1 /* 2 * Copyright (C) 2023 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.internal.util.test; 18 19 import com.android.server.LocalServices; 20 21 import org.junit.rules.TestRule; 22 import org.junit.runner.Description; 23 import org.junit.runners.model.Statement; 24 25 import java.util.ArrayList; 26 import java.util.HashMap; 27 import java.util.List; 28 import java.util.Map; 29 30 /** 31 * JUnit Rule helps override /restore {@link LocalServices} state. 32 */ 33 public class LocalServiceKeeperRule implements TestRule { 34 35 private final Map<Class<?>, Object> mOverriddenServices = new HashMap<>(); 36 private final List<Class<?>> mAddedServices = new ArrayList<>(); 37 38 private volatile boolean mRuleApplied = false; 39 40 /** 41 * Overrides service in LocalServices. Service will be restored to original after test run. 42 */ overrideLocalService(Class<T> type, T service)43 public <T> void overrideLocalService(Class<T> type, T service) { 44 if (!mRuleApplied) { 45 throw new IllegalStateException("Can't override service without applying rule"); 46 } 47 if (mOverriddenServices.containsKey(type) || mAddedServices.contains(type)) { 48 throw new IllegalArgumentException("Type already overridden: " + type); 49 } 50 51 T currentService = LocalServices.getService(type); 52 if (currentService != null) { 53 mOverriddenServices.put(type, currentService); 54 LocalServices.removeServiceForTest(type); 55 } else { 56 mAddedServices.add(type); 57 } 58 LocalServices.addService(type, service); 59 } 60 61 @Override apply(Statement base, Description description)62 public Statement apply(Statement base, Description description) { 63 return new Statement() { 64 public void evaluate() throws Throwable { 65 try { 66 mRuleApplied = true; 67 base.evaluate(); 68 } finally { 69 mRuleApplied = false; 70 mAddedServices.forEach(LocalServices::removeServiceForTest); 71 mOverriddenServices.forEach((clazz, service) -> { 72 LocalServices.removeServiceForTest(clazz); 73 LocalServices.addService((Class) clazz, service); 74 }); 75 mAddedServices.clear(); 76 mOverriddenServices.clear(); 77 } 78 } 79 }; 80 } 81 } 82