Merge "Flake fix : Wait setting applied before returning from setConfig"

tests/cts/net/src/android/net/cts/NetworkValidationTestUtil.kt

@@ -19,12 +19,20 @@ package android.net.cts
 import android.Manifest
 import android.net.util.NetworkStackUtils
 import android.provider.DeviceConfig
+import android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY
+import android.util.Log
 import com.android.testutils.runAsShell
+import com.android.testutils.tryTest
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.Executor
+import java.util.concurrent.TimeUnit
 
 /**
  * Collection of utility methods for configuring network validation.
  */
 internal object NetworkValidationTestUtil {
+    val TAG = NetworkValidationTestUtil::class.simpleName
+    const val TIMEOUT_MS = 20_000L
 
     /**
      * Clear the test network validation URLs.
@@ -59,10 +67,52 @@ internal object NetworkValidationTestUtil {
     @JvmStatic fun setUrlExpirationDeviceConfig(timestamp: Long?) =
             setConfig(NetworkStackUtils.TEST_URL_EXPIRATION_TIME, timestamp?.toString())
 
-    private fun setConfig(configKey: String, value: String?) {
-        runAsShell(Manifest.permission.WRITE_DEVICE_CONFIG) {
-            DeviceConfig.setProperty(
-                    DeviceConfig.NAMESPACE_CONNECTIVITY, configKey, value, false /* makeDefault */)
+    private fun setConfig(configKey: String, value: String?): String? {
+        Log.i(TAG, "Setting config \"$configKey\" to \"$value\"")
+        val readWritePermissions = arrayOf(
+                Manifest.permission.READ_DEVICE_CONFIG,
+                Manifest.permission.WRITE_DEVICE_CONFIG)
+
+        val existingValue = runAsShell(*readWritePermissions) {
+            DeviceConfig.getProperty(NAMESPACE_CONNECTIVITY, configKey)
+        }
+        if (existingValue == value) {
+            // Already the correct value. There may be a race if a change is already in flight,
+            // but if multiple threads update the config there is no way to fix that anyway.
+            Log.i(TAG, "\$configKey\" already had value \"$value\"")
+            return value
+        }
+
+        val future = CompletableFuture<String>()
+        val listener = DeviceConfig.OnPropertiesChangedListener {
+            // The listener receives updates for any change to any key, so don't react to
+            // changes that do not affect the relevant key
+            if (!it.keyset.contains(configKey)) return@OnPropertiesChangedListener
+            if (it.getString(configKey, null) == value) {
+                future.complete(value)
+            }
+        }
+
+        return tryTest {
+            runAsShell(*readWritePermissions) {
+                DeviceConfig.addOnPropertiesChangedListener(
+                        NAMESPACE_CONNECTIVITY,
+                        inlineExecutor,
+                        listener)
+                DeviceConfig.setProperty(
+                        NAMESPACE_CONNECTIVITY,
+                        configKey,
+                        value,
+                        false /* makeDefault */)
+                // Don't drop the permission until the config is applied, just in case
+                future.get(TIMEOUT_MS, TimeUnit.MILLISECONDS)
+            }.also {
+                Log.i(TAG, "Config \"$configKey\" successfully set to \"$value\"")
+            }
+        } cleanup {
+            DeviceConfig.removeOnPropertiesChangedListener(listener)
         }
     }
+
+    private val inlineExecutor get() = Executor { r -> r.run() }
 }

tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java

@@ -476,6 +476,7 @@ public final class CtsNetUtils {
         NetworkCallback callback = new NetworkCallback() {
             @Override
             public void onLinkPropertiesChanged(Network n, LinkProperties lp) {
+                Log.i(TAG, "Link properties of network " + n + " changed to " + lp);
                 if (requiresValidatedServer && lp.getValidatedPrivateDnsServers().isEmpty()) {
                     return;
                 }