No overwrite FileWriter in Ruby

no_overwrite_file_writer.rb

class NoOverwriteFileWriter
  def initialize(default_file_writer)
    @default_file_writer = default_file_writer
  end

  def write(path, contents)
    fail_if_file_exist(path)
    default_file_writer.write(path, contents)
  end

  private
  attr_reader :default_file_writer

  def fail_if_file_exist(path)
    raise 'File already exists!' if file_exist?(path)
  end

  def file_exist?(path)
    File.exist?(path) && !File.zero?(path)
  end
end