Support ShowLabels, add tests

template_nest.go

@@ -15,10 +15,12 @@ type Hash map[string]interface{}
 // Option holds configuration for TemplateNest
 type Option struct {
 	Delimiters        [2]string
-	NameLabel         string
-	TemplateDir       string
-	TemplateExtension string
-	DieOnBadParams    bool
+	NameLabel         string    // Identify the template to be used
+	TemplateDir       string    // directory where templates are located
+	TemplateExtension string    // appended on the label to idenfity the template
+	DieOnBadParams    bool      // attempt to populate a variable that doesn't exist should result in an error
+	ShowLabels        bool      // Prepend & Append a string to every template, helpful in debugging
+	CommentDelimiters [2]string // Used in conjunction with ShowLabels, if HTML then use '<!--', '-->'
 }
 
 type TemplateNest struct {
@@ -60,6 +62,9 @@ func New(opts Option) (*TemplateNest, error) {
 	if opts.Delimiters == [2]string{} {
 		opts.Delimiters = [2]string{"<!--%", "%-->"}
 	}
+	if opts.CommentDelimiters == [2]string{} {
+		opts.CommentDelimiters = [2]string{"<!--", "-->"}
+	}
 	if opts.NameLabel == "" {
 		opts.NameLabel = "TEMPLATE"
 	}
@@ -271,6 +276,18 @@ func (nest *TemplateNest) Render(toRender interface{}) (string, error) {
 			rendered = rendered[:variable.StartPosition] + replacement + rendered[variable.EndPosition:]
 		}
 
+		if nest.option.ShowLabels {
+			labelStart := fmt.Sprintf(
+				"%s BEGIN %s %s\n",
+				nest.option.CommentDelimiters[0], tName, nest.option.CommentDelimiters[1],
+			)
+			labelEnd := fmt.Sprintf(
+				"%s END %s %s\n",
+				nest.option.CommentDelimiters[0], tName, nest.option.CommentDelimiters[1],
+			)
+			rendered = labelStart + rendered + labelEnd
+		}
+
 		return strings.TrimSpace(rendered), nil
 
 	default:

tests/03_show_labels_test.go

@@ -0,0 +1,68 @@
+package tests
+
+import (
+	"git.virtual.blue/tomgracey/template-nest-go"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestRenderWithShowLabels(t *testing.T) {
+	nest, err := templatenest.New(templatenest.Option{
+		TemplateDir: "templates",
+		ShowLabels:  true,
+	})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	nestNoLabels, err := templatenest.New(templatenest.Option{TemplateDir: "templates"})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	page := templatenest.Hash{
+		"TEMPLATE": "00-simple-page",
+		"variable": "Simple Variable",
+		"simple_component": templatenest.Hash{
+			"TEMPLATE": "01-simple-component",
+			"variable": "Simple Variable in Simple Component",
+		},
+	}
+	outputPage := templatenest.Hash{"TEMPLATE": "output/04-simple-page-with-labels"}
+
+	render := nest.MustRender(page)
+	outputRender := nestNoLabels.MustRender(outputPage)
+
+	assert.Equal(t, outputRender, render, "Rendered output does not match expected output")
+}
+
+func TestRenderWithShowLabelsAltDelimiters(t *testing.T) {
+	nest, err := templatenest.New(templatenest.Option{
+		TemplateDir:       "templates",
+		ShowLabels:        true,
+		CommentDelimiters: [2]string{"<!--!", "!-->"},
+	})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	nestNoLabels, err := templatenest.New(templatenest.Option{TemplateDir: "templates"})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	page := templatenest.Hash{
+		"TEMPLATE": "00-simple-page",
+		"variable": "Simple Variable",
+		"simple_component": templatenest.Hash{
+			"TEMPLATE": "01-simple-component",
+			"variable": "Simple Variable in Simple Component",
+		},
+	}
+	outputPage := templatenest.Hash{"TEMPLATE": "output/05-simple-page-with-labels-alt-delims"}
+
+	render := nest.MustRender(page)
+	outputRender := nestNoLabels.MustRender(outputPage)
+
+	assert.Equal(t, outputRender, render, "Rendered output does not match expected output")
+}