diff --git a/tests/unit/java/com/android/server/connectivityservice/CSBasicMethodsTest.kt b/tests/unit/java/com/android/server/connectivityservice/CSBasicMethodsTest.kt
index 58f20a9..a5d5297 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSBasicMethodsTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSBasicMethodsTest.kt
@@ -23,11 +23,12 @@
 import androidx.test.filters.SmallTest
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
 import com.android.testutils.DevSdkIgnoreRunner
-import org.junit.Test
-import org.junit.runner.RunWith
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @IgnoreUpTo(Build.VERSION_CODES.R)
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSBpfNetMapsTest.kt b/tests/unit/java/com/android/server/connectivityservice/CSBpfNetMapsTest.kt
index c26ec53..8155fd0 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSBpfNetMapsTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSBpfNetMapsTest.kt
@@ -38,6 +38,7 @@
 import org.mockito.Mockito.never
 import org.mockito.Mockito.verify
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @IgnoreUpTo(Build.VERSION_CODES.S_V2) // Bpf only supports in T+.
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSDestroyedNetworkTests.kt b/tests/unit/java/com/android/server/connectivityservice/CSDestroyedNetworkTests.kt
index 572c7bb..5c29e3a 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSDestroyedNetworkTests.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSDestroyedNetworkTests.kt
@@ -30,6 +30,7 @@
 
 private const val LONG_TIMEOUT_MS = 5_000
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.R)
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSKeepConnectedTest.kt b/tests/unit/java/com/android/server/connectivityservice/CSKeepConnectedTest.kt
index a753922..94c68c0 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSKeepConnectedTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSKeepConnectedTest.kt
@@ -22,8 +22,8 @@
 import android.net.NetworkCapabilities.TRANSPORT_WIFI
 import android.net.NetworkRequest
 import android.net.NetworkScore
-import android.net.NetworkScore.KEEP_CONNECTED_LOCAL_NETWORK
 import android.net.NetworkScore.KEEP_CONNECTED_FOR_TEST
+import android.net.NetworkScore.KEEP_CONNECTED_LOCAL_NETWORK
 import android.os.Build
 import androidx.test.filters.SmallTest
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo
@@ -33,6 +33,7 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @IgnoreUpTo(Build.VERSION_CODES.TIRAMISU)
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentCreationTests.kt b/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentCreationTests.kt
index 6add6b9..cb98454 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentCreationTests.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentCreationTests.kt
@@ -33,6 +33,7 @@
 import com.android.testutils.DevSdkIgnoreRunner
 import com.android.testutils.RecorderCallback.CallbackEntry.Available
 import com.android.testutils.TestableNetworkCallback
+import kotlin.test.assertFailsWith
 import org.junit.Assert.assertEquals
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -41,7 +42,6 @@
 import org.mockito.Mockito.inOrder
 import org.mockito.Mockito.never
 import org.mockito.Mockito.timeout
-import kotlin.test.assertFailsWith
 
 private const val TIMEOUT_MS = 2_000L
 private const val NO_CALLBACK_TIMEOUT_MS = 200L
@@ -51,6 +51,7 @@
 
 private fun defaultLnc() = FromS(LocalNetworkConfig.Builder().build())
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @IgnoreUpTo(Build.VERSION_CODES.R)
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentTests.kt b/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentTests.kt
index dd0706b..ba14775 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentTests.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSLocalAgentTests.kt
@@ -42,6 +42,7 @@
 import com.android.testutils.RecorderCallback.CallbackEntry.LocalInfoChanged
 import com.android.testutils.RecorderCallback.CallbackEntry.Lost
 import com.android.testutils.TestableNetworkCallback
+import kotlin.test.assertFailsWith
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.mockito.Mockito.clearInvocations
@@ -49,7 +50,6 @@
 import org.mockito.Mockito.never
 import org.mockito.Mockito.timeout
 import org.mockito.Mockito.verify
-import kotlin.test.assertFailsWith
 
