sprints and audit work

src/Policy/__Tests/StellaOps.Policy.Determinization.Tests/DecayedConfidenceCalculatorTests.cs

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+using FluentAssertions;
+using Microsoft.Extensions.Logging.Abstractions;
+using StellaOps.Policy.Determinization.Scoring;
+using Xunit;
+
+namespace StellaOps.Policy.Determinization.Tests;
+
+public class DecayedConfidenceCalculatorTests
+{
+    private readonly DecayedConfidenceCalculator _calculator;
+
+    public DecayedConfidenceCalculatorTests()
+    {
+        _calculator = new DecayedConfidenceCalculator(NullLogger<DecayedConfidenceCalculator>.Instance);
+    }
+
+    [Fact]
+    public void Calculate_ZeroAge_ReturnsBaseConfidence()
+    {
+        // Arrange
+        var baseConfidence = 0.8;
+        var ageDays = 0.0;
+
+        // Act
+        var result = _calculator.Calculate(baseConfidence, ageDays);
+
+        // Assert
+        result.Should().Be(baseConfidence);
+    }
+
+    [Fact]
+    public void Calculate_HalfLife_ReturnsHalfConfidence()
+    {
+        // Arrange
+        var baseConfidence = 1.0;
+        var halfLifeDays = 14.0;
+        var ageDays = 14.0;
+
+        // Act
+        var result = _calculator.Calculate(baseConfidence, ageDays, halfLifeDays);
+
+        // Assert
+        result.Should().BeApproximately(0.5, 0.01);
+    }
+
+    [Fact]
+    public void Calculate_TwoHalfLives_ReturnsQuarterConfidence()
+    {
+        // Arrange
+        var baseConfidence = 1.0;
+        var halfLifeDays = 14.0;
+        var ageDays = 28.0;
+
+        // Act
+        var result = _calculator.Calculate(baseConfidence, ageDays, halfLifeDays);
+
+        // Assert
+        result.Should().BeApproximately(0.25, 0.01);
+    }
+
+    [Fact]
+    public void Calculate_VeryOld_ReturnsFloor()
+    {
+        // Arrange
+        var baseConfidence = 1.0;
+        var halfLifeDays = 14.0;
+        var ageDays = 200.0;
+        var floor = 0.1;
+
+        // Act
+        var result = _calculator.Calculate(baseConfidence, ageDays, halfLifeDays, floor);
+
+        // Assert
+        result.Should().Be(floor);
+    }
+
+    [Fact]
+    public void CalculateDecayFactor_ZeroAge_ReturnsOne()
+    {
+        // Act
+        var factor = _calculator.CalculateDecayFactor(0.0);
+
+        // Assert
+        factor.Should().Be(1.0);
+    }
+
+    [Fact]
+    public void CalculateDecayFactor_HalfLife_ReturnsHalf()
+    {
+        // Act
+        var factor = _calculator.CalculateDecayFactor(14.0, 14.0);
+
+        // Assert
+        factor.Should().BeApproximately(0.5, 0.01);
+    }
+
+    [Theory]
+    [InlineData(-0.1)]
+    [InlineData(1.1)]
+    public void Calculate_InvalidBaseConfidence_ThrowsArgumentOutOfRange(double invalidConfidence)
+    {
+        // Act & Assert
+        var act = () => _calculator.Calculate(invalidConfidence, 10.0);
+        act.Should().Throw<ArgumentOutOfRangeException>();
+    }
+
+    [Fact]
+    public void Calculate_NegativeAge_ThrowsArgumentOutOfRange()
+    {
+        // Act & Assert
+        var act = () => _calculator.Calculate(0.8, -1.0);
+        act.Should().Throw<ArgumentOutOfRangeException>();
+    }
+}