diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index 844d05564b2cb..fb7a4f8ad216b 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -111,6 +111,14 @@ public class NetworkStats implements Parcelable {
                     && operations == 0;
         }
 
+        public void add(Entry another) {
+            this.rxBytes += another.rxBytes;
+            this.rxPackets += another.rxPackets;
+            this.txBytes += another.txBytes;
+            this.txPackets += another.txPackets;
+            this.operations += another.operations;
+        }
+
         @Override
         public String toString() {
             final StringBuilder builder = new StringBuilder();
diff --git a/core/java/android/net/NetworkStatsHistory.java b/core/java/android/net/NetworkStatsHistory.java
index 0003c6e3d6ae0..a37c26f90d73e 100644
--- a/core/java/android/net/NetworkStatsHistory.java
+++ b/core/java/android/net/NetworkStatsHistory.java
@@ -342,11 +342,23 @@ public class NetworkStatsHistory implements Parcelable {
      * for combining together stats for external reporting.
      */
     public void recordEntireHistory(NetworkStatsHistory input) {
+        recordHistory(input, Long.MIN_VALUE, Long.MAX_VALUE);
+    }
+
+    /**
+     * Record given {@link NetworkStatsHistory} into this history, copying only
+     * buckets that atomically occur in the inclusive time range. Doesn't
+     * interpolate across partial buckets.
+     */
+    public void recordHistory(NetworkStatsHistory input, long start, long end) {
         final NetworkStats.Entry entry = new NetworkStats.Entry(
                 IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
         for (int i = 0; i < input.bucketCount; i++) {
-            final long start = input.bucketStart[i];
-            final long end = start + input.bucketDuration;
+            final long bucketStart = input.bucketStart[i];
+            final long bucketEnd = bucketStart + input.bucketDuration;
+
+            // skip when bucket is outside requested range
+            if (bucketStart < start || bucketEnd > end) continue;
 
             entry.rxBytes = getLong(input.rxBytes, i, 0L);
             entry.rxPackets = getLong(input.rxPackets, i, 0L);
@@ -354,7 +366,7 @@ public class NetworkStatsHistory implements Parcelable {
             entry.txPackets = getLong(input.txPackets, i, 0L);
             entry.operations = getLong(input.operations, i, 0L);
 
-            recordData(start, end, entry);
+            recordData(bucketStart, bucketEnd, entry);
         }
     }
 
diff --git a/core/java/android/net/NetworkTemplate.java b/core/java/android/net/NetworkTemplate.java
index 39a4d7bb0d8f4..d8e53d523f074 100644
--- a/core/java/android/net/NetworkTemplate.java
+++ b/core/java/android/net/NetworkTemplate.java
@@ -61,6 +61,13 @@ public class NetworkTemplate implements Parcelable {
                 com.android.internal.R.array.config_data_usage_network_types);
     }
 
+    private static boolean sForceAllNetworkTypes = false;
+
+    // @VisibleForTesting
+    public static void forceAllNetworkTypes() {
+        sForceAllNetworkTypes = true;
+    }
+
     /**
      * Template to match {@link ConnectivityManager#TYPE_MOBILE} networks with
      * the given IMSI.
@@ -225,7 +232,7 @@ public class NetworkTemplate implements Parcelable {
             // TODO: consider matching against WiMAX subscriber identity
             return true;
         } else {
-            return (contains(DATA_USAGE_NETWORK_TYPES, ident.mType)
+            return ((sForceAllNetworkTypes || contains(DATA_USAGE_NETWORK_TYPES, ident.mType))
                     && Objects.equal(mSubscriberId, ident.mSubscriberId));
         }
     }
@@ -291,7 +298,7 @@ public class NetworkTemplate implements Parcelable {
         if (ident.mType == TYPE_WIMAX) {
             return true;
         } else {
-            return contains(DATA_USAGE_NETWORK_TYPES, ident.mType);
+            return sForceAllNetworkTypes || contains(DATA_USAGE_NETWORK_TYPES, ident.mType);
         }
     }
 
