
            List<Point> points = new ArrayList<>();
            points.add(point);
            when(batchPoints.point(point)).thenReturn(batchPoints);

            statsCollector.writeBatches(influxDbConnection, DEFAULT_DATABASE_NAME, points);

            Mockito.verify(influxDbConnection).write(batchPoints);
        }
    }

    @Test
    public void configureExternalStatsPortTestGraphitePort() throws URISyntaxException {
        URI uri = new URI(HOST_ADDRESS);
        statsCollector.externalStatsType = ExternalStatsProtocol.GRAPHITE;
        int port = statsCollector.retrieveExternalStatsPortFromUri(uri);
        Assert.assertEquals(GRAPHITE_DEFAULT_PORT, port);
    }

    @Test
    public void configureExternalStatsPortTestInfluxdbPort() throws URISyntaxException {
        URI uri = new URI(HOST_ADDRESS);
        statsCollector.externalStatsType = ExternalStatsProtocol.INFLUXDB;
        int port = statsCollector.retrieveExternalStatsPortFromUri(uri);
        Assert.assertEquals(INFLUXDB_DEFAULT_PORT, port);
    }

    @Test(expected = URISyntaxException.class)
    public void configureExternalStatsPortTestExpectException() throws URISyntaxException {
        statsCollector.externalStatsType = ExternalStatsProtocol.NONE;
        URI uri = new URI(HOST_ADDRESS);
        statsCollector.retrieveExternalStatsPortFromUri(uri);
    }

    @Test
    public void configureExternalStatsPortTestInfluxDbCustomizedPort() throws URISyntaxException {
        statsCollector.externalStatsType = ExternalStatsProtocol.INFLUXDB;
        URI uri = new URI("test://" + HOST_ADDRESS + ":1234");
        int port = statsCollector.retrieveExternalStatsPortFromUri(uri);
        Assert.assertEquals(1234, port);
    }

    @Test
    public void configureDatabaseNameTestDefaultDbName() throws URISyntaxException {
        URI uri = new URI(URL);
        String dbName = statsCollector.configureDatabaseName(uri);
        Assert.assertEquals(DEFAULT_DATABASE_NAME, dbName);
    }

    @Test
    public void configureDatabaseNameTestCustomDbName() throws URISyntaxException {
        String configuredDbName = "dbName";
        URI uri = new URI(URL + configuredDbName);
        String dbName = statsCollector.configureDatabaseName(uri);
        Assert.assertEquals(configuredDbName, dbName);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestNull() {
        VmDiskStatisticsVO currentVmDiskStatisticsVO = new VmDiskStatisticsVO(1l, 1l, 1l, 1l);
        boolean result = statsCollector.isCurrentVmDiskStatsDifferentFromPrevious(null, currentVmDiskStatisticsVO);
        Assert.assertTrue(result);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestDifferentIoWrite() {
        configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(123l, 123l, 123l, 12l, true);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestDifferentIoRead() {
        configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(123l, 123l, 12l, 123l, true);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestDifferentBytesRead() {
        configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(12l, 123l, 123l, 123l, true);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestDifferentBytesWrite() {
        configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(123l, 12l, 123l, 123l, true);
    }

    @Test
    public void isCurrentVmDiskStatsDifferentFromPreviousTestAllEqual() {
        configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(123l, 123l, 123l, 123l, false);
    }

    private void configureAndTestisCurrentVmDiskStatsDifferentFromPrevious(long bytesRead, long bytesWrite, long ioRead,
            long ioWrite, boolean expectedResult) {
        VmDiskStatisticsVO previousVmDiskStatisticsVO = new VmDiskStatisticsVO(1l, 1l, 1l, 1l);
        previousVmDiskStatisticsVO.setCurrentBytesRead(123l);
        previousVmDiskStatisticsVO.setCurrentBytesWrite(123l);
        previousVmDiskStatisticsVO.setCurrentIORead(123l);
        previousVmDiskStatisticsVO.setCurrentIOWrite(123l);

