1 /* 2 * Copyright (c) 2018 Mockito contributors 3 * This program is made available under the terms of the MIT License. 4 */ 5 package org.mockitoutil.async; 6 7 import java.util.LinkedList; 8 9 /** 10 * Streamlines testing async code for Mockito tests. 11 * 12 * Instances of this class are NOT thread safe (intentionally, they are not required to be thread safe) 13 * 14 * //TODO convert to test rule 15 */ 16 public class AsyncTesting { 17 18 //Sanity limit of threas. Increase it if justified. 19 private final static int MAX_THREADS = 4; 20 21 private final LinkedList<Exception> problems = new LinkedList<Exception>(); 22 private final LinkedList<Thread> threads = new LinkedList<Thread>(); 23 private boolean stopping; 24 25 /** 26 * Schedules execution of runnable with some delay. 27 * Starts thread immediately and returns. 28 * The thread will execute the runnable after given delay in millis. 29 * 30 * @param delayMillis - the delay in millis 31 * @param runnable - to be executed in a thread after delay 32 */ runAfter(final int delayMillis, final Runnable runnable)33 public void runAfter(final int delayMillis, final Runnable runnable) { 34 if (threads.size() == MAX_THREADS) { 35 throw new RuntimeException("Please don't schedule any more threads. Figure out how to test the code with minimum amount of threads"); 36 } 37 Thread t = new Thread() { 38 public void run() { 39 try { 40 Thread.sleep(delayMillis); 41 runnable.run(); 42 } catch (Exception e) { 43 boolean cleanStop = e instanceof InterruptedException && stopping; 44 if (!cleanStop) { 45 problems.add(e); 46 } 47 } 48 } 49 }; 50 System.out.println("[AsyncTesting] Starting thread that will execute the runnable after " + delayMillis + " millis. Threads so far: " + threads.size()); 51 threads.add(t); 52 t.start(); 53 } 54 55 /** 56 * Interrupts and waits for all threads to complete (using 'join()'). 57 * Rethrows exceptions accumulated by the execution of threads. 58 */ cleanUp()59 public void cleanUp() { 60 stopping = true; 61 System.out.println("[AsyncTesting] Interrupting and waiting for " + threads.size() + " threads to complete..."); 62 while(!threads.isEmpty()) { 63 Thread t = threads.removeFirst(); 64 try { 65 t.interrupt(); 66 t.join(); 67 } catch (InterruptedException e) { 68 throw new RuntimeException(e); 69 } 70 } 71 if (!problems.isEmpty()) { 72 throw new RuntimeException("Caught " + problems.size() + " exception(s). First one is included as cause", problems.getFirst()); 73 } 74 } 75 } 76