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Added tests for thread-pool pattern
Fixed concurrency problem in id generation of Task
1 parent 47709e2 commit fd8c058

8 files changed

Lines changed: 198 additions & 5 deletions

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‎thread-pool/pom.xml‎

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<artifactId>junit</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.mockito</groupId>
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<artifactId>mockito-core</artifactId>
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<scope>test</scope>
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</dependency>
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</dependencies>
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</project>

‎thread-pool/src/main/java/com/iluwatar/threadpool/CoffeeMakingTask.java‎

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*/
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public class CoffeeMakingTask extends Task {
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private static final int TIME_PER_CUP = 300;
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private static final int TIME_PER_CUP = 100;
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public CoffeeMakingTask(int numCups) {
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super(numCups * TIME_PER_CUP);

‎thread-pool/src/main/java/com/iluwatar/threadpool/PotatoPeelingTask.java‎

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*/
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public class PotatoPeelingTask extends Task {
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private static final int TIME_PER_POTATO = 500;
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private static final int TIME_PER_POTATO = 200;
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public PotatoPeelingTask(int numPotatoes) {
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super(numPotatoes * TIME_PER_POTATO);

‎thread-pool/src/main/java/com/iluwatar/threadpool/Task.java‎

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package com.iluwatar.threadpool;
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import java.util.concurrent.atomic.AtomicInteger;
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/**
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*
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*
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* Abstract base class for tasks
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*
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*/
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public abstract class Task {
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private static int nextId = 1;
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private static final AtomicInteger ID_GENERATOR = new AtomicInteger();
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private final int id;
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private final int timeMs;
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public Task(final int timeMs) {
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this.id = nextId++;
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this.id = ID_GENERATOR.incrementAndGet();
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this.timeMs = timeMs;
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}
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‎thread-pool/src/test/java/com/iluwatar/threadpool/CoffeeMakingTaskTest.java‎

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package com.iluwatar.threadpool;
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/**
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* Date: 12/30/15 - 18:23 PM
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*
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* @author Jeroen Meulemeester
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*/
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public class CoffeeMakingTaskTest extends TaskTest<CoffeeMakingTask> {
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/**
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* Create a new test instance
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*/
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public CoffeeMakingTaskTest() {
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super(CoffeeMakingTask::new, 100);
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}
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}

‎thread-pool/src/test/java/com/iluwatar/threadpool/PotatoPeelingTaskTest.java‎

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package com.iluwatar.threadpool;
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/**
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* Date: 12/30/15 - 18:23 PM
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*
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* @author Jeroen Meulemeester
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*/
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public class PotatoPeelingTaskTest extends TaskTest<PotatoPeelingTask> {
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/**
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* Create a new test instance
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*/
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public PotatoPeelingTaskTest() {
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super(PotatoPeelingTask::new, 200);
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}
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}

‎thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java‎

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package com.iluwatar.threadpool;
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import org.junit.Test;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Objects;
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import java.util.concurrent.Callable;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.Future;
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import java.util.function.Function;
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import java.util.stream.Collectors;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertNotNull;
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/**
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* Date: 12/30/15 - 18:22 PM
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*
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* @author Jeroen Meulemeester
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*/
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public abstract class TaskTest<T extends Task> {
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/**
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* The number of tasks used during the concurrency test
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*/
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private static final int TASK_COUNT = 128 * 1024;
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/**
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* The number of threads used during the concurrency test
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*/
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private static final int THREAD_COUNT = 8;
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/**
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* The task factory, used to create new test items
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*/
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private final Function<Integer, T> factory;
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/**
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* The expected time needed to run the task 1 single time, in milli seconds
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*/
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private final int expectedExecutionTime;
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/**
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* Create a new test instance
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*
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* @param factory The task factory, used to create new test items
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* @param expectedExecutionTime The expected time needed to run the task 1 time, in milli seconds
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*/
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public TaskTest(final Function<Integer, T> factory, final int expectedExecutionTime) {
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this.factory = factory;
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this.expectedExecutionTime = expectedExecutionTime;
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}
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/**
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* Verify if the generated id is unique for each task, even if the tasks are created in separate
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* threads
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*/
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@Test(timeout = 10000)
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public void testIdGeneration() throws Exception {
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final ExecutorService service = Executors.newFixedThreadPool(THREAD_COUNT);
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final List<Callable<Integer>> tasks = new ArrayList<>();
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for (int i = 0; i < TASK_COUNT; i++) {
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tasks.add(() -> factory.apply(1).getId());
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}
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final List<Integer> ids = service.invokeAll(tasks)
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.stream()
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.map(TaskTest::get)
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.filter(Objects::nonNull)
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.collect(Collectors.toList());
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service.shutdownNow();
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final long uniqueIdCount = ids.stream()
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.distinct()
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.count();
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assertEquals(TASK_COUNT, ids.size());
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assertEquals(TASK_COUNT, uniqueIdCount);
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}
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/**
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* Verify if the time per execution of a task matches the actual time required to execute the task
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* a given number of times
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*/
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@Test
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public void testTimeMs() {
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for (int i = 0; i < 10; i++) {
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assertEquals(this.expectedExecutionTime * i, this.factory.apply(i).getTimeMs());
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}
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}
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/**
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* Verify if the task has some sort of {@link T#toString()}, different from 'null'
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*/
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@Test
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public void testToString() {
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assertNotNull(this.factory.apply(0).toString());
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}
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/**
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* Extract the result from a future or returns 'null' when an exception occurred
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*
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* @param future The future we want the result from
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* @param <O> The result type
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* @return The result or 'null' when a checked exception occurred
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*/
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private static <O> O get(Future<O> future) {
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try {
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return future.get();
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} catch (InterruptedException | ExecutionException e) {
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return null;
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}
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}
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}

‎thread-pool/src/test/java/com/iluwatar/threadpool/WorkerTest.java‎

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package com.iluwatar.threadpool;
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import org.junit.Test;
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import static org.mockito.Mockito.mock;
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import static org.mockito.Mockito.verify;
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import static org.mockito.Mockito.verifyNoMoreInteractions;
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import static org.mockito.Mockito.verifyZeroInteractions;
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/**
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* Date: 12/30/15 - 18:21 PM
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*
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* @author Jeroen Meulemeester
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*/
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public class WorkerTest {
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/**
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* Verify if a worker does the actual job
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*/
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@Test
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public void testRun() {
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final Task task = mock(Task.class);
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final Worker worker = new Worker(task);
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verifyZeroInteractions(task);
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worker.run();
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verify(task).getTimeMs();
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verifyNoMoreInteractions(task);
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}
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}

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