@Test
	public void testNegative() {
	  int[] a = {-42, -2, -12};
	  Queue<Integer>[] buckets = Solution.fillBuckets(a);

	  // Check a has not been changed.
		Assert.assertEquals(-42, a[0]);
		Assert.assertEquals(-2, a[1]);
		Assert.assertEquals(-12, a[2]);

		// Check one bucket has been created
		Assert.assertEquals(41, buckets.length);
		Assert.assertEquals(new Integer(-42), buckets[0].poll());
		Assert.assertEquals(new Integer(-2), buckets[40].poll());
		Assert.assertEquals(new Integer(-12), buckets[30].poll());
	}