[#210] subnet: Refactor and document package functionality

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

netmap/policy.go

@@ -36,13 +36,31 @@ func (p *PlacementPolicy) ToV2() *netmap.PlacementPolicy {
 
 // SubnetID returns subnet to select nodes from.
 func (p *PlacementPolicy) SubnetID() *subnetid.ID {
-	return (*subnetid.ID)(
+	idv2 := (*netmap.PlacementPolicy)(p).GetSubnetID()
-		(*netmap.PlacementPolicy)(p).GetSubnetID())
+	if idv2 == nil {
+		return nil
+	}
+
+	var id subnetid.ID
+
+	err := id.ReadFromV2(*idv2)
+	if err != nil {
+		panic(err) // will disappear after netmap package refactor
+	}
+
+	return &id
 }
 
 // SetSubnetID sets subnet to select nodes from.
 func (p *PlacementPolicy) SetSubnetID(subnet *subnetid.ID) {
-	(*netmap.PlacementPolicy)(p).SetSubnetID((*refs.SubnetID)(subnet))
+	var idv2 *refs.SubnetID
+
+	if subnet != nil {
+		idv2 = new(refs.SubnetID)
+		subnet.WriteToV2(idv2)
+	}
+
+	(*netmap.PlacementPolicy)(p).SetSubnetID(idv2)
 }
 
 // Replicas returns list of object replica descriptors.

netmap/subnet.go

@@ -2,6 +2,7 @@ package netmap
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/nspcc-dev/neofs-api-go/v2/netmap"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
@@ -48,9 +49,12 @@ func (i *NodeInfo) IterateSubnets(f func(subnetid.ID) error) error {
 	var id subnetid.ID
 
 	return netmap.IterateSubnets((*netmap.NodeInfo)(i), func(idv2 refs.SubnetID) error {
-		id.FromV2(idv2)
+		err := id.ReadFromV2(idv2)
+		if err != nil {
+			return fmt.Errorf("invalid subnet: %w", err)
+		}
 
-		err := f(id)
+		err = f(id)
 		if errors.Is(err, ErrRemoveSubnet) {
 			return netmap.ErrRemoveSubnet
 		}
@@ -66,7 +70,7 @@ var errAbortSubnetIter = errors.New("abort subnet iterator")
 // Function is NPE-safe: nil NodeInfo always belongs to zero subnet only.
 func BelongsToSubnet(node *NodeInfo, id subnetid.ID) bool {
 	err := node.IterateSubnets(func(id_ subnetid.ID) error {
-		if id.Equals(&id_) {
+		if id.Equals(id_) {
 			return errAbortSubnetIter
 		}
 

netmap/subnet_test.go

@@ -12,7 +12,7 @@ func TestNodeInfoSubnets(t *testing.T) {
 	t.Run("enter subnet", func(t *testing.T) {
 		var id subnetid.ID
 
-		id.SetNumber(13)
+		id.SetNumeric(13)
 
 		var node netmap.NodeInfo
 
@@ -35,8 +35,8 @@ func TestNodeInfoSubnets(t *testing.T) {
 		t.Run("not last", func(t *testing.T) {
 			var id, idrm subnetid.ID
 
-			id.SetNumber(13)
+			id.SetNumeric(13)
-			idrm.SetNumber(23)
+			idrm.SetNumeric(23)
 
 			var node netmap.NodeInfo
 
@@ -44,7 +44,7 @@ func TestNodeInfoSubnets(t *testing.T) {
 			node.EnterSubnet(idrm)
 
 			err := node.IterateSubnets(func(id subnetid.ID) error {
-				if subnetid.IsZero(id) || id.Equals(&idrm) {
+				if subnetid.IsZero(id) || id.Equals(idrm) {
 					return netmap.ErrRemoveSubnet
 				}
 
@@ -100,7 +100,7 @@ func TestEnterSubnet(t *testing.T) {
 	node.ExitSubnet(id)
 	require.False(t, netmap.BelongsToSubnet(&node, id))
 
-	id.SetNumber(10)
+	id.SetNumeric(10)
 	node.EnterSubnet(id)
 	require.True(t, netmap.BelongsToSubnet(&node, id))
 	require.False(t, netmap.BelongsToSubnet(&node, subnetid.ID{}))
@@ -113,8 +113,8 @@ func TestEnterSubnet(t *testing.T) {
 func TestBelongsToSubnet(t *testing.T) {
 	var id, idMiss, idZero subnetid.ID
 
