[#147] Work around object package

- implement Stringer interface and Parse method for object.Address
- increase test coverage

closes #147

Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>

pkg/object/address.go

@@ -1,6 +1,9 @@
 package object
 
 import (
+	"strings"
+
+	"github.com/nspcc-dev/neofs-api-go/internal"
 	"github.com/nspcc-dev/neofs-api-go/pkg/container"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/pkg/errors"
@@ -9,6 +12,15 @@ import (
 // Address represents v2-compatible object address.
 type Address refs.Address
 
+// ErrBadAddress returns when string representation doesn't
+// contains Container.ID and Object.ID separated by `/`.
+const ErrBadAddress = internal.Error("address should contains container.ID and object.ID separated with `/`")
+
+const (
+	addressParts     = 2
+	addressSeparator = "/"
+)
+
 // NewAddressFromV2 converts v2 Address message to Address.
 func NewAddressFromV2(aV2 *refs.Address) *Address {
 	return (*Address)(aV2)
@@ -59,3 +71,34 @@ func (a *Address) GetObjectID() *ID {
 func (a *Address) SetObjectID(id *ID) {
 	(*refs.Address)(a).SetObjectID(id.ToV2())
 }
+
+// Parse converts base58 string representation into Address.
+func (a *Address) Parse(s string) error {
+	var (
+		err   error
+		oid   = NewID()
+		cid   = container.NewID()
+		parts = strings.Split(s, addressSeparator)
+	)
+
+	if len(parts) != addressParts {
+		return ErrBadAddress
+	} else if err = cid.Parse(parts[0]); err != nil {
+		return err
+	} else if err = oid.Parse(parts[1]); err != nil {
+		return err
+	}
+
+	a.SetObjectID(oid)
+	a.SetContainerID(cid)
+
+	return nil
+}
+
+// String returns string representation of Object.Address.
+func (a *Address) String() string {
+	return strings.Join([]string{
+		a.GetContainerID().String(),
+		a.GetObjectID().String(),
+	}, addressSeparator)
+}

pkg/object/address_test.go

@@ -1,6 +1,7 @@
 package object
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/nspcc-dev/neofs-api-go/pkg/container"
@@ -27,3 +28,35 @@ func TestAddress_SetObjectID(t *testing.T) {
 
 	require.Equal(t, oid, a.GetObjectID())
 }
+
+func TestAddress_Parse(t *testing.T) {
+	cid := container.NewID()
+	cid.SetSHA256(randSHA256Checksum(t))
+
+	oid := NewID()
+	oid.SetSHA256(randSHA256Checksum(t))
+
+	t.Run("should parse successful", func(t *testing.T) {
+		s := strings.Join([]string{cid.String(), oid.String()}, addressSeparator)
+		a := NewAddress()
+
+		require.NoError(t, a.Parse(s))
+		require.Equal(t, oid, a.GetObjectID())
+		require.Equal(t, cid, a.GetContainerID())
+	})
+
+	t.Run("should fail for bad address", func(t *testing.T) {
+		s := strings.Join([]string{cid.String()}, addressSeparator)
+		require.EqualError(t, NewAddress().Parse(s), ErrBadAddress.Error())
+	})
+
+	t.Run("should fail on container.ID", func(t *testing.T) {
+		s := strings.Join([]string{"1", "2"}, addressSeparator)
+		require.EqualError(t, NewAddress().Parse(s), container.ErrBadID.Error())
+	})
+
+	t.Run("should fail on object.ID", func(t *testing.T) {
+		s := strings.Join([]string{cid.String(), "2"}, addressSeparator)
+		require.EqualError(t, NewAddress().Parse(s), ErrBadID.Error())
+	})
+}