        VmDiskStatisticsVO currentVmDiskStatisticsVO = new VmDiskStatisticsVO(1l, 1l, 1l, 1l);
        currentVmDiskStatisticsVO.setCurrentBytesRead(bytesRead);
        currentVmDiskStatisticsVO.setCurrentBytesWrite(bytesWrite);
        currentVmDiskStatisticsVO.setCurrentIORead(ioRead);
        currentVmDiskStatisticsVO.setCurrentIOWrite(ioWrite);

        boolean result = statsCollector.isCurrentVmDiskStatsDifferentFromPrevious(previousVmDiskStatisticsVO, currentVmDiskStatisticsVO);
        Assert.assertEquals(expectedResult, result);
    }

    @Test
    @DataProvider({
            "0,0,0,0,true", "1,0,0,0,false", "0,1,0,0,false", "0,0,1,0,false",
            "0,0,0,1,false", "1,0,0,1,false", "1,0,1,0,false", "1,1,0,0,false",
            "0,1,1,0,false", "0,1,0,1,false", "0,0,1,1,false", "0,1,1,1,false",
            "1,1,0,1,false", "1,0,1,1,false", "1,1,1,0,false", "1,1,1,1,false",
    })
    public void configureAndTestCheckIfDiskStatsAreZero(long bytesRead, long bytesWrite, long ioRead, long ioWrite,
            boolean expected) {
        VmDiskStatsEntry vmDiskStatsEntry = new VmDiskStatsEntry();
        vmDiskStatsEntry.setBytesRead(bytesRead);
        vmDiskStatsEntry.setBytesWrite(bytesWrite);
        vmDiskStatsEntry.setIORead(ioRead);
        vmDiskStatsEntry.setIOWrite(ioWrite);

        boolean result = statsCollector.areAllDiskStatsZero(vmDiskStatsEntry);
        Assert.assertEquals(expected, result);
    }

    private void setVmStatsIncrementMetrics(String value) {
        StatsCollector.vmStatsIncrementMetrics = new ConfigKey<Boolean>("Advanced", Boolean.class, "vm.stats.increment.metrics", value,
                "When set to 'true', VM metrics(NetworkReadKBs, NetworkWriteKBs, DiskWriteKBs, DiskReadKBs, DiskReadIOs and DiskWriteIOs) that are collected from the hypervisor are summed before being returned. "
                        + "On the other hand, when set to 'false', the VM metrics API will just display the latest metrics collected.", true);
    }

    private void setVmStatsMaxRetentionTimeValue(String value) {
        StatsCollector.vmStatsMaxRetentionTime = new ConfigKey<Integer>("Advanced", Integer.class, "vm.stats.max.retention.time", value,
                "The maximum time (in minutes) for keeping VM stats records in the database. The VM stats cleanup process will be disabled if this is set to 0 or less than 0.", true);
    }

    @Test
    public void cleanUpVirtualMachineStatsTestIsDisabled() {
        setVmStatsMaxRetentionTimeValue("0");

        statsCollector.cleanUpVirtualMachineStats();

        Mockito.verify(vmStatsDaoMock, Mockito.never()).removeAllByTimestampLessThan(Mockito.any(), Mockito.anyLong());
    }

    @Test
    public void cleanUpVirtualMachineStatsTestIsEnabled() {
        setVmStatsMaxRetentionTimeValue("1");

        statsCollector.cleanUpVirtualMachineStats();

        Mockito.verify(vmStatsDaoMock).removeAllByTimestampLessThan(Mockito.any(), Mockito.anyLong());
    }

