diff --git a/src/server/routes.go b/src/server/routes.go
index 9cdef97..603d3c0 100644
--- a/src/server/routes.go
+++ b/src/server/routes.go
@@ -141,12 +141,10 @@ func (s *Server) handleFolder(c *router.Context) {
 			c.Out.WriteHeader(http.StatusBadRequest)
 			return
 		}
-		if body.Title != nil {
-			s.db.RenameFolder(id, *body.Title)
-		}
-		if body.IsExpanded != nil {
-			s.db.ToggleFolderExpanded(id, *body.IsExpanded)
-		}
+		s.db.UpdateFolder(id, storage.UpdateFolderParams{
+			Title:      body.Title,
+			IsExpanded: body.IsExpanded,
+		})
 		c.Out.WriteHeader(http.StatusOK)
 	} else if c.Req.Method == "DELETE" {
 		s.db.DeleteFolder(id)
diff --git a/src/storage/folder.go b/src/storage/folder.go
index c06875a..a929631 100644
--- a/src/storage/folder.go
+++ b/src/storage/folder.go
@@ -38,20 +38,27 @@ func (s *Storage) DeleteFolder(folderId int64) bool {
 	return err == nil
 }
 
-func (s *Storage) RenameFolder(folderId int64, newTitle string) bool {
-	_, err := s.db.Exec(`update folders set title = :title where id = :id`,
-		sql.Named("title", newTitle),
-		sql.Named("id", folderId),
-	)
-	return err == nil
+type UpdateFolderParams struct {
+	Title      *string
+	IsExpanded *bool
 }
 
-func (s *Storage) ToggleFolderExpanded(folderId int64, isExpanded bool) bool {
-	_, err := s.db.Exec(`update folders set is_expanded = :is_expanded where id = :id`,
-		sql.Named("is_expanded", isExpanded),
+func (s *Storage) UpdateFolder(folderId int64, params UpdateFolderParams) (bool, error) {
+	_, err := s.db.Exec(`
+		update folders set
+			title       = coalesce(:title, title),
+			is_expanded = coalesce(:is_expanded, is_expanded)
+		where id = :id
+	`,
 		sql.Named("id", folderId),
+		sql.Named("title", params.Title),
+		sql.Named("is_expanded", params.IsExpanded),
 	)
-	return err == nil
+	if err != nil {
+		log.Print(err)
+		return false, err
+	}
+	return true, nil
 }
 
 func (s *Storage) ListFolders() []Folder {
diff --git a/src/storage/folder_test.go b/src/storage/folder_test.go
new file mode 100644
index 0000000..90b304c
--- /dev/null
+++ b/src/storage/folder_test.go
@@ -0,0 +1,78 @@
+package storage
+
+import (
+	"testing"
+)
+
+func TestUpdateFolder(t *testing.T) {
+	db := testDB()
+	folder := db.CreateFolder("old title")
+	if folder.IsExpanded != true {
+		t.Fatal("expected folder to be expanded by default")
+	}
+
+	t.Run("rename only", func(t *testing.T) {
+		newTitle := "new title"
+		ok, err := db.UpdateFolder(folder.Id, UpdateFolderParams{
+			Title: &newTitle,
+		})
+		if !ok || err != nil {
+			t.Fatalf("UpdateFolder failed: %v", err)
+		}
+
+		folders := db.ListFolders()
+		if len(folders) != 1 || folders[0].Title != "new title" {
+			t.Errorf("expected title to be updated, got %s", folders[0].Title)
+		}
+		if folders[0].IsExpanded != true {
+			t.Error("expected expansion state to remain unchanged")
+		}
+	})
+
+	t.Run("toggle expanded only", func(t *testing.T) {
+		isExpanded := false
+		ok, err := db.UpdateFolder(folder.Id, UpdateFolderParams{
+			IsExpanded: &isExpanded,
+		})
+		if !ok || err != nil {
+			t.Fatalf("UpdateFolder failed: %v", err)
+		}
+
+		folders := db.ListFolders()
+		if len(folders) != 1 || folders[0].IsExpanded != false {
+			t.Errorf("expected is_expanded to be false, got %v", folders[0].IsExpanded)
+		}
+		if folders[0].Title != "new title" {
+			t.Error("expected title to remain unchanged")
+		}
+	})
+
+	t.Run("update both", func(t *testing.T) {
+		bothTitle := "both"
+		isExpanded := true
+		ok, err := db.UpdateFolder(folder.Id, UpdateFolderParams{
+			Title:      &bothTitle,
+			IsExpanded: &isExpanded,
+		})
+		if !ok || err != nil {
+			t.Fatalf("UpdateFolder failed: %v", err)
+		}
+
+		folders := db.ListFolders()
+		if len(folders) != 1 || folders[0].Title != "both" || folders[0].IsExpanded != true {
+			t.Errorf("expected both to be updated, got title=%s expanded=%v", folders[0].Title, folders[0].IsExpanded)
+		}
+	})
+
+	t.Run("update none", func(t *testing.T) {
+		ok, err := db.UpdateFolder(folder.Id, UpdateFolderParams{})
+		if !ok || err != nil {
+			t.Fatalf("UpdateFolder failed: %v", err)
+		}
+
+		folders := db.ListFolders()
+		if len(folders) != 1 || folders[0].Title != "both" || folders[0].IsExpanded != true {
+			t.Errorf("expected no changes, got title=%s expanded=%v", folders[0].Title, folders[0].IsExpanded)
+		}
+	})
+}