diff --git a/X10D.Tests/src/Drawing/ColorTests.cs b/X10D.Tests/src/Drawing/ColorTests.cs
index b58964e..0178a69 100644
--- a/X10D.Tests/src/Drawing/ColorTests.cs
+++ b/X10D.Tests/src/Drawing/ColorTests.cs
@@ -1,4 +1,4 @@
-using System.Drawing;
+using System.Drawing;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using X10D.Drawing;
 
@@ -7,26 +7,26 @@ namespace X10D.Tests.Drawing;
 [TestClass]
 public class ColorTests
 {
+    private static readonly Color Black = Color.FromArgb(0, 0, 0);
+    private static readonly Color White = Color.FromArgb(255, 255, 255);
+    private static readonly Color Red = Color.FromArgb(255, 0, 0);
+    private static readonly Color Green = Color.FromArgb(0, 255, 0);
+    private static readonly Color Blue = Color.FromArgb(0, 0, 255);
+    private static readonly Color Cyan = Color.FromArgb(0, 255, 255);
+    private static readonly Color Magenta = Color.FromArgb(255, 0, 255);
+    private static readonly Color Yellow = Color.FromArgb(255, 255, 0);
+
     [TestMethod]
     public void Inverted_ShouldReturnInvertedColor()
     {
-        Color black = Color.FromArgb(0, 0, 0);
-        Color white = Color.FromArgb(255, 255, 255);
-        Color red = Color.FromArgb(255, 0, 0);
-        Color green = Color.FromArgb(0, 255, 0);
-        Color blue = Color.FromArgb(0, 0, 255);
-        Color cyan = Color.FromArgb(0, 255, 255);
-        Color magenta = Color.FromArgb(255, 0, 255);
-        Color yellow = Color.FromArgb(255, 255, 0);
-
-        Assert.AreEqual(white, black.Inverted());
-        Assert.AreEqual(black, white.Inverted());
-        Assert.AreEqual(red, cyan.Inverted());
-        Assert.AreEqual(cyan, red.Inverted());
-        Assert.AreEqual(green, magenta.Inverted());
-        Assert.AreEqual(magenta, green.Inverted());
-        Assert.AreEqual(yellow, blue.Inverted());
-        Assert.AreEqual(blue, yellow.Inverted());
+        Assert.AreEqual(White, Black.Inverted());
+        Assert.AreEqual(Black, White.Inverted());
+        Assert.AreEqual(Red, Cyan.Inverted());
+        Assert.AreEqual(Cyan, Red.Inverted());
+        Assert.AreEqual(Green, Magenta.Inverted());
+        Assert.AreEqual(Magenta, Green.Inverted());
+        Assert.AreEqual(Yellow, Blue.Inverted());
+        Assert.AreEqual(Blue, Yellow.Inverted());
     }
 
