Stop the created handler threads on the tests

The created handler thread will stay there for a while until
all the tests are finished. This is considered as a leakage
which will take the resource from the devices. In low end
devices, this may possibly impact the performance. The created
threads should be closed explicitly.

Test: atest ConnectivityCoverageTests ConntrackSocketTest
Change-Id: Ic1beb2a210e7c8c80c66fc9e0727c47599150672

Tethering/tests/privileged/src/com/android/networkstack/tethering/ConntrackSocketTest.java

@@ -44,6 +44,7 @@ import com.android.net.module.util.netlink.NetlinkMessage;
 import com.android.net.module.util.netlink.NetlinkUtils;
 import com.android.net.module.util.netlink.StructNlMsgHdr;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -84,6 +85,14 @@ public class ConntrackSocketTest {
         mOffloadHw = new OffloadHardwareInterface(mHandler, mLog, mDeps);
     }
 
+    @After
+    public void tearDown() throws Exception {
+        if (mHandlerThread != null) {
+            mHandlerThread.quitSafely();
+            mHandlerThread.join();
+        }
+    }
+
     void findConnectionOrThrow(FileDescriptor fd, InetSocketAddress local, InetSocketAddress remote)
             throws Exception {
         Log.d(TAG, "Looking for socket " + local + " -> " + remote);

tests/unit/java/com/android/server/connectivity/mdns/MdnsMultinetworkSocketClientTest.java

@@ -42,6 +42,7 @@ import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
 import com.android.testutils.HandlerUtils;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -69,6 +70,7 @@ public class MdnsMultinetworkSocketClientTest {
     @Mock private SocketCreationCallback mSocketCreationCallback;
     @Mock private SharedLog mSharedLog;
     private MdnsMultinetworkSocketClient mSocketClient;
+    private HandlerThread mHandlerThread;
     private Handler mHandler;
     private SocketKey mSocketKey;
 
@@ -76,14 +78,23 @@ public class MdnsMultinetworkSocketClientTest {
     public void setUp() throws SocketException {
         MockitoAnnotations.initMocks(this);
 
-        final HandlerThread thread = new HandlerThread("MdnsMultinetworkSocketClientTest");
+        mHandlerThread = new HandlerThread("MdnsMultinetworkSocketClientTest");
-        thread.start();
+        mHandlerThread.start();
-        mHandler = new Handler(thread.getLooper());
+        mHandler = new Handler(mHandlerThread.getLooper());
         mSocketKey = new SocketKey(1000 /* interfaceIndex */);
-        mSocketClient = new MdnsMultinetworkSocketClient(thread.getLooper(), mProvider, mSharedLog);
+        mSocketClient = new MdnsMultinetworkSocketClient(
+                mHandlerThread.getLooper(), mProvider, mSharedLog);
         mHandler.post(() -> mSocketClient.setCallback(mCallback));
     }
 
+    @After
+    public void tearDown() throws Exception {
+        if (mHandlerThread != null) {
+            mHandlerThread.quitSafely();
+            mHandlerThread.join();
+        }
+    }
+
     private SocketCallback expectSocketCallback() {
         return expectSocketCallback(mListener, mNetwork);
     }

tests/unit/java/com/android/server/net/NetworkStatsObserversTest.java

@@ -59,6 +59,7 @@ import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRunner;
 import com.android.testutils.HandlerUtils;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -139,6 +140,14 @@ public class NetworkStatsObserversTest {
         mUsageCallback = new TestableUsageCallback(mUsageCallbackBinder);
     }
 
+    @After
+    public void tearDown() throws Exception {
+        if (mObserverHandlerThread != null) {
+            mObserverHandlerThread.quitSafely();
+            mObserverHandlerThread.join();
+        }
+    }
+
     @Test
     public void testRegister_thresholdTooLow_setsDefaultThreshold() throws Exception {
         final long thresholdTooLowBytes = 1L;