[#230] pkg: Implement storage group type with basic methods

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/storagegroup/storagegroup_test.go

@@ -0,0 +1,79 @@
+package storagegroup_test
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg"
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-api-go/pkg/storagegroup"
+	"github.com/stretchr/testify/require"
+)
+
+func testSHA256() (cs [sha256.Size]byte) {
+	_, _ = rand.Read(cs[:])
+	return
+}
+
+func testChecksum() *pkg.Checksum {
+	h := pkg.NewChecksum()
+	h.SetSHA256(testSHA256())
+
+	return h
+}
+
+func testOID() *object.ID {
+	id := object.NewID()
+	id.SetSHA256(testSHA256())
+
+	return id
+}
+
+func TestStorageGroup(t *testing.T) {
+	sg := storagegroup.New()
+
+	sz := uint64(13)
+	sg.SetValidationDataSize(sz)
+	require.Equal(t, sz, sg.ValidationDataSize())
+
+	cs := testChecksum()
+	sg.SetValidationDataHash(cs)
+	require.Equal(t, cs, sg.ValidationDataHash())
+
+	exp := uint64(33)
+	sg.SetExpirationEpoch(exp)
+	require.Equal(t, exp, sg.ExpirationEpoch())
+
+	members := []*object.ID{testOID(), testOID()}
+	sg.SetMembers(members)
+	require.Equal(t, members, sg.Members())
+}
+
+func TestStorageGroupEncoding(t *testing.T) {
+	sg := storagegroup.New()
+	sg.SetValidationDataSize(13)
+	sg.SetValidationDataHash(testChecksum())
+	sg.SetExpirationEpoch(33)
+	sg.SetMembers([]*object.ID{testOID(), testOID()})
+
+	t.Run("binary", func(t *testing.T) {
+		data, err := sg.Marshal()
+		require.NoError(t, err)
+
+		sg2 := storagegroup.New()
+		require.NoError(t, sg2.Unmarshal(data))
+
+		require.Equal(t, sg, sg2)
+	})
+
+	t.Run("json", func(t *testing.T) {
+		data, err := sg.MarshalJSON()
+		require.NoError(t, err)
+
+		sg2 := storagegroup.New()
+		require.NoError(t, sg2.UnmarshalJSON(data))
+
+		require.Equal(t, sg, sg2)
+	})
+}