pb/testing: triger more race condition by having the progress bar refresh more often

packer/progressbar.go

@@ -35,16 +35,25 @@ type StackableProgressBar struct {
 	items int32
 	total int64
 
-	started bool
+	started             bool
+	ConfigProgressbarFN func(*pb.ProgressBar)
 }
 
 var _ ProgressBar = new(StackableProgressBar)
 
+func defaultProgressbarConfigFn(bar *pb.ProgressBar) {
+	bar.SetUnits(pb.U_BYTES)
+}
+
 func (spb *StackableProgressBar) start() {
-	spb.Bar.ProgressBar = pb.New(0)
-	spb.Bar.ProgressBar.SetUnits(pb.U_BYTES)
+	bar := pb.New(0)
+	if spb.ConfigProgressbarFN == nil {
+		spb.ConfigProgressbarFN = defaultProgressbarConfigFn
+	}
+	spb.ConfigProgressbarFN(bar)
 
-	spb.Bar.ProgressBar.Start()
+	bar.Start()
+	spb.Bar.ProgressBar = bar
 	spb.started = true
 }
 

packer/progressbar_test.go

@@ -3,10 +3,21 @@ package packer
 import (
 	"sync"
 	"testing"
+	"time"
+
+	"github.com/cheggaaa/pb"
 )
 
+func speedyProgressBar(bar *pb.ProgressBar) {
+	bar.SetUnits(pb.U_BYTES)
+	bar.SetRefreshRate(1 * time.Millisecond)
+	bar.NotPrint = true
+}
+
 func TestStackableProgressBar_race(t *testing.T) {
-	bar := &StackableProgressBar{}
+	bar := &StackableProgressBar{
+		ConfigProgressbarFN: speedyProgressBar,
+	}
 
 	start42Fn := func() { bar.Start(42) }
 	finishFn := func() { bar.Finish() }
@@ -24,7 +35,7 @@ func TestStackableProgressBar_race(t *testing.T) {
 		iterations int
 	}{
 		{"all public", fields{nil, []func(){start42Fn, finishFn, add21, add21}, finishFn}, 300},
-		{"all public", fields{start42Fn, []func(){add21, add21}, finishFn}, 300},
+		{"add", fields{start42Fn, []func(){add21}, finishFn}, 300},
 	}
 
 	for _, tt := range tests {