public void Conservative_Rating_Equation_Outputs_Expected(double mean, double sd, double conservativeMultiplier)
{
// Copied from TrueSkillEngine.GetConservativeRating()
var expectedConservativeRating = mean - conservativeMultiplier * sd;
var trueSkillEngine = new TwoPlayerTrueSkillEngine(initialMean: mean, initialStandardDeviation: sd, conservativeRatingMultiplier: conservativeMultiplier);
trueSkillEngine.GetConservativeRating(trueSkillEngine.GetDefaultRating()).Should().Be(expectedConservativeRating, "The conservative rating is calculated using the given formula, so it should match when using the given values.");
}
public void Default_Rating_Should_Have_Expected_Default_Values(double initialMean, double initialSd, double conservativeMultiplier)
{
// Arrange
var trueSkillEngine = new TwoPlayerTrueSkillEngine(initialMean, initialSd, conservativeMultiplier);
// Act
var rating = trueSkillEngine.GetDefaultRating();
// Assert
rating.StandardDeviation.Should().Be(initialSd, "The default rating should have the given initial standard deviation");
rating.Mean.Should().Be(initialMean, "The default rating should have the given initial mean");
}
public void Losers_Rating_Should_Decrease(Rating winner, Rating loser)
{
// Arrange
var trueSkillEngine = new TwoPlayerTrueSkillEngine();
var loserInitialValue = new Rating(loser.Mean, loser.StandardDeviation);
// Act
trueSkillEngine.UpdateRatings(winner, loser);
// Assert
loser.Mean.Should().BeLessThan(loserInitialValue.Mean, "The loser's mean should have decreased due to losing a match.");
loser.StandardDeviation.Should().BeLessThan(loserInitialValue.StandardDeviation, "The loser's standard deviation should have decreased due to having played more matches.");
}
public void Winners_Rating_Should_Increase(Rating winner, Rating loser)
{
// Arrange
var trueSkillEngine = new TwoPlayerTrueSkillEngine();
var winnerInitialValue = new Rating(winner.Mean, winner.StandardDeviation);
// Act
trueSkillEngine.UpdateRatings(winner, loser);
// Assert
winner.Mean.Should().BeGreaterThan(winnerInitialValue.Mean, "The winner's mean should have increased due to winning a match");
winner.StandardDeviation.Should().BeLessThan(winnerInitialValue.StandardDeviation, "The winner's standard deviation should have decreased due to having played more matches");
}
public void Should_Update_Both_Ratings(Rating winner, Rating loser)
{
// Arrange
var trueSkillEngine = new TwoPlayerTrueSkillEngine();
var winnerInitialValue = new Rating(winner.Mean, winner.StandardDeviation);
var loserInitialValue = new Rating(loser.Mean, loser.StandardDeviation);
// Act
trueSkillEngine.UpdateRatings(winner, loser);
// Assert
winner.Should().NotBeEquivalentTo(winnerInitialValue, "Update ratings should update both the winner's mean and standard deviation");
loser.Should().NotBeEquivalentTo(loserInitialValue, "Update ratings should update both the loser's mean and standard deviation");
}