Add e2e auth test (#68)

* Add e2e auth test

pkg/mirror/authn_test.go

@@ -0,0 +1,34 @@
+//go:build e2e
+
+package mirror_test
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/docker/attest/pkg/mirror"
+	"github.com/docker/attest/pkg/oci"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRegistryAuth(t *testing.T) {
+	UnsignedTestImage := filepath.Join("..", "..", "test", "testdata", "unsigned-test-image")
+
+	attIdx, err := oci.SubjectIndexFromPath(UnsignedTestImage)
+	require.NoError(t, err)
+	// test cases for ecr, gcr and dockerhub
+	testCases := []struct {
+		Image string
+	}{
+		{Image: "175142243308.dkr.ecr.us-east-1.amazonaws.com/e2e-test-image:latest"},
+		{Image: "docker/image-signer-verifier-test:latest"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.Image, func(t *testing.T) {
+			err := mirror.PushIndexToRegistry(attIdx.Index, tc.Image)
+			require.NoError(t, err)
+			_, err = oci.SubjectIndexFromRemote(tc.Image)
+			require.NoError(t, err)
+		})
+	}
+}