test(output): Add tree-only mode tests for generator and formats

- Add TestSetTreeOnlyMode to verify setter method
- Add TestPrepareTemplateDataTreeOnly to verify empty files with structure
- Add tree-only tests for markdown, text, and XML format renderers

Author: epilande

internal/generator/formats/formats_test.go

@@ -156,6 +156,82 @@ func createTestTemplateData() generator.TemplateData {
 	}
 }
 
+func createTreeOnlyTemplateData() generator.TemplateData {
+	return generator.TemplateData{
+		Structure: "test-project/\n├── src/\n│   └── main.go\n└── README.md\n",
+		Files:     []generator.FileData{},
+	}
+}
+
+func TestMarkdownFormatTreeOnly(t *testing.T) {
+	format := &MarkdownFormat{}
+	data := createTreeOnlyTemplateData()
+
+	content, tokens, err := format.Render(data)
+	if err != nil {
+		t.Fatalf("Render failed: %v", err)
+	}
+
+	if !strings.Contains(content, "# Project Structure") {
+		t.Errorf("Expected content to contain '# Project Structure'")
+	}
+	if !strings.Contains(content, "test-project/") {
+		t.Errorf("Expected content to contain 'test-project/'")
+	}
+	if strings.Contains(content, "# Project Files") {
+		t.Errorf("Expected content to NOT contain '# Project Files' in tree-only mode")
+	}
+	if tokens <= 0 {
+		t.Errorf("Expected tokens to be positive, got %d", tokens)
+	}
+}
+
+func TestTxtFormatTreeOnly(t *testing.T) {
+	format := &TxtFormat{}
+	data := createTreeOnlyTemplateData()
+
+	content, tokens, err := format.Render(data)
+	if err != nil {
+		t.Fatalf("Render failed: %v", err)
+	}
+
+	if !strings.Contains(content, "PROJECT STRUCTURE") {
+		t.Errorf("Expected content to contain 'PROJECT STRUCTURE'")
+	}
+	if !strings.Contains(content, "test-project/") {
+		t.Errorf("Expected content to contain 'test-project/'")
+	}
+	if strings.Contains(content, "PROJECT FILES") {
+		t.Errorf("Expected content to NOT contain 'PROJECT FILES' in tree-only mode")
+	}
+	if tokens <= 0 {
+		t.Errorf("Expected tokens to be positive, got %d", tokens)
+	}
+}
+
+func TestXMLFormatTreeOnly(t *testing.T) {
+	format := &XMLFormat{}
+	data := createTreeOnlyTemplateData()
+
+	content, tokens, err := format.Render(data)
+	if err != nil {
+		t.Fatalf("Render failed: %v", err)
+	}
+
+	if !strings.Contains(content, "<?xml") {
+		t.Errorf("Expected content to contain '<?xml'")
+	}
+	if !strings.Contains(content, "<project>") {
+		t.Errorf("Expected content to contain '<project>'")
+	}
+	if strings.Contains(content, "<file path=") {
+		t.Errorf("Expected content to NOT contain file elements in tree-only mode")
+	}
+	if tokens <= 0 {
+		t.Errorf("Expected tokens to be positive, got %d", tokens)
+	}
+}
+
 func TestAddFileToTree(t *testing.T) {
 	root := &directoryEntry{
 		name:    ".",

internal/generator/generator_test.go

@@ -214,6 +214,76 @@ func TestGenerateStringWithNoFormat(t *testing.T) {
 	}
 }
 
+func TestSetTreeOnlyMode(t *testing.T) {
+	gen := NewGenerator(".", nil, nil, "", false)
+
+	if gen.TreeOnly {
+		t.Errorf("Expected TreeOnly to be false by default")
+	}
+
+	gen.SetTreeOnlyMode(true)
+	if !gen.TreeOnly {
+		t.Errorf("Expected TreeOnly to be true after SetTreeOnlyMode(true)")
+	}
+
+	gen.SetTreeOnlyMode(false)
+	if gen.TreeOnly {
+		t.Errorf("Expected TreeOnly to be false after SetTreeOnlyMode(false)")
+	}
+}
+
+func TestPrepareTemplateDataTreeOnly(t *testing.T) {
+	cache.ResetGlobalCache()
+
+	tempDir, err := os.MkdirTemp("", "generator-test-treeonly")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	testFiles := []struct {
+		path    string
+		content string
+	}{
+		{"file1.txt", "Content of file1"},
+		{"file2.go", "package main\n\nfunc main() {}"},
+		{"subdir/file3.txt", "Content of file3"},
+	}
+
+	for _, tf := range testFiles {
+		path := filepath.Join(tempDir, filepath.FromSlash(tf.path))
+		dir := filepath.Dir(path)
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			t.Fatalf("Failed to create directory %s: %v", dir, err)
+		}
+		if err := os.WriteFile(path, []byte(tf.content), 0644); err != nil {
+			t.Fatalf("Failed to create file %s: %v", path, err)
+		}
+	}
+
+	gitIgnoreMgr, _ := filesystem.NewGitIgnoreManager(tempDir)
+	filterMgr := filesystem.NewFilterManager()
+	gen := NewGenerator(tempDir, gitIgnoreMgr, filterMgr, "", false)
+	gen.SelectedFiles = map[string]bool{
+		"file1.txt":        true,
+		"file2.go":         true,
+		"subdir/file3.txt": true,
+	}
+	gen.SetTreeOnlyMode(true)
+
+	data, err := gen.PrepareTemplateData()
+	if err != nil {
+		t.Fatalf("PrepareTemplateData failed: %v", err)
+	}
+
+	if data.Structure == "" {
+		t.Errorf("Expected Structure to be non-empty in tree-only mode")
+	}
+	if len(data.Files) != 0 {
+		t.Errorf("Expected Files to be empty in tree-only mode, got %d files", len(data.Files))
+	}
+}
+
 type mockFormat struct {
 	err       error
 	name      string