public virtual void TestEmptyArraySort()
{
#if FEATURE_ARRAYEMPTY
int[] a = Array.Empty <int>();
#else
int[] a = new int[0];
#endif
ArrayUtil.IntroSort(a);
ArrayUtil.TimSort(a);
ArrayUtil.IntroSort(a, Collections.ReverseOrder <int>());
ArrayUtil.TimSort(a, Collections.ReverseOrder <int>());
}
public virtual void TestTimSortStability()
{
Random rnd = Random;
Item[] items = new Item[100];
for (int i = 0; i < items.Length; i++)
{
// half of the items have value but same order. The value of this items is sorted,
// so they should always be in order after sorting.
// The other half has defined order, but no (-1) value (they should appear after
// all above, when sorted).
bool equal = rnd.NextBoolean();
items[i] = new Item(equal ? (i + 1) : -1, equal ? 0 : (rnd.Next(1000) + 1));
}
if (VERBOSE)
{
Console.WriteLine("Before: " + Arrays.ToString(items));
}
// if you replace this with ArrayUtil.quickSort(), test should fail:
ArrayUtil.TimSort(items);
if (VERBOSE)
{
Console.WriteLine("Sorted: " + Arrays.ToString(items));
}
Item last = items[0];
for (int i = 1; i < items.Length; i++)
{
Item act = items[i];
if (act.Order == 0)
{
// order of "equal" items should be not mixed up
Assert.IsTrue(act.Val > last.Val);
}
Assert.IsTrue(act.Order >= last.Order);
last = act;
}
}
public virtual void TestTimSort()
{
int num = AtLeast(50);
for (int i = 0; i < num; i++)
{
int[] a1 = CreateRandomArray(2000), a2 = (int[])a1.Clone();
ArrayUtil.TimSort(a1);
Array.Sort(a2);
Assert.AreEqual(a2, a1);
a1 = CreateRandomArray(2000);
a2 = (int[])a1.Clone();
ArrayUtil.TimSort(a1, Collections.ReverseOrder <int>());
Array.Sort(a2, Collections.ReverseOrder <int>());
Assert.AreEqual(a2, a1);
// reverse back, so we can test that completely backwards sorted array (worst case) is working:
ArrayUtil.TimSort(a1);
Array.Sort(a2);
Assert.AreEqual(a2, a1);
}
}