p2p/protocol/identify: test user agent in tests against the real user agent used

Fixes libp2p#3176

Author: Jorropo

p2p/protocol/identify/id.go

@@ -19,6 +19,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/protocol"
 	"github.com/libp2p/go-libp2p/core/record"
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
+	useragent "github.com/libp2p/go-libp2p/p2p/protocol/identify/internal/user-agent"
 	"github.com/libp2p/go-libp2p/p2p/protocol/identify/pb"
 
 	logging "github.com/ipfs/go-log/v2"
@@ -54,8 +55,6 @@ const (
 	connectedPeerMaxAddrs         = 500
 )
 
-var defaultUserAgent = "github.com/libp2p/go-libp2p"
-
 type identifySnapshot struct {
 	seq       uint64
 	protocols []protocol.ID
@@ -188,7 +187,7 @@ func NewIDService(h host.Host, opts ...Option) (*idService, error) {
 		opt(&cfg)
 	}
 
-	userAgent := defaultUserAgent
+	userAgent := useragent.DefaultUserAgent()
 	if cfg.userAgent != "" {
 		userAgent = cfg.userAgent
 	}

p2p/protocol/identify/id_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/libp2p/go-libp2p/p2p/net/swarm"
 	swarmt "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
 	"github.com/libp2p/go-libp2p/p2p/protocol/identify"
+	useragent "github.com/libp2p/go-libp2p/p2p/protocol/identify/internal/user-agent"
 	"github.com/libp2p/go-libp2p/p2p/protocol/identify/pb"
 
 	mockClock "github.com/benbjohnson/clock"
@@ -45,7 +46,7 @@ func testKnowsAddrs(t *testing.T, h host.Host, p peer.ID, expected []ma.Multiadd
 func testHasAgentVersion(t *testing.T, h host.Host, p peer.ID) {
 	v, err := h.Peerstore().Get(p, "AgentVersion")
 	require.NoError(t, err, "fetching agent version")
-	require.Equal(t, "github.com/libp2p/go-libp2p", v, "agent version")
+	require.Equal(t, useragent.DefaultUserAgent(), v, "agent version")
 }
 
 func testHasPublicKey(t *testing.T, h host.Host, p peer.ID, shouldBe ic.PubKey) {

p2p/protocol/identify/user_agent.go …entify/internal/user-agent/user_agent.gop2p/protocol/identify/user_agent.go renamed to p2p/protocol/identify/internal/user-agent/user_agent.go p2p/protocol/identify/user_agent.go renamed to p2p/protocol/identify/internal/user-agent/user_agent.go

@@ -1,11 +1,20 @@
-package identify
+package useragent
 
 import (
 	"fmt"
 	"runtime/debug"
+	"sync"
 )
 
-func init() {
+func DefaultUserAgent() string {
+	initOnce.Do(checkBuildInfos)
+	return defaultUserAgent
+}
+
+var defaultUserAgent = "github.com/libp2p/go-libp2p"
+var initOnce sync.Once
+
+func checkBuildInfos() {
 	bi, ok := debug.ReadBuildInfo()
 	if !ok {
 		return