     [TestMethod]
diff --git a/X10D.Unity.Tests/Assets/Tests/Drawing/Color32Tests.cs b/X10D.Unity.Tests/Assets/Tests/Drawing/Color32Tests.cs
index 7914299..1816e39 100644
--- a/X10D.Unity.Tests/Assets/Tests/Drawing/Color32Tests.cs
+++ b/X10D.Unity.Tests/Assets/Tests/Drawing/Color32Tests.cs
@@ -8,26 +8,26 @@ namespace X10D.Unity.Tests.Drawing
 {
     public class Color32Tests
     {
+        private static readonly Color32 Black = new(0, 0, 0, 1);
+        private static readonly Color32 White = new(255, 255, 255, 1);
+        private static readonly Color32 Red = new(255, 0, 0, 1);
+        private static readonly Color32 Green = new(0, 255, 0, 1);
+        private static readonly Color32 Blue = new(0, 0, 255, 1);
+        private static readonly Color32 Cyan = new(0, 255, 255, 1);
+        private static readonly Color32 Magenta = new(255, 0, 255, 1);
+        private static readonly Color32 Yellow = new(255, 255, 0, 1);
+
         [UnityTest]
         public IEnumerator Inverted_ShouldReturnInvertedColor()
         {
-            var black = new Color32(0, 0, 0, 1);
-            var white = new Color32(255, 255, 255, 1);
-            var red = new Color32(255, 0, 0, 1);
-            var green = new Color32(0, 255, 0, 1);
-            var blue = new Color32(0, 0, 255, 1);
-            var cyan = new Color32(0, 255, 255, 1);
-            var magenta = new Color32(255, 0, 255, 1);
-            var yellow = new Color32(255, 255, 0, 1);
-
-            Assert.AreEqual(white, black.Inverted());
-            Assert.AreEqual(black, white.Inverted());
-            Assert.AreEqual(red, cyan.Inverted());
-            Assert.AreEqual(cyan, red.Inverted());
-            Assert.AreEqual(green, magenta.Inverted());
-            Assert.AreEqual(magenta, green.Inverted());
-            Assert.AreEqual(yellow, blue.Inverted());
-            Assert.AreEqual(blue, yellow.Inverted());
+            Assert.AreEqual(White, Black.Inverted());
+            Assert.AreEqual(Black, White.Inverted());
+            Assert.AreEqual(Red, Cyan.Inverted());
+            Assert.AreEqual(Cyan, Red.Inverted());
+            Assert.AreEqual(Green, Magenta.Inverted());
+            Assert.AreEqual(Magenta, Green.Inverted());
+            Assert.AreEqual(Yellow, Blue.Inverted());
+            Assert.AreEqual(Blue, Yellow.Inverted());
 
             yield break;
         }
diff --git a/X10D.Unity.Tests/Assets/Tests/Drawing/ColorTests.cs b/X10D.Unity.Tests/Assets/Tests/Drawing/ColorTests.cs
index f7a6a9b..f28b463 100644
--- a/X10D.Unity.Tests/Assets/Tests/Drawing/ColorTests.cs
+++ b/X10D.Unity.Tests/Assets/Tests/Drawing/ColorTests.cs
@@ -8,26 +8,26 @@ namespace X10D.Unity.Tests.Drawing
 {
     public class ColorTests
     {
+        private static readonly Color Black = new(0, 0, 0);
+        private static readonly Color White = new(1, 1, 1);
+        private static readonly Color Red = new(1, 0, 0);
+        private static readonly Color Green = new(0, 1, 0);
+        private static readonly Color Blue = new(0, 0, 1);
+        private static readonly Color Cyan = new(0, 1, 1);
+        private static readonly Color Magenta = new(1, 0, 1);
+        private static readonly Color Yellow = new(1, 1, 0);
+
         [UnityTest]
         public IEnumerator Inverted_ShouldReturnInvertedColor()
         {
-            var black = new Color(0, 0, 0);
-            var white = new Color(1, 1, 1);
-            var red = new Color(1, 0, 0);
-            var green = new Color(0, 1, 0);
-            var blue = new Color(0, 0, 1);
-            var cyan = new Color(0, 1, 1);
-            var magenta = new Color(1, 0, 1);
-            var yellow = new Color(1, 1, 0);
-
-            Assert.AreEqual(white, black.Inverted());
-            Assert.AreEqual(black, white.Inverted());
-            Assert.AreEqual(red, cyan.Inverted());
-            Assert.AreEqual(cyan, red.Inverted());
-            Assert.AreEqual(green, magenta.Inverted());
-            Assert.AreEqual(magenta, green.Inverted());
-            Assert.AreEqual(yellow, blue.Inverted());
-            Assert.AreEqual(blue, yellow.Inverted());
+            Assert.AreEqual(White, Black.Inverted());
+            Assert.AreEqual(Black, White.Inverted());
+            Assert.AreEqual(Red, Cyan.Inverted());
+            Assert.AreEqual(Cyan, Red.Inverted());
+            Assert.AreEqual(Green, Magenta.Inverted());
+            Assert.AreEqual(Magenta, Green.Inverted());
+            Assert.AreEqual(Yellow, Blue.Inverted());
+            Assert.AreEqual(Blue, Yellow.Inverted());
 
             yield break;
         }