add a token container with serialization as CARv1 file

pkg/container/container_test.go

@@ -0,0 +1,52 @@
+package container
+
+import (
+	"bytes"
+	"crypto/rand"
+	"io"
+	"testing"
+
+	"github.com/ipfs/go-cid"
+	mh "github.com/multiformats/go-multihash"
+	"github.com/stretchr/testify/require"
+)
+
+func TestContainerRoundTrip(t *testing.T) {
+	for _, tc := range []struct {
+		name   string
+		writer func(ctn Container, w io.Writer) error
+		reader func(io.Reader) (Container, error)
+	}{
+		{"carBytes", Container.ToCar, FromCar},
+		{"carBase64", Container.ToCarBase64, FromCarBase64},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			ctn := New()
+
+			builder := cid.V1Builder{Codec: cid.Raw, MhType: mh.SHA2_256}
+
+			for i := 0; i < 10; i++ {
+				data := randBytes(32)
+				c, err := builder.Sum(data)
+				require.NoError(t, err)
+				ctn.AddBytes(c, data)
+			}
+
+			buf := bytes.NewBuffer(nil)
+
+			err := tc.writer(ctn, buf)
+			require.NoError(t, err)
+
+			ctn2, err := tc.reader(bytes.NewReader(buf.Bytes()))
+			require.NoError(t, err)
+
+			require.Equal(t, ctn, ctn2)
+		})
+	}
+}
+
+func randBytes(n int) []byte {
+	b := make([]byte, n)
+	_, _ = rand.Read(b)
+	return b
+}