 private const val TIMEOUT_MS = 200L
 private const val MEDIUM_TIMEOUT_MS = 1_000L
@@ -79,6 +79,7 @@
         NetworkScore.Builder().setKeepConnectedReason(KEEP_CONNECTED_FOR_TEST).build()
 )
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.TIRAMISU)
 class CSLocalAgentTests : CSTest() {
diff --git a/tests/unit/java/com/android/server/connectivityservice/CSNetworkActivityTest.kt b/tests/unit/java/com/android/server/connectivityservice/CSNetworkActivityTest.kt
index 526ec9d..df0a2cc 100644
--- a/tests/unit/java/com/android/server/connectivityservice/CSNetworkActivityTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/CSNetworkActivityTest.kt
@@ -63,6 +63,7 @@
 private const val PACKAGE_UID = 123
 private const val TIMEOUT_MS = 250L
 
+@DevSdkIgnoreRunner.MonitorThreadLeak
 @RunWith(DevSdkIgnoreRunner::class)
 @SmallTest
 @IgnoreUpTo(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
diff --git a/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt b/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt
index 958c4f2..7abeee4 100644
--- a/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt
@@ -69,6 +69,7 @@
 import java.util.concurrent.Executors
 import kotlin.test.assertNull
 import kotlin.test.fail
+import org.junit.After
 import org.mockito.AdditionalAnswers.delegatesTo
 import org.mockito.Mockito.doAnswer
 import org.mockito.Mockito.doReturn
@@ -158,7 +159,8 @@
     val bpfNetMaps = mock<BpfNetMaps>()
     val clatCoordinator = mock<ClatCoordinator>()
     val proxyTracker = ProxyTracker(context, mock<Handler>(), 16 /* EVENT_PROXY_HAS_CHANGED */)
-    val alarmManager = makeMockAlarmManager()
+    val alrmHandlerThread = HandlerThread("TestAlarmManager").also { it.start() }
+    val alarmManager = makeMockAlarmManager(alrmHandlerThread)
     val systemConfigManager = makeMockSystemConfigManager()
     val batteryStats = mock<IBatteryStats>()
     val batteryManager = BatteryStatsManager(batteryStats)
@@ -171,6 +173,14 @@
     val cm = ConnectivityManager(context, service)
     val csHandler = Handler(csHandlerThread.looper)
 
+    @After
+    fun tearDown() {
+        csHandlerThread.quitSafely()
+        csHandlerThread.join()
+        alrmHandlerThread.quitSafely()
+        alrmHandlerThread.join()
+    }
+
     inner class CSDeps : ConnectivityService.Dependencies() {
         override fun getResources(ctx: Context) = connResources
         override fun getBpfNetMaps(context: Context, netd: INetd) = this@CSTest.bpfNetMaps
diff --git a/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt b/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt
index c1828b2..8ff790c 100644
--- a/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt
@@ -53,6 +53,7 @@
 import com.android.modules.utils.build.SdkLevel
 import com.android.server.ConnectivityService.Dependencies
 import com.android.server.connectivity.ConnectivityResources
+import kotlin.test.fail
 import org.mockito.ArgumentMatchers
 import org.mockito.ArgumentMatchers.any
 import org.mockito.ArgumentMatchers.anyInt
@@ -64,7 +65,6 @@
 import org.mockito.Mockito.doAnswer
 import org.mockito.Mockito.doNothing
 import org.mockito.Mockito.doReturn
-import kotlin.test.fail
 
 internal inline fun <reified T> mock() = Mockito.mock(T::class.java)
 internal inline fun <reified T> any() = any(T::class.java)
@@ -128,8 +128,8 @@
 }
 
 private val UNREASONABLY_LONG_ALARM_WAIT_MS = 1000
-internal fun makeMockAlarmManager() = mock<AlarmManager>().also { am ->
-    val alrmHdlr = HandlerThread("TestAlarmManager").also { it.start() }.threadHandler
+internal fun makeMockAlarmManager(handlerThread: HandlerThread) = mock<AlarmManager>().also { am ->
+    val alrmHdlr = handlerThread.threadHandler
     doAnswer {
         val (_, date, _, wakeupMsg, handler) = it.arguments
         wakeupMsg as WakeupMessage