What is best?
To crush your requirements, see them driven before your tests, and hear the exultations of their authors.
And what editor is best for that?
THE ONE YOU KNOW WELL ENOUGH TO BE PRODUCTIVE IN.
If that’s plain old Notepad, so be it. If it’s VSCode or Eclipse or Atom or RubyMine or whatever, so be it. If it’s vi or emacs, you’ve probably been around longer than to need this advice.