pflib-net.Tests/dice/DiceTest.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using NUnit.Framework;
 using pflib_net.dice;
 
@@ -8,13 +9,21 @@ namespace pflib_net.Tests;
 [TestOf(typeof(Dice))]
 public class DiceTest
 {
+    private static IEnumerable<Func<Dice, Dice>> OperationCases
+    {
+        get
+        {
+            yield return (dice) => dice.Kh(1);
+            yield return (dice) => dice.Kl(1);
+        }
+    }
 
     [Test]
     [Repeat(100)]
     public void D20RollProducesValueBetween1And20()
     {
         var die = new Dice(20);
-        Assert.That(die.GetValue(), Is.InRange(1, 20));
+        Assert.That(die.Roll(), Is.InRange(1, 20));
     }
 
     [Test]
@@ -23,7 +32,7 @@ public class DiceTest
     public void RollAddsValuesCorrectly(int value)
     {
         var die = new Dice(4, add: value);
-        Assert.That(die.GetValue(), Is.InRange(1 + value, 4 + value));
+        Assert.That(die.Roll(), Is.InRange(1 + value, 4 + value));
     }
 
     [Test]
@@ -31,21 +40,21 @@ public class DiceTest
     public void RollMultipleDiceHasCorrectAmountOfDice()
     {
         var dice = new Dice(4, 20);
-        Assert.That(dice.GetValue(), Is.InRange(20, 4 * 20));
+        Assert.That(dice.Roll(), Is.InRange(20, 4 * 20));
     }
 
     [Test]
     public void KeepHighestHasCorrectNumberOfDice()
     {
         var dice = new Dice(1, 40, 20);
-        Assert.That(dice.GetValue(), Is.EqualTo(20));
+        Assert.That(dice.Roll(), Is.EqualTo(20));
     }
 
     [Test]
     public void KeepLowestHasCorrectNumberOfDice()
     {
         var dice = new Dice(1, 40, keepLowest: 20);
-        Assert.That(dice.GetValue(), Is.EqualTo(20));
+        Assert.That(dice.Roll(), Is.EqualTo(20));
     }
 
     [Test]
@@ -54,4 +63,22 @@ public class DiceTest
         Assert.Throws<InvalidOperationException>(
             () => new Dice(1, 40, 1, 1));
     }
+
+    [Test]
+    [TestCaseSource(nameof(OperationCases))]
+    [Repeat(100)]
+    public void CanBuildUsingIntExtension(Func<Dice, Dice> func)
+    {
+        var dice = func(2.D(6));
+        Assert.That(dice.Roll(), Is.InRange(1, 6));
+    }
+
+    [Test]
+    public void KhAndKlTogetherFails()
+    {
+        Assert.Throws<InvalidOperationException>(
+            () => 1.D(6).Kh(1).Kl(1));
+        Assert.Throws<InvalidOperationException>(
+            () => 1.D(6).Kl(1).Kh(1));
+    }
 }

pflib-net/dice/Dice.cs

@@ -23,7 +23,29 @@ public struct Dice
         Add = add;
     }
 
-    public int GetValue()
+    public Dice Kh(int keepHighest)
+    {
+        if (KeepLowest > 0)
+        {
+            throw new InvalidOperationException("Cannot set keepHighest and keepLowest in the same roll");
+        }
+
+        KeepHighest = keepHighest;
+        return this;
+    }
+
+    public Dice Kl(int keepLowest)
+    {
+        if (KeepHighest > 0)
+        {
+            throw new InvalidOperationException("Cannot set keepHighest and keepLowest in the same roll");
+        }
+
+        KeepLowest = keepLowest;
+        return this;
+    }
+
+    public int Roll()
     {
         var rolls = new List<int>();
         for (var i = 0; i < Count; i++)
@@ -53,3 +75,11 @@ public struct Dice
         return rolls.Sum() + Add;
     }
 }
+
+public static class IntExtension
+{
+    public static Dice D(this int count, int size)
+    {
+        return new Dice(size, count);
+    }
+}