Add unit tests for SBOM ingestion and transformation

- Implement `SbomIngestServiceCollectionExtensionsTests` to verify the SBOM ingestion pipeline exports snapshots correctly.
- Create `SbomIngestTransformerTests` to ensure the transformation produces expected nodes and edges, including deduplication of license nodes and normalization of timestamps.
- Add `SbomSnapshotExporterTests` to test the export functionality for manifest, adjacency, nodes, and edges.
- Introduce `VexOverlayTransformerTests` to validate the transformation of VEX nodes and edges.
- Set up project file for the test project with necessary dependencies and configurations.
- Include JSON fixture files for testing purposes.

src/EvidenceLocker/StellaOps.EvidenceLocker/StellaOps.EvidenceLocker.Worker/Program.cs

@@ -1,7 +1,10 @@
-using StellaOps.EvidenceLocker.Worker;
-
-var builder = Host.CreateApplicationBuilder(args);
-builder.Services.AddHostedService<Worker>();
-
-var host = builder.Build();
-host.Run();
+using StellaOps.EvidenceLocker.Infrastructure.DependencyInjection;
+using StellaOps.EvidenceLocker.Worker;
+
+var builder = Host.CreateApplicationBuilder(args);
+
+builder.Services.AddEvidenceLockerInfrastructure(builder.Configuration);
+builder.Services.AddHostedService<Worker>();
+
+var host = builder.Build();
+await host.RunAsync();

src/EvidenceLocker/StellaOps.EvidenceLocker/StellaOps.EvidenceLocker.Worker/Worker.cs

@@ -1,16 +1,26 @@
-namespace StellaOps.EvidenceLocker.Worker;
-
-public class Worker(ILogger<Worker> logger) : BackgroundService
-{
-    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
-    {
-        while (!stoppingToken.IsCancellationRequested)
-        {
-            if (logger.IsEnabled(LogLevel.Information))
-            {
-                logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);
-            }
-            await Task.Delay(1000, stoppingToken);
-        }
-    }
-}
+using StellaOps.EvidenceLocker.Infrastructure.Db;
+
+namespace StellaOps.EvidenceLocker.Worker;
+
+public sealed class Worker(ILogger<Worker> logger, EvidenceLockerDataSource dataSource) : BackgroundService
+{
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        try
+        {
+            await using var connection = await dataSource.OpenConnectionAsync(stoppingToken);
+
+            if (logger.IsEnabled(LogLevel.Information))
+            {
+                logger.LogInformation("Evidence Locker worker verified connectivity to database '{Database}'", connection.Database);
+            }
+        }
+        catch (Exception ex) when (!stoppingToken.IsCancellationRequested)
+        {
+            logger.LogError(ex, "Evidence Locker worker failed to verify database connectivity.");
+            throw;
+        }
+
+        await Task.Delay(Timeout.Infinite, stoppingToken);
+    }
+}

src/EvidenceLocker/StellaOps.EvidenceLocker/StellaOps.EvidenceLocker.Worker/appsettings.Development.json

@@ -1,8 +1,10 @@
-{
-  "Logging": {
-    "LogLevel": {
-      "Default": "Information",
-      "Microsoft.Hosting.Lifetime": "Information"
-    }
-  }
-}
+{
+  Logging: {
+    LogLevel: {
+      Default: Information,
+      Microsoft.Hosting.Lifetime: Information
+    }
+  },
+  EvidenceLocker: {
+    Database: {
+      ConnectionString: Host=localhost

src/EvidenceLocker/StellaOps.EvidenceLocker/StellaOps.EvidenceLocker.Worker/appsettings.json

@@ -1,8 +1,10 @@
-{
-  "Logging": {
-    "LogLevel": {
-      "Default": "Information",
-      "Microsoft.Hosting.Lifetime": "Information"
-    }
-  }
-}
+{
+  Logging: {
+    LogLevel: {
+      Default: Information,
+      Microsoft.Hosting.Lifetime: Information
+    }
+  },
+  EvidenceLocker: {
+    Database: {
+      ConnectionString: Host=localhost