feat: add oci layout test

pkg/oci/layout_test.go

@@ -0,0 +1,41 @@
+package oci_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/docker/attest/internal/test"
+	"github.com/docker/attest/pkg/attest"
+	"github.com/docker/attest/pkg/attestation"
+	"github.com/docker/attest/pkg/mirror"
+	"github.com/docker/attest/pkg/oci"
+	"github.com/docker/attest/pkg/policy"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestAttestationFromOCILayout(t *testing.T) {
+	ctx, signer := test.Setup(t)
+	outputLayout := test.CreateTempDir(t, "", "attest-oci-layout")
+
+	opts := &attestation.SigningOptions{}
+	attIdx, err := oci.IndexFromPath(oci.UnsignedTestImage)
+	require.NoError(t, err)
+	signedManifests, err := attest.SignStatements(ctx, attIdx.Index, signer, opts)
+	require.NoError(t, err)
+	signedIndex := attIdx.Index
+	signedIndex, err = attestation.UpdateIndexImages(signedIndex, signedManifests)
+	require.NoError(t, err)
+
+	spec, err := oci.ParseImageSpec(oci.LocalPrefix + outputLayout)
+	require.NoError(t, err)
+	err = mirror.SaveIndex([]*oci.ImageSpec{spec}, signedIndex, outputLayout)
+	require.NoError(t, err)
+
+	resolver, err := policy.CreateImageDetailsResolver(spec)
+	require.NoError(t, err)
+	desc, err := resolver.ImageDescriptor(ctx)
+	require.NoError(t, err)
+	digest := desc.Digest.String()
+	assert.True(t, strings.Contains(digest, "sha256:"))
+}