add shuffle method

primitiveCollections/src/test/java/org/lucares/collections/IntListTest.java

@@ -7,6 +7,7 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Random;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.stream.Collectors;
@@ -488,8 +489,37 @@ public class IntListTest {
 		list.addAll(4, 2, 3, 1);
 		list.sort();
 
-		final int[] expectedE = new int[] { 1, 2, 3, 4 };
-		Assert.assertArrayEquals(expectedE, list.toArray());
+		final int[] expected = new int[] { 1, 2, 3, 4 };
+		Assert.assertArrayEquals(expected, list.toArray());
+	}
+
+	@Test
+	public void testSortParallel() {
+		final IntList list = new IntList();
+
+		list.addAll(4, 2, 3, 1);
+		list.parallelSort();
+
+		final int[] expected = new int[] { 1, 2, 3, 4 };
+		Assert.assertArrayEquals(expected, list.toArray());
+	}
+
+	@Test
+	public void testShuffle() {
+		final IntList list = IntList.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
+		final IntList original = list.clone();
+		final IntList original2 = list.clone();
+
+		final Random random = new Random(1);
+		list.shuffle(random);
+
+		Assert.assertEquals(original.size(), list.size());
+
+		original.removeAll(list);
+		Assert.assertTrue("original minus shuffled list: " + original, original.isEmpty());
+
+		list.removeAll(original2);
+		Assert.assertTrue("shuffled list minus original: " + list, list.isEmpty());
 	}
 
 	private int[] removeElements(final int[] data, final int... removedIndices) {