1/* 2 * Copyright (C) 2017 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 17package androidx.arch.core.executor.testing; 18 19import androidx.arch.core.executor.ArchTaskExecutor; 20import androidx.arch.core.executor.TaskExecutor; 21 22import org.junit.rules.TestWatcher; 23import org.junit.runner.Description; 24 25/** 26 * A JUnit Test Rule that swaps the background executor used by the Architecture Components with a 27 * different one which executes each task synchronously. 28 * <p> 29 * You can use this rule for your host side tests that use Architecture Components. 30 */ 31public class InstantTaskExecutorRule extends TestWatcher { 32 @Override 33 protected void starting(Description description) { 34 super.starting(description); 35 ArchTaskExecutor.getInstance().setDelegate(new TaskExecutor() { 36 @Override 37 public void executeOnDiskIO(Runnable runnable) { 38 runnable.run(); 39 } 40 41 @Override 42 public void postToMainThread(Runnable runnable) { 43 runnable.run(); 44 } 45 46 @Override 47 public boolean isMainThread() { 48 return true; 49 } 50 }); 51 } 52 53 @Override 54 protected void finished(Description description) { 55 super.finished(description); 56 ArchTaskExecutor.getInstance().setDelegate(null); 57 } 58} 59