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/solutions/40_text_templates/text_templates.go

@@ -0,0 +1,31 @@
+package exercises
+
+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]any) (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 user's name
+func FormatUserGreeting(name string) (string, error) {
+    const greetingTmpl = "Hello, {{.Name}}!"
+    data := map[string]any{
+        "Name": name,
+    }
+    return RenderTemplate(greetingTmpl, data)
+}

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

@@ -0,0 +1,16 @@
+package exercises
+
+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]any) (string, error) {
+	return "", nil
+}
+
+// FormatUserGreeting returns a greeting using text/template with user's name
+func FormatUserGreeting(name string) (string, error) {
+	return "", nil
+}

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

@@ -0,0 +1,71 @@
+package exercises
+
+import (
+	"testing"
+)
+
+func TestRenderTemplate(t *testing.T) {
+	t.Run("Success", func(t *testing.T) {
+		tmpl := "Name: {{.Name}}, Age: {{.Age}}"
+		data := map[string]any{
+			"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)
+		}
+	})
+
+	t.Run("InvalidSyntax", func(t *testing.T) {
+		tmpl := "Hello {{.Name"
+		data := map[string]any{"Name": "Bob"}
+
+		_, err := RenderTemplate(tmpl, data)
+		if err == nil {
+			t.Error("Expected error for invalid template syntax, got nil")
+		}
+	})
+
+	t.Run("MissingData", func(t *testing.T) {
+		tmpl := "Hello, {{.MissingField}}!"
+		data := map[string]any{"Name": "Charlie"}
+
+		_, err := RenderTemplate(tmpl, data)
+		if err != nil {
+			t.Errorf("RenderTemplate unexpectedly returned error: %v", err)
+		}
+		expected := "Hello, <no value>!"
+		if result, _ := RenderTemplate(tmpl, data); result == expected {
+		}
+	})
+}
+
+func TestFormatUserGreeting(t *testing.T) {
+	t.Run("Success", func(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)
+		}
+	})
+
+	t.Run("EmptyName", func(t *testing.T) {
+		result, err := FormatUserGreeting("")
+		if err != nil {
+			t.Errorf("FormatUserGreeting returned error: %v", err)
+		}
+		expected := "Hello, !"
+		if result != expected {
+			t.Errorf("FormatUserGreeting = %q, want %q", result, expected)
+		}
+	})
+}