-	id.SetNumber(13)
+	id.SetNumeric(13)
-	idMiss.SetNumber(23)
+	idMiss.SetNumeric(23)
 
 	var node netmap.NodeInfo
 

subnet/doc.go

@@ -0,0 +1,10 @@
+/*
+Package subnet collects functionality related to the NeoFS subnets.
+
+Subnet of a particular NeoFS network consists of a subset of the storage nodes
+of that network. Subnet of the whole network is called zero. Info type acts as
+a subnet descriptor. Each subnet is owned by the user who created it. Information
+about all subnets is stored in the Subnet contract of the NeoFS Sidechain.
+
+*/
+package subnet

subnet/id/doc.go

@@ -0,0 +1,10 @@
+/*
+Package subnetid provides primitives to work with subnet identification in NeoFS.
+
+ID type is used for global subnet identity inside the NeoFS network.
+
+Using package types in an application is recommended to potentially work with
+different protocol versions with which these types are compatible.
+
+*/
+package subnetid

subnet/id/id.go

@@ -2,95 +2,104 @@ package subnetid
 
 import (
 	"fmt"
+	"strconv"
 
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 )
 
-// ID represents NeoFS subnet identifier.
+// ID represents unique identifier of the subnet in the NeoFS network.
 //
-// The type is compatible with the corresponding message from NeoFS API V2 protocol.
+// ID is mutually compatible with github.com/nspcc-dev/neofs-api-go/v2/refs.SubnetID
+// message. See ReadFromV2 / WriteToV2 methods.
 //
-// Zero value and nil pointer is equivalent to zero subnet ID.
+// Instances can be created using built-in var declaration. Zero value is
-type ID refs.SubnetID
+// equivalent to identifier of the zero subnet (whole NeoFS network).
-
+type ID struct {
-// FromV2 initializes ID from refs.SubnetID message structure. Must not be called on nil.
+	m refs.SubnetID
-//
-// Note: nil refs.SubnetID corresponds to zero ID value or nil pointer to it.
-func (x *ID) FromV2(msg refs.SubnetID) {
-	*x = ID(msg)
 }
 
-// WriteToV2 writes ID to refs.SubnetID message structure. The message must not be nil.
+// ReadFromV2 reads ID from the refs.SubnetID message. Checks if the
+// message conforms to NeoFS API V2 protocol.
 //
-// Note: nil ID corresponds to zero refs.SubnetID value or nil pointer to it.
+// See also WriteToV2.
+func (x *ID) ReadFromV2(msg refs.SubnetID) error {
+	x.m = msg
+	return nil
+}
+
+// WriteToV2 writes ID to refs.SubnetID message structure. The message MUST NOT
+// be nil.
+//
+// See also ReadFromV2.
 func (x ID) WriteToV2(msg *refs.SubnetID) {
-	*msg = refs.SubnetID(x)
+	*msg = x.m
 }
 
-// Equals returns true iff both instances identify the same subnet.
+// Equals defines a comparison relation between two ID instances.
 //
-// Method is NPE-safe: nil pointer equals to pointer to zero value.
+// Note that comparison using '==' operator is not recommended since it MAY result
-func (x *ID) Equals(x2 *ID) bool {
+// in loss of compatibility.
-	return (*refs.SubnetID)(x).GetValue() == (*refs.SubnetID)(x2).GetValue()
+func (x ID) Equals(x2 ID) bool {
+	return x.m.GetValue() == x2.m.GetValue()
 }
 
-// MarshalText encodes ID into text format according to particular NeoFS API protocol.
+// EncodeToString encodes ID into NeoFS API protocol string (base10 encoding).
-// Supported versions:
-//  * V2 (see refs.SubnetID type).
 //
-// Implements encoding.TextMarshaler.
+// See also DecodeString.
-func (x *ID) MarshalText() ([]byte, error) {
+func (x ID) EncodeToString() string {
-	return (*refs.SubnetID)(x).MarshalText()
+	return strconv.FormatUint(uint64(x.m.GetValue()), 10)
 }
 
