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

tests/interop/StellaOps.Interop.Tests/Analysis/FindingsParityAnalyzer.cs

@@ -0,0 +1,117 @@
+namespace StellaOps.Interop.Tests.Analysis;
+
+/// <summary>
+/// Analyzes and categorizes differences between tool findings.
+/// </summary>
+public sealed class FindingsParityAnalyzer
+{
+    /// <summary>
+    /// Categorizes differences between tools.
+    /// </summary>
+    public ParityAnalysisReport Analyze(
+        IReadOnlyList<Finding> stellaFindings,
+        IReadOnlyList<GrypeFinding> grypeFindings)
+    {
+        var differences = new List<FindingDifference>();
+
+        // Category 1: Version matching differences
+        // (e.g., semver vs non-semver interpretation)
+        var versionDiffs = AnalyzeVersionMatchingDifferences(stellaFindings, grypeFindings);
+        differences.AddRange(versionDiffs);
+
+        // Category 2: Feed coverage differences
+        // (e.g., Stella has feed X, Grype doesn't)
+        var feedDiffs = AnalyzeFeedCoverageDifferences(stellaFindings, grypeFindings);
+        differences.AddRange(feedDiffs);
+
+        // Category 3: Package identification differences
+        // (e.g., different PURL generation)
+        var purlDiffs = AnalyzePurlDifferences(stellaFindings, grypeFindings);
+        differences.AddRange(purlDiffs);
+
+        // Category 4: VEX application differences
+        // (e.g., Stella applies VEX, Grype doesn't)
+        var vexDiffs = AnalyzeVexDifferences(stellaFindings, grypeFindings);
+        differences.AddRange(vexDiffs);
+
+        return new ParityAnalysisReport
+        {
+            TotalDifferences = differences.Count,
+            VersionMatchingDifferences = versionDiffs,
+            FeedCoverageDifferences = feedDiffs,
+            PurlDifferences = purlDiffs,
+            VexDifferences = vexDiffs,
+            AcceptableDifferences = differences.Count(d => d.IsAcceptable),
+            RequiresInvestigation = differences.Count(d => !d.IsAcceptable)
+        };
+    }
+
+    private static List<FindingDifference> AnalyzeVersionMatchingDifferences(
+        IReadOnlyList<Finding> stellaFindings,
+        IReadOnlyList<GrypeFinding> grypeFindings)
+    {
+        var differences = new List<FindingDifference>();
+
+        // TODO: Implement version matching analysis
+        // Compare how Stella and Grype interpret version ranges
+        // e.g., >=1.0.0 vs ^1.0.0
+
+        return differences;
+    }
+
+    private static List<FindingDifference> AnalyzeFeedCoverageDifferences(
+        IReadOnlyList<Finding> stellaFindings,
+        IReadOnlyList<GrypeFinding> grypeFindings)
+    {
+        var differences = new List<FindingDifference>();
+
+        // TODO: Implement feed coverage analysis
+        // Identify which vulnerabilities come from feeds only one tool has
+        // e.g., Stella has GHSA, Grype doesn't, or vice versa
+
+        return differences;
+    }
+
+    private static List<FindingDifference> AnalyzePurlDifferences(
+        IReadOnlyList<Finding> stellaFindings,
+        IReadOnlyList<GrypeFinding> grypeFindings)
+    {
+        var differences = new List<FindingDifference>();
+
+        // TODO: Implement PURL difference analysis
+        // Compare how packages are identified
+        // e.g., pkg:npm/package vs pkg:npm/package@version
+
+        return differences;
+    }
+
+    private static List<FindingDifference> AnalyzeVexDifferences(
+        IReadOnlyList<Finding> stellaFindings,
+        IReadOnlyList<GrypeFinding> grypeFindings)
+    {
+        var differences = new List<FindingDifference>();
+
+        // TODO: Implement VEX application analysis
+        // Stella applies VEX documents, Grype may not
+        // This is an acceptable difference
+
+        return differences;
+    }
+}
+
+public sealed class ParityAnalysisReport
+{
+    public int TotalDifferences { get; init; }
+    public IReadOnlyList<FindingDifference> VersionMatchingDifferences { get; init; } = [];
+    public IReadOnlyList<FindingDifference> FeedCoverageDifferences { get; init; } = [];
+    public IReadOnlyList<FindingDifference> PurlDifferences { get; init; } = [];
+    public IReadOnlyList<FindingDifference> VexDifferences { get; init; } = [];
+    public int AcceptableDifferences { get; init; }
+    public int RequiresInvestigation { get; init; }
+}
+
+public sealed record FindingDifference(
+    string Category,
+    string Description,
+    bool IsAcceptable,
+    string? Reason = null);