/*
 * Copyright (C) 2018 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.wifi;

import static com.android.server.wifi.ActiveModeManager.ROLE_CLIENT_PRIMARY;
import static com.android.server.wifi.WifiMetricsTest.TEST_IFACE_NAME;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.any;
import static org.mockito.Mockito.anyInt;
import static org.mockito.Mockito.anyLong;
import static org.mockito.Mockito.clearInvocations;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import android.content.Context;
import android.net.wifi.WifiInfo;
import android.os.Handler;
import android.os.test.TestLooper;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;

import androidx.test.filters.SmallTest;

import com.android.server.wifi.ActiveModeWarden.PrimaryClientModeManagerChangedCallback;
import com.android.server.wifi.proto.nano.WifiMetricsProto.WifiIsUnusableEvent;
import com.android.wifi.resources.R;

import org.junit.Before;
import org.junit.Test;
import org.mockito.ArgumentCaptor;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.mockito.MockitoSession;

/**
 * Unit tests for {@link com.android.server.wifi.WifiDataStall}.
 */
@SmallTest
public class WifiDataStallTest extends WifiBaseTest {
    private static final int TEST_MIN_TX_BAD = 1;
    private static final int TEST_MIN_TX_SUCCESS_WITHOUT_RX = 1;
    private static final long TEST_WIFI_BYTES =
            WifiDataStall.MAX_MS_DELTA_FOR_DATA_STALL * 1000 / 8;
    private static final int TEST_RSSI = -55;

    @Mock Context mContext;
    MockResources mMockResources = new MockResources();
    @Mock WifiChannelUtilization mWifiChannelUtilization;
    @Mock WifiMetrics mWifiMetrics;
    WifiDataStall mWifiDataStall;
    @Mock Clock mClock;
    @Mock DeviceConfigFacade mDeviceConfigFacade;
    @Mock WifiInfo mWifiInfo;
    @Mock TelephonyManager mTelephonyManager;
    @Mock Handler mHandler;
    @Mock ThroughputPredictor mThroughputPredictor;
    @Mock WifiNative.ConnectionCapabilities mCapabilities;
    @Mock ActiveModeWarden mActiveModeWarden;
    @Mock ClientModeImplMonitor mClientModeImplMonitor;
    @Mock ClientModeManager mClientModeManager;
    @Mock WifiGlobals mWifiGlobals;

    private ActiveModeWarden.ModeChangeCallback mModeChangeCallback;
    private PrimaryClientModeManagerChangedCallback mPrimaryModeChangeCallback;
    private ClientModeImplListener mClientModeImplListener;
    private final WifiLinkLayerStats mOldLlStats = new WifiLinkLayerStats();
    private final WifiLinkLayerStats mNewLlStats = new WifiLinkLayerStats();
    private MockitoSession mSession;
    private long mTxBytes = 0L;
    private long mRxBytes = 0L;
    /**
     * Sets up for unit test
     */
    @Before
    public void setUp() throws Exception {
        MockitoAnnotations.initMocks(this);
        // Ensure Looper exists
        // Required by TelephonyManager.listen()
        TestLooper looper = new TestLooper();
        when(mContext.getResources()).thenReturn(mMockResources);
        when(mContext.getSystemService(Context.TELEPHONY_SERVICE)).thenReturn(mTelephonyManager);
        when(mTelephonyManager.createForSubscriptionId(anyInt())).thenReturn(mTelephonyManager);
        when(mWifiGlobals.getPollRssiIntervalMillis()).thenReturn(3000);

