为什么黄瓜背景的输出只显示一次？

Question

我在 Cucumber Background 部分中放置了一条调试打印语句。

因为 Background 对每个场景都执行一次，所以我希望每个场景都能看到 Background 的输出一次。但是输出只显示一次。为什么？

这是一个简单的例子来说明我的问题：

calculator/features/adding.特征：

Feature: Adding

Background:
  Given calculator is ready

Scenario: Add two numbers
  Given the input "2" and "2"
  When the calculator is run
  Then the output should be "4"

Scenario: Add another two numbers
  Given the input "2" and "3"
  When the calculator is run
  Then the output should be "5"

calculator/features/step_definitions/calculator_steps.rb:

counter = 0

Given(/^calculator is ready$/) do
  puts "*** background ***"
  counter += 1
end

Given(/^the input "([^"]*)" and "([^"]*)"$/) do |x1, x2|
  @x1 = x1
  @x2 = x2
end

When(/^the calculator is run$/) do
  @output = `ruby calc.rb #{@x1} #{@x2}`
end

Then(/^the output should be "([^"]*)"$/) do |expected_output|
  expect(@output).to eq(expected_output)
  puts "counter=#{counter}"
end

calculator/calc.rb:

x1 = ARGV[0].to_i
x2 = ARGV[1].to_i

print ("#{x1+x2}")

执行场景时的输出如下：

$ cucumber
Feature: Adding

  Background:                 # features/adding.feature:3
    Given calculator is ready # features/step_definitions/calculator_steps.rb:3   
    *** background ***

  Scenario: Add two numbers       # features/adding.feature:6
    Given the input "2" and "2"   # features/step_definitions/calculator_steps.rb:8    
    When the calculator is run    # features/step_definitions/calculator_steps.rb:13
    Then the output should be "4" # features/step_definitions/calculator_steps.rb:17
      counter=1

  Scenario: Add another two numbers # features/adding.feature:11
    Given the input "2" and "3"     # features/step_definitions/calculator_steps.rb:8
    When the calculator is run      # features/step_definitions/calculator_steps.rb:13
    Then the output should be "5"   # features/step_definitions/calculator_steps.rb:17
      counter=2

2 scenarios (2 passed)
8 steps (8 passed)
0m0.094s

我希望看到 *** background *** 行两次（因为 Background 被执行了两次），但它只显示了一次。为什么？

Answer 1

在 Cucumber Background 步骤中打印的消息只打印一次，因为 Cucumber 在执行步骤时捕获标准输出并在 Cucumber 的控制下打印它。在 Background 个步骤中打印的消息与步骤名称一起打印：仅一次，在输出的开头。

每次 Background 运行时查看打印消息的方式与每次运行 Background 时查看步骤名称的方式相同。已经有一个问题和答案，但它不适用于当前版本的 Cucumber（我有 2.3.3），所以我写了一个新的答案来显示 how to print everything that Background prints before every scenario.

为什么黄瓜背景的输出只显示一次？

Why is the output from a Cucumber Background shown only once?

ruby

cucumber