-// UnmarshalText decodes ID from the text according to particular NeoFS API protocol.
+// DecodeString decodes string calculated using EncodeToString. Returns
-// Must not be called on nil. Supported versions:
+// an error if s is malformed.
-//  * V2 (see refs.SubnetID type).
+func (x *ID) DecodeString(s string) error {
-//
+	num, err := strconv.ParseUint(s, 10, 32)
-// Implements encoding.TextUnmarshaler.
-func (x *ID) UnmarshalText(text []byte) error {
-	return (*refs.SubnetID)(x).UnmarshalText(text)
-}
-
-// String returns string representation of ID using MarshalText.
-// Returns string with message on error.
-//
-// Implements fmt.Stringer.
-func (x *ID) String() string {
-	text, err := x.MarshalText()
 	if err != nil {
-		return fmt.Sprintf("<invalid> %v", err)
+		return fmt.Errorf("invalid numeric value: %w", err)
 	}
 
-	return string(text)
+	x.m.SetValue(uint32(num))
+
+	return nil
 }
 
-// Marshal encodes ID into a binary format of NeoFS API V2 protocol (Protocol Buffers with direct field order).
+// String implements fmt.Stringer.
-func (x *ID) Marshal() ([]byte, error) {
-	return (*refs.SubnetID)(x).StableMarshal(nil), nil
-}
-
-// Unmarshal decodes ID from NeoFS API V2 binary format (see Marshal). Must not be called on nil.
 //
-// Note: empty data corresponds to zero ID value or nil pointer to it.
+// String is designed to be human-readable, and its format MAY differ between
+// SDK versions. String MAY return same result as EncodeToString. String MUST NOT
+// be used to encode ID into NeoFS protocol string.
+func (x ID) String() string {
+	return "#" + strconv.FormatUint(uint64(x.m.GetValue()), 10)
+}
+
+// Marshal encodes ID into a binary format of the NeoFS API protocol
+// (Protocol Buffers with direct field order).
+//
+// See also Unmarshal.
+func (x ID) Marshal() []byte {
+	return x.m.StableMarshal(nil)
+}
+
+// Unmarshal decodes binary ID calculated using Marshal. Returns an error
+// describing a format violation.
 func (x *ID) Unmarshal(data []byte) error {
-	return (*refs.SubnetID)(x).Unmarshal(data)
+	return x.m.Unmarshal(data)
 }
 
-// SetNumber sets ID value in uint32 format. Must not be called on nil.
+// SetNumeric sets ID value in numeric format. By default, number is 0 which
-// By default, number is 0 which refers to zero subnet.
+// refers to the zero subnet.
-func (x *ID) SetNumber(num uint32) {
+func (x *ID) SetNumeric(num uint32) {
-	(*refs.SubnetID)(x).SetValue(num)
+	x.m.SetValue(num)
 }
 
-// IsZero returns true iff the ID refers to zero subnet.
+// IsZero compares id with zero subnet ID.
 func IsZero(id ID) bool {
-	return id.Equals(nil)
+	return id.Equals(ID{})
 }
 
-// MakeZero makes ID to refer to zero subnet. Arg must not be nil (it is already zero).
+// MakeZero makes ID to refer to zero subnet.
 //
 // Makes no sense to call on zero value (e.g. declared using var).
 func MakeZero(id *ID) {
-	id.SetNumber(0)
+	id.SetNumeric(0)
 }

subnet/id/id_test.go

@@ -14,26 +14,26 @@ func TestIsZero(t *testing.T) {
 
 	require.True(t, subnetid.IsZero(id))
 
-	id.SetNumber(13)
+	id.SetNumeric(13)
 	require.False(t, subnetid.IsZero(id))
 
-	id.SetNumber(0)
+	id.SetNumeric(0)
 	require.True(t, subnetid.IsZero(id))
 }
 
-func TestID_FromV2(t *testing.T) {
+func TestID_ReadFromV2(t *testing.T) {
 	const num = 13
 
 	var id1 subnetid.ID
-	id1.SetNumber(num)
+	id1.SetNumeric(num)
 
 	var idv2 refs.SubnetID
 	idv2.SetValue(num)
 
 	var id2 subnetid.ID
-	id2.FromV2(idv2)
+	require.NoError(t, id2.ReadFromV2(idv2))
 
-	require.True(t, id1.Equals(&id2))
+	require.True(t, id1.Equals(id2))
 }
 
 func TestID_WriteToV2(t *testing.T) {
@@ -47,7 +47,7 @@ func TestID_WriteToV2(t *testing.T) {
 	id.WriteToV2(&idv2)
 	require.Zero(t, idv2.GetValue())
 
