part #2

src/__Tests/interop/StellaOps.Interop.Tests/InteropTestHarness.Attestation.cs

@@ -0,0 +1,27 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace StellaOps.Interop.Tests;
+
+public sealed partial class InteropTestHarness
+{
+    /// <summary>
+    /// Attest SBOM using cosign.
+    /// </summary>
+    public async Task<AttestationResult> AttestWithCosignAsync(
+        string sbomPath,
+        string imageRef,
+        CancellationToken ct = default)
+    {
+        EnsureToolsAvailable();
+        var result = await _toolManager.RunAsync(
+            "cosign",
+            $"attest --predicate {sbomPath} --type cyclonedx {imageRef} --yes",
+            ct).ConfigureAwait(false);
+
+        if (!result.Success)
+            return AttestationResult.Failed(result.Error ?? "Cosign attestation failed");
+
+        return new AttestationResult(Success: true, ImageRef: imageRef);
+    }
+}