command/refresh: Testing backup option

command/refresh.go

@@ -94,7 +94,7 @@ func (c *RefreshCommand) Run(args []string) int {
 	}
 
 	// Create a backup of the state before updating
-	if backupPath != "-" {
+	if backupPath != "-" && c.State != nil {
 		log.Printf("[INFO] Writing backup state to: %s", backupPath)
 		f, err := os.Create(backupPath)
 		if err == nil {

command/refresh_test.go

@@ -221,6 +221,23 @@ func TestRefresh_defaultState(t *testing.T) {
 	if !reflect.DeepEqual(actual, expected) {
 		t.Fatalf("bad: %#v", actual)
 	}
+
+	f, err = os.Open(statePath + DefaultBackupExtention)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	backupState, err := terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual = backupState.Resources["test_instance.foo"]
+	expected = originalState.Resources["test_instance.foo"]
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("bad: %#v", actual)
+	}
 }
 
 func TestRefresh_outPath(t *testing.T) {
@@ -295,6 +312,21 @@ func TestRefresh_outPath(t *testing.T) {
 	if !reflect.DeepEqual(actual, expected) {
 		t.Fatalf("bad: %#v", actual)
 	}
+
+	f, err = os.Open(outPath + DefaultBackupExtention)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	backupState, err := terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if !reflect.DeepEqual(backupState, state) {
+		t.Fatalf("bad: %#v", backupState)
+	}
 }
 
 func TestRefresh_var(t *testing.T) {
@@ -376,6 +408,105 @@ func TestRefresh_varFile(t *testing.T) {
 	}
 }
 
+func TestRefresh_backup(t *testing.T) {
+	state := &terraform.State{
+		Resources: map[string]*terraform.ResourceState{
+			"test_instance.foo": &terraform.ResourceState{
+				ID:   "bar",
+				Type: "test_instance",
+			},
+		},
+	}
+	statePath := testStateFile(t, state)
+
+	// Output path
+	outf, err := ioutil.TempFile("", "tf")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	outPath := outf.Name()
+	outf.Close()
+	os.Remove(outPath)
+
+	// Backup path
+	backupf, err := ioutil.TempFile("", "tf")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	backupPath := backupf.Name()
+	backupf.Close()
+	os.Remove(backupPath)
+
+	p := testProvider()
+	ui := new(cli.MockUi)
+	c := &RefreshCommand{
+		Meta: Meta{
+			ContextOpts: testCtxConfig(p),
+			Ui:          ui,
+		},
+	}
+
+	p.RefreshFn = nil
+	p.RefreshReturn = &terraform.ResourceState{ID: "yes"}
+
+	args := []string{
+		"-state", statePath,
+		"-state-out", outPath,
+		"-backup", backupPath,
+		testFixturePath("refresh"),
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	f, err := os.Open(statePath)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	newState, err := terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if !reflect.DeepEqual(newState, state) {
+		t.Fatalf("bad: %#v", newState)
+	}
+
+	f, err = os.Open(outPath)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	newState, err = terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := newState.Resources["test_instance.foo"]
+	expected := p.RefreshReturn
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("bad: %#v", actual)
+	}
+
+	f, err = os.Open(backupPath)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	backupState, err := terraform.ReadState(f)
+	f.Close()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if !reflect.DeepEqual(backupState, state) {
+		t.Fatalf("bad: %#v", backupState)
+	}
+}
+
 const refreshVarFile = `
 foo = "bar"
 `