public void DoNotSelectFirstCandidateWhenHasZeroAptitudeEvenWithZeroRouletteValue()
{
var itemSelector = new RouletteWheel();
var array = new Single[] { 0F, 1F, 1F, 1F, 1F };
var selected = itemSelector.SelectItem(array, 0F);
Assert.That(selected, Is.Not.EqualTo(0));
}
public void SelectFourthItemWhenRouletteFallsOnTheLeftBoundaryOfTheFourthSector()
{
var itemSelector = new RouletteWheel();
var array = new Single[] { 1F, 1F, 0.1F, 1F, 1F };
//third/fourth boundary is 2.1 / 4.1 = 0.5121951
int?selItem = itemSelector.SelectItem(array, .5122F);
Assert.That(selItem, Is.EqualTo(3));
}
public void SelectThirdItemWhenRouletteFallsOnTheLeftBoundaryOfTheThirdSector()
{
var itemSelector = new RouletteWheel();
var array = new Single[] { 1F, 1F, 0.1F, 1F, 1F };
//second/third boundary is 2 / 4.1 = 0.4878048
int?selItem = itemSelector.SelectItem(array, .4879F);
Assert.That(selItem, Is.EqualTo(2));
}
public void ShouldSelectAnItem()
{
var itemSelector = new RouletteWheel();
var array = new Single[1 + rnd.Next(10)];
for (int i = 0; i < array.Length; i++)
{
array[i] = 1F;
}
var rouletteValue = (float)rnd.NextDouble();
int?selItem = itemSelector.SelectItem(array, rouletteValue);
Assert.That(selItem, Is.GreaterThanOrEqualTo(0).And.LessThanOrEqualTo(array.Length));
}
public void SelectionGivesLastElementWhenRouletteValueIsGreaterThanOne()
{
var itemSelector = new RouletteWheel();
var elems = rnd.Next(100) + 2;
var array = new Single[elems];
for (int i = 0; i < elems; i++)
{
array[i] = 1F;
}
var selected = itemSelector.SelectItem(array, 1.0001F);
Assert.That(selected, Is.EqualTo(elems - 1));
}
public void ShouldSelectNoItemsWhenAptitudeAreAllZero()
{
var itemSelector = new RouletteWheel();
var array = new Single[1 + rnd.Next(10)];
for (int i = 0; i < array.Length; i++)
{
array[i] = 0F;
}
var rouletteValue = (float)rnd.NextDouble();
int?selItem = itemSelector.SelectItem(array, rouletteValue);
Assert.That(selItem, Is.Null);
}
public void ShouldSelectTheOnlyItemWithNonZeroAptitude()
{
var itemSelector = new RouletteWheel();
var array = new Single[1 + rnd.Next(10)];
for (int i = 0; i < array.Length; i++)
{
array[i] = 0F;
}
var nonZeroItemIndex = rnd.Next(array.Length);
array[nonZeroItemIndex] = 1F;
var rouletteValue = (float)rnd.NextDouble();
int?selItem = itemSelector.SelectItem(array, rouletteValue);
Assert.That(selItem, Is.EqualTo(nonZeroItemIndex));
}
public void ShouldNotSelectAnItemWithZeroAptitude()
{
var itemSelector = new RouletteWheel();
var array = new Single[2 + rnd.Next(10)];
for (int i = 0; i < array.Length; i++)
{
array[i] = 1F;
}
var zeroItemIndex = rnd.Next(array.Length);
array[zeroItemIndex] = 0F;
var rouletteValue = (float)rnd.NextDouble();
int?selItem = itemSelector.SelectItem(array, rouletteValue);
Assert.That(selItem,
Is.GreaterThanOrEqualTo(0)
.And
.LessThanOrEqualTo(array.Length)
.And.Not.EqualTo(zeroItemIndex));
}