ruby-on-rails - `allow_any_instance_of` 模拟不在范围内工作

Question

我的 mock 只有在如下所示的 before block 中时才有效。这只是我对我的问题的快速而肮脏的表述。从字面上看，当我将行从 before block 移动到 does not quack 断言时，它停止模拟 :(

describe 'Ducks', type: :feature do
  before do
    ...
    allow_any_instance_of(Duck).to receive(:quack).and_return('bark!')
    visit animal_farm_path
  end

  context 'is an odd duck'
    it 'does not quack' do
      expect(Duck.new.quack).to eq('bark!')
    end
  end
end

我想要它，但它不起作用:

describe 'Ducks', type: :feature do
  before do
    ...
    visit animal_farm_path
  end

  context 'is an odd duck'
    it 'does not quack' do
      allow_any_instance_of(Duck).to receive(:quack).and_return('bark!')
      expect(Duck.new.quack).to eq('bark!')
    end
  end
end

Answer 1

我的错。原来的问题写得不好。访问该页面是调用 #quack 的原因。必须始终在执行任何涉及方法调用的操作之前完成模拟。所以这是我的解决方案

describe 'Ducks', type: :feature do
  before do
    ...
  end

  context 'is an odd duck'
    it 'does not quack' do
      allow_any_instance_of(Duck).to receive(:quack).and_return('bark!')
      visit animal_farm_path

      # In this crude example, the page prints out the animals sound
      expect(page).to have_text('bark!')
    end
  end
end