chore(tvix/nar-bridge): move to nar-bridge-go

Make some space for the rust implementation.

Change-Id: I924dc1657be10abe5a11951c3b9de50bae06db19
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11662
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: yuka <yuka@yuka.dev>

tvix/nar-bridge-go/pkg/importer/util_test.go

@@ -0,0 +1,34 @@
+package importer_test
+
+import (
+	"io"
+	"testing"
+
+	castorev1pb "code.tvl.fyi/tvix/castore-go"
+	"github.com/google/go-cmp/cmp"
+	"google.golang.org/protobuf/testing/protocmp"
+	"lukechampine.com/blake3"
+)
+
+func requireProtoEq(t *testing.T, expected interface{}, actual interface{}) {
+	if diff := cmp.Diff(expected, actual, protocmp.Transform()); diff != "" {
+		t.Errorf("unexpected difference:\n%v", diff)
+	}
+}
+
+func mustDirectoryDigest(d *castorev1pb.Directory) []byte {
+	dgst, err := d.Digest()
+	if err != nil {
+		panic(err)
+	}
+	return dgst
+}
+
+func mustBlobDigest(r io.Reader) []byte {
+	hasher := blake3.New(32, nil)
+	_, err := io.Copy(hasher, r)
+	if err != nil {
+		panic(err)
+	}
+	return hasher.Sum([]byte{})
+}