fix: "ax" is not same as "Ay"

It ignore next chars if
there is a char diffrent only in case before them

Author: GihanSoft

src/NaturalStringComparer/NaturalComparer.cs

@@ -75,10 +75,7 @@ public static int Compare(ReadOnlySpan<char> x, ReadOnlySpan<char> y, StringComp
 
         for (var i = 0; i < length; i++)
         {
-            var xCh = x[i];
-            var yCh = y[i];
-
-            if (char.IsDigit(xCh) && char.IsDigit(yCh))
+            if (char.IsDigit(x[i]) && char.IsDigit(y[i]))
             {
                 var xOut = GetNumber(x.Slice(i), out var xNumAsSpan);
                 var yOut = GetNumber(y.Slice(i), out var yNumAsSpan);
@@ -98,9 +95,10 @@ public static int Compare(ReadOnlySpan<char> x, ReadOnlySpan<char> y, StringComp
                 continue;
             }
 
-            if (xCh != yCh)
+            var charCompareResult = x.Slice(i, 1).CompareTo(y.Slice(i, 1), stringComparison);
+            if (charCompareResult != 0)
             {
-                return x.Slice(i, 1).CompareTo(y.Slice(i, 1), stringComparison);
+                return charCompareResult;
             }
         }
 

test/NaturalStringComparerTest/NaturalStringComparerTest.csproj

@@ -6,6 +6,11 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Content Include="xunit.runner.json" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FluentAssertions" Version="6.12.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="*" />
     <PackageReference Include="xunit" Version="*" />
     <PackageReference Include="xunit.runner.visualstudio" Version="*" />

test/NaturalStringComparerTest/UnitTestUnsafe.cs

@@ -4,6 +4,8 @@ namespace NaturalStringComparerTest
     using System.Collections.Generic;
     using System.Numerics;
 
+    using FluentAssertions;
+
     using GihanSoft.String;
 
     using Xunit;
@@ -24,6 +26,28 @@ public UnitTestUnsafe()
             }
         }
 
+        [InlineData("abc", "ABC")]
+        [InlineData("abc", "aBc")]
+        [InlineData("XX11xx", "xx11XX")]
+        [InlineData("11xx22", "11XX22")]
+        [Theory]
+        public void Given_OrdinalIgnoreCase_When_strings_only_different_in_case_Then_return_0(string x, string y)
+        {
+            var actual = NaturalComparer.Compare(x, y, StringComparison.OrdinalIgnoreCase);
+            actual.Should().Be(0);
+        }
+
+        [Fact]
+        public void Given_OrdinalIgnoreCase_When_there_is_a_different_char_after_a_case_different_char_Then_should_check_rest_of_span()
+        {
+            var x = "ax";
+            var y = "Ay";
+            var expected = StringComparer.OrdinalIgnoreCase.Compare("x", "y");
+
+            var actual = NaturalComparer.Compare(x, y, StringComparison.OrdinalIgnoreCase);
+            actual.Should().Be(expected);
+        }
+
         [Fact]
         public void TestLargeNumber()
         {

test/NaturalStringComparerTest/xunit.runner.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "https://xunit.net/schema/current/xunit.runner.schema.json",
+  "methodDisplayOptions": "all"
+}