DndCharacterTests.cs

public class DndCharacterTests
{
    [Fact]
    public void Ability_modifier_for_score_3_is_4()
    {
        Assert.Equal(-4, DndCharacter.Modifier(3));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_4_is_3()
    {
        Assert.Equal(-3, DndCharacter.Modifier(4));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_5_is_3()
    {
        Assert.Equal(-3, DndCharacter.Modifier(5));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_6_is_2()
    {
        Assert.Equal(-2, DndCharacter.Modifier(6));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_7_is_2()
    {
        Assert.Equal(-2, DndCharacter.Modifier(7));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_8_is_1()
    {
        Assert.Equal(-1, DndCharacter.Modifier(8));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_9_is_1()
    {
        Assert.Equal(-1, DndCharacter.Modifier(9));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_10_is_0()
    {
        Assert.Equal(0, DndCharacter.Modifier(10));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_11_is_0()
    {
        Assert.Equal(0, DndCharacter.Modifier(11));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_12_is_1()
    {
        Assert.Equal(1, DndCharacter.Modifier(12));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_13_is_1()
    {
        Assert.Equal(1, DndCharacter.Modifier(13));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_14_is_2()
    {
        Assert.Equal(2, DndCharacter.Modifier(14));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_15_is_2()
    {
        Assert.Equal(2, DndCharacter.Modifier(15));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_16_is_3()
    {
        Assert.Equal(3, DndCharacter.Modifier(16));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_17_is_3()
    {
        Assert.Equal(3, DndCharacter.Modifier(17));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Ability_modifier_for_score_18_is_4()
    {
        Assert.Equal(4, DndCharacter.Modifier(18));
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Random_ability_is_within_range()
    {
        for (var i = 0; i < 10; i++)
        {
            Assert.InRange(DndCharacter.Ability(), 3, 18);
        }
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Random_character_is_valid()
    {
        for (var i = 0; i < 10; i++)
        {
            var sut = DndCharacter.Generate();
            Assert.InRange(sut.Strength, 3, 18);
            Assert.InRange(sut.Dexterity, 3, 18);
            Assert.InRange(sut.Constitution, 3, 18);
            Assert.InRange(sut.Intelligence, 3, 18);
            Assert.InRange(sut.Wisdom, 3, 18);
            Assert.InRange(sut.Charisma, 3, 18);
            Assert.Equal(sut.Hitpoints, 10 + DndCharacter.Modifier(sut.Constitution));
        }
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Each_ability_is_only_calculated_once()
    {
        for (var i = 0; i < 10; i++)
        {
            var sut = DndCharacter.Generate();
            Assert.Equal(sut.Strength, sut.Strength);
            Assert.Equal(sut.Dexterity, sut.Dexterity);
            Assert.Equal(sut.Constitution, sut.Constitution);
            Assert.Equal(sut.Intelligence, sut.Intelligence);
            Assert.Equal(sut.Wisdom, sut.Wisdom);
            Assert.Equal(sut.Charisma, sut.Charisma);
        }
    }

    [Fact(Skip = "Remove this Skip property to run this test")]
    public void Random_ability_is_distributed_correctly()
    {
        var expectedDistribution = new Dictionary<int, int>
        {
            [3] = 1,
            [4] = 4,
            [5] = 10,
            [6] = 21,
            [7] = 38,
            [8] = 62,
            [9] = 91,
            [10] = 122,
            [11] = 148,
            [12] = 167,
            [13] = 172,
            [14] = 160,
            [15] = 131,
            [16] = 94,
            [17] = 54,
            [18] = 21
        };

        var actualDistribution = new Dictionary<int, int>(expectedDistribution);
        foreach (var key in actualDistribution.Keys)
            actualDistribution[key] = 0;

        const int times = 250;
        const int possibleCombinationsCount = 6 * 6 * 6 * 6; // 4d6
        for (var i = 0; i < times * possibleCombinationsCount; i++)
            actualDistribution[DndCharacter.Ability()]++;

        const double minTimes = times * 0.8;
        const double maxTimes = times * 1.2;
        foreach (var k in expectedDistribution.Keys)
            Assert.InRange(actualDistribution[k], expectedDistribution[k] * minTimes, expectedDistribution[k] * maxTimes);
    }
}