模块化Java:声明式模块化
本文是模块化Java系列文章的第4篇,介绍的是声明式模块化。文中描述了组件如何以声明的方式来定义并组织在一起,而无需让代码依赖于OSGI API。
作者 Sean Miller 译者 张海龙 发布于 2007年10月31日 上午9时56分
RSpec是 一个为Ruby编写的基于行为驱动开发(简称BDD,即Behaviour-Driven Development)的验收测试框架,同时也可用于Java(事实上它一直都可以运行于JRuby中),它提供了一种机制,即由开发人员从业务中获取 验收标准并将它们转换为可读、可运行的示例,以此替代文档、测试和适用于业务的构建报告。
尽管RSpec对单元级测试很有用,但它在集成测试中一直存在一个盲点。Dan North创建了一个独立的扩展,RBehave,它用Given…With…Then…这样的格式以一系列的步骤从故事级别来描述行为。(North最早是在JBehave中描述了这种用于获得需求故事的模式)
David Chelimsky现在已经向RSpec trunk中合并了一个纯文本故事运行器(Plain Text Story Runner),它给RSpec添加了RBehave功能,就像他在 他的 博客中描述的那样。
现在看看North的经典RBehave示例:
So, North's classic RBehave example:require ‘rubygems’
require ‘rbehave’
require ’spec’ # for "should" method
require ‘account’ # the actual application code
Story "transfer to cash account",
%(As a savings account holder
I want to transfer money from my savings account
So that I can get cash easily from an ATM) do
Scenario "savings account is in credit" do
Given "my savings account balance is", 100 do |balance|
@savings_account = Account.new(balance)
end
Given "my cash account balance is", 10 do |balance|
@cash_account = Account.new(balance)
end
When "I transfer", 20 do |amount|
@savings_account.transfer_to(@cash_account, amount)
end
Then "my savings account balance should be", 80 do |expected_amount|
@savings_account.balance.should == expected_amount
end
Then "my cash account balance should be", 30 do |expected_amount|
@cash_account.balance.should == expected_amount
end
end
Scenario "savings account is overdrawn" do
Given "my savings account balance is", -20
Given "my cash account balance is", 10
When "I transfer", 20
Then "my savings account balance should be", -20
Then "my cash account balance should be", 10
end
end
在新的RSpec中它可以变成这样,由一个Ruby文件定义可用的步骤:
在一个纯文本文件中按照那些步骤定义故事的行为:class AccountSteps < Spec::Story::StepGroup
steps do |define|
define.given("my savings account balance is $balance") do |balance|
@savings_account = Account.new(balance.to_f)
end
define.given("my cash account balance is $balance" do |balance|
@cash_account = Account.new(balance.to_f)
end
define.then("my savings account balance should be $expected_amount" do |expected_amount|
@savings_account.balance.should == expected_amount.to_f
end
define.then("my cash account balance should be $expected_amount" do |expected_amount|
@cash_account.balance.should == expected_amount.to_f
end
end
end
steps = AccountSteps.new do |define|
define.when("I transfer $amount") do |amount|
@savings_account.transfer_to(@cash_account, amount.to_f)
end
end
Story: transfer to cash account
As a savings account holder
I want to transfer money from my savings account
So that I can get cash easily from an ATM
Scenario: savings account is in credit
Given my savings account balance is 100
And my cash account balance is 10
When I transfer 20
Then my savings account balance should be 80
And my cash account balance should be 30
Scenario: savings account is overdrawn
Given my savings account balance is -20
And my cash account balance is 10
When I transfer 20
Then my savings account balance should be -20
And my cash account balance should be 10
由一个Ruby文件将他们粘在一起,并运行这些故事:
require 'spec'
require 'path/to/your/library/files'
require 'path/to/file/that/defines/account_steps.rb'
# assumes the other story file is named the same as this file minus ".rb"
runner = Spec::Story::Runner::PlainTextStoryRunner.new(File.expand_path(__FILE__).gsub(".rb",""))
runner.steps << AccountSteps.new
runner.run
纯文本文件中的那些步骤描述,必须与StepGroup中定义的步骤相匹配,这些描述可能会随着步骤数量的增加变得难以理解。Aslak Hellesøy正在为一个基于浏览器的编缉器工作,它将提供步骤的自动补全,并可以在恰当的位置对参数进行编辑,从而使这一问题得以简化。
查看英文原文:RSpec Trunk Now Includes RBehave-like Story Runner
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