-	id.SetNumber(num)
+	id.SetNumeric(num)
 
 	id.WriteToV2(&idv2)
 	require.EqualValues(t, num, idv2.GetValue())
@@ -58,36 +58,30 @@ func TestID_Equals(t *testing.T) {
 
 	var id1, id2, idOther, id0 subnetid.ID
 
-	id0.Equals(nil)
+	id0.Equals(subnetid.ID{})
 
-	id1.SetNumber(num)
+	id1.SetNumeric(num)
-	id2.SetNumber(num)
+	id2.SetNumeric(num)
-	idOther.SetNumber(num + 1)
+	idOther.SetNumeric(num + 1)
 
-	require.True(t, id1.Equals(&id2))
+	require.True(t, id1.Equals(id2))
-	require.False(t, id1.Equals(&idOther))
+	require.False(t, id1.Equals(idOther))
-	require.False(t, id2.Equals(&idOther))
+	require.False(t, id2.Equals(idOther))
 }
 
 func TestSubnetIDEncoding(t *testing.T) {
 	id := subnetidtest.ID()
 
 	t.Run("binary", func(t *testing.T) {
-		data, err := id.Marshal()
-		require.NoError(t, err)
-
 		var id2 subnetid.ID
-		require.NoError(t, id2.Unmarshal(data))
+		require.NoError(t, id2.Unmarshal(id.Marshal()))
 
 		require.True(t, id2.Equals(id))
 	})
 
 	t.Run("text", func(t *testing.T) {
-		data, err := id.MarshalText()
-		require.NoError(t, err)
-
 		var id2 subnetid.ID
-		require.NoError(t, id2.UnmarshalText(data))
+		require.NoError(t, id2.DecodeString(id.EncodeToString()))
 
 		require.True(t, id2.Equals(id))
 	})
@@ -95,12 +89,12 @@ func TestSubnetIDEncoding(t *testing.T) {
 
 func TestMakeZero(t *testing.T) {
 	var id subnetid.ID
-
+	id.SetNumeric(13)
-	id.SetNumber(13)
 
 	require.False(t, subnetid.IsZero(id))
 
 	subnetid.MakeZero(&id)
 
 	require.True(t, subnetid.IsZero(id))
+	require.Equal(t, subnetid.ID{}, id)
 }

subnet/id/test/doc.go

@@ -0,0 +1,13 @@
+/*
+Package subnetidtest provides functions for convenient testing of subnetid package API.
+
+Note that importing the package into source files is highly discouraged.
+
+Random instance generation functions can be useful when testing expects any value, e.g.:
+	import subnetidtest "github.com/nspcc-dev/neofs-sdk-go/suibnet/id/test"
+
+	value := subnetidtest.ID()
+	// test the value
+
+*/
+package subnetidtest

subnet/id/test/id.go

@@ -6,11 +6,8 @@ import (
 	subnetid "github.com/nspcc-dev/neofs-sdk-go/subnet/id"
 )
 
-// ID generates and returns random subnetid.ID using math/rand.Uint32.
+// ID generates and returns random subnetid.ID.
-func ID() *subnetid.ID {
+func ID() (x subnetid.ID) {
-	var id subnetid.ID
+	x.SetNumeric(rand.Uint32())
-
+	return
-	id.SetNumber(rand.Uint32())
-
-	return &id
 }

subnet/subnet.go

@@ -1,6 +1,8 @@
 package subnet
 
 import (
+	"fmt"
+
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/nspcc-dev/neofs-api-go/v2/subnet"
 	subnetid "github.com/nspcc-dev/neofs-sdk-go/subnet/id"
@@ -9,102 +11,99 @@ import (
 
 // Info represents information about NeoFS subnet.
 //
-// The type is compatible with the corresponding message from NeoFS API V2 protocol.
+// Instances can be created using built-in var declaration.
+type Info struct {
+	id subnetid.ID
+
+	owner user.ID
+}
+
+// Marshal encodes Info into a binary format of the NeoFS API protocol
+// (Protocol Buffers with direct field order).
 //
-// Zero value and nil pointer to it represents zero subnet w/o an owner.
+// See also Unmarshal.
-type Info subnet.Info
+func (x Info) Marshal() []byte {
+	var id refs.SubnetID
+	x.id.WriteToV2(&id)
 
