namespace :test do 
  namespace :randomize do 
    desc "Randomize tests"
    Rake::TestTask.new(:all => "db:test:prepare") do |t|
      t.libs << "test"
      t.test_files = Rake::FileList[
        'test/unit/**/*_test.rb','test/functional/**/*_test.rb','test/integration/**/*_test.rb' 
      ].shuffle
      t.verbose = true
    end
  end
end

运行：rake test：randomize：all

请记住,文件测试中仍将按照它们出现的顺序执行.我想你可以通过猴子补丁测试单元来实现这一点.