builder/virtualbox: Set the default boot_wait [GH-44]

builder/virtualbox/builder.go

@@ -89,6 +89,10 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		b.config.OutputDir = "virtualbox"
 	}
 
+	if b.config.RawBootWait == "" {
+		b.config.RawBootWait = "10s"
+	}
+
 	if b.config.SSHHostPortMin == 0 {
 		b.config.SSHHostPortMin = 2222
 	}
@@ -168,11 +172,9 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		errs = append(errs, errors.New("Output directory already exists. It must not exist."))
 	}
 
-	if b.config.RawBootWait != "" {
-		b.config.BootWait, err = time.ParseDuration(b.config.RawBootWait)
-		if err != nil {
-			errs = append(errs, fmt.Errorf("Failed parsing boot_wait: %s", err))
-		}
+	b.config.BootWait, err = time.ParseDuration(b.config.RawBootWait)
+	if err != nil {
+		errs = append(errs, fmt.Errorf("Failed parsing boot_wait: %s", err))
 	}
 
 	if b.config.RawShutdownTimeout == "" {

builder/virtualbox/builder_test.go

@@ -61,9 +61,16 @@ func TestBuilderPrepare_BootWait(t *testing.T) {
 	var b Builder
 	config := testConfig()
 
+	// Test a default boot_wait
+	delete(config, "boot_wait")
+	err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
 	// Test with a bad boot_wait
 	config["boot_wait"] = "this is not good"
-	err := b.Prepare(config)
+	err = b.Prepare(config)
 	if err == nil {
 		t.Fatal("should have error")
 	}