public IEnumerable <T> Shuffle <T>(IEnumerable <T> items)
{
IEnumerable <T> ret;
int shuffleIndicesCount = _shuffleIndices.Count;
if (shuffleIndicesCount == 0)
{
ret = _realChanceService.Shuffle(items);
}
else
{
List <T> retList = new List <T>();
List <T> itemList = items.ToList();
for (var i = 0; i < shuffleIndicesCount; ++i)
{
int selectedIndex = _shuffleIndices[i];
retList.Add(itemList[selectedIndex]);
}
ret = retList;
}
return(ret);
}
public void ShuffleMethod([Values(50, 100, 500)] int numberItems)
{
List <int> preShuffledNumbers = new List <int>();
for (var i = 0; i < numberItems; ++i)
{
preShuffledNumbers.Add(i);
}
List <int> shuffledNumbers = _chanceService.Shuffle(preShuffledNumbers).ToList();
Assert.AreEqual(preShuffledNumbers.Count, shuffledNumbers.Count);
Assert.AreEqual(numberItems, shuffledNumbers.Count);
//Assert original list unaffected
for (var i = 0; i < numberItems; ++i)
{
Assert.AreEqual(i, preShuffledNumbers[i]);
}
int numberDifferent = 0;
int index = 0;
preShuffledNumbers.ForEach(number =>
{
//make sure no elements were duplicated/lost during the shuffle
Assert.Contains(number, shuffledNumbers);
if (index != shuffledNumbers.IndexOf(number))
{
++numberDifferent;
}
++index;
});
Assert.True(numberDifferent > 0, "chances are at least one number is not in the same index as the other.");
}