存出类的实例以测试作为属性给出的回调

Question

我正在尝试使用Rspec 3.9在proc中测试一行代码（请参见下面的代码片段中的proc { |message| flash[:notice] << message }），但我似乎无法将实例存根以执行我想要的事情。

给出以下控制器并进行测试，如何将CreateAccount存根并运行控制器中提供的on_success属性？

这里是控制器文件

class AccountsController < ApplicationController
    def create
        CreateAccount.new(
          on_success: proc { |message| flash[:notice] << message }
        ).process

        redirect_to action: :index
    end
end

这是Rspec测试文件

describe AccountsController, type: :controller do
    describe 'POST #create' do
        subject(:create_action) { post :create, id: 1 }

        let(:success_message) { 'Success!' }

        context 'when created account successfully' do
            it { is_expected.to redirect_to action: :index }
            it do
                create_action
                expect(flash[:notice]).to include success_message
            end
        end
    end
end

我想要这样做的原因是将关注点从控制器分离到CreateAccount对象。没关系，但是到目前为止是CreateAccount对象。

class CreateAccount
    def initialize on_success: proc { |_| }
        @on_success = on_success
    end

    def call
        # Do some meaningful work
        success_message = 'Meaningful message'

        @on_success.call(success_message)
    end
end

Answer 1

我设法找到一种可行的解决方案，但我想知道是否有更清洁的方法

注意：控制器和CreateAction类保持相同。

describe AccountsController, type: :controller do
    describe 'POST #create' do
        subject(:create_action) { post :create, id: 1 }

        context 'when created account successfully' do
            class DummyAction < CreateAction
                MESSAGE = 'Success!'

                def call
                    @on_success.call(MESSAGE)
                end     
            end

            before { stub_constant 'CreateAction', DummyAction }

            it { is_expected.to redirect_to action: :index }
            it do
                create_action
                expect(flash[:notice]).to include DummyAction::MESSAGE
            end
        end
    end
end