Add Thread#join to guarantee the termination of the thread

Also add MonitorThreadLeak annotation to check thread leak.

Test: atest ConnectivityCoverageTests --test-filter mdns*
Change-Id: Ie47f30360e36784428173f6cc87a4a6b09826405

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

@@ -56,6 +56,7 @@ import java.util.List;
 import java.util.concurrent.ScheduledExecutorService;
 
 /** Tests for {@link MdnsDiscoveryManager}. */
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner.class)
 @DevSdkIgnoreRule.IgnoreUpTo(SC_V2)
 public class MdnsDiscoveryManagerTests {
@@ -134,9 +135,10 @@ public class MdnsDiscoveryManagerTests {
     }
 
     @After
-    public void tearDown() {
+    public void tearDown() throws Exception {
         if (thread != null) {
             thread.quitSafely();
+            thread.join();
         }
     }
 

tests/unit/java/com/android/server/connectivity/mdns/MdnsServiceCacheTest.kt

@@ -49,6 +49,7 @@ private const val NO_CALLBACK_TIMEOUT_MS = 200L
 private const val TEST_ELAPSED_REALTIME_MS = 123L
 private const val DEFAULT_TTL_TIME_MS = 120000L
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
 class MdnsServiceCacheTest {
@@ -104,6 +105,7 @@ class MdnsServiceCacheTest {
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     private fun makeFlags(isExpiredServicesRemovalEnabled: Boolean = false) =

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

@@ -87,6 +87,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
 /** Tests for {@link MdnsServiceTypeClient}. */
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner.class)
 @DevSdkIgnoreRule.IgnoreUpTo(SC_V2)
 public class MdnsServiceTypeClientTests {
@@ -230,9 +231,10 @@ public class MdnsServiceTypeClientTests {
     }
 
     @After
-    public void tearDown() {
+    public void tearDown() throws Exception {
         if (thread != null) {
             thread.quitSafely();
+            thread.join();
         }
     }
 

tests/unit/java/com/android/server/connectivity/mdns/internal/SocketNetlinkMonitorTest.kt

@@ -27,6 +27,7 @@ import org.mockito.Mockito.verify
 private val LINKADDRV4 = LinkAddress("192.0.2.0/24")
 private val IFACE_IDX = 32
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.S_V2)
 internal class SocketNetlinkMonitorTest {
@@ -43,6 +44,7 @@ internal class SocketNetlinkMonitorTest {
     @After
     fun tearDown() {
         thread.quitSafely()
+        thread.join()
     }
 
     @Test