Move DeviceConfigRule to libs/net

The utility can be useful for tests in various repositories, not only
CTS.

Test: m
Change-Id: I8d674f96994418717a3adf1454e44c868ce032b1
diff --git a/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt b/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
index aad8804..7c24c95 100644
--- a/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
+++ b/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
@@ -47,6 +47,7 @@
 import androidx.test.platform.app.InstrumentationRegistry.getInstrumentation
 import androidx.test.runner.AndroidJUnit4
 import com.android.modules.utils.build.SdkLevel.isAtLeastR
+import com.android.testutils.DeviceConfigRule
 import com.android.testutils.RecorderCallback
 import com.android.testutils.TestHttpServer
 import com.android.testutils.TestHttpServer.Request
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index c9899a2..f0a67d0 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -192,6 +192,7 @@
 import com.android.testutils.ConnectivityModuleTest;
 import com.android.testutils.DevSdkIgnoreRule;
 import com.android.testutils.DevSdkIgnoreRule.IgnoreUpTo;
+import com.android.testutils.DeviceConfigRule;
 import com.android.testutils.DeviceInfoUtils;
 import com.android.testutils.DumpTestUtils;
 import com.android.testutils.RecorderCallback.CallbackEntry;
diff --git a/tests/cts/net/src/android/net/cts/DeviceConfigRule.kt b/tests/cts/net/src/android/net/cts/DeviceConfigRule.kt
deleted file mode 100644
index 3a36cee..0000000
--- a/tests/cts/net/src/android/net/cts/DeviceConfigRule.kt
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright (C) 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package android.net.cts
-
-import android.Manifest.permission.READ_DEVICE_CONFIG
-import android.Manifest.permission.WRITE_DEVICE_CONFIG
-import android.provider.DeviceConfig
-import android.util.Log
-import com.android.modules.utils.build.SdkLevel
-import com.android.testutils.FunctionalUtils.ThrowingRunnable
-import com.android.testutils.runAsShell
-import com.android.testutils.tryTest
-import org.junit.rules.TestRule
-import org.junit.runner.Description
-import org.junit.runners.model.Statement
-import java.util.concurrent.CompletableFuture
-import java.util.concurrent.Executor
-import java.util.concurrent.TimeUnit
-
-private val TAG = DeviceConfigRule::class.simpleName
-
-/**
- * A [TestRule] that helps set [DeviceConfig] for tests and clean up the test configuration
- * automatically on teardown.
- *
- * The rule can also optionally retry tests when they fail following an external change of
- * DeviceConfig before S; this typically happens because device config flags are synced while the
- * test is running, and DisableConfigSyncTargetPreparer is only usable starting from S.
- *
- * @param retryCountBeforeSIfConfigChanged if > 0, when the test fails before S, check if
- *        the configs that were set through this rule were changed, and retry the test
- *        up to the specified number of times if yes.
- */
-class DeviceConfigRule @JvmOverloads constructor(
-    val retryCountBeforeSIfConfigChanged: Int = 0
-) : TestRule {
-    // Maps (namespace, key) -> value
-    private val originalConfig = mutableMapOf<Pair<String, String>, String?>()
-    private val usedConfig = mutableMapOf<Pair<String, String>, String?>()
-
-    /**
-     * Actions to be run after cleanup of the config, for the current test only.
-     */
-    private val currentTestCleanupActions = mutableListOf<ThrowingRunnable>()
-
-    override fun apply(base: Statement, description: Description): Statement {
-        return TestValidationUrlStatement(base, description)
-    }
-
-    private inner class TestValidationUrlStatement(
-        private val base: Statement,
-        private val description: Description
-    ) : Statement() {
-        override fun evaluate() {
-            var retryCount = if (SdkLevel.isAtLeastS()) 1 else retryCountBeforeSIfConfigChanged + 1
-            while (retryCount > 0) {
-                retryCount--
-                tryTest {
-                    base.evaluate()
-                    // Can't use break/return out of a loop here because this is a tryTest lambda,
-                    // so set retryCount to exit instead
-                    retryCount = 0
-                }.catch<Throwable> { e -> // junit AssertionFailedError does not extend Exception
-                    if (retryCount == 0) throw e
-                    usedConfig.forEach { (key, value) ->
-                        val currentValue = runAsShell(READ_DEVICE_CONFIG) {
