diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index 01ffb03..ea4d82a 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -97,12 +97,14 @@
 import static android.system.OsConstants.ETH_P_ALL;
 import static android.system.OsConstants.IPPROTO_TCP;
 import static android.system.OsConstants.IPPROTO_UDP;
+
 import static com.android.net.module.util.NetworkMonitorUtils.isPrivateDnsValidationRequired;
 import static com.android.net.module.util.PermissionUtils.checkAnyPermissionOf;
 import static com.android.net.module.util.PermissionUtils.enforceAnyPermissionOf;
 import static com.android.net.module.util.PermissionUtils.enforceNetworkStackPermission;
 import static com.android.net.module.util.PermissionUtils.enforceNetworkStackPermissionOr;
 import static com.android.server.ConnectivityStatsLog.CONNECTIVITY_STATE_SAMPLE;
+
 import static java.util.Map.Entry;
 
 import android.Manifest;
@@ -1315,6 +1317,10 @@
             return SdkLevel.isAtLeastU();
         }
 
+        public boolean isAtLeastV() {
+            return SdkLevel.isAtLeastV();
+        }
+
         /**
          * Get system properties to use in ConnectivityService.
          */
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 94242b1..6f9cd07 100644
--- a/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/base/CSTest.kt
@@ -26,19 +26,14 @@
 import android.net.ConnectivityManager
 import android.net.INetd
 import android.net.InetAddresses
-import android.net.IpPrefix
-import android.net.LinkAddress
 import android.net.LinkProperties
 import android.net.NetworkAgentConfig
 import android.net.NetworkCapabilities
-import android.net.NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING
 import android.net.NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED
-import android.net.NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED
 import android.net.NetworkPolicyManager
 import android.net.NetworkProvider
 import android.net.NetworkScore
 import android.net.PacProxyManager
-import android.net.RouteInfo
 import android.net.networkstack.NetworkStackClientBase
 import android.os.BatteryStatsManager
 import android.os.Handler
@@ -76,6 +71,14 @@
 
 open class FromS<Type>(val value: Type)
 
+internal const val VERSION_UNMOCKED = -1
+internal const val VERSION_R = 1
+internal const val VERSION_S = 2
+internal const val VERSION_T = 3
+internal const val VERSION_U = 4
+internal const val VERSION_V = 5
+internal const val VERSION_MAX = VERSION_V
+
 /**
  * Base class for tests testing ConnectivityService and its satellites.
  *
@@ -193,6 +196,24 @@
                 changeId in enabledChangeIds
         override fun isChangeEnabled(changeId: Long, uid: Int) =
                 changeId in enabledChangeIds
+
+        // In AOSP, build version codes are all over the place (e.g. at the time of this writing
+        // U == V). Define custom ones.
+        private var sdkLevel = VERSION_UNMOCKED
+        private val isSdkUnmocked get() = sdkLevel == VERSION_UNMOCKED
+
+        fun setBuildSdk(sdkLevel: Int) {
+            require(sdkLevel <= VERSION_MAX) {
+                "setBuildSdk must not be called with Build.VERSION constants but " +
+                        "CsTest.VERSION_* constants"
+            }
+            visibleOnHandlerThread(csHandler) { this.sdkLevel = sdkLevel }
+        }
+
+        override fun isAtLeastS() = if (isSdkUnmocked) super.isAtLeastS() else sdkLevel >= VERSION_S
+        override fun isAtLeastT() = if (isSdkUnmocked) super.isAtLeastT() else sdkLevel >= VERSION_T
+        override fun isAtLeastU() = if (isSdkUnmocked) super.isAtLeastU() else sdkLevel >= VERSION_U
+        override fun isAtLeastV() = if (isSdkUnmocked) super.isAtLeastV() else sdkLevel >= VERSION_V
     }
 
     inner class CSContext(base: Context) : BroadcastInterceptingContext(base) {
@@ -248,19 +269,6 @@
     // Utility methods for subclasses to use
     fun waitForIdle() = csHandlerThread.waitForIdle(HANDLER_TIMEOUT_MS)
 
-    private fun emptyAgentConfig() = NetworkAgentConfig.Builder().build()
-    private fun defaultNc() = NetworkCapabilities.Builder()
-            // Add sensible defaults for agents that don't want to care
-            .addCapability(NET_CAPABILITY_NOT_SUSPENDED)
-            .addCapability(NET_CAPABILITY_NOT_ROAMING)
-            .addCapability(NET_CAPABILITY_NOT_VCN_MANAGED)
-            .build()
-    private fun defaultScore() = FromS<NetworkScore>(NetworkScore.Builder().build())
-    private fun defaultLp() = LinkProperties().apply {
-        addLinkAddress(LinkAddress(LOCAL_IPV4_ADDRESS, 32))
-        addRoute(RouteInfo(IpPrefix("0.0.0.0/0"), null, null))
-    }
-
     // Network agents. See CSAgentWrapper. This class contains utility methods to simplify
     // creation.
     fun Agent(
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 716d257..2d8607b 100644
--- a/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt
+++ b/tests/unit/java/com/android/server/connectivityservice/base/CSTestHelpers.kt
@@ -30,6 +30,13 @@
 import android.content.res.Resources
 import android.net.IDnsResolver
 import android.net.INetd
+import android.net.IpPrefix
+import android.net.LinkAddress
+import android.net.LinkProperties
+import android.net.NetworkAgentConfig
+import android.net.NetworkCapabilities
+import android.net.NetworkScore
+import android.net.RouteInfo
 import android.net.metrics.IpConnectivityLog
 import android.os.Handler
 import android.os.HandlerThread
@@ -60,6 +67,22 @@
 internal inline fun <reified T> mock() = Mockito.mock(T::class.java)
 internal inline fun <reified T> any() = any(T::class.java)
 
+internal fun emptyAgentConfig() = NetworkAgentConfig.Builder().build()
+
+internal fun defaultNc() = NetworkCapabilities.Builder()
+        // Add sensible defaults for agents that don't want to care
+        .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED)
+        .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING)
+        .addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_VCN_MANAGED)
+        .build()
+
+internal fun defaultScore() = FromS(NetworkScore.Builder().build())
+
+internal fun defaultLp() = LinkProperties().apply {
+    addLinkAddress(LinkAddress(LOCAL_IPV4_ADDRESS, 32))
+    addRoute(RouteInfo(IpPrefix("0.0.0.0/0"), null, null))
+}
+
 internal fun makeMockContentResolver(context: Context) = MockContentResolver(context).apply {
     addProvider(Settings.AUTHORITY, FakeSettingsProvider())
 }