Feat: Add StringColorExtensions with tests for hex-to-RGB conversion

Author: AnnaSasDev

src/CodeOfChaos.Extensions/StringColorExtensions.cs

@@ -0,0 +1,54 @@
+// ---------------------------------------------------------------------------------------------------------------------
+// Imports
+// ---------------------------------------------------------------------------------------------------------------------
+using System.Diagnostics.CodeAnalysis;
+
+// ReSharper disable once CheckNamespace
+namespace System;
+// ---------------------------------------------------------------------------------------------------------------------
+// Code
+// ---------------------------------------------------------------------------------------------------------------------
+public static class StringColorExtensions {
+    public static string ConvertToRgbValues(this string? hexColor) 
+        => hexColor.TryConvertToRgbValues(out string? rgbString) ? rgbString : throw new ArgumentException("Invalid hex color");
+
+    public static bool TryConvertToRgbValues(this string? hexColor, [NotNullWhen(true)] out string? rgbString) {
+        if (hexColor.IsNullOrEmpty()) {
+            rgbString = null;
+            return false;
+        }
+
+        ReadOnlySpan<char> hexSpan = hexColor.AsSpan();
+        int offset = hexSpan.StartsWith('#') ? 1 : 0;
+
+        Range rRange;
+        Range gRange;
+        Range bRange;
+
+        switch (hexSpan.Length - offset) {
+            case 3:
+                rRange = offset..(offset + 1);
+                gRange = (offset + 1)..(offset + 2);
+                bRange = (offset + 2)..(offset + 3);
+                break;
+            case 6:
+                rRange = offset..(offset + 2);
+                gRange = (offset + 2)..(offset + 4);
+                bRange = (offset + 4)..(offset + 6);
+                break;
+            default:
+                rgbString = null;
+                return false;
+        }
+
+        if (!int.TryParse(hexSpan[rRange], Globalization.NumberStyles.HexNumber, null, out int r)
+            || !int.TryParse(hexSpan[gRange], Globalization.NumberStyles.HexNumber, null, out int g)
+            || !int.TryParse(hexSpan[bRange], Globalization.NumberStyles.HexNumber, null, out int b)) {
+            rgbString = null;
+            return false;
+        }
+
+        rgbString = $"{r}, {g}, {b}";
+        return true;
+    }
+}

tests/Tests.CodeOfChaos.Extensions/StringColorExtensionTests.cs

@@ -0,0 +1,85 @@
+// ---------------------------------------------------------------------------------------------------------------------
+// Imports
+// ---------------------------------------------------------------------------------------------------------------------
+namespace Tests.CodeOfChaos.Extensions;
+// ---------------------------------------------------------------------------------------------------------------------
+// Code
+// ---------------------------------------------------------------------------------------------------------------------
+public class StringColorExtensionTests {
+    public static IEnumerable<Func<(string, string)>> ValidDataSources() {
+        yield return () => ("#FF0000", "255, 0, 0");  
+        yield return () => ("FF0000", "255, 0, 0");
+        yield return () => ("#00FF00", "0, 255, 0");
+        yield return () => ("#0000FF", "0, 0, 255");
+        yield return () => ("#F00", "15, 0, 0");
+        yield return () => ("#FFF", "15, 15, 15");
+        
+        // Common Colors
+        yield return () => ("#FFFFFF", "255, 255, 255"); 
+        yield return () => ("#000000", "0, 0, 0"); 
+        yield return () => ("#808080", "128, 128, 128"); 
+        yield return () => ("#FFF", "15, 15, 15"); 
+        yield return () => ("#000", "0, 0, 0"); 
+        
+        yield return () => ("#5BCEFA", "91, 206, 250");
+        yield return () => ("#F5A9B8", "245, 169, 184");
+        yield return () => ("#FFFFFF", "255, 255, 255");
+        yield return () => ("#F5A9B8", "245, 169, 184");
+        yield return () => ("#5BCEFA", "91, 206, 250");
+    }
+
+    public static IEnumerable<Func<string?>> InvalidDataSources() {
+        yield return () => null;
+        yield return () => ("");
+        yield return () => (" ");
+        yield return () => ("#");
+        yield return () => ("#F");
+        yield return () => ("#FF");
+        yield return () => ("#FFFF");
+        yield return () => ("#FFFFF");
+        yield return () => ("#FFFFFFF");
+        yield return () => ("#GG0000");
+        yield return () => ("GGGGGG");
+    }
+    
+    [Test]
+    [MethodDataSource<StringColorExtensionTests>(nameof(ValidDataSources))]
+    public async Task ConvertToRgbValues_ValidHexColors_ReturnsRgbString(string input, string expected) {
+        // Act
+        string result = input.ConvertToRgbValues();
+
+        // Assert
+        await Assert.That(result).IsNotNull().And.IsEquatableOrEqualTo(expected);
+    }
+
+    [Test]
+    [MethodDataSource<StringColorExtensionTests>(nameof(InvalidDataSources))]
+    public async Task ConvertToRgbValues_InvalidInput_ThrowsArgumentException(string? input) {
+        // Act & Assert
+        Assert.Throws<ArgumentException>(() => input.ConvertToRgbValues());
+    }
+
+
+    [Test]
+    [MethodDataSource<StringColorExtensionTests>(nameof(ValidDataSources))]
+    public async Task TryConvertToRgbValues_ValidHexColors_ReturnsTrue(string input, string expected) {
+        // Act
+        bool result = input.TryConvertToRgbValues(out string? rgb);
+
+        // Assert
+        await Assert.That(result).IsTrue();
+        await Assert.That(rgb).IsNotNull().And.IsEquatableOrEqualTo(expected);
+    }
+
+    // ReSharper disable StringLiteralTypo
+    [Test]
+    [MethodDataSource<StringColorExtensionTests>(nameof(InvalidDataSources))]
+    public async Task TryConvertToRgbValues_InvalidInput_ReturnsFalse(string? input) {
+        // Act
+        bool result = input.TryConvertToRgbValues(out string? rgb);
+
+        // Assert
+        await Assert.That(result).IsFalse();
+        await Assert.That(rgb).IsNull();
+    }
+}