-                            DeviceConfig.getProperty(key.first, key.second)
-                        }
-                        if (currentValue != value) {
-                            Log.w(TAG, "Test failed with unexpected device config change, retrying")
-                            return@catch
-                        }
-                    }
-                    throw e
-                } cleanupStep {
-                    runAsShell(WRITE_DEVICE_CONFIG) {
-                        originalConfig.forEach { (key, value) ->
-                            DeviceConfig.setProperty(
-                                    key.first, key.second, value, false /* makeDefault */)
-                        }
-                    }
-                } cleanupStep {
-                    originalConfig.clear()
-                    usedConfig.clear()
-                } cleanup {
-                    // Fold all cleanup actions into cleanup steps of an empty tryTest, so they are
-                    // all run even if exceptions are thrown, and exceptions are reported properly.
-                    currentTestCleanupActions.fold(tryTest { }) {
-                        tryBlock, action -> tryBlock.cleanupStep { action.run() }
-                    }.cleanup {
-                        currentTestCleanupActions.clear()
-                    }
-                }
-            }
-        }
-    }
-
-    /**
-     * Set a configuration key/value. After the test case ends, it will be restored to the value it
-     * had when this method was first called.
-     */
-    fun setConfig(namespace: String, key: String, value: String?): String? {
-        Log.i(TAG, "Setting config \"$key\" to \"$value\"")
-        val readWritePermissions = arrayOf(READ_DEVICE_CONFIG, WRITE_DEVICE_CONFIG)
-
-        val keyPair = Pair(namespace, key)
-        val existingValue = runAsShell(*readWritePermissions) {
-            DeviceConfig.getProperty(namespace, key)
-        }
-        if (!originalConfig.containsKey(keyPair)) {
-            originalConfig[keyPair] = existingValue
-        }
-        usedConfig[keyPair] = value
-        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, "\"$key\" already had value \"$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(key)) return@OnPropertiesChangedListener
-            // "null" means absent in DeviceConfig : there is no such thing as a present but
-            // null value, so the following works even if |value| is null.
-            if (it.getString(key, null) == value) {
-                future.complete(value)
-            }
-        }
-
-        return tryTest {
-            runAsShell(*readWritePermissions) {
-                DeviceConfig.addOnPropertiesChangedListener(
-                        DeviceConfig.NAMESPACE_CONNECTIVITY,
-                        inlineExecutor,
-                        listener)
-                DeviceConfig.setProperty(
-                        DeviceConfig.NAMESPACE_CONNECTIVITY,
-                        key,
-                        value,
-                        false /* makeDefault */)
-                // Don't drop the permission until the config is applied, just in case
-                future.get(NetworkValidationTestUtil.TIMEOUT_MS, TimeUnit.MILLISECONDS)
-            }.also {
-                Log.i(TAG, "Config \"$key\" successfully set to \"$value\"")
-            }
-        } cleanup {
-            DeviceConfig.removeOnPropertiesChangedListener(listener)
-        }
-    }
-
-    private val inlineExecutor get() = Executor { r -> r.run() }
-
-    /**
-     * Add an action to be run after config cleanup when the current test case ends.
-     */
-    fun runAfterNextCleanup(action: ThrowingRunnable) {
-        currentTestCleanupActions.add(action)
-    }
-}
diff --git a/tests/cts/net/src/android/net/cts/NetworkValidationTestUtil.kt b/tests/cts/net/src/android/net/cts/NetworkValidationTestUtil.kt
index 375bfb8..a0b40aa 100644
--- a/tests/cts/net/src/android/net/cts/NetworkValidationTestUtil.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkValidationTestUtil.kt
@@ -20,6 +20,7 @@
 import android.provider.DeviceConfig
 import android.provider.DeviceConfig.NAMESPACE_CONNECTIVITY
 import com.android.net.module.util.NetworkStackConstants
+import com.android.testutils.DeviceConfigRule
 import com.android.testutils.runAsShell
 
 /**
@@ -27,7 +28,6 @@
  */
 internal object NetworkValidationTestUtil {
     val TAG = NetworkValidationTestUtil::class.simpleName
-    const val TIMEOUT_MS = 20_000L
 
     /**
      * Clear the test network validation URLs.