It seems behaviour-driven development is getting more and more popular in recent days. If you are still not sure what BDD is, take a look at following links:
1] Introducing BDD by Dan North
2] Beyond Test Driven Development: Behaviour Driven Development, Google Talk, by Dave Astels
3] Behaviour Driven Development with RSpec, RubyConf 2007, by
The most interesting feature of BDD is using stories of plain text as the test cases. Here the story text itself is not only the description of the application's functionality, but also the executable acceptance criterion of application's behavior. Let's have a look at the story example of a calculator addition feature:
Feature: Addition
In order to avoid silly mistakes
As a math idiot
I want to be told the sum of two numbers
Scenario: Add two numbers
Given I have entered 50 into the calculator
And I have entered 70 into the calculator
When I press add
Then the result should be 120 on the screen
And the result class should be Fixnum
Both developers and customers can benefit from above story since it is in plain text and easily understood. The further question you might ask is that if it is possible to use spoken languages other than English to write our BDD stories? The answer is "definitely yes!". Thanks to the cucumber -- the new RSpec's Story Runner. Multiple spoken languages support is a built-in feature of cucumber.The first step is to install cucumber, make sure you have install rpsec. You can install cucumber from gem:
gem install cucumber
or building gem yourself:git clone git://github.com/aslakhellesoy/cucumber.git
cd cucumber
rake install_gem
The keyword translation for Chinese language in cucumber is defined as following:OK, let's write our story in Chinese:"zh-CN":
feature: 功能
scenario: 场景
given_scenario: 引用场景
given: 假如
when: 当
then: 那么
and: 而且
but: 但是
Save the plain text in Chinese to a file, here we give it name "addition.feature". Now we can run this feature in command line:功能:加法
为了避免一些愚蠢的错误
作为一个数学白痴
我希望有人告诉我数字相加的结果
场景: 两个数相加
假如我已经在计算器里输入6
而且我已经在计算器里输入7
当我按相加按钮
那么我应该在屏幕上看到的结果是13
场景: 三个数相加
假如我已经在计算器里输入6
而且我已经在计算器里输入7
而且我已经在计算器里输入1
当我按相加按钮
那么我应该在屏幕上看到的结果是14
You should see following output:> cucumber --language zh-CN addition.feature
See pending step notification? Yes, that is because we haven't defined the steps for this feature. Before we define the steps, we might first consider writing our calculator code. Following is a simple implementation. Here we add a silly bug(The initial sum is not 0 but 1) to let cucumber report it.功能:加法 # addition.feature
为了避免一些愚蠢的错误
作为一个数学白痴
我希望有人告诉我数字相加的结果
场景: 两个数相加 # addition.feature:6
假如 我已经在计算器里输入6 # addition.feature:7
而且 我已经在计算器里输入7 # addition.feature:8
当 我按相加按钮 # addition.feature:9
那么 我应该在屏幕上看到的结果是13 # addition.feature:10
场景: 三个数相加 # addition.feature:12
假如 我已经在计算器里输入6 # addition.feature:13
而且 我已经在计算器里输入7 # addition.feature:14
而且 我已经在计算器里输入1 # addition.feature:15
当 我按相加按钮 # addition.feature:16
那么 我应该在屏幕上看到的结果是14 # addition.feature:17
9 steps pending
You can use these snippets to implement pending steps:
假如 /^我已经在计算器里输入6$/ do
end
假如 /^我已经在计算器里输入7$/ do
end
当 /^我按相加按钮$/ do
end
那么 /^我应该在屏幕上看到的结果是13$/ do
end
假如 /^我已经在计算器里输入1$/ do
end
那么 /^我应该在屏幕上看到的结果是14$/ do
end
def push(n)
class Calculator
@args ||= []
@args << n
end
def add
@args.inject(1){|n,sum| sum+=n}
end
end
Now run the feature again, you should see:require 'spec'
require 'calculator'
Before do
@calc = Calculator.new
end
After do
end
Given "我已经在计算器里输入$n" do |n|
@calc.push n.to_i
end
When /我按(.*)按钮/ do |op|
if op == '相加'
@result = @calc.send "add"
end
end
Then /我应该在屏幕上看到的结果是(.*)/ do |result|
@result.should == result.to_f
end
Lets change the calculator class to fix the bug:功能:加法 # addition.feature
为了避免一些愚蠢的错误
作为一个数学白痴
我希望有人告诉我数字相加的结果
场景: 两个数相加 # addition.feature:6
假如 我已经在计算器里输入6 # calculator_steps.rb:11
而且 我已经在计算器里输入7 # calculator_steps.rb:11
当 我按相加按钮 # calculator_steps.rb:15
那么 我应该在屏幕上看到的结果是13 # calculator_steps.rb:21
expected: 13.0,
got: 14 (using ==) (Spec::Expectations::ExpectationNotMetError)
./calculator_steps.rb:22:in `那么 /461021457224505745453450456117457125447012473413451060473204477323463634463057(.*)/'
addition.feature:10:in `那么 我应该在屏幕上看到的结果是13'
场景: 三个数相加 # addition.feature:12
假如 我已经在计算器里输入6 # calculator_steps.rb:11
而且 我已经在计算器里输入7 # calculator_steps.rb:11
而且 我已经在计算器里输入1 # calculator_steps.rb:11
当 我按相加按钮 # calculator_steps.rb:15
那么 我应该在屏幕上看到的结果是14 # calculator_steps.rb:21
expected: 14.0,
got: 15 (using ==) (Spec::Expectations::ExpectationNotMetError)
./calculator_steps.rb:22:in `那么 /461021457224505745453450456117457125447012473413451060473204477323463634463057(.*)/'
addition.feature:17:in `那么 我应该在屏幕上看到的结果是14'
class Calculator
def push(n)
@args ||= []
@args << n
end
def add
@args.inject(0){|n,sum| sum+=n}
end
end
And run cucumber again, you should see:
功能:加法 # addition.feature
为了避免一些愚蠢的错误
作为一个数学白痴
我希望有人告诉我数字相加的结果
场景: 两个数相加 # addition.feature:6
假如 我已经在计算器里输入6 # calculator_steps.rb:11
而且 我已经在计算器里输入7 # calculator_steps.rb:11
当 我按相加按钮 # calculator_steps.rb:15
那么 我应该在屏幕上看到的结果是13 # calculator_steps.rb:21
场景: 三个数相加 # addition.feature:12
假如 我已经在计算器里输入6 # calculator_steps.rb:11
而且 我已经在计算器里输入7 # calculator_steps.rb:11
而且 我已经在计算器里输入1 # calculator_steps.rb:11
当 我按相加按钮 # calculator_steps.rb:15
那么 我应该在屏幕上看到的结果是14 # calculator_steps.rb:21
9 steps passed
Congratulations! All steps passed!You can find the code of this example at /examples/chinese_simplified_calculator of cucumber git repository(git://github.com/aslakhellesoy/cucumber.git).