test(expvarhandler): fix failure when using -count to run more than o…

…nce (#1688)

expvarhandler/expvar_test.go

@@ -4,17 +4,24 @@ import (
  "encoding/json"
  "expvar"
  "strings"
+ "sync"
  "testing"
 
  "github.com/valyala/fasthttp"
 )
 
+var once sync.Once
+
 func TestExpvarHandlerBasic(t *testing.T) {
  t.Parallel()
 
- expvar.Publish("customVar", expvar.Func(func() any {
- return "foobar"
- }))
+ // Publish panics if the same var is published more than once,
+ // which can happen if the test is run with -count
+ once.Do(func() {
+ expvar.Publish("customVar", expvar.Func(func() any {
+ return "foobar"
+ }))
+ })
 
  var ctx fasthttp.RequestCtx