Simplify IccProfileId IsSet

src/ImageSharp/MetaData/Profiles/ICC/Various/IccProfileId.cs

@@ -13,7 +13,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Icc
         /// <summary>
         /// A profile ID with all values set to zero
         /// </summary>
-        public static readonly IccProfileId Zero = new IccProfileId(0, 0, 0, 0);
+        public static readonly IccProfileId Zero = default;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="IccProfileId"/> struct.
@@ -53,16 +53,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Icc
         /// <summary>
         /// Gets a value indicating whether the ID is set or just consists of zeros
         /// </summary>
-        public bool IsSet
-        {
-            get
-            {
-                return this.Part1 != 0
-                    && this.Part2 != 0
-                    && this.Part3 != 0
-                    && this.Part4 != 0;
-            }
-        }
+        public bool IsSet => !this.Equals(Zero);
 
         /// <summary>
         /// Compares two <see cref="IccProfileId"/> objects for equality.
@@ -131,4 +122,4 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Icc
             return value.ToString("X").PadLeft(8, '0');
         }
     }
-}
+}

tests/ImageSharp.Tests/MetaData/Profiles/ICC/Various/IccProfileIdTests.cs

@@ -0,0 +1,32 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using SixLabors.ImageSharp.MetaData.Profiles.Icc;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Icc
+{
+    public class IccProfileIdTests
+    {
+        [Fact]
+        public void ZeroIsEqualToDefault()
+        {
+            Assert.True(IccProfileId.Zero.Equals(default));
+
+            Assert.False(default(IccProfileId).IsSet);
+        }
+
+        [Fact]
+        public void SetIsTrueWhenNonDefaultValue()
+        {
+            var id = new IccProfileId(1, 2, 3, 4);
+
+            Assert.True(id.IsSet);
+
+            Assert.Equal(1u, id.Part1);
+            Assert.Equal(2u, id.Part2);
+            Assert.Equal(3u, id.Part3);
+            Assert.Equal(4u, id.Part4);
+        }
+    }
+}