diff --git a/core/tests/coretests/src/android/net/NetworkStatsTest.java b/core/tests/coretests/src/android/net/NetworkStatsTest.java
new file mode 100644
index 0000000000..45719c28a9
--- /dev/null
+++ b/core/tests/coretests/src/android/net/NetworkStatsTest.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2011 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 android.net;
+
+import android.os.SystemClock;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import junit.framework.TestCase;
+
+@SmallTest
+public class NetworkStatsTest extends TestCase {
+
+    private static final String TEST_IFACE = "test0";
+
+    public void testFindIndex() throws Exception {
+        final NetworkStats stats = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 3)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024)
+                .addEntry(TEST_IFACE, 102, 1024, 1024).build();
+
+        assertEquals(2, stats.findIndex(TEST_IFACE, 102));
+        assertEquals(2, stats.findIndex(TEST_IFACE, 102));
+        assertEquals(0, stats.findIndex(TEST_IFACE, 100));
+        assertEquals(-1, stats.findIndex(TEST_IFACE, 6));
+    }
+
+    public void testSubtractIdenticalData() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        assertEquals(0, result.rx[0]);
+        assertEquals(0, result.tx[0]);
+        assertEquals(0, result.rx[1]);
+        assertEquals(0, result.tx[1]);
+    }
+
+    public void testSubtractIdenticalRows() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1025, 2)
+                .addEntry(TEST_IFACE, 101, 3, 1028).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        // expect delta between measurements
+        assertEquals(1, result.rx[0]);
+        assertEquals(2, result.tx[0]);
+        assertEquals(3, result.rx[1]);
+        assertEquals(4, result.tx[1]);
+    }
+
+    public void testSubtractNewRows() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 3)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024)
+                .addEntry(TEST_IFACE, 102, 1024, 1024).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        // its okay to have new rows
+        assertEquals(0, result.rx[0]);
+        assertEquals(0, result.tx[0]);
+        assertEquals(0, result.rx[1]);
+        assertEquals(0, result.tx[1]);
+        assertEquals(1024, result.rx[2]);
+        assertEquals(1024, result.tx[2]);
+    }
+
+}