    @Test
    public void persistVirtualMachineStatsTestPersistsSuccessfully() {
        statsCollector.msId = 1L;
        Date timestamp = new Date();
        VmStatsEntry statsForCurrentIteration = new VmStatsEntry(2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, "vm");
        Mockito.doReturn(new VmStatsVO()).when(vmStatsDaoMock).persist(Mockito.any());
        String expectedVmStatsStr = "{\"vmId\":2,\"cpuUtilization\":6.0,\"networkReadKBs\":7.0,\"networkWriteKBs\":8.0,\"diskReadIOs\":12.0,\"diskWriteIOs\":13.0,\"diskReadKBs\":10.0"
                + ",\"diskWriteKBs\":11.0,\"memoryKBs\":3.0,\"intFreeMemoryKBs\":4.0,\"targetMemoryKBs\":5.0,\"numCPUs\":9,\"entityType\":\"vm\"}";

        statsCollector.persistVirtualMachineStats(statsForCurrentIteration, timestamp);

        Mockito.verify(vmStatsDaoMock).persist(vmStatsVOCaptor.capture());
        VmStatsVO actual = vmStatsVOCaptor.getAllValues().get(0);
        Assert.assertEquals(Long.valueOf(2L), actual.getVmId());
        Assert.assertEquals(Long.valueOf(1L), actual.getMgmtServerId());
        Assert.assertEquals(convertJsonToOrderedMap(expectedVmStatsStr), convertJsonToOrderedMap(actual.getVmStatsData()));
        Assert.assertEquals(timestamp, actual.getTimestamp());
    }

    @Test
    public void getVmStatsTestWithAccumulateNotNull() {
        Mockito.doReturn(Arrays.asList(vmStatsVoMock1)).when(vmStatsDaoMock).findByVmIdOrderByTimestampDesc(Mockito.anyLong());
        Mockito.doReturn(vmStatsEntryMock).when(statsCollector).getLatestOrAccumulatedVmMetricsStats(Mockito.anyList(), Mockito.anyBoolean());

        VmStats result = statsCollector.getVmStats(1L, false);

        Mockito.verify(statsCollector).getLatestOrAccumulatedVmMetricsStats(Mockito.anyList(), booleanCaptor.capture());
        boolean actualArg = booleanCaptor.getValue().booleanValue();
        Assert.assertEquals(false, actualArg);
        Assert.assertEquals(vmStatsEntryMock, result);
    }

    @Test
    public void getVmStatsTestWithNullAccumulate() {
        setVmStatsIncrementMetrics("true");
        Mockito.doReturn(Arrays.asList(vmStatsVoMock1)).when(vmStatsDaoMock).findByVmIdOrderByTimestampDesc(Mockito.anyLong());
        Mockito.doReturn(vmStatsEntryMock).when(statsCollector).getLatestOrAccumulatedVmMetricsStats(Mockito.anyList(), Mockito.anyBoolean());

        VmStats result = statsCollector.getVmStats(1L, null);

        Mockito.verify(statsCollector).getLatestOrAccumulatedVmMetricsStats(Mockito.anyList(), booleanCaptor.capture());
        boolean actualArg = booleanCaptor.getValue().booleanValue();
        Assert.assertEquals(true, actualArg);
        Assert.assertEquals(vmStatsEntryMock, result);
    }

    @Test
    public void getLatestOrAccumulatedVmMetricsStatsTestAccumulate() {
        Mockito.doReturn(null).when(statsCollector).accumulateVmMetricsStats(Mockito.anyList());

        statsCollector.getLatestOrAccumulatedVmMetricsStats(Arrays.asList(vmStatsVoMock1), true);

        Mockito.verify(statsCollector).accumulateVmMetricsStats(Mockito.anyList());
    }

    @Test
    public void getLatestOrAccumulatedVmMetricsStatsTestLatest() {
        statsCollector.getLatestOrAccumulatedVmMetricsStats(Arrays.asList(vmStatsVoMock1), false);

        Mockito.verify(statsCollector, Mockito.never()).accumulateVmMetricsStats(Mockito.anyList());
    }