        mMockResources.setInteger(
                R.integer.config_wifiDataStallMinTxBad, TEST_MIN_TX_BAD);
        mMockResources.setInteger(
                R.integer.config_wifiDataStallMinTxSuccessWithoutRx,
                TEST_MIN_TX_SUCCESS_WITHOUT_RX);
        when(mDeviceConfigFacade.getDataStallDurationMs()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        when(mDeviceConfigFacade.getDataStallTxTputThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_TX_TPUT_THR_KBPS);
        when(mDeviceConfigFacade.getDataStallRxTputThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_RX_TPUT_THR_KBPS);
        when(mDeviceConfigFacade.getDataStallTxPerThr()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_TX_PER_THR);
        when(mDeviceConfigFacade.getDataStallCcaLevelThr()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_CCA_LEVEL_THR);
        when(mDeviceConfigFacade.getTxTputSufficientLowThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_TX_TPUT_SUFFICIENT_THR_LOW_KBPS);
        when(mDeviceConfigFacade.getTxTputSufficientHighThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_TX_TPUT_SUFFICIENT_THR_HIGH_KBPS);
        when(mDeviceConfigFacade.getRxTputSufficientLowThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_RX_TPUT_SUFFICIENT_THR_LOW_KBPS);
        when(mDeviceConfigFacade.getRxTputSufficientHighThrKbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_RX_TPUT_SUFFICIENT_THR_HIGH_KBPS);
        when(mDeviceConfigFacade.getTputSufficientRatioThrNum()).thenReturn(
                DeviceConfigFacade.DEFAULT_TPUT_SUFFICIENT_RATIO_THR_NUM);
        when(mDeviceConfigFacade.getTputSufficientRatioThrDen()).thenReturn(
                DeviceConfigFacade.DEFAULT_TPUT_SUFFICIENT_RATIO_THR_DEN);
        when(mDeviceConfigFacade.getTxPktPerSecondThr()).thenReturn(
                DeviceConfigFacade.DEFAULT_TX_PACKET_PER_SECOND_THR);
        when(mDeviceConfigFacade.getRxPktPerSecondThr()).thenReturn(
                DeviceConfigFacade.DEFAULT_RX_PACKET_PER_SECOND_THR);
        when(mDeviceConfigFacade.getTxLinkSpeedLowThresholdMbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_TX_LINK_SPEED_LOW_THRESHOLD_MBPS);
        when(mDeviceConfigFacade.getRxLinkSpeedLowThresholdMbps()).thenReturn(
                DeviceConfigFacade.DEFAULT_RX_LINK_SPEED_LOW_THRESHOLD_MBPS);

        when(mWifiInfo.getLinkSpeed()).thenReturn(10);
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(10);
        when(mWifiInfo.getFrequency()).thenReturn(5850);
        when(mWifiInfo.getBSSID()).thenReturn("5G_WiFi");
        when(mWifiInfo.getRssi()).thenReturn(TEST_RSSI);

        mWifiDataStall = new WifiDataStall(mWifiMetrics, mContext,
                mDeviceConfigFacade, mWifiChannelUtilization, mClock, mHandler,
                mThroughputPredictor, mActiveModeWarden, mClientModeImplMonitor,
                mWifiGlobals);
        mWifiDataStall.enableVerboseLogging(true);
        mOldLlStats.txmpdu_be = 1000;
        mOldLlStats.retries_be = 1000;
        mOldLlStats.lostmpdu_be = 3000;
        mOldLlStats.rxmpdu_be = 4000;
        mOldLlStats.timeStampInMs = 10000;

        mNewLlStats.txmpdu_be = 2 * mOldLlStats.txmpdu_be;
        mNewLlStats.retries_be = 10 * mOldLlStats.retries_be;
        mNewLlStats.lostmpdu_be = mOldLlStats.lostmpdu_be;
        mNewLlStats.rxmpdu_be = mOldLlStats.rxmpdu_be + 130;
        mNewLlStats.timeStampInMs = mOldLlStats.timeStampInMs
                + WifiDataStall.MAX_MS_DELTA_FOR_DATA_STALL - 1;
        when(mWifiChannelUtilization.getUtilizationRatio(anyInt())).thenReturn(10);
        when(mThroughputPredictor.predictTxThroughput(any(), anyInt(), anyInt(), anyInt()))
                .thenReturn(50);
        when(mThroughputPredictor.predictRxThroughput(any(), anyInt(), anyInt(), anyInt()))
                .thenReturn(150);
        when(mActiveModeWarden.getPrimaryClientModeManager()).thenReturn(mClientModeManager);

        ArgumentCaptor<ActiveModeWarden.ModeChangeCallback> modeChangeCallbackArgumentCaptor =
                ArgumentCaptor.forClass(ActiveModeWarden.ModeChangeCallback.class);
        verify(mActiveModeWarden).registerModeChangeCallback(
                modeChangeCallbackArgumentCaptor.capture());
        mModeChangeCallback = modeChangeCallbackArgumentCaptor.getValue();
        ArgumentCaptor<PrimaryClientModeManagerChangedCallback>
                primaryModeChangeCallbackArgumentCaptor =
                ArgumentCaptor.forClass(PrimaryClientModeManagerChangedCallback.class);
        verify(mActiveModeWarden).registerPrimaryClientModeManagerChangedCallback(
                primaryModeChangeCallbackArgumentCaptor.capture());
        mPrimaryModeChangeCallback = primaryModeChangeCallbackArgumentCaptor.getValue();
        ArgumentCaptor<ClientModeImplListener> clientModeImplListenerArgumentCaptor =
                ArgumentCaptor.forClass(ClientModeImplListener.class);
        verify(mClientModeImplMonitor).registerListener(
                clientModeImplListenerArgumentCaptor.capture());
        mClientModeImplListener = clientModeImplListenerArgumentCaptor.getValue();
        mPrimaryModeChangeCallback.onChange(null, mock(ConcreteClientModeManager.class));
        setUpWifiBytes(1, 1);
    }

