nns: add ResolveFSContract example

By @cthulhu-rider, thanks.

Signed-off-by: Roman Khimov <[email protected]>

rpc/nns/example_test.go

@@ -0,0 +1,51 @@
+package nns_test
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
+	"github.com/nspcc-dev/neofs-contract/rpc/nns"
+)
+
+// Resolve addresses of NeoFS smart contracts deployed in a particular
+// NeoFS sidechain by their NNS domain names.
+func ExampleContractReader_ResolveFSContract() {
+	const sidechainRPCEndpoint = "https://rpc1.morph.fs.neo.org:40341"
+
+	c, err := rpcclient.New(context.Background(), sidechainRPCEndpoint, rpcclient.Options{})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = c.Init()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	nnsAddress, err := nns.InferHash(c)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	nnsContract := nns.NewReader(invoker.New(c, nil), nnsAddress)
+
+	for _, name := range []string{
+		nns.NameAudit,
+		nns.NameBalance,
+		nns.NameContainer,
+		nns.NameNeoFSID,
+		nns.NameNetmap,
+		nns.NameProxy,
+		nns.NameReputation,
+	} {
+		addr, err := nnsContract.ResolveFSContract(name)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fmt.Printf("%s: %s\n", name, addr)
+	}
+}