    @Test
    public void accumulateVmMetricsStatsTest() {
        String fakeStatsData1 = "{\"vmId\":1,\"cpuUtilization\":1.0,\"networkReadKBs\":1.0,"
                + "\"networkWriteKBs\":1.1,\"diskReadIOs\":3.0,\"diskWriteIOs\":3.1,\"diskReadKBs\":2.0,"
                + "\"diskWriteKBs\":2.1,\"memoryKBs\":1.0,\"intFreeMemoryKBs\":1.0,"
                + "\"targetMemoryKBs\":1.0,\"numCPUs\":1,\"entityType\":\"vm\"}";
        String fakeStatsData2 = "{\"vmId\":1,\"cpuUtilization\":10.0,\"networkReadKBs\":1.0,"
                + "\"networkWriteKBs\":1.1,\"diskReadIOs\":3.0,\"diskWriteIOs\":3.1,\"diskReadKBs\":2.0,"
                + "\"diskWriteKBs\":2.1,\"memoryKBs\":1.0,\"intFreeMemoryKBs\":1.0,"
                + "\"targetMemoryKBs\":1.0,\"numCPUs\":1,\"entityType\":\"vm\"}";
        Mockito.when(vmStatsVoMock1.getVmStatsData()).thenReturn(fakeStatsData1);
        Mockito.when(vmStatsVoMock2.getVmStatsData()).thenReturn(fakeStatsData2);

        VmStatsEntry result = statsCollector.accumulateVmMetricsStats(new ArrayList<VmStatsVO>(
                Arrays.asList(vmStatsVoMock1, vmStatsVoMock2)));

        Assert.assertEquals("vm", result.getEntityType());
        Assert.assertEquals(1, result.getVmId());
        Assert.assertEquals(1.0, result.getCPUUtilization(), 0);
        Assert.assertEquals(1, result.getNumCPUs());
        Assert.assertEquals(1.0, result.getMemoryKBs(), 0);
        Assert.assertEquals(1.0, result.getIntFreeMemoryKBs(), 0);
        Assert.assertEquals(1.0, result.getTargetMemoryKBs(), 0);
        Assert.assertEquals(2.0, result.getNetworkReadKBs(), 0);
        Assert.assertEquals(2.2, result.getNetworkWriteKBs(), 0);
        Assert.assertEquals(4.0, result.getDiskReadKBs(), 0);
        Assert.assertEquals(4.2, result.getDiskWriteKBs(), 0);
        Assert.assertEquals(6.0, result.getDiskReadIOs(), 0);
        Assert.assertEquals(6.2, result.getDiskWriteIOs(), 0);
    }

    @Test
    public void testIsDbIpv6Local() {
        Properties p = new Properties();
        p.put("db.cloud.host", "::1");
        when(statsCollector.getDbProperties()).thenReturn(p);

        Assert.assertTrue(statsCollector.isDbLocal());
    }

    @Test
    public void testIsDbIpv4Local() {
        Properties p = new Properties();
        p.put("db.cloud.host", "127.0.0.1");
        when(statsCollector.getDbProperties()).thenReturn(p);

        Assert.assertTrue(statsCollector.isDbLocal());
    }

    @Test
    public void testIsDbSymbolicLocal() {
        Properties p = new Properties();
        p.put("db.cloud.host", "localhost");
        when(statsCollector.getDbProperties()).thenReturn(p);

        Assert.assertTrue(statsCollector.isDbLocal());
    }

    @Test
    public void testIsDbOnSameIp() {
        Properties p = new Properties();
        p.put("db.cloud.host", "10.10.10.10");
        p.put("cluster.node.IP", "10.10.10.10");
        when(statsCollector.getDbProperties()).thenReturn(p);

        Assert.assertTrue(statsCollector.isDbLocal());
    }

    @Test
    public void testIsDbNotLocal() {
        Properties p = new Properties();
        p.put("db.cloud.host", "10.10.10.11");
        p.put("cluster.node.IP", "10.10.10.10");
        when(statsCollector.getDbProperties()).thenReturn(p);

