ruby-on-rails – 加速rspec控制器测试：使用之前都失败？

context "POST :create" do
  before (:each) do
    post :create,:user_id => @user.id,:account => { .. some data ... }
  end
  it { response.status.should == 201 }
  it { response.location.should be_present }
end

现在我想到了一个非常简单的方法来加速这个测试,并且使用before(：all)而不是before(：each).在这种情况下,该职位只会做一次.

所以我写道：

context "POST :create" do
  before (:all) do
    post :create,:account => { .. some data ... }
  end
  it { response.status.should == 201 }
  it { response.location.should be_present }
end

但是,我收到以下错误：

RuntimeError:
   @routes is nil: make sure you set it in your test's setup method.

这是设计吗？有办法规避吗？