make IntList serializable

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

@@ -1,5 +1,10 @@
 package org.lucares.collections;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.ThreadLocalRandom;
@@ -413,4 +418,41 @@ public class IntListTest {
 
 		return result;
 	}
+
+	@Test
+	public void testSerialize() throws IOException, ClassNotFoundException {
+		final IntList emptyList = new IntList(0);
+		internalSerializeTest(emptyList);
+
+		final IntList emptyListWithCapacity = new IntList(10);
+		internalSerializeTest(emptyListWithCapacity);
+
+		final IntList threeElements = new IntList(10000);
+		threeElements.addAll(1, 2, 3);
+		internalSerializeTest(threeElements);
+
+		final IntList trimmedList = new IntList(10000);
+		trimmedList.addAll(1, 2, 3);
+		trimmedList.trim();
+		internalSerializeTest(trimmedList);
+	}
+
+	private void internalSerializeTest(final IntList list) throws IOException, ClassNotFoundException {
+		final ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();
+		try (final ObjectOutputStream out = new ObjectOutputStream(byteBuffer)) {
+			out.writeObject(list);
+		}
+
+		try (ByteArrayInputStream byteInputStream = new ByteArrayInputStream(byteBuffer.toByteArray());
+				ObjectInputStream in = new ObjectInputStream(byteInputStream)) {
+			final IntList actual = (IntList) in.readObject();
+
+			Assert.assertEquals(list, actual);
+
+			Assert.assertEquals(
+					"The capacity of the deserialized list. Should be equal to the number of inserted "
+							+ "values, because we don't want to serialize the unused part of the array",
+					list.size(), actual.getCapacity());
+		}
+	}
 }