        Assert.assertFalse(statsCollector.isDbLocal());
    }

    private void performPersistVolumeStatsTest(Hypervisor.HypervisorType hypervisorType) {
        Date timestamp = new Date();
        String vmName = "vm";
        String path = "path";
        long ioReadDiff = 100;
        long ioWriteDiff = 200;
        long readDiff = 1024;
        long writeDiff = 0;
        Long volumeId = 1L;
        VmDiskStatsEntry statsForCurrentIteration = null;
        if (Hypervisor.HypervisorType.KVM.equals(hypervisorType)) {
            statsForCurrentIteration = new VmDiskStatsEntry(vmName, path,
                    2000 + ioWriteDiff,
                    1000 + ioReadDiff,
                    20480 + writeDiff,
                    10240 + readDiff);
            statsForCurrentIteration.setDeltaIoRead(ioReadDiff);
            statsForCurrentIteration.setDeltaIoWrite(ioWriteDiff);
            statsForCurrentIteration.setDeltaBytesRead(readDiff);
            statsForCurrentIteration.setDeltaBytesWrite(writeDiff);
        } else {
            statsForCurrentIteration = new VmDiskStatsEntry(vmName, path,
                    ioWriteDiff,
                    ioReadDiff,
                    writeDiff,
                    readDiff);
        }
        List<VolumeStatsVO> persistedStats = new ArrayList<>();
        Mockito.when(volumeStatsDao.persist(Mockito.any(VolumeStatsVO.class))).thenAnswer((Answer<VolumeStatsVO>) invocation -> {
            VolumeStatsVO statsVO = (VolumeStatsVO) invocation.getArguments()[0];
            persistedStats.add(statsVO);
            return statsVO;
        });
        statsCollector.persistVolumeStats(volumeId, statsForCurrentIteration, hypervisorType, timestamp);
        Assert.assertTrue(CollectionUtils.isNotEmpty(persistedStats));
        Assert.assertNotNull(persistedStats.get(0));
        VolumeStatsVO stat = persistedStats.get(0);
        Assert.assertEquals(volumeId, stat.getVolumeId());
        VmDiskStatsEntry entry = gson.fromJson(stat.getVolumeStatsData(), VmDiskStatsEntry.class);
        Assert.assertEquals(vmName, entry.getVmName());
        Assert.assertEquals(path, entry.getPath());
        Assert.assertEquals(ioReadDiff, entry.getIORead());
        Assert.assertEquals(ioWriteDiff, entry.getIOWrite());
        Assert.assertEquals(readDiff, entry.getBytesRead());
        Assert.assertEquals(writeDiff, entry.getBytesWrite());
    }

    @Test
    public void testPersistVolumeStatsKVM() {
        performPersistVolumeStatsTest(Hypervisor.HypervisorType.KVM);
    }

    @Test
    public void testPersistVolumeStatsVmware() {
        performPersistVolumeStatsTest(Hypervisor.HypervisorType.VMware);
    }

    private Map<String, String> convertJsonToOrderedMap(String json) {
        Map<String, String> jsonMap = new TreeMap<String, String>();
        String[] keyValuePairs = json.replace("{", "").replace("}", "").split(",");
        for (String pair : keyValuePairs) {
            String[] keyValue = pair.split(":");
            jsonMap.put(keyValue[0], keyValue[1]);
        }
        return jsonMap;
    }

    private void setCollectorIopsStats(long poolId, Long capacityIops, Long usedIops) {
        ConcurrentHashMap<Long, StorageStats> storagePoolStats = new ConcurrentHashMap<>();
        storagePoolStats.put(poolId, new GetStorageStatsAnswer(Mockito.mock(GetStorageStatsCommand.class),
                10L, 2L, capacityIops, usedIops));
        ReflectionTestUtils.setField(statsCollector, "_storagePoolStats", storagePoolStats);
    }

