Remove FluentAssertions; add internal xUnit assertion shims

Replaced FluentAssertions with custom extension methods in AssertionExtensions.cs that provide a similar API using xUnit's Assert. Removed the FluentAssertions package and related global using. This reduces dependencies and keeps assertion syntax familiar.

Author: electricessence

Tests/AssertionExtensions.cs

@@ -0,0 +1,48 @@
+namespace Open.Text.Tests;
+
+/// <summary>
+/// Lightweight shim providing FluentAssertions-like API using xUnit assertions.
+/// </summary>
+public static class AssertionExtensions
+{
+	public static AssertionResult<T> Should<T>(this T actual) => new(actual);
+
+	public readonly struct AssertionResult<T>
+	{
+		private readonly T _actual;
+
+		public AssertionResult(T actual) => _actual = actual;
+
+		public void Be(T expected) => Assert.Equal(expected, _actual);
+		
+		public void BeEquivalentTo(T expected) => Assert.Equal(expected, _actual);
+	}
+
+	public static BoolAssertionResult Should(this bool actual) => new(actual);
+
+	public readonly struct BoolAssertionResult
+	{
+		private readonly bool _actual;
+
+		public BoolAssertionResult(bool actual) => _actual = actual;
+
+		public void Be(bool expected) => Assert.Equal(expected, _actual);
+		
+		public void BeTrue() => Assert.True(_actual);
+		
+		public void BeFalse() => Assert.False(_actual);
+	}
+
+	public static StringAssertionResult Should(this string? actual) => new(actual);
+
+	public readonly struct StringAssertionResult
+	{
+		private readonly string? _actual;
+
+		public StringAssertionResult(string? actual) => _actual = actual;
+
+		public void Be(string? expected) => Assert.Equal(expected, _actual);
+		
+		public void BeEquivalentTo(string? expected) => Assert.Equal(expected, _actual);
+	}
+}

Tests/Open.Text.Tests.csproj

@@ -20,7 +20,6 @@
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 			<PrivateAssets>all</PrivateAssets>
 		</PackageReference>
-		<PackageReference Include="FluentAssertions" Version="6.12.2" />
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
 		<PackageReference Include="xunit" Version="2.9.3" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">

Tests/_Global.cs

@@ -1,3 +1,2 @@
-global using FluentAssertions;
-global using System.Diagnostics.CodeAnalysis;
+global using System.Diagnostics.CodeAnalysis;
 global using Xunit;