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 17 package androidx.arch.core.executor.testing; 18 19 import androidx.arch.core.executor.ArchTaskExecutor; 20 import androidx.arch.core.executor.TaskExecutor; 21 22 import org.jspecify.annotations.NonNull; 23 import org.junit.rules.TestWatcher; 24 import org.junit.runner.Description; 25 26 /** 27 * A JUnit Test Rule that swaps the background executor used by the Architecture Components with a 28 * different one which executes each task synchronously. 29 * <p> 30 * You can use this rule for your host side tests that use Architecture Components. 31 */ 32 public class InstantTaskExecutorRule extends TestWatcher { 33 @Override starting(Description description)34 protected void starting(Description description) { 35 super.starting(description); 36 ArchTaskExecutor.getInstance().setDelegate(new TaskExecutor() { 37 @Override 38 public void executeOnDiskIO(@NonNull Runnable runnable) { 39 runnable.run(); 40 } 41 42 @Override 43 public void postToMainThread(@NonNull Runnable runnable) { 44 runnable.run(); 45 } 46 47 @Override 48 public boolean isMainThread() { 49 return true; 50 } 51 }); 52 } 53 54 @Override finished(Description description)55 protected void finished(Description description) { 56 super.finished(description); 57 ArchTaskExecutor.getInstance().setDelegate(null); 58 } 59 } 60