Add Text Templates exercise templates and tests (#79) - Hacktoberfest Contribution

internal/exercises/catalog.yaml

@@ -251,3 +251,11 @@ projects:
       - "Use time.Parse() to parse time strings with known layouts"
       - "Use time.LoadLocation() to work with different timezones"
       - "Extract time components using .Date() and .Clock() methods"
+- slug: 40_text_templates
+  title: "Text Templates"
+  difficulty: beginner
+  topics: ["text/template", "strings", "formatting"]
+  hints:
+    - "Use Go's text/template package to create and execute templates."
+    - "Define template actions like {{.Field}} to inject data."
+    - "Use template functions like printf for formatting."

internal/exercises/templates/40_text_templates/text_templates.go

@@ -0,0 +1,31 @@
+package texttemplates
+
+import (
+	"bytes"
+	"text/template"
+)
+
+// RenderTemplate takes a template string and data map,returns the rendered string or error.
+func RenderTemplate(tmplStr string, data map[string]interface{}) (string, error) {
+	tmpl, err := template.New("exercise").Parse(tmplStr)
+	if err != nil {
+		return "", err
+	}
+
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, data)
+	if err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
+// FormatUserGreeting returns a greeting using text/template with users name
+func FormatUserGreeting(name string) (string, error) {
+	const greetingTmpl = "Hello, {{.Name}}!"
+	data := map[string]interface{}{
+		"Name": name,
+	}
+	return RenderTemplate(greetingTmpl, data)
+}

internal/exercises/templates/40_text_templates/text_templates_test.go

@@ -0,0 +1,33 @@
+package texttemplates
+
+import (
+	"testing"
+)
+
+func TestRenderTemplate(t *testing.T) {
+	tmpl := "Name: {{.Name}}, Age: {{.Age}}"
+	data := map[string]interface{}{
+		"Name": "Alice",
+		"Age":  30,
+	}
+
+	result, err := RenderTemplate(tmpl, data)
+	if err != nil {
+		t.Errorf("RenderTemplate returned error: %v", err)
+	}
+	expected := "Name: Alice, Age: 30"
+	if result != expected {
+		t.Errorf("RenderTemplate = %q, want %q", result, expected)
+	}
+}
+
+func TestFormatUserGreeting(t *testing.T) {
+	result, err := FormatUserGreeting("Bob")
+	if err != nil {
+		t.Errorf("FormatUserGreeting returned error: %v", err)
+	}
+	expected := "Hello, Bob!"
+	if result != expected {
+		t.Errorf("FormatUserGreeting = %q, want %q", result, expected)
+	}
+}