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index ea3cab44477c7..a0641d5db1b61 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -4210,6 +4210,8 @@ public final class Settings {
         public static final String NETSTATS_GLOBAL_ALERT_BYTES = "netstats_global_alert_bytes";
         /** {@hide} */
         public static final String NETSTATS_SAMPLE_ENABLED = "netstats_sample_enabled";
+        /** {@hide} */
+        public static final String NETSTATS_REPORT_XT_OVER_DEV = "netstats_report_xt_over_dev";
 
         /** {@hide} */
         public static final String NETSTATS_DEV_BUCKET_DURATION = "netstats_dev_bucket_duration";
diff --git a/services/java/com/android/server/net/NetworkStatsCollection.java b/services/java/com/android/server/net/NetworkStatsCollection.java
index c2e475a5b4ead..9ddf011069147 100644
--- a/services/java/com/android/server/net/NetworkStatsCollection.java
+++ b/services/java/com/android/server/net/NetworkStatsCollection.java
@@ -71,7 +71,7 @@ public class NetworkStatsCollection implements FileRotator.Reader {
 
     private HashMap<Key, NetworkStatsHistory> mStats = Maps.newHashMap();
 
-    private long mBucketDuration;
+    private final long mBucketDuration;
 
     private long mStartMillis;
     private long mEndMillis;
@@ -95,6 +95,18 @@ public class NetworkStatsCollection implements FileRotator.Reader {
         return mStartMillis;
     }
 
+    /**
+     * Return first atomic bucket in this collection, which is more conservative
+     * than {@link #mStartMillis}.
+     */
+    public long getFirstAtomicBucketMillis() {
+        if (mStartMillis == Long.MAX_VALUE) {
+            return Long.MAX_VALUE;
+        } else {
+            return mStartMillis + mBucketDuration;
+        }
+    }
+
     public long getEndMillis() {
         return mEndMillis;
     }
@@ -121,6 +133,15 @@ public class NetworkStatsCollection implements FileRotator.Reader {
      */
     public NetworkStatsHistory getHistory(
             NetworkTemplate template, int uid, int set, int tag, int fields) {
+        return getHistory(template, uid, set, tag, fields, Long.MIN_VALUE, Long.MAX_VALUE);
+    }
+
+    /**
+     * Combine all {@link NetworkStatsHistory} in this collection which match
+     * the requested parameters.
+     */
+    public NetworkStatsHistory getHistory(
+            NetworkTemplate template, int uid, int set, int tag, int fields, long start, long end) {
         final NetworkStatsHistory combined = new NetworkStatsHistory(
                 mBucketDuration, estimateBuckets(), fields);
         for (Map.Entry<Key, NetworkStatsHistory> entry : mStats.entrySet()) {
@@ -128,7 +149,7 @@ public class NetworkStatsCollection implements FileRotator.Reader {
             final boolean setMatches = set == SET_ALL || key.set == set;
             if (key.uid == uid && setMatches && key.tag == tag
                     && templateMatches(template, key.ident)) {
-                combined.recordEntireHistory(entry.getValue());
+                combined.recordHistory(entry.getValue(), start, end);
             }
         }
         return combined;
@@ -145,6 +166,9 @@ public class NetworkStatsCollection implements FileRotator.Reader {
         final NetworkStats.Entry entry = new NetworkStats.Entry();
         NetworkStatsHistory.Entry historyEntry = null;
 
+        // shortcut when we know stats will be empty
+        if (start == end) return stats;
+
         for (Map.Entry<Key, NetworkStatsHistory> mapEntry : mStats.entrySet()) {
             final Key key = mapEntry.getKey();
             if (templateMatches(template, key.ident)) {
@@ -175,8 +199,9 @@ public class NetworkStatsCollection implements FileRotator.Reader {
      */
     public void recordData(NetworkIdentitySet ident, int uid, int set, int tag, long start,
             long end, NetworkStats.Entry entry) {
-        noteRecordedHistory(start, end, entry.rxBytes + entry.txBytes);
-        findOrCreateHistory(ident, uid, set, tag).recordData(start, end, entry);
+        final NetworkStatsHistory history = findOrCreateHistory(ident, uid, set, tag);
+        history.recordData(start, end, entry);
+        noteRecordedHistory(history.getStart(), history.getEnd(), entry.rxBytes + entry.txBytes);
     }
 