    @Test
    public void testPoolNeedsIopsStatsUpdating_NoChanges() {
        long poolId = 1L;
        long capacityIops = 100L;
        long usedIops = 50L;
        when(mockPool.getId()).thenReturn(poolId);
        when(mockPool.getCapacityIops()).thenReturn(capacityIops);
        when(mockPool.getUsedIops()).thenReturn(usedIops);

        setCollectorIopsStats(poolId, capacityIops, usedIops);

        boolean result = statsCollector.isPoolNeedsIopsStatsUpdate(mockPool, capacityIops, usedIops);
        Assert.assertFalse(result);
        Mockito.verify(mockPool, Mockito.never()).setCapacityIops(Mockito.anyLong());
        Mockito.verify(mockPool, Mockito.never()).setUsedIops(Mockito.anyLong());
    }

    @Test
    public void testPoolNeedsIopsStatsUpdating_CapacityIopsNeedsUpdating() {
        long poolId = 1L;
        when(mockPool.getId()).thenReturn(poolId);
        when(mockPool.getCapacityIops()).thenReturn(100L);
        when(mockPool.getUsedIops()).thenReturn(50L);

        setCollectorIopsStats(poolId, 90L, 50L);

        boolean result = statsCollector.isPoolNeedsIopsStatsUpdate(mockPool, 120L, 50L);
        Assert.assertTrue(result);
        Mockito.verify(mockPool).setCapacityIops(120L);
        Mockito.verify(mockPool, Mockito.never()).setUsedIops(Mockito.anyLong());
    }

    @Test
    public void testPoolNeedsIopsStatsUpdating_UsedIopsNeedsUpdating() {
        long poolId = 1L;
        when(mockPool.getId()).thenReturn(poolId);
        when(mockPool.getCapacityIops()).thenReturn(100L);
        when(mockPool.getUsedIops()).thenReturn(50L);

        setCollectorIopsStats(poolId, 100L, 45L);

        boolean result = statsCollector.isPoolNeedsIopsStatsUpdate(mockPool, 100L, 60L);
        Assert.assertTrue(result);
        Mockito.verify(mockPool).setUsedIops(60L);
        Mockito.verify(mockPool, Mockito.never()).setCapacityIops(Mockito.anyLong());
    }

    @Test
    public void testPoolNeedsIopsStatsUpdating_BothNeedUpdating() {
        long poolId = 1L;
        when(mockPool.getId()).thenReturn(poolId);
        when(mockPool.getCapacityIops()).thenReturn(100L);
        when(mockPool.getUsedIops()).thenReturn(50L);

        setCollectorIopsStats(poolId, 90L, 45L);

        boolean result = statsCollector.isPoolNeedsIopsStatsUpdate(mockPool, 120L, 60L);
        Assert.assertTrue(result);
        Mockito.verify(mockPool).setCapacityIops(120L);
        Mockito.verify(mockPool).setUsedIops(60L);
    }

    @Test
    public void testPoolNeedsIopsStatsUpdating_NullIops() {
        long poolId = 1L;
        when(mockPool.getId()).thenReturn(poolId);

        boolean result = statsCollector.isPoolNeedsIopsStatsUpdate(mockPool, null, null);
        Assert.assertFalse(result);
        Mockito.verify(mockPool, Mockito.never()).setCapacityIops(Mockito.anyLong());
        Mockito.verify(mockPool, Mockito.never()).setUsedIops(Mockito.anyLong());
    }

    @Test
    public void testGsonDateFormatSerialization() {
        Date now = new Date();
        TestClass testObj = new TestClass("TestString", 999, now);
        String json = msStatsGson.toJson(testObj);

        Assert.assertTrue(json.contains("TestString"));
        Assert.assertTrue(json.contains("999"));
        String expectedDate = new SimpleDateFormat(DateUtil.ZONED_DATETIME_FORMAT).format(now);
        Assert.assertTrue(json.contains(expectedDate));
    }

