Jeroen Meulemeester fd8c05846f Added tests for thread-pool pattern
Fixed concurrency problem in id generation of Task
2015-12-30 20:55:22 +01:00

121 lines
3.2 KiB
Java

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