public void _08_NextBalloonFromArray_ShouldReturnRandomItemFromBalloonArray()
{
AssertNextBalloonFromArrayMethodIsDefinedCorrectly();
int numberOfBalloons = 10000;
Balloon[] allBalloons = new Balloon[numberOfBalloons];
for (int i = 0; i < numberOfBalloons; i++)
{
allBalloons[i] = new Balloon(Color.Red, 10);
}
var pickedBalloons = new HashSet <Balloon>();
int numberOfPicks = 100;
int numberOfDuplicatePicks = 0;
for (int i = 0; i < numberOfPicks; i++)
{
Balloon balloon = InvokeNextBalloonFromArray(allBalloons);
Assert.That(balloon, Is.Not.Null, "The returned balloon cannot be null");
Assert.That(allBalloons.Any(b => b == balloon), Is.True, "The returned balloon must be a balloon from the array.");
if (pickedBalloons.Contains(balloon))
{
numberOfDuplicatePicks++;
}
else
{
pickedBalloons.Add(balloon);
}
}
if (numberOfDuplicatePicks > numberOfPicks * 0.2) //20% duplicate picks on 10000 balloons is nearly impossible
{
Assert.Fail(
"The picking of a balloon seems not to be random. " +
$"{numberOfDuplicatePicks * 100.0 / numberOfPicks}% of {numberOfPicks} balloon picks " +
$"in a balloon array of size {numberOfBalloons} pick an already picked balloon");
}
}