    private void setUpWifiBytes(long txBytes, long rxBytes) {
        mTxBytes = txBytes;
        mRxBytes = rxBytes;
    }

    /**
     * Verify that LinkLayerStats for WifiIsUnusableEvent is correctly updated
     */
    private void verifyUpdateWifiIsUnusableLinkLayerStats() {
        verify(mWifiMetrics).updateWifiIsUnusableLinkLayerStats(
                mNewLlStats.txmpdu_be - mOldLlStats.txmpdu_be,
                mNewLlStats.retries_be - mOldLlStats.retries_be,
                mNewLlStats.lostmpdu_be - mOldLlStats.lostmpdu_be,
                mNewLlStats.rxmpdu_be - mOldLlStats.rxmpdu_be,
                mNewLlStats.timeStampInMs - mOldLlStats.timeStampInMs);
    }

    private PhoneStateListener mockPhoneStateListener() {
        PhoneStateListener dataConnectionStateListener = null;
        /* Capture the PhoneStateListener */
        ArgumentCaptor<PhoneStateListener> phoneStateListenerCaptor =
                ArgumentCaptor.forClass(PhoneStateListener.class);
        verify(mTelephonyManager).listen(phoneStateListenerCaptor.capture(),
                eq(PhoneStateListener.LISTEN_DATA_CONNECTION_STATE));
        dataConnectionStateListener = phoneStateListenerCaptor.getValue();
        assertNotNull(dataConnectionStateListener);
        return dataConnectionStateListener;
    }

    private void setWifiEnabled(boolean enabled) {
        if (enabled) {
            when(mActiveModeWarden.getPrimaryClientModeManagerNullable())
                    .thenReturn(mock(ConcreteClientModeManager.class));
            mModeChangeCallback.onActiveModeManagerAdded(mock(ConcreteClientModeManager.class));
        } else {
            when(mActiveModeWarden.getPrimaryClientModeManagerNullable()).thenReturn(null);
            mModeChangeCallback.onActiveModeManagerRemoved(mock(ConcreteClientModeManager.class));
        }
    }

    /**
     * Test cellular data connection is on and then off
     */
    @Test
    public void testCellularDataConnectionOnOff() throws Exception {
        setWifiEnabled(false);
        setWifiEnabled(true);

        PhoneStateListener phoneStateListener = mockPhoneStateListener();
        phoneStateListener.onDataConnectionStateChanged(TelephonyManager.DATA_CONNECTED,
                TelephonyManager.NETWORK_TYPE_LTE);
        assertEquals(true, mWifiDataStall.isCellularDataAvailable());
        verify(mClientModeManager).onCellularConnectivityChanged(
                WifiDataStall.CELLULAR_DATA_AVAILABLE);
        phoneStateListener.onDataConnectionStateChanged(
                TelephonyManager.DATA_DISCONNECTED, TelephonyManager.NETWORK_TYPE_LTE);
        assertEquals(false, mWifiDataStall.isCellularDataAvailable());
        verify(mClientModeManager).onCellularConnectivityChanged(
                WifiDataStall.CELLULAR_DATA_NOT_AVAILABLE);
        setWifiEnabled(false);
        verify(mTelephonyManager, times(1)).listen(phoneStateListener,
                PhoneStateListener.LISTEN_NONE);
        setWifiEnabled(false);
        verify(mTelephonyManager, times(1)).listen(phoneStateListener,
                PhoneStateListener.LISTEN_NONE);
    }

    /**
     * Verify that resetPhoneStateListener re-registers the phoneStateListener so that it is
     * listening to changes to the default data subription.
     */
    @Test
    public void testCellularDataListenerReset() throws Exception {
        setWifiEnabled(false);
        setWifiEnabled(true);