     /**
diff --git a/services/java/com/android/server/net/NetworkStatsService.java b/services/java/com/android/server/net/NetworkStatsService.java
index 0e93b0affc6b6..ba122ecdf2317 100644
--- a/services/java/com/android/server/net/NetworkStatsService.java
+++ b/services/java/com/android/server/net/NetworkStatsService.java
@@ -44,6 +44,7 @@ import static android.provider.Settings.Secure.NETSTATS_DEV_PERSIST_BYTES;
 import static android.provider.Settings.Secure.NETSTATS_DEV_ROTATE_AGE;
 import static android.provider.Settings.Secure.NETSTATS_GLOBAL_ALERT_BYTES;
 import static android.provider.Settings.Secure.NETSTATS_POLL_INTERVAL;
+import static android.provider.Settings.Secure.NETSTATS_REPORT_XT_OVER_DEV;
 import static android.provider.Settings.Secure.NETSTATS_SAMPLE_ENABLED;
 import static android.provider.Settings.Secure.NETSTATS_TIME_CACHE_MAX_AGE;
 import static android.provider.Settings.Secure.NETSTATS_UID_BUCKET_DURATION;
@@ -177,6 +178,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         public long getPollInterval();
         public long getTimeCacheMaxAge();
         public boolean getSampleEnabled();
+        public boolean getReportXtOverDev();
 
         public static class Config {
             public final long bucketDuration;
@@ -221,6 +223,8 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
 
     /** Cached {@link #mDevRecorder} stats. */
     private NetworkStatsCollection mDevStatsCached;
+    /** Cached {@link #mXtRecorder} stats. */
+    private NetworkStatsCollection mXtStatsCached;
 
     /** Current counter sets for each UID. */
     private SparseIntArray mActiveUidCounterSet = new SparseIntArray();
@@ -295,6 +299,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             // read historical network stats from disk, since policy service
             // might need them right away.
             mDevStatsCached = mDevRecorder.getOrLoadCompleteLocked();
+            mXtStatsCached = mXtRecorder.getOrLoadCompleteLocked();
 
             // bootstrap initial stats to prevent double-counting later
             bootstrapStatsLocked();
@@ -371,6 +376,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         mUidTagRecorder = null;
 
         mDevStatsCached = null;
+        mXtStatsCached = null;
 
         mSystemReady = false;
     }
@@ -469,12 +475,12 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             @Override
             public NetworkStats getSummaryForNetwork(
                     NetworkTemplate template, long start, long end) {
-                return mDevStatsCached.getSummary(template, start, end);
+                return internalGetSummaryForNetwork(template, start, end);
             }
 
             @Override
             public NetworkStatsHistory getHistoryForNetwork(NetworkTemplate template, int fields) {
-                return mDevStatsCached.getHistory(template, UID_ALL, SET_ALL, TAG_NONE, fields);
+                return internalGetHistoryForNetwork(template, fields);
             }
 
             @Override
@@ -507,11 +513,56 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         };
     }
 
+    /**
+     * Return network summary, splicing between {@link #mDevStatsCached}
+     * and {@link #mXtStatsCached} when appropriate.
+     */
+    private NetworkStats internalGetSummaryForNetwork(
+            NetworkTemplate template, long start, long end) {
+        if (!mSettings.getReportXtOverDev()) {
+            // shortcut when XT reporting disabled
+            return mDevStatsCached.getSummary(template, start, end);
+        }
+
+        // splice stats between DEV and XT, switching over from DEV to XT at
+        // first atomic bucket.
+        final long firstAtomicBucket = mXtStatsCached.getFirstAtomicBucketMillis();
+        final NetworkStats dev = mDevStatsCached.getSummary(
+                template, Math.min(start, firstAtomicBucket), Math.min(end, firstAtomicBucket));
+        final NetworkStats xt = mXtStatsCached.getSummary(
+                template, Math.max(start, firstAtomicBucket), Math.max(end, firstAtomicBucket));
+
+        xt.combineAllValues(dev);
+        return xt;
+    }
+
+    /**
+     * Return network history, splicing between {@link #mDevStatsCached}
+     * and {@link #mXtStatsCached} when appropriate.
+     */
+    private NetworkStatsHistory internalGetHistoryForNetwork(NetworkTemplate template, int fields) {
+        if (!mSettings.getReportXtOverDev()) {
+            // shortcut when XT reporting disabled
+            return mDevStatsCached.getHistory(template, UID_ALL, SET_ALL, TAG_NONE, fields);
+        }
+
+        // splice stats between DEV and XT, switching over from DEV to XT at
+        // first atomic bucket.
+        final long firstAtomicBucket = mXtStatsCached.getFirstAtomicBucketMillis();
+        final NetworkStatsHistory dev = mDevStatsCached.getHistory(
+                template, UID_ALL, SET_ALL, TAG_NONE, fields, Long.MIN_VALUE, firstAtomicBucket);
+        final NetworkStatsHistory xt = mXtStatsCached.getHistory(
+                template, UID_ALL, SET_ALL, TAG_NONE, fields, firstAtomicBucket, Long.MAX_VALUE);
+
+        xt.recordEntireHistory(dev);
+        return xt;
+    }
+
     @Override
     public long getNetworkTotalBytes(NetworkTemplate template, long start, long end) {
         mContext.enforceCallingOrSelfPermission(READ_NETWORK_USAGE_HISTORY, TAG);
         assertBandwidthControlEnabled();
-        return mDevStatsCached.getSummary(template, start, end).getTotalBytes();
+        return internalGetSummaryForNetwork(template, start, end).getTotalBytes();
     }
 
