Place this file in the `lib/tasks` folder of your Rails project. Run `rake -T` to see available rake tasks. This will dynamically create a single rake task for each single `*_spec.rb` file. It will also create additional rake tasks that run all `*_spec.rb` files in a given sub-directory.

rspec.rake

require 'rspec/core/rake_task'
orm_setting = Rails.configuration.generators.options[:rails][:orm]
spec_prereq = if(orm_setting == :active_record)
  Rails.configuration.active_record[:schema_format] == :sql ? "db:test:clone_structure" : "db:test:prepare"
else
  :noop
end
namespace :spec do
  [:requests, :models, :controllers, :views, :helpers, :mailers, :lib, :routing].each do |sub|
    dn = "#{File.expand_path(::Rails.root.to_s)}/spec/#{sub}"
    if File.exists?(dn) and File.directory?(dn)
      sub_files = Dir.open(dn).map{|fn| fn unless [".",".."].include?(fn)}.compact
      namespace sub.to_s.singularize.to_sym do
        (sub_files.map do |fn|
          unless File.exists?("#{dn}/#{fn}") and File.directory?("#{dn}/#{fn}")
            if File.extname(fn)==".rb" and File.basename(fn,".rb").match(/\w+(_spec?)/)
              File.basename(fn,".rb").chomp("_spec")
            end
          end
        end).flatten.compact.sort.each do |spec|
          desc "Run the code examples in spec/#{sub}/#{spec}_spec.rb"
          RSpec::Core::RakeTask.new(spec.gsub(/(_routing|_controller|_helper)$/,'') => spec_prereq) do |t|
            t.pattern = "./spec/#{sub}/#{spec}_spec.rb"
          end
        end
        sub_files.each do |fn|
          if File.exists?("#{dn}/#{fn}") and File.directory?("#{dn}/#{fn}")
            sub_sub_files = (Dir.open("#{dn}/#{fn}").map do |sub_fn|
              if File.extname(sub_fn)==".rb" and File.basename(sub_fn,".rb").match(/\w+(_spec?)/)
                File.basename(sub_fn,".rb").chomp("_spec")
              end
            end).flatten.compact.sort
            if sub_sub_files.size > 0
              desc "Run the code examples in spec/#{sub}/#{fn}"
              RSpec::Core::RakeTask.new(fn => spec_prereq) do |t|
                t.pattern = "./spec/#{sub}/#{fn}/*_spec.rb"
              end
            end
            namespace fn.to_s.singularize.to_sym do
              sub_sub_files.each do |spec|
                desc "Run the code examples in spec/#{sub}/#{fn}/#{spec}_spec.rb"
                RSpec::Core::RakeTask.new(spec.split(".")[0] => spec_prereq) do |t|
                  t.pattern = "./spec/#{sub}/#{fn}/#{spec}_spec.rb"
                end
              end
            end
          end
        end
      end
    end
  end
end