        PhoneStateListener phoneStateListener = mockPhoneStateListener();
        // Verify 0 unregister and 1 register call to TelephonyManager
        verify(mTelephonyManager, never()).listen(phoneStateListener,
                PhoneStateListener.LISTEN_NONE);
        verify(mTelephonyManager, times(1)).listen(phoneStateListener,
                PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);

        // Verify that resetPhoneStateListener will unregister the listener and the register it.
        mWifiDataStall.resetPhoneStateListener();
        verify(mTelephonyManager, times(1)).listen(phoneStateListener,
                PhoneStateListener.LISTEN_NONE);
        verify(mTelephonyManager, times(2)).listen(phoneStateListener,
                PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);
        verify(mClientModeManager).onCellularConnectivityChanged(
                WifiDataStall.CELLULAR_DATA_UNKNOWN);

        // Verify the phone state listener still works
        phoneStateListener.onDataConnectionStateChanged(TelephonyManager.DATA_CONNECTED,
                TelephonyManager.NETWORK_TYPE_LTE);
        assertEquals(true, mWifiDataStall.isCellularDataAvailable());
        verify(mClientModeManager).onCellularConnectivityChanged(
                WifiDataStall.CELLULAR_DATA_AVAILABLE);
    }

    /**
     * Verify throughput when Rx link speed is unavailable.
     * Also verify the logging of channel utilization and throughput.
     */
    @Test
    public void verifyThroughputNoRxLinkSpeed() throws Exception {
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, null, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        verify(mWifiMetrics).incrementChannelUtilizationCount(10, 5850);
        verify(mWifiMetrics).incrementThroughputKbpsCount(50_000, 150_000, 5850);
        assertEquals(50_000, mWifiDataStall.getTxThroughputKbps());
        assertEquals(150_000, mWifiDataStall.getRxThroughputKbps());
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(-1);
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        assertEquals(960, mWifiDataStall.getTxThroughputKbps());
        assertEquals(-1, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics).incrementThroughputKbpsCount(960, -1, 5850);
    }

    private void verifyDataStallTxFailureInternal() {
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verify(mWifiMetrics).incrementThroughputKbpsCount(960, 9609, 5850);
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        assertEquals(960, mWifiDataStall.getTxThroughputKbps());
        assertEquals(9609, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
    }

    /**
     * Verify there is a Tx data stall from high Tx PER and low Tx throughput
     */
    @Test
    public void verifyDataStallTxFailure() throws Exception {
        verifyDataStallTxFailureInternal();
    }

    @Test
    public void verifyDataStallTxFailureAfterConnectionEnd() throws Exception {
        verifyDataStallTxFailureInternal();
        clearInvocations(mWifiMetrics);

        ConcreteClientModeManager cmm = mock(ConcreteClientModeManager.class);
        when(cmm.getRole()).thenReturn(ROLE_CLIENT_PRIMARY);
        mClientModeImplListener.onConnectionEnd(cmm);

        verifyDataStallTxFailureInternal();
    }

    @Test
    public void verifyDataStallTxFailureAfterWifiToggle() throws Exception {
        verifyDataStallTxFailureInternal();
        clearInvocations(mWifiMetrics);

        // Wifi off
        mPrimaryModeChangeCallback.onChange(mock(ConcreteClientModeManager.class), null);
        // Wifi on.
        mPrimaryModeChangeCallback.onChange(null, mock(ConcreteClientModeManager.class));

        verifyDataStallTxFailureInternal();
    }

    /**
     * Verify there is no data stall if tx tput is above the threshold and Tx per is low
     */
    @Test
    public void verifyNoDataStallTxFailureWhenTxTputIsHigh() throws Exception {
        when(mWifiInfo.getLinkSpeed()).thenReturn(867);
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);
        mNewLlStats.retries_be = mOldLlStats.retries_be;

        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(true, mWifiDataStall.isThroughputSufficient());
        assertEquals(833132, mWifiDataStall.getTxThroughputKbps());
        assertEquals(9609, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
    }


    /**
     * Verify there is no data stall from tx failures if tx is not consecutively bad
     */
    @Test
    public void verifyNoDataStallWhenTxFailureIsNotConsecutive() throws Exception {
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);

        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(true, mWifiDataStall.isThroughputSufficient());
        verifyUpdateWifiIsUnusableLinkLayerStats();

        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        mNewLlStats.retries_be = 2 * mOldLlStats.retries_be;
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(true, mWifiDataStall.isThroughputSufficient());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
    }