     @Override
@@ -1190,6 +1241,10 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             return getSecureBoolean(NETSTATS_SAMPLE_ENABLED, true);
         }
         @Override
+        public boolean getReportXtOverDev() {
+            return getSecureBoolean(NETSTATS_REPORT_XT_OVER_DEV, true);
+        }
+        @Override
         public Config getDevConfig() {
             return new Config(getSecureLong(NETSTATS_DEV_BUCKET_DURATION, HOUR_IN_MILLIS),
                     getSecureLong(NETSTATS_DEV_ROTATE_AGE, 15 * DAY_IN_MILLIS),
diff --git a/services/tests/servicestests/src/com/android/server/NetworkStatsServiceTest.java b/services/tests/servicestests/src/com/android/server/NetworkStatsServiceTest.java
index 332d1980167f7..cdc4d784cf01c 100644
--- a/services/tests/servicestests/src/com/android/server/NetworkStatsServiceTest.java
+++ b/services/tests/servicestests/src/com/android/server/NetworkStatsServiceTest.java
@@ -777,10 +777,80 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
 
     }
 
+    public void testReportXtOverDev() throws Exception {
+        // bring mobile network online
+        expectCurrentTime();
+        expectDefaultSettings();
+        expectNetworkState(buildMobile3gState(IMSI_1));
+        expectNetworkStatsSummary(buildEmptyStats());
+        expectNetworkStatsUidDetail(buildEmptyStats());
+        expectNetworkStatsPoll();
+
+        replay();
+        mServiceContext.sendBroadcast(new Intent(CONNECTIVITY_ACTION_IMMEDIATE));
+        verifyAndReset();
+
+        // create some traffic, but only for DEV, and across 1.5 buckets
+        incrementCurrentTime(90 * MINUTE_IN_MILLIS);
+        expectCurrentTime();
+        expectDefaultSettings();
+        expectNetworkStatsSummaryDev(new NetworkStats(getElapsedRealtime(), 1)
+                .addIfaceValues(TEST_IFACE, 6000L, 60L, 3000L, 30L));
+        expectNetworkStatsSummaryXt(buildEmptyStats());
+        expectNetworkStatsUidDetail(buildEmptyStats());
+        expectNetworkStatsPoll();
+
+        replay();
+        mServiceContext.sendBroadcast(new Intent(ACTION_NETWORK_STATS_POLL));
+
+        // verify service recorded history:
+        // 4000(dev) + 2000(dev)
+        assertNetworkTotal(sTemplateImsi1, 6000L, 60L, 3000L, 30L, 0);
+        verifyAndReset();
+
+        // create traffic on both DEV and XT, across two buckets
+        incrementCurrentTime(2 * HOUR_IN_MILLIS);
+        expectCurrentTime();
+        expectDefaultSettings();
+        expectNetworkStatsSummaryDev(new NetworkStats(getElapsedRealtime(), 1)
+                .addIfaceValues(TEST_IFACE, 6004L, 64L, 3004L, 34L));
+        expectNetworkStatsSummaryXt(new NetworkStats(getElapsedRealtime(), 1)
+                .addIfaceValues(TEST_IFACE, 10240L, 0L, 0L, 0L));
+        expectNetworkStatsUidDetail(buildEmptyStats());
+        expectNetworkStatsPoll();
+
+        replay();
+        mServiceContext.sendBroadcast(new Intent(ACTION_NETWORK_STATS_POLL));
+
+        // verify that we switching reporting at the first atomic XT bucket,
+        // which should give us:
+        // 4000(dev) + 2000(dev) + 1(dev) + 5120(xt) + 2560(xt)
