Add Rgb specific tests

src/ImageSharp/ColorSpaces/Rgb.cs

@@ -118,7 +118,7 @@ namespace SixLabors.ImageSharp.ColorSpaces
         [MethodImpl(InliningOptions.ShortMethod)]
         public static implicit operator Rgb(Rgba32 color)
         {
-            return new Rgba32(color.R / 255F, color.G / 255F, color.B / 255F);
+            return new Rgb(color.R / 255F, color.G / 255F, color.B / 255F);
         }
 
         /// <summary>

src/ImageSharp/PixelFormats/Rgba32.cs

@@ -224,12 +224,8 @@ namespace SixLabors.ImageSharp.PixelFormats
         /// <summary>
         /// Compares two <see cref="Rgba32"/> objects for equality.
         /// </summary>
-        /// <param name="left">
-        /// The <see cref="Rgba32"/> on the left side of the operand.
-        /// </param>
-        /// <param name="right">
-        /// The <see cref="Rgba32"/> on the right side of the operand.
-        /// </param>
+        /// <param name="left">The <see cref="Rgba32"/> on the left side of the operand.</param>
+        /// <param name="right">The <see cref="Rgba32"/> on the right side of the operand.</param>
         /// <returns>
         /// True if the <paramref name="left"/> parameter is equal to the <paramref name="right"/> parameter; otherwise, false.
         /// </returns>

tests/ImageSharp.Tests/Colorspaces/ColorSpaceEqualityTests.cs

@@ -137,17 +137,6 @@ namespace SixLabors.ImageSharp.Tests.Colorspaces
             Assert.False(x.Equals(y));
         }
 
-        [Fact]
-        public void RgbEquality()
-        {
-            var x = default(Rgb);
-            var y = new Rgb(Vector3.One);
-            Assert.Equal(default(Rgb), default(Rgb));
-            Assert.Equal(new Rgb(1, 0, 1), new Rgb(1, 0, 1));
-            Assert.Equal(new Rgb(Vector3.One), new Rgb(Vector3.One));
-            Assert.False(x.Equals(y));
-        }
-
         [Fact]
         public void YCbCrEquality()
         {

tests/ImageSharp.Tests/Colorspaces/RgbTests.cs

@@ -0,0 +1,86 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System.Numerics;
+using SixLabors.ImageSharp.ColorSpaces;
+using SixLabors.ImageSharp.PixelFormats;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Tests.Colorspaces
+{
+
+    /// <summary>
+    /// Tests the <see cref="Rgb"/> struct.
+    /// </summary>
+    public class RgbTests
+    {
+        [Fact]
+        public void RgbConstructorAssignsFields()
+        {
+            const float r = .75F;
+            const float g = .64F;
+            const float b = .87F;
+            var rgb = new Rgb(r, g, b);
+
+            Assert.Equal(r, rgb.R);
+            Assert.Equal(g, rgb.G);
+            Assert.Equal(b, rgb.B);
+        }
+
+        [Fact]
+        public void RgbEquality()
+        {
+            var x = default(Rgb);
+            var y = new Rgb(Vector3.One);
+
+            Assert.True(default(Rgb) == default(Rgb));
+            Assert.False(default(Rgb) != default(Rgb));
+            Assert.Equal(default(Rgb), default(Rgb));
+            Assert.Equal(new Rgb(1, 0, 1), new Rgb(1, 0, 1));
+            Assert.Equal(new Rgb(Vector3.One), new Rgb(Vector3.One));
+            Assert.False(x.Equals(y));
+        }
+
+        [Fact]
+        public void RgbAndRgb24Operators()
+        {
+            const byte r = 64;
+            const byte g = 128;
+            const byte b = 255;
+
+            var rgb = new Rgb(r / 255F, g / 255F, b / 255F);
+
+            Rgb24 rgb24 = rgb;
+            Rgb rgb2 = rgb24;
+
+            Assert.Equal(r, rgb24.R);
+            Assert.Equal(g, rgb24.G);
+            Assert.Equal(b, rgb24.B);
+
+            Assert.Equal(r / 255F, rgb2.R);
+            Assert.Equal(g / 255F, rgb2.G);
+            Assert.Equal(b / 255F, rgb2.B);
+        }
+
+        [Fact]
+        public void RgbAndRgba32Operators()
+        {
+            const byte r = 64;
+            const byte g = 128;
+            const byte b = 255;
+
+            var rgb = new Rgb(r / 255F, g / 255F, b / 255F);
+
+            Rgba32 rgba32 = rgb;
+            Rgb rgb2 = rgba32;
+
+            Assert.Equal(r, rgba32.R);
+            Assert.Equal(g, rgba32.G);
+            Assert.Equal(b, rgba32.B);
+
+            Assert.Equal(r / 255F, rgb2.R);
+            Assert.Equal(g / 255F, rgb2.G);
+            Assert.Equal(b / 255F, rgb2.B);
+        }
+    }
+}