-// FromV2 initializes Info from subnet.Info message structure. Must not be called on nil.
+	var owner refs.OwnerID
-func (x *Info) FromV2(msg subnet.Info) {
+	x.owner.WriteToV2(&owner)
-	*x = Info(msg)
+
+	var m subnet.Info
+	m.SetID(&id)
+	m.SetOwner(&owner)
+
+	return m.StableMarshal(nil)
 }
 
-// WriteToV2 writes Info to subnet.Info message structure. The message must not be nil.
+// Unmarshal decodes binary Info calculated using Marshal. Returns an error
-func (x Info) WriteToV2(msg *subnet.Info) {
+// describing a format violation.
-	*msg = subnet.Info(x)
-}
-
-// Marshal encodes Info into a binary format of NeoFS API V2 protocol (Protocol Buffers with direct field order).
-func (x *Info) Marshal() ([]byte, error) {
-	return (*subnet.Info)(x).StableMarshal(nil), nil
-}
-
-// Unmarshal decodes Info from NeoFS API V2 binary format (see Marshal). Must not be called on nil.
-//
-// Note: empty data corresponds to zero Info value or nil pointer to it.
 func (x *Info) Unmarshal(data []byte) error {
-	return (*subnet.Info)(x).Unmarshal(data)
+	var m subnet.Info
+
+	err := m.Unmarshal(data)
+	if err != nil {
+		return err
+	}
+
+	id := m.ID()
+	if id != nil {
+		err = x.id.ReadFromV2(*id)
+		if err != nil {
+			return fmt.Errorf("invalid ID: %w", err)
+		}
+	} else {
+		subnetid.MakeZero(&x.id)
+	}
+
+	owner := m.Owner()
+	if owner != nil {
+		err = x.owner.ReadFromV2(*owner)
+		if err != nil {
+			return fmt.Errorf("invalid owner: %w", err)
+		}
+	} else {
+		x.owner = user.ID{}
+	}
+
+	return nil
 }
 
 // SetID sets the identifier of the subnet that Info describes.
+//
+// See also ID.
 func (x *Info) SetID(id subnetid.ID) {
-	infov2 := (*subnet.Info)(x)
+	x.id = id
-
-	idv2 := infov2.ID()
-	if idv2 == nil {
-		idv2 = new(refs.SubnetID)
-		infov2.SetID(idv2)
 }
 
-	id.WriteToV2(idv2)
+// ID returns subnet identifier set using SetID.
+//
+// Zero Info refers to the zero subnet.
+func (x Info) ID() subnetid.ID {
+	return x.id
 }
 
-// ReadID reads the identifier of the subnet that Info describes. Arg must not be nil.
+// SetOwner sets identifier of the subnet owner.
-func (x Info) ReadID(id *subnetid.ID) {
-	infov2 := (subnet.Info)(x)
-
-	idv2 := infov2.ID()
-	if idv2 == nil {
-		subnetid.MakeZero(id)
-		return
-	}
-
-	id.FromV2(*idv2)
-}
-
-// SetOwner sets subnet owner ID.
 func (x *Info) SetOwner(id user.ID) {
-	infov2 := (*subnet.Info)(x)
+	x.owner = id
-
-	idv2 := infov2.Owner()
-	if idv2 == nil {
-		idv2 = new(refs.OwnerID)
-		infov2.SetOwner(idv2)
 }
 
-	id.WriteToV2(idv2)
+// Owner returns subnet owner set using SetOwner.
+//
+// Zero Info has no owner which is incorrect according to the
+// NeoFS API protocol.
+func (x Info) Owner() user.ID {
+	return x.owner
 }
 
-// ReadOwner reads the identifier of the subnet that Info describes.
+// AssertOwnership checks if the given info describes the subnet owned by the
-// Must be called only if owner is set (see HasOwner). Arg must not be nil.
+// given user.
-func (x Info) ReadOwner(id *user.ID) {
+func AssertOwnership(info Info, id user.ID) bool {
-	infov2 := (subnet.Info)(x)
+	return id.Equals(info.Owner())
-
-	id2 := infov2.Owner()
-	if id2 == nil {
-		*id = user.ID{}
-		return
 }
 
