Return hack with double.Epsilon

src/Avalonia.Base/Properties/AssemblyInfo.cs

@@ -8,4 +8,3 @@ using Avalonia.Metadata;
 [assembly: InternalsVisibleTo("Avalonia.Base.UnitTests")]
 [assembly: InternalsVisibleTo("Avalonia.UnitTests")]
 [assembly: InternalsVisibleTo("DynamicProxyGenAssembly2")]
-[assembly: InternalsVisibleTo("Avalonia.Controls")]

src/Avalonia.Base/Utilities/MathUtilities.cs

@@ -9,7 +9,7 @@ namespace Avalonia.Utilities
     public static class MathUtilities
     {
         // smallest such that 1.0+DoubleEpsilon != 1.0
-        internal static readonly double DoubleEpsilon = 2.2204460492503131e-016;
+        private const double DoubleEpsilon = 2.2204460492503131e-016;
 
         /// <summary>
         /// AreClose - Returns whether or not two doubles are "close".  That is, whether or 

src/Avalonia.Controls/Slider.cs

@@ -193,7 +193,8 @@ namespace Avalonia.Controls
             var orient = Orientation == Orientation.Horizontal;
 
             var pointDen = orient ? _track.Bounds.Width : _track.Bounds.Height;
-            pointDen += MathUtilities.DoubleEpsilon; // Just add epsilon to avoid divide by zero exceptions.
+            // Just add epsilon to avoid NaN in case 0/0
+            pointDen += double.Epsilon;
 
             var pointNum = orient ? x.Position.X : x.Position.Y;
             var logicalPos = MathUtilities.Clamp(pointNum / pointDen, 0.0d, 1.0d);

tests/Avalonia.Base.UnitTests/Utilities/MathUtilitiesTests.cs

@@ -1,3 +1,4 @@
+using System;
 using Avalonia.Utilities;
 using Xunit;
 
@@ -18,6 +19,7 @@ namespace Avalonia.Base.UnitTests.Utilities
             var actual = MathUtilities.AreClose(x, y);
 
             Assert.True(actual);
+            Assert.Equal(x, Math.Round(y, 14));
         }
 
         [Fact]
@@ -32,6 +34,7 @@ namespace Avalonia.Base.UnitTests.Utilities
             var actual = MathUtilities.IsOne(x);
 
             Assert.True(actual);
+            Assert.Equal(1.0, Math.Round(x, 15));
         }
 
         [Fact]
@@ -46,6 +49,32 @@ namespace Avalonia.Base.UnitTests.Utilities
             var actual = MathUtilities.IsZero(x);
 
             Assert.True(actual);
+            Assert.Equal(0.0, Math.Round(x, 15));
+        }
+
+        [Fact]
+        public void Clamp_Input_NaN_Return_NaN()
+        {
+            var clamp = MathUtilities.Clamp(double.NaN, 0.0, 1.0);
+            Assert.True(double.IsNaN(clamp));
+        }
+
+        [Fact]
+        public void Clamp_Input_NegativeInfinity_Return_Min()
+        {
+            const double min = 0.0;
+            const double max = 1.0;
+            var actual = MathUtilities.Clamp(double.NegativeInfinity, min, max);
+            Assert.Equal(min, actual);
+        }
+
+        [Fact]
+        public void Clamp_Input_PositiveInfinity_Return_Max()
+        {
+            const double min = 0.0;
+            const double max = 1.0;
+            var actual = MathUtilities.Clamp(double.PositiveInfinity, min, max);
+            Assert.Equal(max, actual);
         }
     }
 }