    @Test
    public void testGsonDateFormatDeserializationWithSameDateFormat() throws Exception {
        String json = "{\"str\":\"TestString\",\"num\":999,\"date\":\"2025-08-22T15:39:43+0000\"}";
        TestClass testObj = msStatsGson.fromJson(json, TestClass.class);

        Assert.assertEquals("TestString", testObj.getStr());
        Assert.assertEquals(999, testObj.getNum());
        Date expectedDate = new SimpleDateFormat(DateUtil.ZONED_DATETIME_FORMAT).parse("2025-08-22T15:39:43+0000");
        Assert.assertEquals(expectedDate, testObj.getDate());
    }

    @Test (expected = JsonSyntaxException.class)
    public void testGsonDateFormatDeserializationWithDifferentDateFormat() throws Exception {
        String json = "{\"str\":\"TestString\",\"num\":999,\"date\":\"22/08/2025T15:39:43+0000\"}";
        msStatsGson.fromJson(json, TestClass.class);
        /* Deserialization throws the below exception:
        com.google.gson.JsonSyntaxException: 22/08/2025T15:39:43+0000
            at com.google.gson.DefaultTypeAdapters$DefaultDateTypeAdapter.deserializeToDate(DefaultTypeAdapters.java:376)
            at com.google.gson.DefaultTypeAdapters$DefaultDateTypeAdapter.deserialize(DefaultTypeAdapters.java:351)
            at com.google.gson.DefaultTypeAdapters$DefaultDateTypeAdapter.deserialize(DefaultTypeAdapters.java:307)
            at com.google.gson.JsonDeserializationVisitor.invokeCustomDeserializer(JsonDeserializationVisitor.java:92)
            at com.google.gson.JsonObjectDeserializationVisitor.visitFieldUsingCustomHandler(JsonObjectDeserializationVisitor.java:117)
            at com.google.gson.ReflectingFieldNavigator.visitFieldsReflectively(ReflectingFieldNavigator.java:63)
            at com.google.gson.ObjectNavigator.accept(ObjectNavigator.java:120)
            at com.google.gson.JsonDeserializationContextDefault.fromJsonObject(JsonDeserializationContextDefault.java:76)
            at com.google.gson.JsonDeserializationContextDefault.deserialize(JsonDeserializationContextDefault.java:54)
            at com.google.gson.Gson.fromJson(Gson.java:551)
            at com.google.gson.Gson.fromJson(Gson.java:498)
            at com.google.gson.Gson.fromJson(Gson.java:467)
            at com.google.gson.Gson.fromJson(Gson.java:417)
            at com.google.gson.Gson.fromJson(Gson.java:389)
            at com.cloud.serializer.GsonHelperTest.testGsonDateFormatDeserializationWithDifferentDateFormat(GsonHelperTest.java:113)
            at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
            at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
            at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
            at java.base/java.lang.reflect.Method.invoke(Method.java:566)
            at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
            at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
            at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
            at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
            at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
            at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
            at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
            at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
            at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
            at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
            at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
            at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
            at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
            at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
            at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
            at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
            at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
            at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
            at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
            at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
            at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
            at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
            at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:231)
            at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:55)
        Caused by: java.text.ParseException: Unparseable date: "22/08/2025T15:39:43+0000"
            at java.base/java.text.DateFormat.parse(DateFormat.java:395)
            at com.google.gson.DefaultTypeAdapters$DefaultDateTypeAdapter.deserializeToDate(DefaultTypeAdapters.java:374)
            ... 42 more
         */
    }

    // -----------------------------------------------------------------------
    // Tests for isNetworkEligibleForNetworkStats
    // -----------------------------------------------------------------------

    private VlanVO buildVlan(VlanType type) {
        VlanVO vlan = Mockito.mock(VlanVO.class);
        Mockito.when(vlan.getVlanType()).thenReturn(type);
        return vlan;
    }

