ImageProperty is no longer a struct and added unit tests for equality.

Former-commit-id: e140d562a45ef0dc7fa3e1e5dfc3ec330040b696
Former-commit-id: 9256abfb4eca778a2051d32edc198979bd359de2
Former-commit-id: 0076f821040d894bb10e923c4a5a370932eae48b

src/ImageProcessorCore/Image/ImageProperty.cs

@@ -12,7 +12,7 @@ namespace ImageProcessorCore
     /// the copyright information, the date, where the image was created
     /// or some other information.
     /// </summary>
-    public struct ImageProperty : IEquatable<ImageProperty>
+    public class ImageProperty : IEquatable<ImageProperty>
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="ImageProperty"/> struct.
@@ -56,7 +56,7 @@ namespace ImageProcessorCore
         /// </returns>
         public static bool operator ==(ImageProperty left, ImageProperty right)
         {
-            return left.Equals(right);
+            return Equals(left, right);
         }
 
         /// <summary>
@@ -75,7 +75,7 @@ namespace ImageProcessorCore
         /// </returns>
         public static bool operator !=(ImageProperty left, ImageProperty right)
         {
-            return !left.Equals(right);
+            return !Equals(left, right);
         }
 
         /// <summary>
@@ -90,13 +90,13 @@ namespace ImageProcessorCore
         /// </returns>
         public override bool Equals(object obj)
         {
-            if (!(obj is ImageProperty))
+            ImageProperty other = obj as ImageProperty;
+
+            if (other == null)
             {
                 return false;
             }
 
-            ImageProperty other = (ImageProperty)obj;
-
             return other.Name == this.Name && other.Value == this.Value;
         }
 
@@ -136,6 +136,16 @@ namespace ImageProcessorCore
         /// <param name="other">An object to compare with this object.</param>
         public bool Equals(ImageProperty other)
         {
+            if (ReferenceEquals(other, null))
+            {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other))
+            {
+                return true;
+            }
+
             return this.Name.Equals(other.Name) && this.Value.Equals(other.Value);
         }
     }

tests/ImageProcessorCore.Tests/Image/ImagePropertyTests.cs

@@ -0,0 +1,52 @@
+// <copyright file="ColorConversionTests.cs" company="James Jackson-South">
+// Copyright (c) James Jackson-South and contributors.
+// Licensed under the Apache License, Version 2.0.
+// </copyright>
+
+namespace ImageProcessorCore.Tests
+{
+    using Xunit;
+
+    /// <summary>
+    /// Tests the <see cref="ImageProperty"/> class.
+    /// </summary>
+    public class ImagePropertyTests
+    {
+        /// <summary>
+        /// Tests the equality operators for inequality.
+        /// </summary>
+        [Fact]
+        public void AreEqual()
+        {
+            ImageProperty property1 = new ImageProperty("Foo", "Bar");
+            ImageProperty property2 = new ImageProperty("Foo", "Bar");
+            ImageProperty property3 = null;
+
+            Assert.Equal(property1, property2);
+            Assert.True(property1 == property2);
+            Assert.Equal(property3, null);
+        }
+
+        /// <summary>
+        /// Tests the equality operators for equality.
+        /// </summary>
+        [Fact]
+        public void AreNotEqual()
+        {
+            ImageProperty property1 = new ImageProperty("Foo", "Bar");
+            ImageProperty property2 = new ImageProperty("Foo", "Foo");
+            ImageProperty property3 = new ImageProperty("Bar", "Bar");
+
+            Assert.False(property1.Equals("Foo"));
+
+            Assert.NotEqual(property1, null);
+
+            Assert.NotEqual(property1, property2);
+            Assert.True(property1 != property2);
+
+            Assert.NotEqual(property1, property3);
+            Assert.True(property1 != property3);
+        }
+
+    }
+}