add a sleep provisioner

mainly for testing purposes

provisioner/sleep/provisioner.go

@@ -0,0 +1,30 @@
+package sleep
+
+import (
+	"context"
+	"time"
+
+	"github.com/hashicorp/packer/helper/config"
+	"github.com/hashicorp/packer/packer"
+)
+
+type Provisioner struct {
+	Duration time.Duration
+}
+
+var _ packer.Provisioner = new(Provisioner)
+
+func (p *Provisioner) Prepare(raws ...interface{}) error {
+	return config.Decode(&p, &config.DecodeOpts{}, raws...)
+}
+
+func (p *Provisioner) Provision(ctx context.Context, _ packer.Ui, _ packer.Communicator) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-time.After(p.Duration):
+		return nil
+	}
+}
+
+func (p *Provisioner) Cancel() {}

provisioner/sleep/provisioner_test.go

@@ -0,0 +1,56 @@
+package sleep
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+func test1sConfig() map[string]interface{} {
+	return map[string]interface{}{
+		"duration": "1s",
+	}
+}
+
+func TestConfigPrepare_1s(t *testing.T) {
+	raw := test1sConfig()
+	var p Provisioner
+	err := p.Prepare(raw)
+	if err != nil {
+		t.Fatalf("prerare failed: %v", err)
+	}
+
+	if p.Duration != time.Second {
+		t.Fatal("wrong duration")
+	}
+}
+
+func TestProvisioner_Provision(t *testing.T) {
+	ctxCancelled, cancel := context.WithCancel(context.Background())
+	cancel()
+	type fields struct {
+		Duration time.Duration
+	}
+	type args struct {
+		ctx context.Context
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		args    args
+		wantErr bool
+	}{
+		{"valid sleep", fields{time.Millisecond}, args{context.Background()}, false},
+		{"timeout", fields{time.Millisecond}, args{ctxCancelled}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &Provisioner{
+				Duration: tt.fields.Duration,
+			}
+			if err := p.Provision(tt.args.ctx, nil, nil); (err != nil) != tt.wantErr {
+				t.Errorf("Provisioner.Provision() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}