@Test
public void testConcat() {

  final byte[] left = randomUUID().toString().getBytes();
  final byte[] right = randomUUID().toString().getBytes();
  final byte[] concated = new byte[left.length + right.length];
  System.arraycopy(left, 0, concated, 0, left.length);
  System.arraycopy(right, 0, concated, left.length, right.length);
  assertTrue(Arrays.equals(left, ArrayUtils.concat(left, null)));
  assertTrue(Arrays.equals(right, ArrayUtils.concat(null, right)));
}