+        assertNetworkTotal(sTemplateImsi1, 13681L, 61L, 3001L, 31L, 0);
+
+        // also test pure-DEV and pure-XT ranges
+        assertNetworkTotal(sTemplateImsi1, startTimeMillis(),
+                startTimeMillis() + 2 * HOUR_IN_MILLIS, 6001L, 61L, 3001L, 31L, 0);
+        assertNetworkTotal(sTemplateImsi1, startTimeMillis() + 2 * HOUR_IN_MILLIS,
+                startTimeMillis() + 4 * HOUR_IN_MILLIS, 7680L, 0L, 0L, 0L, 0);
+
+        verifyAndReset();
+    }
+
     private void assertNetworkTotal(NetworkTemplate template, long rxBytes, long rxPackets,
             long txBytes, long txPackets, int operations) throws Exception {
+        assertNetworkTotal(template, Long.MIN_VALUE, Long.MAX_VALUE, rxBytes, rxPackets, txBytes,
+                txPackets, operations);
+    }
+
+    private void assertNetworkTotal(NetworkTemplate template, long start, long end, long rxBytes,
+            long rxPackets, long txBytes, long txPackets, int operations) throws Exception {
+        // verify history API
         final NetworkStatsHistory history = mSession.getHistoryForNetwork(template, FIELD_ALL);
-        assertValues(history, Long.MIN_VALUE, Long.MAX_VALUE, rxBytes, rxPackets, txBytes,
+        assertValues(history, start, end, rxBytes, rxPackets, txBytes, txPackets, operations);
+
+        // verify summary API
+        final NetworkStats stats = mSession.getSummaryForNetwork(template, start, end);
+        assertValues(stats, IFACE_ALL, UID_ALL, SET_DEFAULT, TAG_NONE, rxBytes, rxPackets, txBytes,
                 txPackets, operations);
     }
 
@@ -791,10 +861,17 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
 
     private void assertUidTotal(NetworkTemplate template, int uid, int set, long rxBytes,
             long rxPackets, long txBytes, long txPackets, int operations) throws Exception {
+        // verify history API
         final NetworkStatsHistory history = mSession.getHistoryForUid(
                 template, uid, set, TAG_NONE, FIELD_ALL);
         assertValues(history, Long.MIN_VALUE, Long.MAX_VALUE, rxBytes, rxPackets, txBytes,
                 txPackets, operations);
+
+        // verify summary API
+        final NetworkStats stats = mSession.getSummaryForAllUid(
+                template, Long.MIN_VALUE, Long.MAX_VALUE, false);
+        assertValues(stats, IFACE_ALL, uid, set, TAG_NONE, rxBytes, rxPackets, txBytes, txPackets,
+                operations);
     }
 
     private void expectSystemReady() throws Exception {
@@ -819,7 +896,15 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
     }
 
     private void expectNetworkStatsSummary(NetworkStats summary) throws Exception {
+        expectNetworkStatsSummaryDev(summary);
+        expectNetworkStatsSummaryXt(summary);
+    }
+
+    private void expectNetworkStatsSummaryDev(NetworkStats summary) throws Exception {
         expect(mNetManager.getNetworkStatsSummaryDev()).andReturn(summary).atLeastOnce();
+    }
+
+    private void expectNetworkStatsSummaryXt(NetworkStats summary) throws Exception {
         expect(mNetManager.getNetworkStatsSummaryXt()).andReturn(summary).atLeastOnce();
     }
 
