Improve HexToRGB24Converter

Author: niklasweimann

src/RxTelegram.Bot/Utils/HexToRGB24Converter.cs

@@ -3,11 +3,29 @@
 
 namespace RxTelegram.Bot.Utils;
 
-public class HexToRgb24
+public static class HexToRgb24
 {
-    public int Convert(string hexColor) => int.Parse(FormatHexString(hexColor), NumberStyles.HexNumber);
+    public static int Convert(string hexColor)
+    {
+        var formatHexString = FormatHexString(hexColor);
+        if (formatHexString.Length != 6)
+        {
+            throw new ArgumentException("Invalid hex color", nameof(hexColor));
+        }
+        return int.Parse(formatHexString, NumberStyles.HexNumber);
+    }
 
-    public bool TryConvert(string hexColor, out int result) => int.TryParse(FormatHexString(hexColor), NumberStyles.HexNumber, null, out result);
+    public static bool TryConvert(string hexColor, out int result)
+    {
+        var formatHexString = FormatHexString(hexColor);
+        if (formatHexString.Length == 6)
+        {
+            return int.TryParse(FormatHexString(hexColor), NumberStyles.HexNumber, null, out result);
+        }
+
+        result = -1;
+        return false;
+    }
 
     private static string FormatHexString(string hexColor)
     {
@@ -16,10 +34,6 @@ private static string FormatHexString(string hexColor)
         {
             hexColor = string.Concat(hexColor[0], hexColor[0], hexColor[1], hexColor[1], hexColor[2], hexColor[2]);
         }
-        else if (hexColor.Length != 6)
-        {
-            throw new ArgumentException("Hex color must be 3 or 6 characters long.");
-        }
 
         return hexColor;
     }

src/UnitTests/HexToRgb24Tests.cs

@@ -0,0 +1,62 @@
+using System;
+using NUnit.Framework;
+using RxTelegram.Bot.Utils;
+
+namespace RxTelegram.Bot.UnitTests;
+
+[TestFixture]
+public class HexToRgb24Tests
+{
+    [TestCase("#FF0000", ExpectedResult = 16711680)] // Red
+    [TestCase("#00FF00", ExpectedResult = 65280)] // Green
+    [TestCase("#0000FF", ExpectedResult = 255)] // Blue
+    [TestCase("#000000", ExpectedResult = 0)] // Black
+    [TestCase("#FFFFFF", ExpectedResult = 16777215)] // White
+    [TestCase("#ABCDEF", ExpectedResult = 11259375)] // Random color
+    public int Convert_ValidHexColor_ReturnsRgbValue(string hexColor) => HexToRgb24.Convert(hexColor);
+
+    [TestCase("#0000000")]
+    [TestCase("#00000000")]
+    public void Convert_InvalidHexLength_ThrowsArgumentException(string hexColor) =>
+        Assert.Throws<ArgumentException>(() => HexToRgb24.Convert(hexColor));
+
+    [TestCase("#G00000")]
+    [TestCase("#00000G")]
+    public void Convert_InvalidHexColor_ThrowsFormatException(string hexColor) =>
+        Assert.Throws<FormatException>(() => HexToRgb24.Convert(hexColor));
+
+    [TestCase("#0000000")]
+    [TestCase("#00000000")]
+    public void TryConvert_InvalidHexLength_ThrowsArgumentException(string hexColor) =>
+        Assert.That(HexToRgb24.TryConvert(hexColor, out _), Is.False);
+
+    [TestCase("#G00000")]
+    [TestCase("#00000G")]
+    public void TryConvert_InvalidHexColor_ThrowsFormatException(string hexColor) =>
+        Assert.That(HexToRgb24.TryConvert(hexColor, out _), Is.False);
+
+    [TestCase("#FF0000", ExpectedResult = true)] // Red
+    [TestCase("#00FF00", ExpectedResult = true)] // Green
+    [TestCase("#0000FF", ExpectedResult = true)] // Blue
+    [TestCase("#000000", ExpectedResult = true)] // Black
+    [TestCase("#FFFFFF", ExpectedResult = true)] // White
+    [TestCase("#ABCDEF", ExpectedResult = true)] // Random color
+    [TestCase("#G00000", ExpectedResult = false)]
+    [TestCase("#00000G", ExpectedResult = false)]
+    [TestCase("#0000000", ExpectedResult = false)]
+    [TestCase("#00000000", ExpectedResult = false)]
+    public bool TryConvert_ValidHexColor_ReturnsTrue(string hexColor) => HexToRgb24.TryConvert(hexColor, out _);
+
+    [TestCase("#FF0000", 16711680)] // Red
+    [TestCase("#00FF00", 65280)] // Green
+    [TestCase("#0000FF", 255)] // Blue
+    [TestCase("#000000", 0)] // Black
+    [TestCase("#FFFFFF", 16777215)] // White
+    [TestCase("#ABCDEF", 11259375)] // Random color
+    public void TryConvert_ValidHexColor_ReturnsRgbValue(string hexColor, int expected)
+    {
+        HexToRgb24.TryConvert(hexColor, out var result);
+        Assert.That(result, Is.EqualTo(expected));
+    }
+
+}