Refine

test/server.go

@@ -3,7 +3,7 @@ package test
 import (
 	"fmt"
 	"heckel.io/ntfy/v2/server"
-	"math/rand"
+	"net"
 	"net/http"
 	"path/filepath"
 	"testing"
@@ -16,7 +16,7 @@ func StartServer(t *testing.T) (*server.Server, int) {
 
 // StartServerWithConfig starts a server.Server with a random port and waits for the server to be up
 func StartServerWithConfig(t *testing.T, conf *server.Config) (*server.Server, int) {
-	port := 10000 + rand.Intn(30000)
+	port := findAvailablePort(t)
 	conf.ListenHTTP = fmt.Sprintf(":%d", port)
 	conf.AttachmentCacheDir = t.TempDir()
 	conf.CacheFile = filepath.Join(t.TempDir(), "cache.db")
@@ -33,6 +33,17 @@ func StartServerWithConfig(t *testing.T, conf *server.Config) (*server.Server, i
 	return s, port
 }
 
+// findAvailablePort asks the OS for a free port by binding to :0
+func findAvailablePort(t *testing.T) int {
+	listener, err := net.Listen("tcp", ":0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	port := listener.Addr().(*net.TCPAddr).Port
+	listener.Close()
+	return port
+}
+
 // StopServer stops the test server and waits for the port to be down
 func StopServer(t *testing.T, s *server.Server, port int) {
 	s.Stop()