最近在看The rspec book这本书，由于平时工作不是这方面的，自己只是非常有兴趣，而且私下时间也不多，只靠每晚学习看的容易忘记，就在这里写一些笔记做复习。
cucumber主要是由features目录下的多个.feature文件构成BDD场景测试内容，然后针对其中的Given,When,Then,And等语句在featurs目录下的step_definitions子目录中增加ruby语法的行为步骤定义，来实现针对场景的测试执行。
参照书中的例子，逐步进行学习。
首先选择一个有趣的游戏--> Codebreaker
原文对游戏的介绍:
Codebreaker is a logic game in which a code-breaker tries to break a secret code created by a code-maker. The code-maker, which will be played by the application we’re going to write, creates a secret code of four numbers between 1 and 6.
The code-breaker then gets some number of chances to break the code. In each turn, the code-breaker makes a guess of four numbers (again, 1 to 6). The code-maker then marks the guess with up to four + and - signs.
A + indicates an exact match: one of the numbers in the guess is the same as one of the numbers in the secret code and in the same position.
A - indicates a number match: one of the numbers in the guess is the same as one of the numbers in the secret code but in a different position.
For example, given a secret code 1234, a guess with 4256 would earn a +-. The + is for the 2 in the second position in the guess, which matches the 2 in the secret code in both number and position: an exact match. The - is for the 4 in the first position in the guess, which matches the 4 in the code but not in the same position: a number match.
简单的说就是计算机给出一个4位的随机数，然后我们输入我们猜想的数字，如果其中有数字和位置都匹配上，那么会返回一个+号，如果只有数字匹配上，那么则返回一个-号。
然后开始我们的迭代一，选定以下story进行交付:
- Code-breaker starts game
- Code-breaker submits guess
接下来就可以写cucumber场景测试，首先在features目录下创建一个codebreaker_starts_game.feature，这里我们要测试的是游戏启动:
Feature: code-breaker starts the game
As a code-breaker
I want to start a game
So that I can break the code
Scenario: start game
Given I am not yet playing
When I start a new game
Then I should see "Welcome to Codebreaker!"
And I should see "Enter guess:"
再创建一个codebreaker_submits_guess.feature，来测试输入猜想的数字，并看到结果:
Feature: code-breaker submits guess
In order to play this game
As a code breaker
I want to submit a guess
So that I can try to breake the code
Scenario: all exact matches
Given the secret code is "1234"
When I guess "1234"
Then the mark should be "++++"
Scenario: 2 exact matches and 2 number matches
Given the secret code is "1234"
When I guess "1243"
Then the mark should be "++--"
Scenario: 1 exact match and 3 number matches
Given the secret code is "1234"
When I guess "1342"
Then the mark should be "+---"
Scenario: 4 number matches
Given the secret code is "1234"
When I guess "4321"
Then the mark should be "----"
这样看来，没写几个测试场景呢，用例就已经很复杂了，而且很重复，DRY，我们可以用Scenario Outline来实现简洁:
Feature: code-breaker submits guess
In order to play this game
As a code breaker
I want to submit a guess
So that I can try to breake the code
Scenario Outline: submit guess
Given the secret code is "<code>"
When I guess "<guess>"
Then the mark should be "<mark>"
Scenarios: no matches
| code | guess | mark |
| 1234 | 5678 | |
Scenarios: 1 number correct
| code | guess | mark |
| 1234 | 1555 | + |
| 1234 | 2555 | _ |
Scenarios: 2 number correct
| code | guess | mark |
| 1234 | 5254 | ++ |
| 1234 | 5154 | +- |
| 1234 | 2545 | -- |
Scenarios: 3 mumber correct
| code | guess | mark |
| 1234 | 5234 | +++ |
| 1234 | 5134 | ++- |
| 1234 | 5124 | +-- |
| 1234 | 5123 | --- |
Scenarios: all number correct
| code | guess | mark |
| 1234 | 1234 | ++++ |
| 1234 | 1243 | ++-- |
| 1234 | 1423 | +--- |
| 1234 | 4321 | ---- |
这样就好多了，容易读也好理解，就算是非技术人员也能看懂了。
接下来我们要定义测试步骤了，在features目录下建立子文件夹step_definitions,再建立codebreaker_steps.rb文件。
Given /^I am not yet playing$/ do
end
When /^I start a new game$/ do
game = Codebreaker::Game.new(output)
game.start
end
Then /^I should see "([^"]*)"$/ do |message|
output.messages.should include(message)
end
class Output
def messages
@messages ||= []
end
def puts(message)
messages << message
end
end
def output
@output ||= Output.new
end
测试会失败，我们需要写我们game.rb程序了
module Codebreaker
class Game
def initialize(output)
end
def start
end
end
end
再进行测试我们会看到提示输出与期望的不一致
Scenario: start game
Given I am not yet playing
When I start a new game
Then I should see "Welcome to Codebreaker!"
expected [] to include "Welcome to Codebreaker!"
至于这里怎么再修改，我们会在后面进行学习。
总结一下：这里我们了解了cucumber的基本目录结构，学习了gherkin语法，包括feature, Scenario, Given, When, Then以及Scenario Outline的用法，到此我们已经从Codebreaker游戏的行为出发点来用cucumber语法进行描述测试，下一节我们会学习使用rspec对每个独立对象的行为进行分析。