    @Test
    public void isNetworkEligibleForNetworkStats_RoutedNetwork_ReturnsTrue() {
        Long networkId = 1L;
        NetworkVO networkVO = Mockito.mock(NetworkVO.class);
        Mockito.when(networkDao.findById(networkId)).thenReturn(networkVO);
        Mockito.when(vlanDao.listVlansByNetworkId(networkId)).thenReturn(Collections.emptyList());
        Mockito.when(routedIpv4Manager.isRoutedNetwork(networkVO)).thenReturn(true);

        Assert.assertTrue(statsCollector.isNetworkEligibleForNetworkStats(networkId));
    }

    @Test
    public void isNetworkEligibleForNetworkStats_DirectAttachedNetwork_ReturnsTrue() {
        Long networkId = 1L;
        NetworkVO networkVO = Mockito.mock(NetworkVO.class);
        Mockito.when(networkDao.findById(networkId)).thenReturn(networkVO);
        Mockito.when(routedIpv4Manager.isRoutedNetwork(networkVO)).thenReturn(false);
        List<VlanVO> vlans = Collections.singletonList(buildVlan(VlanType.DirectAttached));
        Mockito.when(vlanDao.listVlansByNetworkId(networkId)).thenReturn(vlans);

        Assert.assertTrue(statsCollector.isNetworkEligibleForNetworkStats(networkId));
    }

    @Test
    public void isNetworkEligibleForNetworkStats_NeitherRoutedNorDirectAttached_ReturnsFalse() {
        Long networkId = 1L;
        NetworkVO networkVO = Mockito.mock(NetworkVO.class);
        Mockito.when(networkDao.findById(networkId)).thenReturn(networkVO);
        Mockito.when(routedIpv4Manager.isRoutedNetwork(networkVO)).thenReturn(false);
        List<VlanVO> vlans = Collections.singletonList(buildVlan(VlanType.VirtualNetwork));
        Mockito.when(vlanDao.listVlansByNetworkId(networkId)).thenReturn(vlans);

        Assert.assertFalse(statsCollector.isNetworkEligibleForNetworkStats(networkId));
    }

    @Test
    public void isNetworkEligibleForNetworkStats_NullNetworkAndEmptyVlans_ReturnsFalse() {
        Long networkId = 1L;
        Mockito.when(networkDao.findById(networkId)).thenReturn(null);
        Mockito.when(vlanDao.listVlansByNetworkId(networkId)).thenReturn(Collections.emptyList());

        Assert.assertFalse(statsCollector.isNetworkEligibleForNetworkStats(networkId));
    }

    @Test
    public void isNetworkEligibleForNetworkStats_NullNetworkButDirectAttached_ReturnsTrue() {
        Long networkId = 1L;
        Mockito.when(networkDao.findById(networkId)).thenReturn(null);
        List<VlanVO> vlans = Collections.singletonList(buildVlan(VlanType.DirectAttached));
        Mockito.when(vlanDao.listVlansByNetworkId(networkId)).thenReturn(vlans);

        Assert.assertTrue(statsCollector.isNetworkEligibleForNetworkStats(networkId));
        Mockito.verify(routedIpv4Manager, Mockito.never()).isRoutedNetwork(Mockito.any());
    }

    @Test
    public void isNetworkEligibleForNetworkStats_NullNetworkId_ReturnsFalse() {
        Assert.assertFalse(statsCollector.isNetworkEligibleForNetworkStats(null));
        Mockito.verify(networkDao, Mockito.never()).findById(Mockito.anyLong());
        Mockito.verify(vlanDao, Mockito.never()).listVlansByNetworkId(Mockito.anyLong());
    }

    private static class TestClass {
        private String str;
        private int num;
        private Date date;

        public TestClass(String str, int num, Date date) {
            this.str = str;
            this.num = num;
            this.date = date;
        }

        public String getStr() {
            return str;
        }

        public int getNum() {
            return num;
        }

        public Date getDate() {
            return date;
        }
    }
}