public async Task GivenMultipleCandidates_EachOneIsReturnedInStatisticallyEvenNumber()
{
// Arrange
const int warId = 987;
const int contestantCount = 10;
const int iterations = 100000;
const float lowerBoundPercentage = 0.9f;
const float upperBoundPercentage = 1.1f;
List <Contestant> contestants = CreateContestantsCollection(contestantCount);
SetupContestantRepository(warId, contestants);
var factory = new RandomMatchStrategy(_stubMatchRepository.Object, _stubContestantRepository.Object);
var matches = new List <MatchWithContestants>();
// Act
for (var i = 0; i < iterations; i++)
{
var match = await factory.Create(warId, _userId);
matches.Add(match);
}
// Assert
var groupedByContestant1 = matches.GroupBy(x => x.Contestant1.Id);
foreach (var g in groupedByContestant1)
{
const float expectedCount = (iterations / contestantCount);
var actualCount = (float)g.Count();
actualCount.Should().BeInRange(expectedCount * lowerBoundPercentage, expectedCount * upperBoundPercentage);
float expectedRivalCounts = actualCount / (contestantCount - 1);
var groupedByContestant2 = g.GroupBy(x => x.Contestant2.Id);
groupedByContestant2.Select(x => (float)x.Count()).Should().OnlyContain(x => x >= expectedRivalCounts * lowerBoundPercentage && x <= expectedRivalCounts * upperBoundPercentage);
}
}
public void InitializeTests()
{
_userId = new UserIdentifier();
_contestant1 = new Contestant {
Id = Guid.NewGuid()
};
_contestant2 = new Contestant {
Id = Guid.NewGuid()
};
_matchId = Guid.NewGuid();
_stubContestantRepository = new Mock <IContestantRepository>();
_stubContestantRepository.Setup(x => x.GetCount(WarId)).Returns(Task.FromResult(ContestantCount));
_stubMatchRepository = new Mock <IMatchRepository>();
_stubMatchRepository.Setup(x => x.Create(WarId,
It.Is <MatchRequest>(m => m.Contestant1 == _contestant1.Id &&
m.Contestant2 == _contestant2.Id &&
m.UserIdentifier == _userId)))
.Returns(Task.FromResult(_matchId));
randomNumbers = new Queue <int>();
_factory = new RandomMatchStrategy(_stubMatchRepository.Object, _stubContestantRepository.Object, GenerateRandomNumber);
}