[#990] morph/client: Add NodeAllowed subnet method

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/morph/client/subnet/node.go

@@ -0,0 +1,58 @@
+package morphsubnet
+
+import (
+	"fmt"
+
+	"github.com/nspcc-dev/neofs-node/pkg/morph/client"
+)
+
+// NodeAllowedPrm groups parameters of NodeAllowed method of Subnet contract.
+type NodeAllowedPrm struct {
+	cliPrm client.TestInvokePrm
+
+	args [2]interface{}
+}
+
+// SetID sets identifier of the subnet of the node in a binary NeoFS API protocol format.
+func (x *NodeAllowedPrm) SetID(id []byte) {
+	x.args[0] = id
+}
+
+// SetNode sets public key of the node that is being checked.
+func (x *NodeAllowedPrm) SetNode(id []byte) {
+	x.args[1] = id
+}
+
+// NodeAllowedRes groups resulting values of NodeAllowed method of Subnet contract.
+type NodeAllowedRes struct {
+	result bool
+}
+
+// Allowed returns true iff the node is allowed to enter the subnet.
+func (x NodeAllowedRes) Allowed() bool {
+	return x.result
+}
+
+// NodeAllowed checks if the node is included in the subnetwork.
+func (x *Client) NodeAllowed(prm NodeAllowedPrm) (*NodeAllowedRes, error) {
+	prm.cliPrm.SetMethod("nodeAllowed")
+	prm.cliPrm.SetArgs(prm.args[:]...)
+
+	res, err := x.client.TestInvoke(prm.cliPrm)
+	if err != nil {
+		return nil, fmt.Errorf("could not make test invoke: %w", err)
+	}
+
+	if len(res) == 0 {
+		return nil, errEmptyResponse
+	}
+
+	result, err := client.BoolFromStackItem(res[0])
+	if err != nil {
+		return nil, err
+	}
+
+	return &NodeAllowedRes{
+		result: result,
+	}, nil
+}