Refactor code structure for improved readability and maintainability; removed redundant code blocks and optimized function calls.

src/Graph/__Tests/StellaOps.Graph.Indexer.Tests/GraphIdentityTests.cs

@@ -0,0 +1,46 @@
+using System.Collections.Immutable;
+using StellaOps.Graph.Indexer.Schema;
+
+namespace StellaOps.Graph.Indexer.Tests;
+
+public sealed class GraphIdentityTests
+{
+    [Fact]
+    public void ComputeNodeId_IsDeterministic_WhenTupleOrderChanges()
+    {
+        var tupleA = ImmutableDictionary<string, string>.Empty
+            .Add("purl", "pkg:npm/test@1.0.0")
+            .Add("reason", "declared")
+            .Add("scope", "runtime");
+
+        var tupleB = ImmutableDictionary<string, string>.Empty
+            .Add("scope", "runtime")
+            .Add("reason", "declared")
+            .Add("purl", "pkg:npm/test@1.0.0");
+
+        var idA = GraphIdentity.ComputeNodeId("Tenant-A", "Component", tupleA);
+        var idB = GraphIdentity.ComputeNodeId("tenant-a", "component", tupleB);
+
+        Assert.Equal(idA, idB);
+        Assert.StartsWith("gn:tenant-a:component:", idA);
+    }
+
+    [Fact]
+    public void ComputeEdgeId_IsCaseInsensitiveExceptFingerprintFields()
+    {
+        var tupleLower = ImmutableDictionary<string, string>.Empty
+            .Add("digest", "sha256:ABC")
+            .Add("source", "sbom");
+
+        var tupleUpper = ImmutableDictionary<string, string>.Empty
+            .Add("digest", "sha256:abc")
+            .Add("source", "SBOM");
+
+        var edgeA = GraphIdentity.ComputeEdgeId("TENANT", "depends_on", tupleLower);
+        var edgeB = GraphIdentity.ComputeEdgeId("tenant", "DEPENDS_ON", tupleUpper);
+
+        // digest key is case-sensitive by design; different casing produces different id when value changes.
+        Assert.NotEqual(edgeA, edgeB);
+        Assert.StartsWith("ge:tenant:DEPENDS_ON:", edgeA);
+    }
+}