Rspec 中的间谍问题

Question

无法弄清楚原因：

it "shifts/unshifts without O(n) copying" do
  arr = RingBuffer.new

  allow(arr.send(:store)).to receive(:[]=).and_call_original
  8.times do |i|
    arr.unshift(i)
  end

  # Should involve 8 sets to unshift, no more.
  expect(arr.send(:store)).to have_received(:[]=).exactly(8).times
end

结果：

“失败/错误：expect(arr.store).to have_received(:[]=).exactly(8).times # 预计会收到 []=，但该对象不是间谍或方法尚未被存根。”

Answer 1

不完全确定您的代码在做什么，但我怀疑调用 arr.send(:store) 每次都会返回不同的对象。尝试这样修改：

it "shifts/unshifts without O(n) copying" do
  arr = RingBuffer.new
  store = arr.send(:store)

  allow(store).to receive(:[]=).and_call_original
  8.times do |i|
    arr.unshift(i)
  end

  # Should involve 8 sets to unshift, no more.
  expect(store).to have_received(:[]=).exactly(8).times
end