Refactor code structure for improved readability and maintainability; optimize performance in key functions.

src/__Libraries/__Tests/StellaOps.Canonicalization.Tests/CanonicalJsonSerializerTests.cs

@@ -0,0 +1,58 @@
+using FluentAssertions;
+using StellaOps.Canonicalization.Json;
+using StellaOps.Canonicalization.Ordering;
+using Xunit;
+
+namespace StellaOps.Canonicalization.Tests;
+
+public class CanonicalJsonSerializerTests
+{
+    [Fact]
+    public void Serialize_Dictionary_OrdersKeysAlphabetically()
+    {
+        var dict = new Dictionary<string, int> { ["z"] = 1, ["a"] = 2, ["m"] = 3 };
+        var json = CanonicalJsonSerializer.Serialize(dict);
+        json.Should().Be("{\"a\":2,\"m\":3,\"z\":1}");
+    }
+
+    [Fact]
+    public void Serialize_DateTimeOffset_UsesUtcIso8601()
+    {
+        var dt = new DateTimeOffset(2024, 1, 15, 10, 30, 0, TimeSpan.FromHours(5));
+        var obj = new { Timestamp = dt };
+        var json = CanonicalJsonSerializer.Serialize(obj);
+        json.Should().Contain("2024-01-15T05:30:00.000Z");
+    }
+
+    [Fact]
+    public void Serialize_NullValues_AreOmitted()
+    {
+        var obj = new { Name = "test", Value = (string?)null };
+        var json = CanonicalJsonSerializer.Serialize(obj);
+        json.Should().NotContain("value");
+    }
+
+    [Fact]
+    public void SerializeWithDigest_ProducesConsistentDigest()
+    {
+        var obj = new { Name = "test", Value = 123 };
+        var (_, digest1) = CanonicalJsonSerializer.SerializeWithDigest(obj);
+        var (_, digest2) = CanonicalJsonSerializer.SerializeWithDigest(obj);
+        digest1.Should().Be(digest2);
+    }
+}
+
+public class PackageOrdererTests
+{
+    [Fact]
+    public void StableOrder_OrdersByPurlFirst()
+    {
+        var packages = new[]
+        {
+            (purl: "pkg:npm/b@1.0.0", name: "b", version: "1.0.0"),
+            (purl: "pkg:npm/a@1.0.0", name: "a", version: "1.0.0")
+        };
+        var ordered = packages.StableOrder(p => p.purl, p => p.name, p => p.version, _ => null).ToList();
+        ordered[0].purl.Should().Be("pkg:npm/a@1.0.0");
+    }
+}

src/__Libraries/__Tests/StellaOps.Canonicalization.Tests/Properties/CanonicalJsonProperties.cs

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+using FsCheck;
+using FsCheck.Xunit;
+using StellaOps.Canonicalization.Json;
+using StellaOps.Canonicalization.Ordering;
+
+namespace StellaOps.Canonicalization.Tests.Properties;
+
+public class CanonicalJsonProperties
+{
+    [Property]
+    public Property Serialize_IsIdempotent(Dictionary<string, int> dict)
+    {
+        var json1 = CanonicalJsonSerializer.Serialize(dict);
+        var json2 = CanonicalJsonSerializer.Serialize(dict);
+        return (json1 == json2).ToProperty();
+    }
+
+    [Property]
+    public Property Serialize_OrderIndependent(Dictionary<string, int> dict)
+    {
+        var reversed = dict.Reverse().ToDictionary(x => x.Key, x => x.Value);
+        var json1 = CanonicalJsonSerializer.Serialize(dict);
+        var json2 = CanonicalJsonSerializer.Serialize(reversed);
+        return (json1 == json2).ToProperty();
+    }
+
+    [Property]
+    public Property Digest_IsDeterministic(string input)
+    {
+        var obj = new { Value = input ?? string.Empty };
+        var (_, digest1) = CanonicalJsonSerializer.SerializeWithDigest(obj);
+        var (_, digest2) = CanonicalJsonSerializer.SerializeWithDigest(obj);
+        return (digest1 == digest2).ToProperty();
+    }
+}
+
+public class OrderingProperties
+{
+    [Property]
+    public Property PackageOrdering_IsStable(List<(string purl, string name, string version)> packages)
+    {
+        var ordered1 = packages.StableOrder(p => p.purl, p => p.name, p => p.version, _ => null).ToList();
+        var ordered2 = packages.StableOrder(p => p.purl, p => p.name, p => p.version, _ => null).ToList();
+        return ordered1.SequenceEqual(ordered2).ToProperty();
+    }
+}

src/__Libraries/__Tests/StellaOps.Canonicalization.Tests/StellaOps.Canonicalization.Tests.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FsCheck.Xunit" Version="2.16.6" />
+    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="xunit" Version="2.9.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.7">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\StellaOps.Canonicalization\StellaOps.Canonicalization.csproj" />
+  </ItemGroup>
+</Project>