    /**
     * Verify there is a data stall when Rx tput is low
     */
    @Test
    public void verifyDataStallRxFailure() throws Exception {
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(2);
        when(mDeviceConfigFacade.getTputSufficientRatioThrDen()).thenReturn(1);
        when(mDeviceConfigFacade.getTputSufficientRatioThrNum()).thenReturn(3);
        when(mDeviceConfigFacade.getRxTputSufficientLowThrKbps()).thenReturn(1);

        mNewLlStats.retries_be = 2 * mOldLlStats.retries_be;
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_DATA_STALL_TX_WITHOUT_RX, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        assertEquals(4804, mWifiDataStall.getTxThroughputKbps());
        assertEquals(1921, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_TX_WITHOUT_RX);
    }

    /**
     * Verify there is no data stall and throughput is sufficient if there is no sufficient traffic
     */
    @Test
    public void verifyNoDataStallTrafficLow() throws Exception {
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(1);
        mNewLlStats.txmpdu_be = mOldLlStats.txmpdu_be + 1;
        mNewLlStats.retries_be = mOldLlStats.retries_be + 1;
        mNewLlStats.lostmpdu_be = mOldLlStats.lostmpdu_be + 1;
        mNewLlStats.rxmpdu_be = mOldLlStats.rxmpdu_be + 1;
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);

        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(true, mWifiDataStall.isThroughputSufficient());
        assertEquals(9128, mWifiDataStall.getTxThroughputKbps());
        assertEquals(-1, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(any(), anyInt());
    }

    /**
     * Verify there is a data stall from low tx and rx throughput
     */
    @Test
    public void verifyDataStallBothTxRxFailure() throws Exception {
        // 1st poll with low tx and rx throughput
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(1);
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);

        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        assertEquals(960, mWifiDataStall.getTxThroughputKbps());
        assertEquals(960, mWifiDataStall.getRxThroughputKbps());

        // 2nd poll with low tx and rx throughput
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_DATA_STALL_BOTH, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        assertEquals(960, mWifiDataStall.getTxThroughputKbps());
        assertEquals(960, mWifiDataStall.getRxThroughputKbps());
        verify(mWifiMetrics).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BOTH);

        // 3rd poll with low tx/rx traffic and throughput
        when(mWifiInfo.getLinkSpeed()).thenReturn(1);
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(1);
        mNewLlStats.txmpdu_be = mOldLlStats.txmpdu_be + 1;
        mNewLlStats.retries_be = mOldLlStats.retries_be + 1;
        mNewLlStats.lostmpdu_be = mOldLlStats.lostmpdu_be + 1;
        mNewLlStats.rxmpdu_be = mOldLlStats.rxmpdu_be + 1;
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + 2 * DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);

        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        assertEquals(960, mWifiDataStall.getTxThroughputKbps());
        assertEquals(960, mWifiDataStall.getRxThroughputKbps());

        // 4th poll with low tx/rx traffic, high throughput and unknown channel utilization
        when(mWifiChannelUtilization.getUtilizationRatio(anyInt())).thenReturn(-1);
        when(mWifiInfo.getLinkSpeed()).thenReturn(10);
        when(mWifiInfo.getRxLinkSpeedMbps()).thenReturn(10);
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + 2 * DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(true, mWifiDataStall.isThroughputSufficient());
        assertEquals(8943, mWifiDataStall.getTxThroughputKbps());
        assertEquals(9414, mWifiDataStall.getRxThroughputKbps());
    }

    /**
     * Verify that we can change the duration of evaluating Wifi conditions
     * to trigger data stall from DeviceConfigFacade
     */
    @Test
    public void verifyDataStallDurationDeviceConfigChange() throws Exception {
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);
        when(mDeviceConfigFacade.getDataStallDurationMs()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS + 1);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
    }

    /**
     * Verify that we can change the threshold of Tx packet error rate to trigger a data stall
     * from DeviceConfigFacade
     */
    @Test
    public void verifyDataStallTxPerThrDeviceConfigChange() throws Exception {
        when(mClock.getElapsedSinceBootMillis()).thenReturn(10L);
        when(mDeviceConfigFacade.getDataStallTxPerThr()).thenReturn(
                DeviceConfigFacade.DEFAULT_DATA_STALL_TX_PER_THR + 1);
        when(mDeviceConfigFacade.getDataStallTxTputThrKbps()).thenReturn(800);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        when(mClock.getElapsedSinceBootMillis()).thenReturn(
                10L + DeviceConfigFacade.DEFAULT_DATA_STALL_DURATION_MS);
        setUpWifiBytes(TEST_WIFI_BYTES, TEST_WIFI_BYTES);
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        assertEquals(false, mWifiDataStall.isThroughputSufficient());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(TEST_IFACE_NAME,
                WifiIsUnusableEvent.TYPE_DATA_STALL_BAD_TX);
    }

