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 * SciJava library facilitating consistent parallel processing.
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package org.scijava.concurrent;

import org.junit.jupiter.api.Test;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.atomic.AtomicInteger;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assumptions.assumeTrue;

/**
 * Tests {@link Parallelization}.
 *
 * @author Matthias Arzt
 */
public class ParallelizationTest {

	@Test
	public void testSingleThreaded() {
		int parallelism = Parallelization.runSingleThreaded(() -> Parallelization
			.getTaskExecutor().getParallelism());
		assertEquals(1, parallelism);
	}

	@Test
	public void testSingleThreadedWithRunnable() {
		AtomicInteger parallelism = new AtomicInteger();
		Parallelization.runSingleThreaded(() -> parallelism.set(Parallelization
			.getTaskExecutor().getParallelism()));
		assertEquals(1, parallelism.get());
	}

	@Test
	public void testMultiThreaded() {
		assumeTrue(ForkJoinPool.commonPool().getParallelism() > 1);
		int parallelism = Parallelization.runMultiThreaded(() -> Parallelization
			.getTaskExecutor().getParallelism());
		assertTrue(parallelism > 1);
	}

	@Test
	public void testWithExecutor() {
		ExecutorService executor = Executors.newFixedThreadPool(2);
		ExecutorService result = Parallelization.runWithExecutor(executor,
			() -> Parallelization.getTaskExecutor().getExecutorService());
		assertEquals(executor, result);
	}

	@Test
	public void testSetExecutorService() {
		TaskExecutor outside = Parallelization.getTaskExecutor();
		TaskExecutor inside = TaskExecutors.forExecutorService(
			new TaskExecutors.SequentialExecutorService());
		try (Parallelization.Frame frame = Parallelization.setExecutorRequiresReset(
			inside))
		{
			assertSame(inside, Parallelization.getTaskExecutor());
		}
		assertSame(outside, Parallelization.getTaskExecutor());
	}
}
