use GlobalID where provided, add test for `vagrant up` args generation

builder/vagrant/step_up.go

@@ -14,23 +14,28 @@ type StepUp struct {
 	GlobalID       string
 }
 
+func (s *StepUp) generateArgs() []string {
+	box := "source"
+	if s.GlobalID != "" {
+		box = s.GlobalID
+	}
+
+	// start only the source box
+	args := []string{box}
+
+	if s.Provider != "" {
+		args = append(args, fmt.Sprintf("--provider=%s", s.Provider))
+	}
+	return args
+}
+
 func (s *StepUp) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
 	driver := state.Get("driver").(VagrantDriver)
 	ui := state.Get("ui").(packer.Ui)
 
 	ui.Say("Calling Vagrant Up...")
 
-	// start only the source box
-	args := []string{"source"}
-	if s.GlobalID != "" {
-		args = append(args, s.GlobalID)
-	}
-
-	if s.Provider != "" {
-		args = append(args, fmt.Sprintf("--provider=%s", s.Provider))
-	}
-
-	_, _, err := driver.Up(args)
+	_, _, err := driver.Up(s.generateArgs())
 
 	if err != nil {
 		state.Put("error", err)
@@ -46,13 +51,18 @@ func (s *StepUp) Cleanup(state multistep.StateBag) {
 
 	ui.Say(fmt.Sprintf("%sing Vagrant box...", s.TeardownMethod))
 
+	box := "source"
+	if s.GlobalID != "" {
+		box = s.GlobalID
+	}
+
 	var err error
 	if s.TeardownMethod == "halt" {
-		err = driver.Halt(s.GlobalID)
+		err = driver.Halt(box)
 	} else if s.TeardownMethod == "suspend" {
-		err = driver.Suspend(s.GlobalID)
+		err = driver.Suspend(box)
 	} else if s.TeardownMethod == "destroy" {
-		err = driver.Destroy(s.GlobalID)
+		err = driver.Destroy(box)
 	} else {
 		// Should never get here because of template validation
 		state.Put("error", fmt.Errorf("Invalid teardown method selected; must be either halt, suspend, or destory."))

builder/vagrant/step_up_test.go

@@ -0,0 +1,40 @@
+package vagrant
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestPrepUpArgs(t *testing.T) {
+	type testArgs struct {
+		Step     StepUp
+		Expected []string
+	}
+	tests := []testArgs{
+		{
+			Step: StepUp{
+				GlobalID: "foo",
+				Provider: "bar",
+			},
+			Expected: []string{"foo", "--provider=bar"},
+		},
+		{
+			Step:     StepUp{},
+			Expected: []string{"source"},
+		},
+		{
+			Step: StepUp{
+				Provider: "pro",
+			},
+			Expected: []string{"source", "--provider=pro"},
+		},
+	}
+	for _, test := range tests {
+		args := test.Step.generateArgs()
+		for i, val := range test.Expected {
+			if strings.Compare(args[i], val) != 0 {
+				t.Fatalf("expected %#v but received %#v", test.Expected, args)
+			}
+		}
+	}
+}