Made TolerantMath.Default a readonly property,

allow consuming one-dimensional input in ImageDataAttribute.

src/ImageSharp/Common/Helpers/TolerantMath.cs

@@ -16,6 +16,13 @@ namespace SixLabors.ImageSharp
 
         private readonly double negEpsilon;
 
+        /// <summary>
+        /// A read-only default instance for <see cref="TolerantMath"/> using 1e-8 as epsilon.
+        /// It is a field so it can be passed as an 'in' parameter.
+        /// Does not necessarily fit all use cases!
+        /// </summary>
+        public static readonly TolerantMath Default = new TolerantMath(1e-8);
+
         public TolerantMath(double epsilon)
         {
             DebugGuard.MustBeGreaterThan(epsilon, 0, nameof(epsilon));
@@ -24,8 +31,6 @@ namespace SixLabors.ImageSharp
             this.negEpsilon = -epsilon;
         }
 
-        public static TolerantMath Default { get; } = new TolerantMath(1e-8);
-
         /// <summary>
         /// <paramref name="a"/> == 0
         /// </summary>

tests/ImageSharp.Tests/TestUtilities/Attributes/ImageDataAttributeBase.cs

@@ -61,7 +61,7 @@ namespace SixLabors.ImageSharp.Tests
                         addedRows = memberItems.Select(x => x as object[]);
                         if (addedRows.Any(x => x == null))
                         {
-                            throw new ArgumentException($"Property {this.MemberName} on {this.MemberType ?? testMethod.DeclaringType} yielded an item that is not an object[]");
+                            addedRows = memberItems.Select(x => new[] { x });
                         }
                     }
                 }