    /**
     * Verify there is no data stall when there are no new tx/rx failures
     */
    @Test
    public void verifyNoDataStallWhenNoFail() throws Exception {
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verify(mWifiMetrics, never()).resetWifiIsUnusableLinkLayerStats();
        verifyUpdateWifiIsUnusableLinkLayerStats();
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(any(), anyInt());
    }

    /**
     * Verify there is no data stall when the time difference between
     * two WifiLinkLayerStats is too big.
     */
    @Test
    public void verifyNoDataStallBigTimeGap() throws Exception {
        mNewLlStats.lostmpdu_be = mOldLlStats.lostmpdu_be + TEST_MIN_TX_BAD;
        mNewLlStats.timeStampInMs = mOldLlStats.timeStampInMs
                + WifiDataStall.MAX_MS_DELTA_FOR_DATA_STALL + 1;
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verifyUpdateWifiIsUnusableLinkLayerStats();
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(any(), anyInt());
    }

    /**
     * Verify that metrics get reset when there is a reset in WifiLinkLayerStats
     */
    @Test
    public void verifyReset() throws Exception {
        mNewLlStats.lostmpdu_be = mOldLlStats.lostmpdu_be - 1;
        assertEquals(WifiIsUnusableEvent.TYPE_UNKNOWN, mWifiDataStall
                .checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                        mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes));
        verify(mWifiMetrics).resetWifiIsUnusableLinkLayerStats();
        verify(mWifiMetrics, never()).updateWifiIsUnusableLinkLayerStats(
                anyLong(), anyLong(), anyLong(), anyLong(), anyLong());
        verify(mWifiMetrics, never()).logWifiIsUnusableEvent(any(), anyInt());
    }

    /**
     * Check incrementConnectionDuration under various conditions
     */
    @Test
    public void testIncrementConnectionDuration() throws Exception {
        setWifiEnabled(true);
        PhoneStateListener phoneStateListener = mockPhoneStateListener();
        phoneStateListener.onDataConnectionStateChanged(TelephonyManager.DATA_CONNECTED,
                TelephonyManager.NETWORK_TYPE_LTE);
        assertEquals(true, mWifiDataStall.isCellularDataAvailable());
        mNewLlStats.timeStampInMs = mOldLlStats.timeStampInMs + 1000;
        // Expect 1st throughput sufficiency check to return true
        // because it hits mLastTxBytes == 0 || mLastRxBytes == 0
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        verify(mWifiMetrics, times(1)).incrementConnectionDuration(TEST_IFACE_NAME,
                1000, true, true, TEST_RSSI, 960, 9609);

        // Expect 2nd throughput sufficiency check to return false
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        verify(mWifiMetrics, times(1)).incrementConnectionDuration(TEST_IFACE_NAME,
                1000, false, true, TEST_RSSI, 960, 9609);

        mNewLlStats.timeStampInMs = mOldLlStats.timeStampInMs + 2000;
        phoneStateListener.onDataConnectionStateChanged(
                TelephonyManager.DATA_DISCONNECTED, TelephonyManager.NETWORK_TYPE_LTE);
        assertEquals(false, mWifiDataStall.isCellularDataAvailable());
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        verify(mWifiMetrics, times(1)).incrementConnectionDuration(TEST_IFACE_NAME,
                2000, false, false, TEST_RSSI, 960, 9609);

        // Expect this update to be ignored by connection duration counters due to its
        // too large poll interval
        mNewLlStats.timeStampInMs = mOldLlStats.timeStampInMs + 10000;
        mWifiDataStall.checkDataStallAndThroughputSufficiency(TEST_IFACE_NAME,
                mCapabilities, mOldLlStats, mNewLlStats, mWifiInfo, mTxBytes, mRxBytes);
        verify(mWifiMetrics, never()).incrementConnectionDuration(TEST_IFACE_NAME,
                10000, false, false, TEST_RSSI, 960, 9609);
        setWifiEnabled(false);
    }
}