断言 Redis 发布

Question

我正在为 after_create 回调编写规范。规范如下所示：

it 'broadcasts creation' do
  message = Message.create(body: 'foo')
  expect(Redis.any_instance).to have_received(:publish)
end

我的Message 模型如下所示：

class Message < ActiveRecord::Base
  after_create -> { publish(:create) }

  private

  def publish(name)
    Redis.new.publish(
      self.class.inferred_channel_name,
      json(action)
    )

    Redis.new.publish(
      inferred_channel_name_for_single_record,
      json(action)
    )

    puts 'published!'
  end
end

我知道回调会运行，因为我在最后打印“已发布”，并且我已经验证 Redis 确实发布了两次。

不过，我的规范失败并显示以下消息：

1) Message Methods #entangle without options broadcasts creation
 Failure/Error: expect(Redis.any_instance).to have_received(:publish)
   unstubbed, expected exactly once, not yet invoked: #<AnyInstance:Redis>.publish(any_parameters)
 # ./spec/models/message_spec.rb:20:in `block (5 levels) in <top (required)>'

我正在使用 bourne 和 mocha 来使用 have_received 匹配器。

我怎样才能让这个测试通过？

Answer 1

为Redis 创建一个模拟，并存根类和实例方法——分别为new 和publish。

it "broadcasts creation" do
  redis = stub_redis

  Message.create(body: "foo")

  expect(redis).to have_received(:publish).twice
end

def stub_redis
  mock("redis").tap do |redis|
    redis.stubs(:publish)
    Redis.stubs(:new).returns(redis)
  end
end

Answer 2

您可以尝试使用 expect_any_instance_of 模拟。

it 'broadcasts creation' do
  expect(Redis.any_instance).to receive(:publish).twice
  message = Message.create(body: 'foo')
end

https://www.relishapp.com/rspec/rspec-mocks/v/3-2/docs/working-with-legacy-code/any-instance