package test import ( "testing" "time" ) func TestDemo2(t *testing.T) { t.Run("Adapters_test", test21) } func test21(t *testing.T) { a := make(chan bool) b := make(chan bool) defer close(b) go func() { for { select { case <-a: default: <-b } } }() time.Sleep(1 * time.Second) a <- true }