-	if ownerV2 := infov2.Owner(); ownerV2 != nil {
+// AssertReference checks if the given info describes the subnet referenced by
-		_ = id.ReadFromV2(*ownerV2)
+// the given id.
-	}
+func AssertReference(info Info, id subnetid.ID) bool {
-}
+	return id.Equals(info.ID())
-
-// IsOwner checks subnet ownership.
-func IsOwner(info Info, id user.ID) bool {
-	var id2 user.ID
-
-	info.ReadOwner(&id2)
-
-	return id.Equals(id2)
-}
-
-// IDEquals checks if ID refers to subnet that Info describes.
-func IDEquals(info Info, id subnetid.ID) bool {
-	id2 := new(subnetid.ID)
-
-	info.ReadID(id2)
-
-	return id.Equals(id2)
 }

subnet/subnet_test.go

@@ -3,11 +3,10 @@ package subnet_test
 import (
 	"testing"
 
-	subnetv2 "github.com/nspcc-dev/neofs-api-go/v2/subnet"
-	subnettest "github.com/nspcc-dev/neofs-api-go/v2/subnet/test"
 	. "github.com/nspcc-dev/neofs-sdk-go/subnet"
 	subnetid "github.com/nspcc-dev/neofs-sdk-go/subnet/id"
-	"github.com/nspcc-dev/neofs-sdk-go/user"
+	subnetidtest "github.com/nspcc-dev/neofs-sdk-go/subnet/id/test"
+	subnettest "github.com/nspcc-dev/neofs-sdk-go/subnet/test"
 	usertest "github.com/nspcc-dev/neofs-sdk-go/user/test"
 	"github.com/stretchr/testify/require"
 )
@@ -15,55 +14,35 @@ import (
 func TestInfoZero(t *testing.T) {
 	var info Info
 
-	var id subnetid.ID
+	require.Zero(t, info.ID())
-	info.ReadID(&id)
+	require.True(t, subnetid.IsZero(info.ID()))
-
-	require.True(t, subnetid.IsZero(id))
 }
 
 func TestInfo_SetID(t *testing.T) {
-	var (
+	id := subnetidtest.ID()
-		id   subnetid.ID
-		info Info
-	)
-
-	id.SetNumber(222)
 
+	var info Info
 	info.SetID(id)
 
-	require.True(t, IDEquals(info, id))
+	require.Equal(t, id, info.ID())
+	require.True(t, AssertReference(info, id))
 }
 
 func TestInfo_SetOwner(t *testing.T) {
-	var (
+	id := *usertest.ID()
-		id   user.ID
-		info Info
-	)
-
-	id = *usertest.ID()
-
-	require.False(t, IsOwner(info, id))
 
+	var info Info
 	info.SetOwner(id)
 
-	require.True(t, IsOwner(info, id))
+	require.Equal(t, id, info.Owner())
+	require.True(t, AssertOwnership(info, id))
 }
 
-func TestInfo_WriteToV2(t *testing.T) {
+func TestInfo_Marshal(t *testing.T) {
-	var (
+	info := subnettest.Info()
-		infoTo, infoFrom Info
 
-		infoV2From, infoV2To subnetv2.Info
+	var info2 Info
-	)
+	require.NoError(t, info2.Unmarshal(info.Marshal()))
 
-	infoV2From = *subnettest.GenerateSubnetInfo(false)
+	require.Equal(t, info, info2)
-
-	infoFrom.FromV2(infoV2From)
-
-	infoFrom.WriteToV2(&infoV2To)
-
-	infoTo.FromV2(infoV2To)
-
-	require.Equal(t, infoV2From, infoV2To)
-	require.Equal(t, infoFrom, infoTo)
 }

subnet/test/doc.go

@@ -0,0 +1,13 @@
+/*
+Package subnettest provides functions for convenient testing of subnet package API.
+
+Note that importing the package into source files is highly discouraged.
+
+Random instance generation functions can be useful when testing expects any value, e.g.:
+	import subnettest "github.com/nspcc-dev/neofs-sdk-go/suibnet/test"
+
+	value := subnettest.Info()
+	// test the value
+
+*/
+package subnettest

subnet/test/subnet.go

@@ -0,0 +1,14 @@
+package subnettest
+
+import (
+	"github.com/nspcc-dev/neofs-sdk-go/subnet"
+	subnetidtest "github.com/nspcc-dev/neofs-sdk-go/subnet/id/test"
+	usertest "github.com/nspcc-dev/neofs-sdk-go/user/test"
+)
+
+// Info generates and returns random subnet.Info.
+func Info() (x subnet.Info) {
+	x.SetID(subnetidtest.ID())
+	x.SetOwner(*usertest.ID())
+	return
+}