add support for the version negotiation test

interop/client/main.go

@@ -9,8 +9,10 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"strings"
 
 	"github.com/lucas-clemente/quic-go/http3"
+	"github.com/lucas-clemente/quic-go/internal/protocol"
 	"github.com/lucas-clemente/quic-go/interop/http09"
 	"golang.org/x/sync/errgroup"
 )
@@ -49,6 +51,8 @@ func runTestcase(testcase string) error {
 		defer r.Close()
 		return downloadFiles(r, urls)
 	case "handshake", "transfer", "retry":
+	case "versionnegotiation":
+		return runVersionNegotiationTest(urls)
 	case "resumption":
 		return runResumptionTest(urls)
 	default:
@@ -62,6 +66,21 @@ func runTestcase(testcase string) error {
 	return downloadFiles(r, urls)
 }
 
+func runVersionNegotiationTest(urls []string) error {
+	if len(urls) != 1 {
+		return errors.New("expected at least 2 URLs")
+	}
+	protocol.SupportedVersions = []protocol.VersionNumber{0x1a2a3a4a}
+	err := downloadFile(&http09.RoundTripper{}, urls[0])
+	if err == nil {
+		return errors.New("expected version negotiation to fail")
+	}
+	if !strings.Contains(err.Error(), "No compatible QUIC version found") {
+		return fmt.Errorf("expect version negotiation error, got: %s", err.Error())
+	}
+	return nil
+}
+
 func runResumptionTest(urls []string) error {
 	if len(urls) < 2 {
 		return errors.New("expected at least 2 URLs")

interop/server/main.go

@@ -30,7 +30,7 @@ func main() {
 	}
 
 	switch testcase {
-	case "handshake", "transfer", "resumption":
+	case "versionnegotiation", "handshake", "transfer", "resumption":
 		err = runHTTP09Server(quicConf)
 	case "retry":
 		// By default, quic-go performs a Retry on every incoming connection.