@@ -847,6 +932,7 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
         expect(mSettings.getPollInterval()).andReturn(HOUR_IN_MILLIS).anyTimes();
         expect(mSettings.getTimeCacheMaxAge()).andReturn(DAY_IN_MILLIS).anyTimes();
         expect(mSettings.getSampleEnabled()).andReturn(true).anyTimes();
+        expect(mSettings.getReportXtOverDev()).andReturn(true).anyTimes();
 
         final Config config = new Config(bucketDuration, deleteAge, deleteAge);
         expect(mSettings.getDevConfig()).andReturn(config).anyTimes();
@@ -885,8 +971,20 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
 
     private static void assertValues(NetworkStats stats, String iface, int uid, int set,
             int tag, long rxBytes, long rxPackets, long txBytes, long txPackets, int operations) {
-        final int i = stats.findIndex(iface, uid, set, tag);
-        final NetworkStats.Entry entry = stats.getValues(i, null);
+        final NetworkStats.Entry entry = new NetworkStats.Entry();
+        if (set == SET_DEFAULT || set == SET_ALL) {
+            final int i = stats.findIndex(iface, uid, SET_DEFAULT, tag);
+            if (i != -1) {
+                entry.add(stats.getValues(i, null));
+            }
+        }
+        if (set == SET_FOREGROUND || set == SET_ALL) {
+            final int i = stats.findIndex(iface, uid, SET_FOREGROUND, tag);
+            if (i != -1) {
+                entry.add(stats.getValues(i, null));
+            }
+        }
+
         assertEquals("unexpected rxBytes", rxBytes, entry.rxBytes);
         assertEquals("unexpected rxPackets", rxPackets, entry.rxPackets);
         assertEquals("unexpected txBytes", txBytes, entry.txBytes);
diff --git a/services/tests/servicestests/src/com/android/server/net/NetworkStatsCollectionTest.java b/services/tests/servicestests/src/com/android/server/net/NetworkStatsCollectionTest.java
index 863482156e87e..1a6c289316887 100644
--- a/services/tests/servicestests/src/com/android/server/net/NetworkStatsCollectionTest.java
+++ b/services/tests/servicestests/src/com/android/server/net/NetworkStatsCollectionTest.java
@@ -16,7 +16,11 @@
 
 package com.android.server.net;
 
+import static android.net.NetworkStats.SET_DEFAULT;
+import static android.net.NetworkStats.TAG_NONE;
+import static android.net.NetworkStats.UID_ALL;
 import static android.net.NetworkTemplate.buildTemplateMobileAll;
+import static android.text.format.DateUtils.HOUR_IN_MILLIS;
 import static android.text.format.DateUtils.MINUTE_IN_MILLIS;
 
 import android.content.res.Resources;
@@ -47,6 +51,14 @@ public class NetworkStatsCollectionTest extends AndroidTestCase {
     private static final String TEST_FILE = "test.bin";
     private static final String TEST_IMSI = "310260000000000";
 
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+
+        // ignore any device overlay while testing
+        NetworkTemplate.forceAllNetworkTypes();
+    }
+
     public void testReadLegacyNetwork() throws Exception {
         final File testFile = new File(getContext().getFilesDir(), TEST_FILE);
         stageFile(R.raw.netstats_v1, testFile);
@@ -125,6 +137,20 @@ public class NetworkStatsCollectionTest extends AndroidTestCase {
                 77017831L, 100995L, 35436758L, 92344L);
     }
 
+    public void testStartEndAtomicBuckets() throws Exception {
+        final NetworkStatsCollection collection = new NetworkStatsCollection(HOUR_IN_MILLIS);
+
+        // record empty data straddling between buckets
+        final NetworkStats.Entry entry = new NetworkStats.Entry();
+        entry.rxBytes = 32;
+        collection.recordData(null, UID_ALL, SET_DEFAULT, TAG_NONE, 30 * MINUTE_IN_MILLIS,
+                90 * MINUTE_IN_MILLIS, entry);
+
+        // assert that we report boundary in atomic buckets
+        assertEquals(0, collection.getStartMillis());
+        assertEquals(2 * HOUR_IN_MILLIS, collection.getEndMillis());
+    }
+
     /**
      * Copy a {@link Resources#openRawResource(int)} into {@link File} for
      * testing purposes.