ruby – RSpec之前,之后和周围的顺序是什么顺序运行？

require "spec_helper"

describe "The order:" do

  before(:all) {
    puts "before_all"
  }

  after(:all) {
    puts "after_all"
  }

  before(:each) {
    puts "before_each"
  }

  after(:each) {
    puts "after_each"
  }

  describe "DESC A" do
    before {
      puts "A_before"
    }
    it "A_it_1" do      
      expect(1).to eq(1)
    end
    it "A_it_2" do
      expect(1).to eq(1)
    end
  end

  describe "DESC B" do
    before {
      puts "B_before"
    }
    it "B_it_1" do      
      expect(1).to eq(1)
    end
    it "B_it_2" do
      expect(1).to eq(1)
    end
  end  
end

我得到了什么：

The order:

before_all

  DESC A
before_each
A_before
after_each
    A_it_1
before_each
A_before
after_each
    A_it_2
  DESC B
before_each
B_before
after_each
    B_it_1
before_each
B_before
after_each
    B_it_2

after_all

这里发生了什么 ？？为什么after_each在A_it_1之前运行？

更新：

添加(：每个)更有趣：

around(:each) do |example|
    puts "around_in"
    example.run
    puts "around_out"
  end

和结果：

The order:
before_all
  DESC A
around_in
before_each
A_before
after_each
around_out
    A_it_1
around_in
before_each
A_before
after_each
around_out
    A_it_2
  DESC B
around_in
before_each
B_before
after_each
around_out
    B_it_1
around_in
before_each
B_before
after_each
around_out
    B_it_2
after_all