Improve #275 - Add test coverage for hash codes

Author: craigfowler

CSF.Screenplay.Selenium/Color.cs

@@ -192,7 +192,7 @@ public override bool Equals(object obj)
         public override string ToString() => ToRgbaString();
 
         /// <inheritdoc/>
-        public override int GetHashCode() => HashCode.Combine(Red, Green, Blue, Alpha);
+        public override int GetHashCode() => HashCode.Combine(Red, Green, Blue, AlphaAsByte);
 
         /// <summary>
         /// Creates a new instance of <see cref="Color"/> from the specified RGBA values.

Tests/CSF.Screenplay.Selenium.Tests/ColorTests.cs

@@ -211,4 +211,29 @@ public void ParseFollowedByToHexStringShouldRoundtripTheColor(string colorString
     {
         Assert.That(() => Color.Parse(colorString).ToHexString(), Is.EqualTo(colorString));
     }
+
+    [TestCase("rgb(1, 2, 3)", 1, 2, 3, 1)]
+    [TestCase("rgb(10%, 20%, 30%)", 25, 51, 76, 1)]
+    [TestCase("rgb(\t1,     2,        3)", 1, 2, 3, 1)]
+    [TestCase("rgba(1, 2, 3, 0.5)", 1, 2, 3, 0.5D)]
+    [TestCase("rgba(10%, 20%, 30%, 0.5)", 25, 51, 76, 0.5D)]
+    [TestCase("#ff00a0", 255, 0, 160, 1)]
+    [TestCase("#01Ff03", 1, 255, 3, 1)]
+    [TestCase("#00FF33", 0, 255, 51, 1)]
+    [TestCase("#0f3", 0, 255, 51, 1)]
+    [TestCase("hsl(120, 100%, 25%)", 0, 128, 0, 1)]
+    [TestCase("hsl(100, 0%, 50%)", 128, 128, 128, 1)]
+    [TestCase("hsl(0, 100%, 50%)", 255, 0, 0, 1)]
+    [TestCase("hsl(120, 100%, 50%)", 0, 255, 0, 1)]
+    [TestCase("hsl(240, 100%, 50%)", 0, 0, 255, 1)]
+    [TestCase("hsl(0, 0%, 100%)", 255, 255, 255, 1)]
+    [TestCase("hsla(120, 100%, 25%, 1)", 0, 128, 0, 1)]
+    [TestCase("hsla(100, 0%, 50%, 0.5)", 128, 128, 128, 0.5)]
+    [TestCase("green", 0, 128, 0, 1)]
+    [TestCase("gray", 128, 128, 128, 1)]
+    [TestCase("transparent", 0, 0, 0, 0)]
+    public void GetHashCodeShouldReturnTheSameResultForEquivalentColors(string colorString, byte red, byte green, byte blue, double alpha)
+    {
+        Assert.That(() => Color.Parse(colorString).GetHashCode(), Is.EqualTo(new Color(red, green, blue, alpha).GetHashCode()));
+    }
 }