[#214] object: Implement Get\Head requests for EC object

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

object/error_test.go

@@ -1,9 +1,12 @@
 package object_test
 
 import (
+	"crypto/rand"
 	"errors"
 	"testing"
 
+	objectV2 "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
 	"github.com/stretchr/testify/require"
 )
@@ -31,3 +34,43 @@ func generateSplitInfo() *object.SplitInfo {
 
 	return si
 }
+
+func TestNewECInfoError(t *testing.T) {
+	var (
+		ei = generateECInfo()
+
+		err         error = object.NewECInfoError(ei)
+		expectedErr *object.ECInfoError
+	)
+
+	require.True(t, errors.As(err, &expectedErr))
+
+	eiErr, ok := err.(*object.ECInfoError)
+	require.True(t, ok)
+	require.Equal(t, ei, eiErr.ECInfo())
+}
+
+func generateECInfo() *object.ECInfo {
+	ei := object.NewECInfo()
+	ei.Chunks = append(ei.Chunks, objectV2.ECChunk{
+		ID:    generateV2ID(),
+		Index: 0,
+		Total: 2,
+	})
+	ei.Chunks = append(ei.Chunks, objectV2.ECChunk{
+		ID:    generateV2ID(),
+		Index: 1,
+		Total: 2,
+	})
+	return ei
+}
+
+func generateV2ID() refs.ObjectID {
+	var buf [32]byte
+	_, _ = rand.Read(buf[:])
+
+	var id refs.ObjectID
+	id.SetValue(buf[:])
+
+	return id
+}