Adapt dynamic question difficulty to learner Elo

2026-07-23 16:18:44 -05:00
parent 5b5741de37
commit fae38d2ded
13 changed files with 519 additions and 33 deletions
@@ -80,6 +80,71 @@ public sealed class DynamicQuestionTests
        Assert.Equal(first.Choices.Select(value => value.Id), regenerated.Choices.Select(value => value.Id));
    }

+    [Fact]
+    public void DifficultyPolicy_BlendsThenSpecializes_AndTargetsSixtyPercent()
+    {
+        Assert.Equal(1200, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, null));
+        var early = new DynamicObjectiveMastery { Elo = 1500, Attempts = 1 };
+        var established = new DynamicObjectiveMastery { Elo = 1500, Attempts = 10 };
+        Assert.Equal(1224, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, early));
+        Assert.Equal(1440, DynamicDifficultyPolicy.EffectiveAbility(1100, 1300, established));
+        Assert.Equal(1370, DynamicDifficultyPolicy.TargetFamilyElo(1440));
+    }
+
+    [Fact]
+    public void DifficultyPolicy_SelectsClosestNonrecentFamily()
+    {
+        var families = new List<DynamicCaseFamily>
+        {
+            new() { Id = "foundation", DifficultyTier = "foundation", NominalElo = 850 },
+            new() { Id = "standard", DifficultyTier = "standard", NominalElo = 1050 },
+            new() { Id = "advanced-a", DifficultyTier = "advanced", NominalElo = 1250 },
+            new() { Id = "advanced-b", DifficultyTier = "advanced", NominalElo = 1250 },
+            new() { Id = "expert", DifficultyTier = "expert", NominalElo = 1450 }
+        };
+        var selected = DynamicDifficultyPolicy.SelectFamily(
+            families, new Dictionary<string, DynamicFamilyRating>(), 1260,
+            new HashSet<string> { "advanced-a" }, 0);
+        Assert.Equal("advanced-b", selected.Id);
+    }
+
+    [Fact]
+    public void DifficultyPolicy_RatingsMoveInOppositeDirections()
+    {
+        Assert.True(DynamicDifficultyPolicy.LearnerDelta(1000, 1050, true, 0) > 0);
+        Assert.True(DynamicDifficultyPolicy.FamilyDelta(1000, 1050, true, 0) < 0);
+        Assert.True(DynamicDifficultyPolicy.LearnerDelta(1000, 1050, false, 0) < 0);
+        Assert.True(DynamicDifficultyPolicy.FamilyDelta(1000, 1050, false, 0) > 0);
+        Assert.Equal(600, DynamicDifficultyPolicy.Clamp(-100));
+        Assert.Equal(1800, DynamicDifficultyPolicy.Clamp(5000));
+    }
+
+    [Fact]
+    public void AdaptiveContent_ResolvesToFourCompleteTiers()
+    {
+        var options = new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web)
+            { PropertyNameCaseInsensitive = true };
+        var root = Path.GetFullPath(Path.Combine(
+            AppContext.BaseDirectory, "..", "..", "..", "..", "..", "content", "dynamic_questions"));
+        var source = Directory.EnumerateFiles(root, "*.json")
+            .SelectMany(file => System.Text.Json.JsonSerializer.Deserialize<List<DynamicQuestionBlueprint>>(
+                File.ReadAllText(file), options) ?? [])
+            .ToList();
+        var adaptive = DynamicBlueprintResolver.ResolveAll(source)
+            .Where(value => value.QualityStandardVersion >= 3).ToList();
+
+        Assert.Equal(5, adaptive.Count);
+        Assert.All(adaptive, blueprint =>
+        {
+            Assert.Equal(8, blueprint.CaseFamilies.Count);
+            Assert.All(DynamicDifficultyPolicy.TierElos.Keys, tier =>
+                Assert.Equal(2, blueprint.CaseFamilies.Count(value => value.DifficultyTier == tier)));
+            Assert.All(blueprint.CaseFamilies, family =>
+                Assert.False(family.StemTemplate.EndsWith(family.LeadIn, StringComparison.Ordinal)));
+            Assert.Null(DynamicQuestionGenerator.Validate(blueprint));
+        });
+    }
+
    private static DynamicQuestionBlueprint Blueprint() => new()
    {
        ExternalId = "test",